Anyway to programmatically animate layout weight property of linear layout

Question

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?

Answer 1

You can simply use ObjectAnimator.

ObjectAnimator anim = ObjectAnimator.ofFloat(                 viewToAnimate,                 "weight",                 startValue,                 endValue);         anim.setDuration(2500);         anim.start(); 

The one problem is that View class has no setWeight() method (which is required by ObjectAnimator). To address this I wrote simple wrapper which helps archive view weight animation.

public class ViewWeightAnimationWrapper {     private View view;      public ViewWeightAnimationWrapper(View view) {         if (view.getLayoutParams() instanceof LinearLayout.LayoutParams) {             this.view = view;         } else {             throw new IllegalArgumentException("The view should have LinearLayout as parent");         }     }      public void setWeight(float weight) {         LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) view.getLayoutParams();         params.weight = weight;         view.getParent().requestLayout();     }      public float getWeight() {         return ((LinearLayout.LayoutParams) view.getLayoutParams()).weight;     } } 

Use it in this way:

    ViewWeightAnimationWrapper animationWrapper = new ViewWeightAnimationWrapper(view);     ObjectAnimator anim = ObjectAnimator.ofFloat(animationWrapper,                     "weight",                     animationWrapper.getWeight(),                     weight);             anim.setDuration(2500);             anim.start();