ImageView:onDraw方法在图像背景"后面"绘制,而不是在顶部

Question

以下是ImageView的简单扩展代码,允许用户用手指绘制.

public class MyImageView extends ImageView {

    List<Point> points = new ArrayList<Point>();
    Paint paint = new Paint();

    public MyImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    public void onDraw(Canvas canvas) {
        for (Point point : points) {
            canvas.drawCircle(point.x, point.y, 5, paint);
            // Log.d(TAG, "Painting: "+point);
        }
        super.onDraw(canvas);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        super.onTouchEvent(event);
        Point point = new Point();
        point.x = event.getX();
        point.y = event.getY();
        points.add(point);
        invalidate();
        Log.d("", "point: " + point);
        return true;
    }

    class Point {
        float x, y;
        @Override
        public String toString() {
            return x + ", " + y;
        }
    }
}

这项工作相当不错.

现在,我想使用此代码在位图的顶部绘制.

我用了:

MyImageView ivPic = (MyImageView) dialog.findViewById(R.id.ivPic);
ivPic.setImageBitmap(picture);

但是绘图是在Bitmap"后面"绘制的:

你知道我怎么能在位图的"顶部"画出来吗？

Answer 1

我已经改变了onDraw方法的顺序,我把super.onDraw(canvas);它放在开头,我觉得它现在有效