javaandroid-studioandroid-animationobjectanimatoranimatorset

AnimatorSet stopping when playing sequentially


I have some code which creates a list of points called path.

Here is a sample list: [[1, 3], [2, 3], [2, 4]]

Here is the code I wrote to animate movement to these points sequentially:

        ArrayList<Animator> movements = new ArrayList<>();
        int prevY = start[1];
        int prevX = start[0];
        for (int[] square : path) {

            ObjectAnimator motion = new ObjectAnimator();

            float[] coord = screenFromGrid(square[0], square[1], gridSizeY);
            long speed = (long) (6000.0 / this.displayMetrics.widthPixels);
            speed = (long) (speed * getSquareSize(gridSizeY));

            if (square[0] != prevX) {

                motion = ObjectAnimator.ofFloat(this.sprite1, "x", coord[0]);
                motion.setInterpolator(new LinearInterpolator());
                motion.setDuration(speed);
                movements.add(motion);
                prevX = square[0];
            } else if (square[1] != prevY) {

                motion = ObjectAnimator.ofFloat(this.sprite1, "y", coord[1]);
                motion.setInterpolator(new LinearInterpolator());
                motion.setDuration(speed);
                movements.add(motion);
                prevY = square[1];
            }
        }
        AnimatorSet animatorSet = new AnimatorSet();
        animatorSet.playSequentially(movements);
        animatorSet.start();

The problem is that animation completely stops in the middle without throwing any error.

I checked the debugger and it says all the animations have been stored properly.

Does anyone know why this is happening?


Solution

  • All I know from experience is, that AnimatorSet is buggy, and does not always work as expected, I have also had my issues with it, and luckily found another, better approach : ViewPropertyAnimator is a nice way to animate Views with short and concise code. You could write your own method which you can modify and reuse as wanted, something like :

    private void customAnimation(View view, float toX, float toY, int duration, boolean loop) {
        view.animate()
            .translationX(toX)
            .translationY(toY)
            .setDuration(duration)
            .setInterpolator(new LinearInterpolator())
            .setListener(new AnimatorListenerAdapter() {
                @Override
                public void onAnimationEnd(Animator animation) {
                    if(loop) {
                        customAnimation(..., false);
                    }
                }
            });
    

    The listener waits for the first animation to finish, so you can call the next animation there. To play sequentially without looping forever I have added a boolean to the parameters which only executes the next animation if true.

    That would also shorten the rest of your code to something like this :

    int prevY = start[1];
    int prevX = start[0];
    for (int[] square : path) {
        float[] coord = screenFromGrid(square[0], square[1], gridSizeY);
        long speed = (long) (6000.0 / this.displayMetrics.widthPixels);
        speed = (long) (speed * getSquareSize(gridSizeY));
    
        if (square[0] != prevX) {
            customAnimation(this.sprite1, coord[0], 0, speed, true);
            prevX = square[0];
        } else if (square[1] != prevY) {
            customAnimation(this.sprite1, 0, coord[1], speed, true);
            prevY = square[1];
        }
    }
    

    Be sure to check the docs for all available methods, maybe .translationXBy(float byX) is more suited in your case than .translationX(float toX)