android – Screech Studios

Custom Toast

Intro

Toasts are the preferred Android mechanism to deliver short messages to users. But, they tend to be kind of boring. So, why not make them more exciting? Let’s build a custom toast and make it pop!

Custom Toast

Custom Layout

First thing we’ll need is a custom layout for amazing toast. Let’s start off with something simple, a TextView and an ImageView:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:background="#DAAA"
              android:gravity="center"
              android:orientation="horizontal"
              android:padding="10dp">

    <TextView
        android:id="@+id/toastTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="Large Text"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:textColor="#ffffff"
        android:textStyle="bold"/>

    <ImageView
        android:id="@+id/toastButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="15dp"
        android:background="@null"
        android:clickable="true"
        android:src="@mipmap/ic_launcher"/>

</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:background="#DAAA"

android:gravity="center"

android:orientation="horizontal"

android:padding="10dp">

<TextView

android:id="@+id/toastTextView"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:gravity="center"

android:text="Large Text"

android:textAppearance="?android:attr/textAppearanceLarge"

android:textColor="#ffffff"

android:textStyle="bold"/>

<ImageView

android:id="@+id/toastButton"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginLeft="15dp"

android:background="@null"

android:clickable="true"

android:src="@mipmap/ic_launcher"/>

</LinearLayout>

Custom Toast

Awesome, we’ve defined our Toast’s layout. Time to use it.

First thing we’ll need to do is inflate it and initialize its views:

View rootLayout = activity.getLayoutInflater().inflate(R.layout.view_toast, null);

((TextView) rootLayout.findViewById(R.id.toastTextView)).setText(message);

View rootLayout = activity.getLayoutInflater().inflate(R.layout.view_toast, null);

((TextView) rootLayout.findViewById(R.id.toastTextView)).setText(message);

Next, we’ll create a new toast and add our custom view to it:

Toast toast = new Toast(activity);
toast.setDuration(Toast.LENGTH_LONG);
toast.setView(rootLayout);
toast.show();

Toast toast = new Toast(activity);

toast.setDuration(Toast.LENGTH_LONG);

toast.setView(rootLayout);

toast.show();

We can customize it even further: to make things interesting, we can also define the Toast’s gravity – to control where it appears on the screen:

toast.setGravity(gravity, xOffset, yOffset);

1	toast.setGravity(gravity, xOffset, yOffset);

And we’re done, simple as that! This is what the final thing looks like:

private void showToastWithImage(String message, int gravity,
                                    int xOffset, int yOffset, Activity activity) {

    View rootLayout = activity.getLayoutInflater().inflate(R.layout.view_toast, null);

    ((TextView) rootLayout.findViewById(R.id.toastTextView)).setText(message);

    Toast toast = new Toast(activity);
    toast.setDuration(Toast.LENGTH_LONG);
    toast.setView(rootLayout);
    toast.setGravity(gravity, xOffset, yOffset);
    toast.show();
}

private void showToastWithImage(String message, int gravity,

int xOffset, int yOffset, Activity activity) {

View rootLayout = activity.getLayoutInflater().inflate(R.layout.view_toast, null);

((TextView) rootLayout.findViewById(R.id.toastTextView)).setText(message);

Toast toast = new Toast(activity);

toast.setDuration(Toast.LENGTH_LONG);

toast.setView(rootLayout);

toast.setGravity(gravity, xOffset, yOffset);

toast.show();

}

And just call it with:

showToastWithImage("This is a center Toast", Gravity.CENTER, 0, 0, MainActivity.this);

1	showToastWithImage("This is a center Toast", Gravity.CENTER, 0, 0, MainActivity.this);

Get the full source code here.

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Password EditText

Introduction

Ever wished that Android had a built-in Password EditText with a Show/Hide button? No? Well, here’s a tutorial for one anyway.

Password EditText

Building a custom Password Edit Text

In order to get a Password EditText we’ll first need to create a custom view extending a EditText. Let’s create a new PasswordEditText.java class:

public class PasswordEditText extends EditText {

    public PasswordEditText(Context context) {
        super(context);
        init(null);
    }

    public PasswordEditText(Context context, AttributeSet attrs) {
        super(context, attrs);
        init(attrs);
    }

    public PasswordEditText(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init(attrs);
    }

public class PasswordEditText extends EditText {

public PasswordEditText(Context context) {

super(context);

init(null);

}

public PasswordEditText(Context context, AttributeSet attrs) {

super(context, attrs);

init(attrs);

}

public PasswordEditText(Context context, AttributeSet attrs, int defStyle) {

super(context, attrs, defStyle);

init(attrs);

}

Next, we’ll need to define some custom attributes for our view. Let’s start off by defining its: action text, colour and size. To make things easier, we’ll need to be able to define these attributes in the view’s layout.xml file. As a result, we’ll need to define these attributes as styleables, by creating a new /res/values/attrs.xml file:

<resources>
    <declare-styleable name="PasswordEditText">
        <attr name="showActionText" format="string"/>
        <attr name="hideActionText" format="string"/>
        <attr name="actionLabelColor" format="color"/>
        <attr name="actionLabelSize" format="dimension"/>
    </declare-styleable>
</resources>

<declare-styleable name="PasswordEditText">

</declare-styleable>

</resources>

Next, we’ll need to associate these attributes with our custom view. So, let’s start off by giving them some default values:

private static final String TEXT_SHOW = "SHOW";
private static final String TEXT_HIDE = "HIDE";
private static final int ACTION_COLOR = Color.BLUE;
private static final float ACTION_SIZE = 11.0f;

private String showActionText;
private String hideActionText;
private int actionLabelColor;
private float actionLabelDimension;

private static final String TEXT_SHOW = "SHOW";

private static final String TEXT_HIDE = "HIDE";

private static final int ACTION_COLOR = Color.BLUE;

private static final float ACTION_SIZE = 11.0f;

private String showActionText;

private String hideActionText;

private int actionLabelColor;

private float actionLabelDimension;

