AnimButton is a custom ImageButton which is imitating the whatsapp's send button behavior. Basically, it will change the image source when you enter some text on the edittext and it will go back when you clear the edittext. You can also read more on http://gunhansancar.com/anim-button-inspired-by-whatsapp/

AnimButton.java

package com.gunhansancar.android.animbutton;

import android.animation.ValueAnimator;
import android.content.Context;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.InsetDrawable;
import android.graphics.drawable.LayerDrawable;
import android.util.AttributeSet;
import android.view.animation.AccelerateDecelerateInterpolator;
import android.view.animation.Interpolator;
import android.widget.ImageButton;

/**
 * Created by Günhan on 17.08.2015.
 */
public class AnimButton extends ImageButton {
    private static final Interpolator interpolator = new AccelerateDecelerateInterpolator();

    public static final int FIRST_STATE = 1;
    public static final int SECOND_STATE = 2;

    private Drawable firstDrawable;
    private Drawable secondDrawable;

    private int state = FIRST_STATE;
    private int total = 100;
    private int duration = 200;
    private boolean init = false;

    public AnimButton(Context context) {
        super(context);
    }

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

    public AnimButton(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init(context, attrs);
    }

    private void init(Context context, AttributeSet attrs) {
        TypedArray array = context.obtainStyledAttributes(attrs, R.styleable.AnimButton, 0, 0);

        int first = array.getResourceId(R.styleable.AnimButton_first, -1);
        int second = array.getResourceId(R.styleable.AnimButton_second, -1);
        duration = array.getInteger(R.styleable.AnimButton_duration, duration);

        if (array != null) {
            array.recycle();
        }

        if (first > 0 && second > 0) {
            init = true;

            Resources resources = context.getResources();
            firstDrawable = resources.getDrawable(first);
            secondDrawable = resources.getDrawable(second);

            setImageDrawable(firstDrawable);
        }
    }

    public void goToState(int state) {
        if (!init || this.state == state) return;

        switch (state) {
            case FIRST_STATE:
                animate(firstDrawable, secondDrawable);
                break;
            case SECOND_STATE:
                animate(secondDrawable, firstDrawable);
                break;
        }

        this.state = state;
    }

    private Drawable makeInsetDrawable(Drawable drawable, int inset) {
        return new InsetDrawable(drawable, inset, inset, inset, inset);
    }

    private void animate(final Drawable from, final Drawable to) {
        ValueAnimator animator = ValueAnimator.ofInt(0, total);
        animator.setDuration(duration);
        animator.setInterpolator(interpolator);

        animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            public void onAnimationUpdate(ValueAnimator animation) {
                Integer value = (Integer) animation.getAnimatedValue();
                int left = total - value;

                Drawable firstInset = makeInsetDrawable(from, left);
                Drawable secondInset = makeInsetDrawable(to, value);

                LayerDrawable layer = new LayerDrawable(new Drawable[]{firstInset, secondInset});
                setImageDrawable(layer);
            }
        });

        animator.start();
    }
}

Hi,

i am no find you R.styleable.AnimButton and etc. Thanks