Rotating image. Animation list or animated rotate? (Android)

Question

I want to create a rotating progress image, and wonder what's the best way to proceed. I can make it work with an animation list with for example 12 images changing every 100ms. This works fine, but it's quite tedious to create 12 images or for every size and resolution:

I suppose that an easier solution is to use one image per resolution, but rather rotate it for each frame. In the platform resources (android-sdk-windows/platforms...) I found something called animated-rotate in the file drawable/search_spinner.xml, but if I copy the code get a compiler error complaining about android:framesCount and android:frameDuration (Google APIs 2.2 in Eclipse):

I have also tried using a repeating rotate animation (using in the anim resource folder), but I actually prefer the look of the animation list version.

What is the recommended way of solving this problem?

user_5318303 · Answer

Thank @vokilam. This similar solution (a custom view that rotates automatically) uses dynamically in its implementation:

public class FramesAnimatorView extends AppCompatImageView {
    private int framesCount;
    private int duration;
    private Bitmap frameBitmap;

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

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

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

    private void init(Context context, AttributeSet attrs) {
        final TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.FramesAnimatorView);
        framesCount = typedArray.getInt(R.styleable.FramesAnimatorView_framesCount, 12);
        duration = typedArray.getInt(R.styleable.FramesAnimatorView_duration, 1200);
        typedArray.recycle();

        // Method 1: Use  as Animation (RotateAnimation) and startAnimation() (Rotate view itself).
        //method1(framesCount, duration);

        // Method 2: Use  as Drawable (RotateDrawable) and ObjectAnimator. Usable for API 21+ (because of using RotateDrawable.setDrawable).
        //method2();

        // Method 3 (Recommended): Use  (AnimationDrawable) dynamically.
        final int frameDuration = this.duration / framesCount;
        final AnimationDrawable animationDrawable = (AnimationDrawable) getDrawable();

        for (int i = 0; i < framesCount; i++)
            animationDrawable.addFrame(
                    new RotatedDrawable(frameBitmap, i * 360f / framesCount, getResources()),
                    frameDuration);

        animationDrawable.start();
    }

    @Override public void setImageResource(int resId) { //info();
        frameBitmap = BitmapFactory.decodeResource(getResources(), resId);
        super.setImageDrawable(new AnimationDrawable());
    }

    @Override public void setImageDrawable(@Nullable Drawable drawable) { //info();
        frameBitmap = drawableToBitmap(drawable);
        super.setImageDrawable(new AnimationDrawable());
    }

    @Override public void setImageBitmap(Bitmap bitmap) { //info();
        frameBitmap = bitmap;
        super.setImageDrawable(new AnimationDrawable());
    }

    /**
     * See @android-developer's answer on stackoverflow.com.
     */
    private static class RotatedDrawable extends BitmapDrawable {
        private final float degrees;
        private int pivotX;
        private int pivotY;

        RotatedDrawable(Bitmap bitmap, float degrees, Resources res) {
            super(res, bitmap);
            pivotX = bitmap.getWidth() / 2;
            pivotY = bitmap.getHeight() / 2;
            this.degrees = degrees;
        }

        @Override public void draw(final Canvas canvas) {
            canvas.save();
            canvas.rotate(degrees, pivotX, pivotY);
            super.draw(canvas);
            canvas.restore();
        }
    }

    /**
     * See @André's answer on stackoverflow.com.
     */
    @NonNull private static Bitmap drawableToBitmap(Drawable drawable) {
        final Bitmap bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
        final Canvas canvas = new Canvas(bitmap);
        drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
        drawable.draw(canvas);
        return bitmap;
    }
}

See Android-FramesAnimatorView on GitHub for full (and probably more updated) source code.

Rotating image. Animation list or animated rotate? (Android)

6 Answers