We’ll now need to initialize them when our view is created:

private void init(AttributeSet attrs) {

   //Set default attributes
    setActionLabelColor(ACTION_COLOR);
    setActionLabelDimension(ACTION_SIZE);

    if (attrs != null) {
        TypedArray typedArray = getContext().getTheme().obtainStyledAttributes(attrs, R.styleable.PasswordEditText, 0, 0);

        try {         setShowActionText(typedArray.getString(R.styleable.PasswordEditText_showActionText));
         setHideActionText(typedArray.getString(R.styleable.PasswordEditText_hideActionText));
            setActionLabelColor(typedArray.getColor(R.styleable.PasswordEditText_actionLabelColor, ACTION_COLOR));
            setActionLabelDimension(typedArray.getDimension(R.styleable.PasswordEditText_actionLabelSize, ACTION_SIZE));
        } finally {
            typedArray.recycle();
        }
    }

    if (getShowActionText() == null) {
        setShowActionText(TEXT_SHOW);
    }
    if (getHideActionText() == null) {
        setHideActionText(TEXT_HIDE);
    }

    setTransformationMethod(new PasswordTransformationMethod());
    setPasswordVisibilityDrawable(isPasswordVisible);
}

private void init(AttributeSet attrs) {

//Set default attributes

setActionLabelColor(ACTION_COLOR);

setActionLabelDimension(ACTION_SIZE);

if (attrs != null) {

TypedArray typedArray = getContext().getTheme().obtainStyledAttributes(attrs, R.styleable.PasswordEditText, 0, 0);

try { setShowActionText(typedArray.getString(R.styleable.PasswordEditText_showActionText));

setHideActionText(typedArray.getString(R.styleable.PasswordEditText_hideActionText));

setActionLabelColor(typedArray.getColor(R.styleable.PasswordEditText_actionLabelColor, ACTION_COLOR));

setActionLabelDimension(typedArray.getDimension(R.styleable.PasswordEditText_actionLabelSize, ACTION_SIZE));

} finally {

typedArray.recycle();

}

if (getShowActionText() == null) {

setShowActionText(TEXT_SHOW);

}

if (getHideActionText() == null) {

setHideActionText(TEXT_HIDE);

}

setTransformationMethod(new PasswordTransformationMethod());

setPasswordVisibilityDrawable(isPasswordVisible);

}

Awesome, all we need now is the Show/Hide action text. The EditText (being an extension of TextView) has built-in Compound Drawables and we’ll use those to house our action text. Since the end goal is to insert an editable message (SHOW / HIDE) in our custom view, we’ll just need to find a way to convert a String into a drawable – this is where the magic happens. We’ll create TextView and style it with our custom attributes (text, colour, size). Once we’re happy with it, we just essentially take a screenshot of it, convert that into a drawable and assign it as a Compound Drawable:

private void setPasswordVisibilityDrawable(boolean isPasswordVisible) {
    TextView textView = new TextView(getContext());
    textView.setTextSize(TypedValue.COMPLEX_UNIT_SP, getActionLabelDimension());
    textView.setTextColor(getActionLabelColor());
    if (isPasswordVisible) {
        textView.setText(getHideActionText());
    } else {
        textView.setText(getShowActionText());
    }

    textView.setDrawingCacheEnabled(true);
    // Without this, the view will have a dimension of 0,0 and the bitmap will be null
    textView.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),
                MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
    textView.layout(0, 0, textView.getMeasuredWidth(), textView.getMeasuredHeight());
    textView.buildDrawingCache(true);

    try {
        Bitmap bitmap = Bitmap.createBitmap(textView.getDrawingCache());
        // clear drawing cache
        textView.setDrawingCacheEnabled(false);

        Drawable showHide = new BitmapDrawable(getResources(), bitmap);
        showHide.setBounds(0, 0, showHide.getIntrinsicWidth(), showHide.getIntrinsicHeight());
        setCompoundDrawables(getCompoundDrawables()[0], getCompoundDrawables()[1], showHide, getCompoundDrawables()[3]);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

private void setPasswordVisibilityDrawable(boolean isPasswordVisible) {

TextView textView = new TextView(getContext());

textView.setTextSize(TypedValue.COMPLEX_UNIT_SP, getActionLabelDimension());

textView.setTextColor(getActionLabelColor());

if (isPasswordVisible) {

textView.setText(getHideActionText());

} else {

textView.setText(getShowActionText());

}

textView.setDrawingCacheEnabled(true);

// Without this, the view will have a dimension of 0,0 and the bitmap will be null

textView.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),

MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));

textView.layout(0, 0, textView.getMeasuredWidth(), textView.getMeasuredHeight());

textView.buildDrawingCache(true);

try {

Bitmap bitmap = Bitmap.createBitmap(textView.getDrawingCache());

// clear drawing cache

textView.setDrawingCacheEnabled(false);

Drawable showHide = new BitmapDrawable(getResources(), bitmap);

showHide.setBounds(0, 0, showHide.getIntrinsicWidth(), showHide.getIntrinsicHeight());

setCompoundDrawables(getCompoundDrawables()[0], getCompoundDrawables()[1], showHide, getCompoundDrawables()[3]);

} catch (Exception e) {

e.printStackTrace();

}

Great, now we’ve got a custom drawable inside our view. We just need a way to handle touch events to determine what happens when users click it. To do this, our custom view will need to implement a View.OnTouchListener to handle this event. Then, all we have to do is get our drawable’s dimensions and decide what happens when a touch event is registered within those coordinates:

public class PasswordEditText extends EditText implements View.OnTouchListener {

    private OnTouchListener onTouchListener;

    @Override
    public void setOnTouchListener(OnTouchListener onTouchListener) {
        this.onTouchListener = onTouchListener;
    }

    @Override
    public boolean onTouch(View v, MotionEvent event) {
        if (getCompoundDrawables()[2] != null) {
            boolean tappedX = event.getX() > (getWidth() - getPaddingRight() - getCompoundDrawables()[2].getIntrinsicWidth());
            if (tappedX) {
                if (event.getAction() == MotionEvent.ACTION_UP) {
                    if (isPasswordVisible) {
                        setTransformationMethod(new PasswordTransformationMethod());
                        isPasswordVisible = false;
                    } else {
                        setTransformationMethod(null);
                        isPasswordVisible = true;
                    }
                    setSelection(getText().length());
                    setPasswordVisibilityDrawable(isPasswordVisible);
                }
                return true;
            }
        }
        if (onTouchListener != null) {
            return onTouchListener.onTouch(v, event);
        }
        return false;
    }

    ....

    private void init(AttributeSet attrs) {

    ....

    super.setOnTouchListener(this);
    }
}

public class PasswordEditText extends EditText implements View.OnTouchListener {

private OnTouchListener onTouchListener;

