Android: Expand/collapse animation

Question

Let\'s say I have a vertical linearLayout with :

[v1]
[v2]

By default v1 has visibily = GONE. I would like to show v1 with an expand animat

Answer 1

Use ValueAnimator:

ValueAnimator expandAnimation = ValueAnimator.ofInt(mainView.getHeight(), 400);
expandAnimation.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
    @Override
    public void onAnimationUpdate(final ValueAnimator animation) {
        int height = (Integer) animation.getAnimatedValue();
        RelativeLayout.LayoutParams lp = (LayoutParams) mainView.getLayoutParams();
        lp.height = height;
    }
});


expandAnimation.setDuration(500);
expandAnimation.start();