Android AnimationDrawable and knowing when animation ends

Question

I want to do an animation with several image-files, and for this the AnimationDrawable works very well. However, I need to know when the animation starts and when it ends (i.e add a listener like the Animation.AnimationListener). After having searched for answers, I'm having a bad feeling the AnimationDrawable does not support listeners..

Does anyone know how to create a frame-by-frame image animation with a listener on Android?

Answer 1

After doing some reading, I came up with this solution. I'm still surprised there isn't a listener as part of the AnimationDrawable object, but I didn't want to pass callbacks back and forward so instead I created an abstract class which raises an onAnimationFinish() method. I hope this helps someone.

The custom animation drawable class:

public abstract class CustomAnimationDrawableNew extends AnimationDrawable {

    /** Handles the animation callback. */
    Handler mAnimationHandler;

    public CustomAnimationDrawableNew(AnimationDrawable aniDrawable) {
        /* Add each frame to our animation drawable */
        for (int i = 0; i < aniDrawable.getNumberOfFrames(); i++) {
            this.addFrame(aniDrawable.getFrame(i), aniDrawable.getDuration(i));
        }
    }

    @Override
    public void start() {
        super.start();
        /*
         * Call super.start() to call the base class start animation method.
         * Then add a handler to call onAnimationFinish() when the total
         * duration for the animation has passed
         */
        mAnimationHandler = new Handler();
        mAnimationHandler.post(new Runnable() {
            @Override
            public void run() {
                onAnimationStart();
            }  
        };
        mAnimationHandler.postDelayed(new Runnable() {
            @Override
            public void run() {
                onAnimationFinish();
            }
        }, getTotalDuration());

    }

    /**
     * Gets the total duration of all frames.
     * 
     * @return The total duration.
     */
    public int getTotalDuration() {

        int iDuration = 0;

        for (int i = 0; i < this.getNumberOfFrames(); i++) {
            iDuration += this.getDuration(i);
        }

        return iDuration;
    }

    /**
     * Called when the animation finishes.
     */
    public abstract void onAnimationFinish();
   /**
     * Called when the animation starts.
     */
    public abstract void onAnimationStart();
}

To use this class:

    ImageView iv = (ImageView) findViewById(R.id.iv_testing_testani);

    iv.setOnClickListener(new OnClickListener() {
        public void onClick(final View v) {

            // Pass our animation drawable to our custom drawable class
            CustomAnimationDrawableNew cad = new CustomAnimationDrawableNew(
                    (AnimationDrawable) getResources().getDrawable(
                            R.drawable.anim_test)) {
                @Override
                void onAnimationStart() {
                    // Animation has started...
                }

                @Override
                void onAnimationFinish() {
                    // Animation has finished...
                }
            };

            // Set the views drawable to our custom drawable
            v.setBackgroundDrawable(cad);

            // Start the animation
            cad.start();
        }
    });