@Override

public void setOnTouchListener(OnTouchListener onTouchListener) {

this.onTouchListener = onTouchListener;

}

@Override

public boolean onTouch(View v, MotionEvent event) {

if (getCompoundDrawables()[2] != null) {

boolean tappedX = event.getX() > (getWidth() - getPaddingRight() - getCompoundDrawables()[2].getIntrinsicWidth());

if (tappedX) {

if (event.getAction() == MotionEvent.ACTION_UP) {

if (isPasswordVisible) {

setTransformationMethod(new PasswordTransformationMethod());

isPasswordVisible = false;

} else {

setTransformationMethod(null);

isPasswordVisible = true;

}

setSelection(getText().length());

setPasswordVisibilityDrawable(isPasswordVisible);

}

return true;

}

if (onTouchListener != null) {

return onTouchListener.onTouch(v, event);

}

return false;

}

....

private void init(AttributeSet attrs) {

....

super.setOnTouchListener(this);

}

Wrapping things up

And that’s basically it. We’ve created a custom Password EditText, defined it’s attributes, added a custom editable drawable and defined what happens when users tap it. This is how the final PasswordEditText.java class looks like:

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.Color;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.text.method.PasswordTransformationMethod;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.MotionEvent;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;

/**
 * Displays a Password EditText with a SHOW/HIDE button at the right-hand side.
 */
public class PasswordEditText extends EditText implements View.OnTouchListener {

    private static final String TEXT_SHOW = "SHOW";
    private static final String TEXT_HIDE = "HIDE";
    private static final int ACTION_COLOR = Color.BLUE;
    private static final float ACTION_SIZE = 11.0f;

    private OnTouchListener onTouchListener;
    private boolean isPasswordVisible = false;

    private String showActionText;
    private String hideActionText;
    private int actionLabelColor;
    private float actionLabelDimension;

    /**
     * Creates the PasswordEditText
     *
     * @param context Context
     */
    public PasswordEditText(Context context) {
        super(context);
        init(null);
    }

    /**
     * Creates the PasswordEditText
     *
     * @param context Context
     * @param attrs   AttributeSet
     */
    public PasswordEditText(Context context, AttributeSet attrs) {
        super(context, attrs);
        init(attrs);
    }

    /**
     * Creates the PasswordEditText
     *
     * @param context  Context
     * @param attrs    AttributeSet
     * @param defStyle int
     */
    public PasswordEditText(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init(attrs);
    }

    public String getShowActionText() {
        return showActionText;
    }

    public void setShowActionText(String showActionText) {
        this.showActionText = showActionText;
        setPasswordVisibilityDrawable(isPasswordVisible);
    }

    public String getHideActionText() {
        return hideActionText;
    }

    public void setHideActionText(String hideActionText) {
        this.hideActionText = hideActionText;
        setPasswordVisibilityDrawable(isPasswordVisible);
    }

    public int getActionLabelColor() {
        return actionLabelColor;
    }

    public void setActionLabelColor(int actionLabelColor) {
        this.actionLabelColor = actionLabelColor;
        setPasswordVisibilityDrawable(isPasswordVisible);
    }

    public float getActionLabelDimension() {
        return actionLabelDimension;
    }

    public void setActionLabelDimension(float actionLabelDimension) {
        this.actionLabelDimension = actionLabelDimension;
        setPasswordVisibilityDrawable(isPasswordVisible);
    }

    @Override
    public void setOnTouchListener(OnTouchListener onTouchListener) {
        this.onTouchListener = onTouchListener;
    }

    @Override
    public boolean onTouch(View v, MotionEvent event) {
        if (getCompoundDrawables()[2] != null) {
            boolean tappedX = event.getX() > (getWidth() - getPaddingRight() - getCompoundDrawables()[2].getIntrinsicWidth());
            if (tappedX) {
                if (event.getAction() == MotionEvent.ACTION_UP) {
                    if (isPasswordVisible) {
                        setTransformationMethod(new PasswordTransformationMethod());
                        isPasswordVisible = false;
                    } else {
                        setTransformationMethod(null);
                        isPasswordVisible = true;
                    }
                    setSelection(getText().length());
                    setPasswordVisibilityDrawable(isPasswordVisible);
                }
                return true;
            }
        }
        if (onTouchListener != null) {
            return onTouchListener.onTouch(v, event);
        }
        return false;
    }

    private void init(AttributeSet attrs) {

        //Set default attributes
        setActionLabelColor(ACTION_COLOR);
        setActionLabelDimension(ACTION_SIZE);

        if (attrs != null) {
            TypedArray typedArray = getContext().getTheme().obtainStyledAttributes(attrs, R.styleable.PasswordEditText, 0, 0);

            try {
                setShowActionText(typedArray.getString(R.styleable.PasswordEditText_showActionText));
                setHideActionText(typedArray.getString(R.styleable.PasswordEditText_hideActionText));
                setActionLabelColor(typedArray.getColor(R.styleable.PasswordEditText_actionLabelColor, ACTION_COLOR));
                setActionLabelDimension(typedArray.getDimension(R.styleable.PasswordEditText_actionLabelSize, ACTION_SIZE));
            } finally {
                typedArray.recycle();
            }
        }

        if (getShowActionText() == null) {
            setShowActionText(TEXT_SHOW);
        }
        if (getHideActionText() == null) {
            setHideActionText(TEXT_HIDE);
        }

        setTransformationMethod(new PasswordTransformationMethod());
        setPasswordVisibilityDrawable(isPasswordVisible);

        super.setOnTouchListener(this);
    }

    private void setPasswordVisibilityDrawable(boolean isPasswordVisible) {
        TextView textView = new TextView(getContext());
        textView.setTextSize(TypedValue.COMPLEX_UNIT_SP, getActionLabelDimension());
        textView.setTextColor(getActionLabelColor());
        if (isPasswordVisible) {
            textView.setText(getHideActionText());
        } else {
            textView.setText(getShowActionText());
        }

        textView.setDrawingCacheEnabled(true);
        // Without this, the view will have a dimension of 0,0 and the bitmap will be null
        textView.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),
                MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
        textView.layout(0, 0, textView.getMeasuredWidth(), textView.getMeasuredHeight());
        textView.buildDrawingCache(true);

        try {
            Bitmap bitmap = Bitmap.createBitmap(textView.getDrawingCache());
            // clear drawing cache
            textView.setDrawingCacheEnabled(false);

