android - Invalidate() doesn't actually redraw children -

so, have pretty weird setup, , i'm getting weird visual bugs out of it. basically, have 2 views in relative layout: first imageview background image; second same background image blurred give kind of behind-frosted-glass effect:

<relativelayout xmlns:android="http://schemas.android.com/apk/res/android"     xmlns:tools="http://schemas.android.com/tools"     android:id="@+id/profile_holder"     android:layout_width="match_parent"     android:layout_height="match_parent" >      <!-- background -->     <imageview         android:id="@+id/backgroundimage"         android:layout_width="match_parent"         android:layout_height="match_parent"         android:layout_alignparentleft="true"         android:layout_alignparenttop="true"         android:layout_marginleft="0dp"         android:layout_margintop="0dp"         android:scaletype="centercrop"         android:src="@drawable/default_logo" />      <!-- blurry background -->     <com.custom.maskedblurredbackgroundview_         android:id="@+id/blurred_background"         android:layout_width="match_parent"         android:layout_height="match_parent"         android:layout_alignparentleft="true"         android:layout_alignparenttop="true"         android:layout_marginleft="0dp"         android:layout_margintop="0dp" />  <scrollview     android:id="@+id/scrolly"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:fillviewport="true"     android:layout_alignparentleft="true"     android:layout_alignparenttop="true" >              <com.custom.halvedlinearlayout_                 android:paddingtop="100dp"                 android:id="@+id/profileholder"                 android:layout_width="match_parent"                 android:layout_height="wrap_content"                 android:orientation="vertical"                  >                  <button                     android:id="@+id/profilebuttontracks"                     style="@style/profilebuttons"                     android:drawableleft="@drawable/ic_profile_menu_music"                     android:text="@string/profile_button_tracks" />  ... 

the blurred background should behind halvedlinearlayout_ view, scrolls up, need blurred background mask above halvedlinearlayout_ non-blurry background shows through:

scrolly  = ((scrollview) rootview.findviewbyid(r.id.scrolly)); scrolly.setonscrolllistener(new scrollview.onscrolllistener() {      private boolean hasscrolled = false;      @override     public void onscrollchanged(int l, int t, int oldl, int oldt) {          if (!hasscrolled) {             hasscrolled = true;             logger.action(logger.action.bioview, band);         }          positionmask();     } });  ...  protected void positionmask() {     if (blurredbackground == null) return;      logger.d(tag, "positionmask() " + rootview.getid());      //blurredbackground.setmaskbottom(blurredbackground.getheight() - profileholder.getpaddingtop() - scrolly);     blurredbackground.setmaskbottom(profileholder.gettop() + profileholder.getpaddingtop() - scrolly.getscrolly());     //blurredbackground.invalidate();     //profileholder.invalidate();     rootview.postinvalidate(); } 

now, problem works should, except huge glaring fact when scroll scrollview, blurredbackground draws on halvedlinearlayout_, obliterating buttons in it. (but halfway, sometimes. fine, half button drawn on , other half preserved... kinds of weird glitches.)

i started debugging, , noticed interesting: calling invalidate() on rootview doesn't invalidate() children. overrode invalidate , draw functions logging stuff:

public class maskedblurredbackgroundview extends blurredbackgroundview {     /***      * sets mask cover above given y coordinate      * @param t y coordinate in pixels      */     public void setmaskbottom(int y) {         maskbottom  = y;     }      private void clipcanvas(canvas canvas) {         logger.d(tag, "dispatchdraw clipping: " + maskbottom + ", " + getwidth() + "," + getheight());         canvas.cliprect(0, maskbottom, getwidth(), getheight(), region.op.replace);     }      @override     protected void dispatchdraw(canvas canvas) {         canvas.save();         clipcanvas(canvas);         super.dispatchdraw(canvas);          canvas.restore();     }     @override     protected boolean drawchild(canvas canvas, view child, long drawingtime) {         logger.d(tag, "drawchild: " + child + getwidth() + "," + getheight());          return super.drawchild(canvas, child, drawingtime);     }      @override     public void invalidate() {         logger.d(tag, "invalidate: " + getwidth() + "," + getheight());         super.invalidate();     } 

and when @ log, rootview.invalidate() firing when scroll, children never redraw:

07-23 12:36:49.328: d/banddetailfrag(12982): positionmask() 2131165298 07-23 12:36:49.348: d/banddetailfrag(12982): positionmask() 2131165298 07-23 12:36:49.348: d/banddetailfrag(12982): positionmask() 2131165298 07-23 12:36:49.368: d/banddetailfrag(12982): positionmask() 2131165298 07-23 12:36:49.368: d/banddetailfrag(12982): positionmask() 2131165298 07-23 12:36:49.378: d/banddetailfrag(12982): positionmask() 2131165298 07-23 12:36:49.398: d/banddetailfrag(12982): positionmask() 2131165298 07-23 12:36:49.418: d/banddetailfrag(12982): positionmask() 2131165298 07-23 12:36:49.448: d/banddetailfrag(12982): positionmask() 2131165298 07-23 12:36:49.478: d/banddetailfrag(12982): positionmask() 2131165298 

how force children redraw, in correct order? right i'm guessing draw out of order , that's why blurry background drawing on top of else.

here's screenshot of glitch:

ok, figured out how rid of glitching, @ least: had change "region.op.replace" "region.op.intersect" , works!

invalidate() still doesn't redraw children, guess i'll let slide it's working.