Add AnimationDrawable (PNG Sequence) to Canvas?

Question

I have started venturing into a bit of Canvas stuff and managed to add some statis PNG files to it.

Now I'd like to load in a PNG sequence, which I believe is an AnimationDrawable (rather then Bitmap)

I have written the XML file for the animation but then I am stumped.

I cannot find any examples of people adding PNG sequences to a Canvas object.

Answer 1

here is sample:

public class MainActivity extends Activity {

    private static final int FRAME_DELAY = 200; // in ms

    private ArrayList<Bitmap> mBitmaps;
    private final AtomicInteger mBitmapIndex = new AtomicInteger();
    private View mView;
    private Thread mThread;

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

        // load resources
        mBitmaps = new ArrayList<Bitmap>();
        for(int resId : new int[]{
                // resource ids here
                R.drawable.ic_launcher,
                R.drawable.ddms_128,
                R.drawable.ddms_icon
                }){
            mBitmaps.add(BitmapFactory.decodeResource(getResources(), resId));
        }

        // create View and implement 'draw'
        ViewGroup root = (ViewGroup) findViewById(R.id.root);
        root.addView(mView = new View(this){
            @Override
            public void draw(Canvas canvas) {
                canvas.drawBitmap(mBitmaps.get(Math.abs(mBitmapIndex.get() % mBitmaps.size())), 10, 10, null);
                super.draw(canvas);
            }
        });
    }

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

        mThread = new Thread(){
            @Override
            public void run() {
                // wait and invalidate view until interrupted
                while(true){
                    try {
                        Thread.sleep(FRAME_DELAY);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                        break; // get out if interrupted
                    }
                    mBitmapIndex.incrementAndGet();
                    mView.postInvalidate();
                }
            }
        };

        mThread.start();
    }

    @Override
    protected void onStop() {
        mThread.interrupt();
        super.onStop();
    }
}

activity_main.xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/root"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

</RelativeLayout>

Answer 2

Canvas allows to draw line/shapes/bitmaps. You managed to draw one bitmap. Animation is just drawing one bitmap from bunch of them. Canvas does nothing with drawables. The logic neither related to Canvas nor to drawables.

Answer 3

Draw the first frame, then use a Handler to post delayed Message that when handled moves to the next frame and calls invalidate().

What you need to do is:

Step #1. Override VisualizerView.verifyDrawable(Drawable who)

@Override
protected boolean verifyDrawable(Drawable who) {
    return true;
}

Step #2. Modify MainActivity.addAnimationRenderer()

private void addAnimationRenderer() {
    final AnimationDrawable anim = (AnimationDrawable) getResources().getDrawable(R.drawable.png1);

    AnimationRenderer animRenderer = new AnimationRenderer(anim);
    mVisualizerView.addRenderer(animRenderer);

    anim.setCallback(mVisualizerView);
    mVisualizerView.post(new Runnable() {
        @Override
        public void run() {
            anim.start();
        }
    });
}

Step #3. Modify AnimationRenderer: delete

mBitmap.setCallback(null);
mBitmap.start();