Question

I am creating a scalable shape by adding a shape and handles as separate views to a ViewGroup. Once a handler is clicked, how do I get a reference to the ViewGroup so that I can scale everything? handle.getParent() returns null. My ViewGroup was created programmatically.

public class ShapeView extends ViewGroup {

    private SelectorView mSelectorView;

     public ShapeView (Context context) {
          super(context);
          RelativeLayout.LayoutParams p = new RelativeLayout.LayoutParams(200, 200);
          this.setLayoutParams(p);
          mSelectorView = new SelectorView(context);
          this.addView(mSelectorView);
    }
}


public class SelectorView extends View {

public RectangleDrawable mRectangleDrawable;

    public SelectorView (Context context) {
          super(context);
          Log.v(TAG, "constructor");
          mRectangleDrawable = new RectangleDrawable();
          RelativeLayout.LayoutParams p = new RelativeLayout.LayoutParams(20, 20);
          this.setLayoutParams(p);
    }

    @Override
    protected void onDraw(Canvas canvas) {  
          super.onDraw(canvas);
          mRectangleDrawable.draw(canvas); 
    }


    public boolean onTouchEvent(MotionEvent event) {

          switch (event.getAction()) {
             case MotionEvent.ACTION_DOWN: {
               ViewGroup parentView = (ViewGroup)this.getParent();
               parentView.setX(100);
               parentView.setY(100);
               break;
              }
           }
           return true; 
    }

}

Answer 1

Please use SelectorView.this.getParent() instead of this.getParent()

public class SelectorView extends View {

public RectangleDrawable mRectangleDrawable;

public SelectorView (Context context) {
      super(context);
      Log.v(TAG, "constructor");
      mRectangleDrawable = new RectangleDrawable();
      RelativeLayout.LayoutParams p = new RelativeLayout.LayoutParams(20, 20);
      this.setLayoutParams(p);
}

@Override
protected void onDraw(Canvas canvas) {  
      super.onDraw(canvas);
      mRectangleDrawable.draw(canvas); 
}


public boolean onTouchEvent(MotionEvent event) {

      switch (event.getAction()) {
         case MotionEvent.ACTION_DOWN: {
           ViewGroup parentView = (ViewGroup)SelectorView.this.getParent();
           parentView.setX(100);
           parentView.setY(100);
           break;
          }
       }
       return true; 
}

}