Android: Expand/collapse animation -

let's have vertical linearlayout :

[v1] [v2] 

by default v1 has visibily = gone. show v1 expand animation , push down v2 @ same time.

i tried this:

animation = new animation() {     int initialheight;      @override     protected void applytransformation(float interpolatedtime, transformation t) {         final int newheight = (int)(initialheight * interpolatedtime);         v.getlayoutparams().height = newheight;         v.requestlayout();     }      @override     public void initialize(int width, int height, int parentwidth, int parentheight) {         super.initialize(width, height, parentwidth, parentheight);         initialheight = height;     }      @override     public boolean willchangebounds() {         return true;     } }; 

but solution, have blink when animation starts. think it's caused v1 displaying full size before animation applied.

with javascript, 1 line of jquery! simple way android?

i see question became popular post actual solution. main advantage don't have know expanded height apply animation , once view expanded, adapts height if content changes. works great me.

public static void expand(final view v) {     v.measure(layoutparams.match_parent, layoutparams.wrap_content);     final int targetheight = v.getmeasuredheight();      // older versions of android (pre api 21) cancel animations views height of 0.     v.getlayoutparams().height = 1;     v.setvisibility(view.visible);     animation = new animation()     {         @override         protected void applytransformation(float interpolatedtime, transformation t) {             v.getlayoutparams().height = interpolatedtime == 1                     ? layoutparams.wrap_content                     : (int)(targetheight * interpolatedtime);             v.requestlayout();         }          @override         public boolean willchangebounds() {             return true;         }     };      // 1dp/ms     a.setduration((int)(targetheight / v.getcontext().getresources().getdisplaymetrics().density));     v.startanimation(a); }  public static void collapse(final view v) {     final int initialheight = v.getmeasuredheight();      animation = new animation()     {         @override         protected void applytransformation(float interpolatedtime, transformation t) {             if(interpolatedtime == 1){                 v.setvisibility(view.gone);             }else{                 v.getlayoutparams().height = initialheight - (int)(initialheight * interpolatedtime);                 v.requestlayout();             }         }          @override         public boolean willchangebounds() {             return true;         }     };      // 1dp/ms     a.setduration((int)(initialheight / v.getcontext().getresources().getdisplaymetrics().density));     v.startanimation(a); }