Android使用画布绘制自定义形状

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    Paint paint = new Paint();
    paint.setColor(Color.RED);
    paint.setStyle(Paint.Style.FILL);
    canvas.drawRect(50, 50, 200, 200, paint);
}

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    Paint paint = new Paint();
    paint.setColor(Color.BLUE);
    paint.setStyle(Paint.Style.FILL);
    int centerX = getWidth() / 2;
    int centerY = getHeight() / 2;
    int radius = Math.min(centerX, centerY) - 50;
    canvas.drawCircle(centerX, centerY, radius, paint);
}

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    Paint paint = new Paint();
    paint.setColor(Color.GREEN);
    paint.setStyle(Paint.Style.FILL);

    Path path = new Path();
    path.moveTo(100, 100);
    path.lineTo(200, 200);
    path.lineTo(300, 150);
    path.close();

    canvas.drawPath(path, paint);
}