            Drawable showHide = new BitmapDrawable(getResources(), bitmap);
            showHide.setBounds(0, 0, showHide.getIntrinsicWidth(), showHide.getIntrinsicHeight());
            setCompoundDrawables(getCompoundDrawables()[0], getCompoundDrawables()[1], showHide, getCompoundDrawables()[3]);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

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import android.content.Context;

import android.content.res.TypedArray;

import android.graphics.Bitmap;

import android.graphics.Color;

import android.graphics.drawable.BitmapDrawable;

import android.graphics.drawable.Drawable;

import android.text.method.PasswordTransformationMethod;

import android.util.AttributeSet;

import android.util.TypedValue;

import android.view.MotionEvent;

import android.view.View;

import android.widget.EditText;

import android.widget.TextView;

/**

* Displays a Password EditText with a SHOW/HIDE button at the right-hand side.

public class PasswordEditText extends EditText implements View.OnTouchListener {

private static final String TEXT_SHOW = "SHOW";

private static final String TEXT_HIDE = "HIDE";

private static final int ACTION_COLOR = Color.BLUE;

private static final float ACTION_SIZE = 11.0f;

private OnTouchListener onTouchListener;

private boolean isPasswordVisible = false;

private String showActionText;

private String hideActionText;

private int actionLabelColor;

private float actionLabelDimension;

/**

* Creates the PasswordEditText

* @param context Context

public PasswordEditText(Context context) {

super(context);

init(null);

}

/**

* Creates the PasswordEditText

* @param context Context

* @param attrs AttributeSet

public PasswordEditText(Context context, AttributeSet attrs) {

super(context, attrs);

init(attrs);

}

/**

* Creates the PasswordEditText

* @param context Context

* @param attrs AttributeSet

* @param defStyle int

public PasswordEditText(Context context, AttributeSet attrs, int defStyle) {

super(context, attrs, defStyle);

init(attrs);

}

public String getShowActionText() {

return showActionText;

}

public void setShowActionText(String showActionText) {

this.showActionText = showActionText;

setPasswordVisibilityDrawable(isPasswordVisible);

}

public String getHideActionText() {

return hideActionText;

}

public void setHideActionText(String hideActionText) {

this.hideActionText = hideActionText;

setPasswordVisibilityDrawable(isPasswordVisible);

}

public int getActionLabelColor() {

return actionLabelColor;

}

public void setActionLabelColor(int actionLabelColor) {

this.actionLabelColor = actionLabelColor;

setPasswordVisibilityDrawable(isPasswordVisible);

}

public float getActionLabelDimension() {

return actionLabelDimension;

}

public void setActionLabelDimension(float actionLabelDimension) {

this.actionLabelDimension = actionLabelDimension;

setPasswordVisibilityDrawable(isPasswordVisible);

}

@Override

public void setOnTouchListener(OnTouchListener onTouchListener) {

this.onTouchListener = onTouchListener;

}

@Override

public boolean onTouch(View v, MotionEvent event) {

if (getCompoundDrawables()[2] != null) {

boolean tappedX = event.getX() > (getWidth() - getPaddingRight() - getCompoundDrawables()[2].getIntrinsicWidth());

if (tappedX) {

if (event.getAction() == MotionEvent.ACTION_UP) {

if (isPasswordVisible) {

setTransformationMethod(new PasswordTransformationMethod());

isPasswordVisible = false;

} else {

setTransformationMethod(null);

isPasswordVisible = true;

}

setSelection(getText().length());

setPasswordVisibilityDrawable(isPasswordVisible);

}

return true;

}

if (onTouchListener != null) {

return onTouchListener.onTouch(v, event);

}

return false;

}

private void init(AttributeSet attrs) {

//Set default attributes

setActionLabelColor(ACTION_COLOR);

setActionLabelDimension(ACTION_SIZE);

if (attrs != null) {

TypedArray typedArray = getContext().getTheme().obtainStyledAttributes(attrs, R.styleable.PasswordEditText, 0, 0);

try {

setShowActionText(typedArray.getString(R.styleable.PasswordEditText_showActionText));

setHideActionText(typedArray.getString(R.styleable.PasswordEditText_hideActionText));

setActionLabelColor(typedArray.getColor(R.styleable.PasswordEditText_actionLabelColor, ACTION_COLOR));

setActionLabelDimension(typedArray.getDimension(R.styleable.PasswordEditText_actionLabelSize, ACTION_SIZE));

} finally {

typedArray.recycle();

}

if (getShowActionText() == null) {

setShowActionText(TEXT_SHOW);

}

if (getHideActionText() == null) {

setHideActionText(TEXT_HIDE);

}

setTransformationMethod(new PasswordTransformationMethod());

setPasswordVisibilityDrawable(isPasswordVisible);

super.setOnTouchListener(this);

}

private void setPasswordVisibilityDrawable(boolean isPasswordVisible) {

TextView textView = new TextView(getContext());

textView.setTextSize(TypedValue.COMPLEX_UNIT_SP, getActionLabelDimension());

textView.setTextColor(getActionLabelColor());

if (isPasswordVisible) {

textView.setText(getHideActionText());

} else {

textView.setText(getShowActionText());

}

textView.setDrawingCacheEnabled(true);

// Without this, the view will have a dimension of 0,0 and the bitmap will be null

textView.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),

MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));

textView.layout(0, 0, textView.getMeasuredWidth(), textView.getMeasuredHeight());

textView.buildDrawingCache(true);

try {

Bitmap bitmap = Bitmap.createBitmap(textView.getDrawingCache());

// clear drawing cache

textView.setDrawingCacheEnabled(false);

Drawable showHide = new BitmapDrawable(getResources(), bitmap);

showHide.setBounds(0, 0, showHide.getIntrinsicWidth(), showHide.getIntrinsicHeight());

setCompoundDrawables(getCompoundDrawables()[0], getCompoundDrawables()[1], showHide, getCompoundDrawables()[3]);

} catch (Exception e) {

e.printStackTrace();

}

We just need to add it to res/layout/activity_main.xml and see it in action:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.screechstuidos.passwordedittext.MainActivity">

    <com.screechstuidos.passwordedittext.PasswordEditText
        android:id="@+id/password"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        app:actionLabelColor="#009688"
        app:hideActionText="HIDE"
        app:showActionText="SHOW"/>

