Question

我正在尝试在画布中移动绘图。我有工作代码，但问题是，当我点击画布第二次拖动时，它会将自身重置为其初始位置（默认位置）n然后再次开始移动。我想让它从我第一次拖动的地方移开。

在我的自定义视图代码中，我有一个名为setupCoordinates的函数，其中初始化了我的绘图坐标。（x和y，我用它来移动图纸。这些值由我活动的onTouch监听器更新）

我将视图添加到相对布局

relLay.addView(custView);

我的布局有一个onTouch侦听器

relLay.setOntouchListener(touch);

在我的触控听众中，我通过传递evet.getX（）和event.getY（）来更新我的绘图

custView.setXY(evet.getX(), event.getY());

以下是我正在绘制的自定义视图的代码：

public CustView(Context context) {
    super(context);
            setupDrawing();
            setupCoordinates();
}

private void setupDrawing() {
    path = new Path();
    paint = new Paint();
    borderPaint = new Paint();
    paint.setColor(color);
    paint.setAntiAlias(true);
    paint.setStyle(Paint.Style.FILL);
    borderPaint.setColor(Color.BLACK);
    borderPaint.setAntiAlias(true);
    borderPaint.setStyle(Paint.Style.STROKE);
}

private void setupCoordinates() {
    x = 0;
    y = 0;
    top = 150 ;
    right = 450 ;
    left = 200 ;
    bottom = 400 ;
    linex = 120;
    liney = 300;
    openSize = 20;
}

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
        path.reset();
        mCanvas = canvas;

         rectf = new RectF(left+x, top+y, right+x, bottom+y);
         rect = rectf;
         int angle = (int) angle(new Point((getWidth())/2, (getHeight())/2), new Point(linex,liney)); 


        int startAngle = angle + (openSize/2);
        int sweepAngle = 360 - openSize;

        path.arcTo(rectf, startAngle, sweepAngle);
        path.lineTo(linex, liney);

        canvas.drawPath(path, paint);
        canvas.drawPath(path, borderPaint);

}

public void setXY(int dx, int dy){
    x = dx;
    y = dy;
    invalidate();
}

private double angle(Point point1, Point point2) {
    double deltaX = (point1.x - point2.x);
    double deltaY = (point1.y - point2.y);
    double angle =  Math.toDegrees(Math.atan2(deltaY, deltaX));
    if (angle < 0) {
        angle += 360;
    }

    if (angle > 360) {
        angle -= 360;
    }
    // Compensate for 0
    angle -= 180;
    return angle;
}

任何人都可以告诉我为什么在第二次拖动时它会重置到初始位置？

我也对在画布内移动图纸的其他方法持开放态度，如有，请告诉我。我不想只移动视图或画布。

提前致谢：）

Answer 1

以下是如何避免捕捉的示例，并调整应该起作用的值：

switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
    mCustomView.setXYAnimated((int) event.getX(),
            (int) event.getY());
    break;
case MotionEvent.ACTION_MOVE:
    mCustomView.setXY((int) event.getX(),
            (int) event.getY());
    break;
case MotionEvent.ACTION_UP:
    mCustomView.setXY((int) event.getX(),
            (int) event.getY());
    break;
}

在自定义视图中：

private int x = -1;
private int y = -1;
private CountDownTimer mCountDownTimer;

public void setXY(int dx, int dy) {
    if (mCountDownTimer == null) {
        x = dx;
        y = dy;

        invalidate();
    }
}

public void setXYAnimated(final int newX, final int newY) {
    if (x == -1 && y == -1) {
        setXY(newX, newY);
    } else {
        if (mCountDownTimer == null) {
            final int time = 250;

            mCountDownTimer = new CountDownTimer(time, 10) {

                @Override
                public void onTick(long millisUntilFinished) {
                    float progress = 1 - ((float) millisUntilFinished / time);

                    int x2, y2;

                    if (x < newX) {
                        x2 = (int) (x + (progress * (newX - x)));
                    } else {
                        x2 = (int) (x - (progress * (x - newX)));
                    }

                    if (y < newY) {
                        y2 = (int) (y + (progress * (newY - y)));
                    } else {
                        y2 = (int) (y - (progress * (y - newY)));
                    }

                    x = x2;
                    y = y2;

                    postInvalidate();
                }

                @Override
                public void onFinish() {
                    mCountDownTimer = null;

                    setXY(newX, newY);
                }
            }.start();
        }
    }
}

在画布android中移动绘图

1 个答案: