Android獲取繪製背景顏色

Question

我試圖在繪製CardView元素的畫布時更改背景顏色。所以我想在onDraw事件上獲得背景顏色，但我沒有得到。

如何獲取CardView onDaw事件的背景顏色？

public class MyCardView extends CardView { 
    public MyCardView(Context context) { 
     super(context); 
    } 

    @Override 
    protected void onDraw(Canvas canvas) { 
     int bgColor = ???some method???; 
     if(bgColor == 0) { 
      setBackgroundColor(Color.RED); 
     } 
     super.onDraw(canvas); 
    } 
} 

Answer 1

提示：在onDraw()

public class MyCardView extends CardView { 
    private Drawable background; 
    private int color = Color.RED; 

    public MyCardView(Context context) { 
     super(context); 
     background = ((View) this.getParent()).getBackground(); 
     if (background instanceof ColorDrawable) { 
      color = ((ColorDrawable) background).getColor(); 
     } 
    } 

    @Override 
    protected void onDraw(Canvas canvas) { 
     setBackgroundColor(color); 
     super.onDraw(canvas); 
    } 
} 

避免分配