</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout

xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:app="http://schemas.android.com/apk/res-auto"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:paddingBottom="@dimen/activity_vertical_margin"

android:paddingLeft="@dimen/activity_horizontal_margin"

android:paddingRight="@dimen/activity_horizontal_margin"

android:paddingTop="@dimen/activity_vertical_margin"

tools:context="com.screechstuidos.passwordedittext.MainActivity">

<com.screechstuidos.passwordedittext.PasswordEditText

android:id="@+id/password"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_centerInParent="true"

app:actionLabelColor="#009688"

app:hideActionText="HIDE"

app:showActionText="SHOW"/>

</RelativeLayout>

Notice that we’re setting our custom attributes in a XML layout file. We can also do the same programmatically:

public class MainActivity extends Activity {

    private PasswordEditText passwordEditText;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        passwordEditText = (PasswordEditText) findViewById(R.id.password);

        
        //Change Password Edit Text attributes programmatically

        passwordEditText.setShowActionText("UNMASK");
        passwordEditText.setHideActionText("MASK");
        passwordEditText.setActionLabelColor(Color.RED);
        passwordEditText.setActionLabelDimension(45);
        
    }
}

public class MainActivity extends Activity {

private PasswordEditText passwordEditText;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

passwordEditText = (PasswordEditText) findViewById(R.id.password);

//Change Password Edit Text attributes programmatically

passwordEditText.setShowActionText("UNMASK");

passwordEditText.setHideActionText("MASK");

passwordEditText.setActionLabelColor(Color.RED);

passwordEditText.setActionLabelDimension(45);

}

That’s it. Check out the full source code here.

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Logcat Recorder

Introduction

Logcat is an Android mechanism used to collect and view system debug output. This is extremely useful for debugging and QA testing, as it provides valuable information about what the apps are doing.

Under normal conditions, logcat is visible via Android Device Monitor or directly executed from the ADB shell via the logcat command. The purpose of this tutorial is to present a simple mechanism to programmatically capture and filter logcat entries.

Logcat recorder

First thing’s first, we need a nice way to handle the logcat recorder’s status (recording, new log entry, idle). As a result, we create a simple OnLogcatRecorderListener.java interface to define these events:

/**
 * An interface used to notify the log recording status.
 */
public interface OnLogcatRecorderListener {
    /**
     * Called when recording has started.
     */
    void onStartRecording();

    /**
     * Called when a new log entry is recorded.
     *
     * @param logEntry Log entry.
     */
    void onNewLogEntry(final String logEntry);

    /**
     * Called when recording has stopped.
     *
     * @param log Returns the recorded log.
     */
    void onStopRecording(final String log);
}

/**

* An interface used to notify the log recording status.

public interface OnLogcatRecorderListener {

/**

* Called when recording has started.

void onStartRecording();

/**

* Called when a new log entry is recorded.

* @param logEntry Log entry.

void onNewLogEntry(final String logEntry);

/**

* Called when recording has stopped.

* @param log Returns the recorded log.

void onStopRecording(final String log);

}

Next, we need to define a basic LogcatRecorder.java class and introduce our listener:

/**
 * Class used to capture the logcat output.
 * Contains a listener interface for the recorder status.
 */
public class LogcatRecorder {

    private Process continuousLogging;
    private StringBuilder log;
    private boolean recording;

    private OnLogcatRecorderListener onLogcatRecorderListener;

    /**
     * LogcatSpy constructor with a predefined OnLogcatRecorderListener.
     *
     * @param onLogcatRecorderListener OnLogcatRecorderListener to handle recorder states.
     */
    public LogcatRecorder(OnLogcatRecorderListener onLogcatRecorderListener) {
        this.recording = false;
        this.onLogcatRecorderListener = onLogcatRecorderListener;
    }

/**

* Class used to capture the logcat output.

* Contains a listener interface for the recorder status.

public class LogcatRecorder {

private Process continuousLogging;

private StringBuilder log;

private boolean recording;

private OnLogcatRecorderListener onLogcatRecorderListener;

/**

* LogcatSpy constructor with a predefined OnLogcatRecorderListener.

* @param onLogcatRecorderListener OnLogcatRecorderListener to handle recorder states.

public LogcatRecorder(OnLogcatRecorderListener onLogcatRecorderListener) {

this.recording = false;

this.onLogcatRecorderListener = onLogcatRecorderListener;

}

Now, we need a mechanism to start() recording the logcat. This will essentially create a new thread (to avoid locking the main UI thread), containing a Runtime Process to execute the logcat shell command and continuously record its output:

/**
 * Start recording the log output with a specific filter.
 *
 * @param filter Log filter.
 * @throws IllegalStateException When log recording is already in place.
 */
public void start(final String filter) throws IllegalStateException {

    if (!recording) {
        recording = true;

        if (onLogcatRecorderListener != null) {
            onLogcatRecorderListener.onStartRecording();
        }

        Thread thread = new Thread() {
            public void run() {
                log = new StringBuilder();
                String line;
                try {
                    //Clear all logcat entries, up until this point.
                    continuousLogging = Runtime.getRuntime().exec("logcat -c");
                    if (filter != null && filter.length() > 0) {
                        //Apply filter to logcat output.
                        continuousLogging = Runtime.getRuntime().exec("logcat | grep " + filter);
                    } else {
                        //Get full logcat output.
                        continuousLogging = Runtime.getRuntime().exec("logcat");
                    }

                    //Get the Runtime Process' output.
                    BufferedReader bufferedReader = new BufferedReader(
                            new InputStreamReader(continuousLogging.getInputStream()));

                    while ((line = bufferedReader.readLine()) != null) {
                        final String logEntry = line + "\n";

                        log.append(logEntry);

                        if (onLogcatRecorderListener != null) {
                            onLogcatRecorderListener.onNewLogEntry(logEntry);
                        }
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                    recording = false;
                }
            }

        };
     thread.start();
    } else {
        throw new IllegalStateException("Unable to call start(): Already recording.");
    }
}

/**

* Start recording the log output with a specific filter.

* @param filter Log filter.

* @throws IllegalStateException When log recording is already in place.

public void start(final String filter) throws IllegalStateException {

if (!recording) {

recording = true;

if (onLogcatRecorderListener != null) {

onLogcatRecorderListener.onStartRecording();

}

Thread thread = new Thread() {

public void run() {

log = new StringBuilder();

String line;

try {

//Clear all logcat entries, up until this point.

continuousLogging = Runtime.getRuntime().exec("logcat -c");

if (filter != null && filter.length() > 0) {

//Apply filter to logcat output.

continuousLogging = Runtime.getRuntime().exec("logcat | grep " + filter);

} else {

//Get full logcat output.

continuousLogging = Runtime.getRuntime().exec("logcat");

}

//Get the Runtime Process' output.

