使用UIPanGestureRecognizer获取视图的翻译-Swift-以编程方式

问题描述

我正在使用UIPanGestureRecognizer方法转换视图：

 @objc fileprivate func handlePan(_ gestureRecognizer : UIPanGestureRecognizer){
    if gestureRecognizer.state == .began || gestureRecognizer.state == .changed {
        makedisappearButtons()
        deleteBox.isHidden = false
        let translation = gestureRecognizer.translation(in: self.view)
        // note: 'view' is optional and need to be unwrapped
        gestureRecognizer.view!.center = CGPoint(x: gestureRecognizer.view!.center.x + translation.x,y: gestureRecognizer.view!.center.y + translation.y)
        gestureRecognizer.setTranslation(CGPoint.zero,in: self.view)
        if gestureRecognizer.view!.frame.intersects(deleteBox.frame) {
            UIView.animate(withDuration: 0.3,delay: 0,options: .curveEaseInOut,animations: {
                gestureRecognizer.view!.transform = .init(scaleX: 0.6,y: 0.6)
                self.deleteBox.transform = .init(scaleX: 1.2,y: 1.2)
            },completion: nil)
        } else {
            gestureRecognizer.view!.setNeedsdisplay()
            gestureRecognizer.setTranslation(.zero,in: self.view)
            UIView.animate(withDuration: 0.3,animations: {
                self.deleteBox.transform = .identity
                gestureRecognizer.view!.transform = .identity
            },completion: nil)
        }
    }
    
    if gestureRecognizer.state == .ended {
        makeButtonsReAppear()
        if gestureRecognizer.view!.frame.intersects(deleteBox.frame) {
            gestureRecognizer.view!.isHidden = true
            gestureRecognizer.view?.removeFromSuperview()
        } else {
            gestureRecognizer.view!.setNeedsdisplay()
            gestureRecognizer.setTranslation(.zero,in: self.view)
            gestureRecognizer.view!.transform = .identity
        }
        print(gestureRecognizer.translation(in: self.view))
        deleteBox.isHidden = true
    }
}

我想知道gestureRecognizer.state ==中视图的翻译。但是当我尝试打印视图时，它是x：0，y：0。

解决方法

每次手势处理程序调用{​​{1}}时，您都将转换回.zero。

changed

但是，当手指抬起时，状态会更改为gestureRecognizer.setTranslation(.zero,in: self.view) ，而此时的平移不再改变。 documentation说：

当用户的手指从屏幕上抬起时，手势识别器进入UIGestureRecognizer.State.ended状态。

因此翻译与上次ended调用和 changed的相同相同-并且因为您已经设置了框架ended中的gestureRecognizer.view中，您无需在changed内部进行任何操作。

,

可以从哪里调用此方法，然后将其放在viewDidAppear中并尝试。否则，请调用setNeedsDisplay和LayoutIfNeeded方法。