Android ViewGroup删除子视图时应该注意的一个问题

public class scrollHorizon extends ViewGroup {          private Context context;          public scrollHorizon(Context context) {           super(context);                      this.context = context;                      createLayout();                      deleteAllView();       }       @Override       protected void onLayout(boolean changed, int l, int t, int r, int b) {                      int childCount = this.getChildCount();           int childLeft = 0;           int childTop = 0;           for(int i = 0; i < childCount; i++){               View child = getChildAt(i);               child.setVisibility(View.VISIBLE);               child.measure(r - l, b - t);               child.layout(childLeft, childTop, childLeft + child.getMeasuredWidth(),childTop + child.getMeasuredHeight());               if(childLeft <= 320){                   childLeft = childLeft + child.getMeasuredWidth();               }               else{                   childLeft = 0;                   childTop = childTop + child.getMeasuredHeight();               }           }       }          public void createLayout(){                  Resources resource = this.getResources();                      PackageManager pmanager = context.getPackageManager();                      final Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);                   mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);                              List<ResolveInfo> list = pmanager.queryIntentActivities(mainIntent, 0);                                     for( int i = 0; i < list.size(); i++){                         int icon = R.drawable.contacts_button_normal;                         LinearLayout linear = new LinearLayout(context);                         linear.setLayoutParams(new LayoutParams(45, 45));                         linear.setBackgroundDrawable(this.getResources().getDrawable(R.drawable.icon));                                        ImageView image2 = new ImageView(context);                         image2.setBackgroundDrawable(this.getResources().getDrawable(R.drawable.icon));                         Drawable drawable = resource.getDrawable(icon);                                        ImageView image = new ImageView(context);                                        image.setBackgroundDrawable(drawable);                         linear.addView(image2);                         linear.addView(image);                         this.addView(linear);                  }       }              public void deleteAllView(){           int size = this.getChildCount();           for( int i = 0; i < size; i++){               this.removeViewAt(i);           }       }   }