java - 定位 path.lineTo()

Question

我目前正在 Android Studio 上学习 Canvas，我不太确定使用正确的标题，但我一直在研究如何在使用 Seekbar 拖动红点时控制三角形位置。以下是详细信息

下面是我成功绘制三角形的代码。

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

        paint.setColor(Color.RED);
        canvas.drawRoundRect(100, 300, 900, 700, 50, 50,paint);

        Point pointTop = new Point(250, 400);
        Point pointLeft = new Point(150, 150);
        Point pointRight = new Point(350, 150);


        paint.setColor(Color.YELLOW);
        path.setFillType(Path.FillType.EVEN_ODD);
        path.lineTo(pointTop.x, pointTop.y);
        path.lineTo(pointLeft.x, pointLeft.y);
        path.lineTo(pointRight.x, pointRight.y);
        path.lineTo(pointTop.x, pointTop.y);
        path.close();

        canvas.drawPath(path, paint);
        }

图像结果:

预期结果

注意:只有1个红点和1个三角形。

非常感谢=)

Answer 1

阅读下面链接的文档并添加代码后，我已经解决了我的问题

https://developer.android.com/reference/android/graphics/Path

享受 :)

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

        paint.setColor(Color.RED);
        canvas.drawRoundRect(100, 300, 900, 700, 50, 50,paint);

        Point pointTop = new Point(250, 400);
        Point pointLeft = new Point(150, 150);
        Point pointRight = new Point(350, 150);


        paint.setColor(Color.YELLOW);
--------------------- added -------------------------------
        path.moveTo(pointLeft.x, pointLeft.y);
        path.moveTo(pointRight.x, pointRight.y);
        path.moveTo(pointTop.x, pointTop.y);
        path.reset();
--------------------- added -------------------------------
        path.setFillType(Path.FillType.EVEN_ODD);
        path.lineTo(pointTop.x, pointTop.y);
        path.lineTo(pointLeft.x, pointLeft.y);
        path.lineTo(pointRight.x, pointRight.y);
        path.lineTo(pointTop.x, pointTop.y);
        path.close();

        canvas.drawPath(path, paint);
        }