使FrameLayout扩展，它也是孩子

Question

如何动态更改FrameLayout的大小，并且它的孩子也得到了扩展？

编辑：到目前为止，我得到了这一点，但不起作用：

public class ResizableArea extends FrameLayout { 
    private View child; 

    public ResizableArea(Context context) { 
     super(context); 
    } 

    @Override 
    public boolean onTouchEvent(MotionEvent event) { 
     if (event.getPointerCount() > 1){ 
      Vector2D p1 = new Vector2D(event.getX(0), event.getY(0)); 
      Vector2D p2 = new Vector2D(event.getX(1), event.getY(1)); 

      float dist = p1.minus(p2).getSize(); 

      resizeChildBy(dist); 
     } 
     return true; 
    } 

    private void resizeChildBy(float size) { 
     LayoutParams params = (LayoutParams) child.getLayoutParams(); 
     params.height -= size; 
     params.width -= size; 
     child.setLayoutParams(params); 
     invalidate(); 
    } 


    @Override 
    public void addView(View child) { 
     if (getChildCount() != 0) 
      throw new IllegalStateException("ResizableArea can only have one child attached!"); 

     this.child = child; 
     super.addView(child); 
    } 

} 

Answer 1

其实，这是一个正确的答案：

public class ResizableArea extends FrameLayout { 
    private View child; 

    public ResizableArea(Context context) { 
     super(context); 
    } 

    @Override 
    public boolean onTouchEvent(MotionEvent event) { 
     if (event.getPointerCount() > 1){ 
      Vector2D p1 = new Vector2D(event.getX(0), event.getY(0)); 
      Vector2D p2 = new Vector2D(event.getX(1), event.getY(1)); 

      float dist = p1.minus(p2).getSize(); 

      if (lastDist == 0) { 
       lastDist = dist; 
       return true; 
      } 

      resizeChildsBy(lastDist - dist); 
      lastDist = dist; 
     } 
     return true; 
    } 

    private void resizeChildBy(float size) { 
     LayoutParams params = (LayoutParams) child.getLayoutParams(); 
     params.height -= size; 
     params.width -= size; 
     child.setLayoutParams(params); 
     invalidate(); 
    } 


    @Override 
    public void addView(View child) { 
     if (getChildCount() != 0) 
      throw new IllegalStateException("ResizableArea can only have one child attached!"); 

     this.child = child; 
     super.addView(child); 
    } 

}