在 2 个固定点之间滑动 UIView

Question

我试图让 UIView 在滑动触摸时在 2 个点之间滑动。我试过使用 UIPanGestureRecognizer。滑动很好，但是当视图到达极限点时，会有一个颠簸的跳跃。这并不顺利。这是我的手势功能：

    func wasDragged(gestureRecognizer: UIPanGestureRecognizer) {
    if gestureRecognizer.state == UIGestureRecognizerState.began || gestureRecognizer.state == UIGestureRecognizerState.changed {
        let translation = gestureRecognizer.translation(in: self.view)
        print(gestureRecognizer.view!.center.x)
        if(gestureRecognizer.view!.center.x <= self.view.frame.width) && (gestureRecognizer.view!.center.x >= self.view.frame.width - 100) {
            gestureRecognizer.view!.center = CGPoint(x: gestureRecognizer.view!.center.x + translation.x, y:  gestureRecognizer.view!.center.y)
        }else if (gestureRecognizer.view!.center.x > self.view.frame.width){
            gestureRecognizer.view!.center = CGPoint(x: self.view.frame.width, y: gestureRecognizer.view!.center.y)
        }else if (gestureRecognizer.view!.center.x < self.view.frame.width - 100){
            gestureRecognizer.view!.center = CGPoint(x: self.view.frame.width - 100, y: gestureRecognizer.view!.center.y)
        }

        gestureRecognizer.setTranslation(CGPoint(x: 0,y: 0), in: self.view)
    }


}

有什么帮助吗？谢谢

Answer 1

您的问题是您查看的是视图现在所在的位置，而不是应用当前移动后视图所在的位置。

我通过引入 newx 修复了您的代码，它显示了视图试图移动到的位置。这就是您要约束的值。

@IBAction func wasDragged(gestureRecognizer: UIPanGestureRecognizer) {
    if gestureRecognizer.state == .began || gestureRecognizer.state == .changed {
        let translation = gestureRecognizer.translation(in: self.view)
        print(gestureRecognizer.view!.center.x)
        let newx = gestureRecognizer.view!.center.x + translation.x

        if(newx <= self.view.frame.width) && (newx >= self.view.frame.width - 100) {
            gestureRecognizer.view!.center = CGPoint(x: newx, y:  gestureRecognizer.view!.center.y)
        }else if (newx > self.view.frame.width){
            gestureRecognizer.view!.center = CGPoint(x: self.view.frame.width, y: gestureRecognizer.view!.center.y)
        }else if (newx < self.view.frame.width - 100){
            gestureRecognizer.view!.center = CGPoint(x: self.view.frame.width - 100, y: gestureRecognizer.view!.center.y)
        }

        gestureRecognizer.setTranslation(CGPoint(x: 0,y: 0), in: self.view)
    }
}

您可能还想考虑更改最后的 setTranslation 通话。如果用户试图在视图已经在其左侧限制时向左拖动视图，然后（不抬起手指）改变方向并向右移动，即使他们的手指不再位于视图上方，您的代码也会将视图向右移动.

通过以下更改，在用户的手指回到原始触摸点之前，视图不会向右移动：

gestureRecognizer.setTranslation(CGPoint(x: newx - gestureRecognizer.view!.center.x ,y: 0), in: self.view)

试试看你喜欢哪个。

在 2 个固定点之间滑动 UIView

Sliding UIView between 2 fixed points

touch

slide

uiview

ios

swift