BufferedReader bufferedReader = new BufferedReader(

new InputStreamReader(continuousLogging.getInputStream()));

while ((line = bufferedReader.readLine()) != null) {

final String logEntry = line + "\n";

log.append(logEntry);

if (onLogcatRecorderListener != null) {

onLogcatRecorderListener.onNewLogEntry(logEntry);

}

} catch (Exception e) {

e.printStackTrace();

recording = false;

}

};

thread.start();

} else {

throw new IllegalStateException("Unable to call start(): Already recording.");

}

We first need to clear the current log via the “logcat -c” runtime process call. Once the log is clear, we can start recording it Runtime.getRuntime().exec(“logcat“) and, optionally, add a filter to our recorder Runtime.getRuntime().exec(“logcat | grep ” + filter). Whilst recording, we call our interface’s onNewLogEntry() method to pass on each new log entry.

To wrap this up, we also need a method to stop() the recording process:

/**
 * Stops recording the log output.
 *
 * @throws IllegalStateException When log recording has already been stopped.
 */
public void stop() throws IllegalStateException {
    if (recording) {
        if (onLogcatRecorderListener != null) {
            if (log == null || log.toString().length() == 0) {
                log = new StringBuilder("n/a");
            }
            onLogcatRecorderListener.onStopRecording(log.toString());
        }

        if (continuousLogging != null) {
            //Kill the Runtime Process.
            continuousLogging.destroy();
        }

        recording = false;
    } else {
        throw new IllegalStateException("Unable to call stop(): Currently not recording.");
    }
}

/**

* Stops recording the log output.

* @throws IllegalStateException When log recording has already been stopped.

public void stop() throws IllegalStateException {

if (recording) {

if (onLogcatRecorderListener != null) {

if (log == null || log.toString().length() == 0) {

log = new StringBuilder("n/a");

}

onLogcatRecorderListener.onStopRecording(log.toString());

}

if (continuousLogging != null) {

//Kill the Runtime Process.

continuousLogging.destroy();

}

recording = false;

} else {

throw new IllegalStateException("Unable to call stop(): Currently not recording.");

}

In order to do this, we first check our recorder’s state and simply destroy the logging Runtime Process. Once the recording is done, our interface will serve the full list of recorded log entries via onLogcatRecorderListener.onStopRecording(log.toString());

Finally

We just need to add the LogcatRecorder to a new Activity. First, we define ../res/layout/activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.screechstudios.logcatrecorder.MainActivity">

    <ToggleButton
        android:id="@+id/toggleButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentTop="true"/>

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/toggleButton"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_alignParentTop="true"
        android:layout_toLeftOf="@+id/toggleButton"
        android:layout_toStartOf="@+id/toggleButton"
        android:gravity="center"
        android:text="Record Logcat:"
        android:textAppearance="?android:attr/textAppearanceLarge"/>

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignEnd="@+id/toggleButton"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_alignRight="@+id/toggleButton"
        android:layout_below="@+id/textView"
        android:text="Write to console"/>

    <ScrollView
        android:id="@+id/scrollView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_below="@+id/button">

        <TextView
            android:id="@+id/outputTextView"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:textAppearance="?android:attr/textAppearanceMedium"/>
    </ScrollView>

</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout

xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:paddingBottom="@dimen/activity_vertical_margin"

android:paddingLeft="@dimen/activity_horizontal_margin"

android:paddingRight="@dimen/activity_horizontal_margin"

android:paddingTop="@dimen/activity_vertical_margin"

tools:context="com.screechstudios.logcatrecorder.MainActivity">

<ToggleButton

android:id="@+id/toggleButton"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignParentEnd="true"

android:layout_alignParentRight="true"

android:layout_alignParentTop="true"/>

<TextView

android:id="@+id/textView"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignBottom="@+id/toggleButton"

android:layout_alignParentLeft="true"

android:layout_alignParentStart="true"

android:layout_alignParentTop="true"

android:layout_toLeftOf="@+id/toggleButton"

android:layout_toStartOf="@+id/toggleButton"

android:gravity="center"

android:text="Record Logcat:"

android:textAppearance="?android:attr/textAppearanceLarge"/>

<Button

android:id="@+id/button"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignEnd="@+id/toggleButton"

android:layout_alignParentLeft="true"

android:layout_alignParentStart="true"

android:layout_alignRight="@+id/toggleButton"

android:layout_below="@+id/textView"

android:text="Write to console"/>

<ScrollView

android:id="@+id/scrollView"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:layout_alignParentLeft="true"

android:layout_alignParentStart="true"

android:layout_below="@+id/button">

<TextView

android:id="@+id/outputTextView"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:textAppearance="?android:attr/textAppearanceMedium"/>

</ScrollView>

</RelativeLayout>

Finally, we define MainActivity.java and add a new instance of our LogcatRecorder to it:

public class MainActivity extends Activity {

    private LogcatRecorder logcatRecorder;
    private TextView outputText;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        outputText = (TextView) findViewById(R.id.outputTextView);

        //Initialize the LogcatRecorder
        logcatRecorder = new LogcatRecorder(new OnLogcatRecorderListener() {
            @Override
            public void onStartRecording() {
                outputText.setText("");
                Toast.makeText(MainActivity.this, "Recording logcat...", Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onNewLogEntry(final String logEntry) {

                //Run on the main UI thread, since the call is made from a separate thread.
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        outputText.append(logEntry);
                    }
                });
            }

            @Override
            public void onStopRecording(final String log) {
                outputText.setText(log);
                Toast.makeText(MainActivity.this, "Recording stopped...", Toast.LENGTH_SHORT).show();
            }
        });

        //Record button
        ((ToggleButton) findViewById(R.id.toggleButton)).setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                if (isChecked) {
                    try {
                        //Start recording the logcat and filter it by the app's own PID.
                        logcatRecorder.start();
                    } catch (IllegalStateException e) {
                        e.printStackTrace();
                        Toast.makeText(MainActivity.this, "Already recording...", Toast.LENGTH_SHORT).show();
                    }
                } else {
                    try {
                        //Stop recording the logcat.
                        logcatRecorder.stop();
                    } catch (IllegalStateException e) {
                        e.printStackTrace();
                        Toast.makeText(MainActivity.this, "Already stopped...", Toast.LENGTH_SHORT).show();
                    }
                }
            }
        });

