I have two views in a linear layout, I programmatically change their layout_weight property. Is there a way I could animate this change in weight so when the weight is changed views slides towards a new size?
5 Answers
Note: I am not sure that this is the best way, but I tried it and it's working fine
Simply using ValueAnimator
ValueAnimator m1 = ValueAnimator.ofFloat(0.2f, 0.5f); //fromWeight, toWeight
m1.setDuration(400);
m1.setStartDelay(100); //Optional Delay
m1.setInterpolator(new LinearInterpolator());
m1.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
((LinearLayout.LayoutParams) viewToAnimate.getLayoutParams()).weight = (float) animation.getAnimatedValue();
viewToAnimate.requestLayout();
}
});
m1.start();
Another way is to use old Animation class, as described in https://stackoverflow.com/a/20334557/2914140. In this case you can simultaneously change weights of several Views.
private static class ExpandAnimation extends Animation {
private final View[] views;
private final float startWeight;
private final float deltaWeight;
ExpandAnimation(View[] views, float startWeight, float endWeight) {
this.views = views;
this.startWeight = startWeight;
this.deltaWeight = endWeight - startWeight;
}
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
float weight = startWeight + (deltaWeight * interpolatedTime);
for (View view : views) {
LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) view.getLayoutParams();
lp.weight = weight;
view.setLayoutParams(lp);
}
views[0].getParent().requestLayout();
}
@Override
public boolean willChangeBounds() {
return true;
}
}
All of the answers above weren't working for me (they would simply "snap" and not animate), but after I added weight_sum="1" to the parent layout, it started working. Just in case someone else comes up with the same issue.
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