Repeated Background Animation

Question

In my project, I would like to animate a background with a large image template endlessly as follows:

At first I used a matrix (for scaling and translation) using ValueAnimator to create a translation animation, but I have no idea how to repeat the template.

What is the way to develop this effect? Thank you for your help.

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Update, my source code without repetition (Note: in the GIF animation, I drew the image template horizontally to simplify the presentation, but in reality I need animation with vertical translation):

background.setImageResource(R.drawable.background);
background.setScaleType(ScaleType.MATRIX);

ValueAnimator animator = ValueAnimator.ofFloat(0, 1);
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
    private Matrix matrix = new Matrix();
    @Override public void onAnimationUpdate(ValueAnimator animation) {
        float factor = (Float) animation.getAnimatedValue();
        int width = background.getDrawable().getIntrinsicWidth();
        int height = background.getDrawable().getIntrinsicHeight();
        float scale = (float) background.getWidth() / (float) width;
        matrix.reset();
        matrix.postTranslate(0, -height * factor);
        matrix.postScale(scale, scale);
        background.setImageMatrix(matrix);
    }
});

animator.setInterpolator(new LinearInterpolator());
animator.setRepeatCount(ValueAnimator.INFINITE);
animator.setRepeatMode(ValueAnimator.RESTART);
animator.setDuration(10000);
animator.start();

Answer 1

I finally extends BitmapDrawable to override the draw () method:

Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.background);
BitmapDrawable drawable = new BitmapDrawable(getResources(), bitmap) {
    @Override
    public void draw(Canvas canvas) {
        super.draw(canvas);
        canvas.drawBitmap(getBitmap(), 0, getIntrinsicHeight(), null);
    }
};

background.setImageDrawable(drawable);
background.setScaleType(ScaleType.MATRIX);

ValueAnimator animator = ValueAnimator.ofFloat(0);
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
    private Matrix matrix = new Matrix();
    @Override
    public void onAnimationUpdate(ValueAnimator animator) {
        matrix.reset();
        int height = background.getDrawable().getIntrinsicHeight();
        float translate = -height * animator.getAnimatedFraction();
        matrix.postTranslate(0, translate);
        float width = background.getDrawable().getIntrinsicWidth();
        float scale = background.getWidth() / width;
        matrix.postScale(scale, scale);
        background.setImageMatrix(matrix);
    }
});

animator.setInterpolator(new LinearInterpolator());
animator.setRepeatCount(ValueAnimator.INFINITE);
animator.setRepeatMode(ValueAnimator.RESTART);
animator.setDuration(10000);
animator.start();

: drawable.setTileModeXY(TileMode.REPEAT, TileMode.REPEAT) imageView.setScaleType(ScaleType.MATRIX).

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