        //Add some random output to the logcat.
        findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                System.out.println("Some output: " + Math.random());
                Log.d("LogcatRecorder", "Some log entry: " + Math.random());
            }
        });
    }
}

public class MainActivity extends Activity {

private LogcatRecorder logcatRecorder;

private TextView outputText;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

outputText = (TextView) findViewById(R.id.outputTextView);

//Initialize the LogcatRecorder

logcatRecorder = new LogcatRecorder(new OnLogcatRecorderListener() {

@Override

public void onStartRecording() {

outputText.setText("");

Toast.makeText(MainActivity.this, "Recording logcat...", Toast.LENGTH_SHORT).show();

}

@Override

public void onNewLogEntry(final String logEntry) {

//Run on the main UI thread, since the call is made from a separate thread.

runOnUiThread(new Runnable() {

@Override

public void run() {

outputText.append(logEntry);

}

});

}

@Override

public void onStopRecording(final String log) {

outputText.setText(log);

Toast.makeText(MainActivity.this, "Recording stopped...", Toast.LENGTH_SHORT).show();

}

});

//Record button

((ToggleButton) findViewById(R.id.toggleButton)).setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {

@Override

public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

if (isChecked) {

try {

//Start recording the logcat and filter it by the app's own PID.

logcatRecorder.start();

} catch (IllegalStateException e) {

e.printStackTrace();

Toast.makeText(MainActivity.this, "Already recording...", Toast.LENGTH_SHORT).show();

}

} else {

try {

//Stop recording the logcat.

logcatRecorder.stop();

} catch (IllegalStateException e) {

e.printStackTrace();

Toast.makeText(MainActivity.this, "Already stopped...", Toast.LENGTH_SHORT).show();

}

});

//Add some random output to the logcat.

findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

System.out.println("Some output: " + Math.random());

Log.d("LogcatRecorder", "Some log entry: " + Math.random());

}

});

}

Get the full project on GitHub.

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Creating a Compound View in Android

Introduction

Often, when developing Android applications, groups of views tend to be used in multiple places. In order to make things easier, it is considered good practice to encapsulate them in a custom compound view. This allows the same custom view component to be reused throughout the app.

A compound view or compound component is just a view composed of a group of views. This tutorial focuses on building a very basic compound view and defining some methods that change its state.

Creating the Compound View

Creating a Compound View is, in some respects, somewhat similar to creating a new Activity. A new class is created which contains all the view’s children and some methods to manipulate them.

To get started, we’ll first create a new XML layout file in /res/layout/view_article.xml. This will contain the compound view’s children:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content">

    <ProgressBar
        android:id="@+id/loadingProgressBar"
        style="?android:attr/progressBarStyleLarge"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:visibility="invisible"/>

    <LinearLayout
        android:id="@+id/contentLayout"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:padding="10dp"
        android:visibility="visible">

        <TextView
            android:id="@+id/titleTextView"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:textStyle="bold|italic"/>

        <TextView
            android:id="@+id/contentTextView"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:textAppearance="?android:attr/textAppearanceMedium"/>
    </LinearLayout>
</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="wrap_content"

android:layout_height="wrap_content">

<ProgressBar

android:id="@+id/loadingProgressBar"

style="?android:attr/progressBarStyleLarge"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_centerHorizontal="true"

android:layout_centerVertical="true"

android:visibility="invisible"/>

<LinearLayout

android:id="@+id/contentLayout"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:orientation="vertical"

android:padding="10dp"

android:visibility="visible">

<TextView

android:id="@+id/titleTextView"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceLarge"

android:textStyle="bold|italic"/>

<TextView

android:id="@+id/contentTextView"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:textAppearance="?android:attr/textAppearanceMedium"/>

</LinearLayout>

</RelativeLayout>

Next, we need a class to inflate our new Article View. For simplicity’s sake, we’ll extend a basic RelativeLayout and define our child components. When the view is added to an Activity, it will basically act as a RelativeLayout and allow developers to customize it accordingly.

public class ArticleView extends RelativeLayout {

    private TextView titleTextView;
    private TextView contentTextView;
    private LinearLayout contentLayout;
    private ProgressBar loadingProgress;

    public ArticleView(Context context) {
        super(context);

        initView(context);
    }

    public ArticleView(Context context, AttributeSet attrs) {
        super(context, attrs);

        initView(context);
    }

    public ArticleView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);

        initView(context);
    }

    private void initView(Context context) {
        inflate(context, R.layout.view_article, this);
    }

    @Override
    protected void onFinishInflate() {
        super.onFinishInflate();

        titleTextView = (TextView) findViewById(R.id.titleTextView);
        contentTextView = (TextView) findViewById(R.id.contentTextView);
        contentLayout = (LinearLayout) findViewById(R.id.contentLayout);
        loadingProgress = (ProgressBar) findViewById(R.id.loadingProgressBar);
    }
}

public class ArticleView extends RelativeLayout {

private TextView titleTextView;

private TextView contentTextView;

private LinearLayout contentLayout;

private ProgressBar loadingProgress;

public ArticleView(Context context) {

super(context);

initView(context);

}

public ArticleView(Context context, AttributeSet attrs) {

super(context, attrs);

initView(context);

}

public ArticleView(Context context, AttributeSet attrs, int defStyleAttr) {

super(context, attrs, defStyleAttr);

initView(context);

}

private void initView(Context context) {

inflate(context, R.layout.view_article, this);

}

@Override

protected void onFinishInflate() {

super.onFinishInflate();

titleTextView = (TextView) findViewById(R.id.titleTextView);

contentTextView = (TextView) findViewById(R.id.contentTextView);

contentLayout = (LinearLayout) findViewById(R.id.contentLayout);

loadingProgress = (ProgressBar) findViewById(R.id.loadingProgressBar);

}

It is considered best practice to handle the instantiation of our UI components in the onFinishInflate() method in order to prevent any NullPointerExceptions, especially when using ImageViews with large Bitmaps.

