Android 如何在onDraw中绘制4条线？-安卓

回到另一个问题

如何在onDraw中绘制4条线？ 这是4条红色的恒定线，代表我的视图边界。 我试着画画，但只能画一条线，甚至那条线的宽度也和我的屏幕不一样

建议

谢谢

void    drawLine(float startX, float startY, float stopX, float stopY, Paint paint)
Draw a line segment with the specified start and stop x,y coordinates, using the specified paint.

更改x、y和x1、y1的值

更改x、y和x1、y1的值尝试：

public void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    Paint redPaint = new Paint();
    redPaint.setColor(Color.RED);
    redPaint.setStrokeWidth(5); // set stroke so you can actually see the lines

    canvas.drawLine(0, 0, getMeasuredWidth(), 0, redPaint);
    canvas.drawLine(getMeasuredWidth(), 0, getMeasuredWidth(), getMeasuredHeight(), redPaint);
    canvas.drawLine(getMeasuredWidth(), getMeasuredHeight(), 0, getMeasuredHeight(), redPaint);
    canvas.drawLine(0, getMeasuredHeight(), 0, 0, redPaint);
}

尝试：

public void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    Paint redPaint = new Paint();
    redPaint.setColor(Color.RED);
    redPaint.setStrokeWidth(5); // set stroke so you can actually see the lines

    canvas.drawLine(0, 0, getMeasuredWidth(), 0, redPaint);
    canvas.drawLine(getMeasuredWidth(), 0, getMeasuredWidth(), getMeasuredHeight(), redPaint);
    canvas.drawLine(getMeasuredWidth(), getMeasuredHeight(), 0, getMeasuredHeight(), redPaint);
    canvas.drawLine(0, getMeasuredHeight(), 0, 0, redPaint);
}