At this point, our new Article View doesn’t really do anything special except displaying its children components. As a result, we’ll add some custom methods to manipulate its states:

    public void setLoading(boolean isLoading) {
        if (isLoading) {
            contentLayout.setVisibility(INVISIBLE);
            loadingProgress.setVisibility(VISIBLE);
        } else {
            contentLayout.setVisibility(VISIBLE);
            loadingProgress.setVisibility(INVISIBLE);
        }
    }

    public void populate(String title, String content) {
        titleTextView.setText(title);
        contentTextView.setText(content);
    }

    public void setBackground(int color) {
        contentLayout.setBackgroundColor(color);
    }

public void setLoading(boolean isLoading) {

if (isLoading) {

contentLayout.setVisibility(INVISIBLE);

loadingProgress.setVisibility(VISIBLE);

} else {

contentLayout.setVisibility(VISIBLE);

loadingProgress.setVisibility(INVISIBLE);

}

public void populate(String title, String content) {

titleTextView.setText(title);

contentTextView.setText(content);

}

public void setBackground(int color) {

contentLayout.setBackgroundColor(color);

}

Finally

Now that the ArticleView is complete, we just need to add it to an Activity. We will first add it to the Activity’s layout XML file:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.screechstudios.compoundview.MainActivity">

    <com.screechstudios.compoundview.ArticleView
        android:id="@+id/articleView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Show Article"
        android:id="@+id/button"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true" />

</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:paddingBottom="@dimen/activity_vertical_margin"

android:paddingLeft="@dimen/activity_horizontal_margin"

android:paddingRight="@dimen/activity_horizontal_margin"

android:paddingTop="@dimen/activity_vertical_margin"

tools:context="com.screechstudios.compoundview.MainActivity">

<com.screechstudios.compoundview.ArticleView

android:id="@+id/articleView"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_centerInParent="true" />

<Button

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="Show Article"

android:id="@+id/button"

android:layout_alignParentBottom="true"

android:layout_centerHorizontal="true" />

</RelativeLayout>

Finally, we initialize it in the Activity and make use of it’s methods in order to change the ArticleView’s state:

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //Initialize the ArticleView
        final ArticleView articleView = (ArticleView) findViewById(R.id.articleView);

        findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                populateArticle(articleView);
            }
        });
    }

    private void populateArticle(final ArticleView articleView) {
        articleView.setLoading(true);

        // Display the article after 3 seconds.
        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                articleView.setLoading(false);
                articleView.setBackground(Color.LTGRAY);
                articleView.populate("My First Article", "This is my first ever article, hope you enjoy!");
            }
        }, 3000);
    }
}

public class MainActivity extends AppCompatActivity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

//Initialize the ArticleView

final ArticleView articleView = (ArticleView) findViewById(R.id.articleView);

findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

populateArticle(articleView);

}

});

}

private void populateArticle(final ArticleView articleView) {

articleView.setLoading(true);

// Display the article after 3 seconds.

new Handler().postDelayed(new Runnable() {

@Override

public void run() {

articleView.setLoading(false);

articleView.setBackground(Color.LTGRAY);

articleView.populate("My First Article", "This is my first ever article, hope you enjoy!");

}

}, 3000);

}

Get the full sample project here.

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MVP for Android

Why use the MVP pattern?

One of the problems with traditional Android development is the tight coupling between Activities and business logic. This tends to make testing, extensibility and maintenance rather difficult.

The main idea behind using MVP is to take abstract away most (or all) of the business logic into separate entities (presenters) and only keep the UI logic in Activities.

There are many different types of MVP implementations for Android out there, this article only focuses on the basic principles behind them.

Presenter:

The presenter is a separate class that contains the business logic and a reference to its associated view.

The view itself is abstracted away through an interface. This is implemented mainly to allow the view to be mocked in a unit test or replaced with any other view that implements this particular interface.

public class Presenter {

    //The associated view
    MainView mainView;

    public Presenter(MainView mainView) {
        this.mainView = mainView;
    }

    /**
     * Some business logic
     */
    public void getSomeResult() {
        //call a method from the view
        mainView.showToast("Here's your result!");
    }
}

public class Presenter {

//The associated view

MainView mainView;

public Presenter(MainView mainView) {

this.mainView = mainView;

}

/**

* Some business logic

public void getSomeResult() {

//call a method from the view

mainView.showToast("Here's your result!");

}

View:

The view is defined as an Interface which can be implemented by any Activity, Fragment or any type of Android View. This view contains methods that handle all UI logic.

public interface MainView {

    void showLoading(boolean loading);

    void displayResult(String result);

    void showToast(String message);
}

public interface MainView {

void showLoading(boolean loading);

void displayResult(String result);

void showToast(String message);

}

Finally

The last step is to link everything together: a new Activity is created which holds a reference to the presenter and implements the View Interface.

public class MainActivity extends Activity implements MainView {

    private TextView textView;
    private ProgressDialog progress;

    private Presenter presenter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //Initialize the presenter.
        presenter = new Presenter(this);

        textView = (TextView) findViewById(R.id.textView);
        progress = new ProgressDialog(this);
        progress.setTitle("Loading");
        progress.setMessage("Wait while loading...");

        findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //execute some business logic
                presenter.startSomeTask();
            }
        });

        findViewById(R.id.button2).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //execute some additional business logic
                presenter.getSomeResult();
            }
        });
    }

    @Override
    public void showLoading(boolean loading) {
        if (loading) {
            progress.show();
        } else {
            progress.dismiss();
        }
    }

    @Override
    public void displayResult(String result) {
        textView.setText(result);
    }

    @Override
    public void showToast(String message) {
        Toast.makeText(MainActivity.this, message, Toast.LENGTH_SHORT).show();
    }
}

public class MainActivity extends Activity implements MainView {

private TextView textView;

private ProgressDialog progress;

private Presenter presenter;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

//Initialize the presenter.

presenter = new Presenter(this);

textView = (TextView) findViewById(R.id.textView);

progress = new ProgressDialog(this);

progress.setTitle("Loading");

progress.setMessage("Wait while loading...");

findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

//execute some business logic

presenter.startSomeTask();

}

});

findViewById(R.id.button2).setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

//execute some additional business logic

presenter.getSomeResult();

}

});

}

@Override

public void showLoading(boolean loading) {

if (loading) {

progress.show();

} else {

progress.dismiss();

}

@Override

public void displayResult(String result) {

textView.setText(result);

}

@Override

public void showToast(String message) {

Toast.makeText(MainActivity.this, message, Toast.LENGTH_SHORT).show();

}

Get the full sample project here.

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