我如何使用CGAffineTransform进行正确的拖放

Question

我想通过UIPanGestureRecognizer对UITextView进行拖放，并在屏幕中心进行自动对齐。对于第一次拖动，它的效果很好，但是如果我再次尝试，则拖动将从UITextView的初始化点开始。我不知道如何解决。

第一次拖动

第二次拖动

@objc func handlePan(gesture: UIPanGestureRecognizer) {
    let translation = gesture.translation(in: nil)

    switch gesture.state {
    case .changed:
        dragingText.transform = CGAffineTransform(translationX: translation.x, y: translation.y)

    case .ended:

        UIView.animate(withDuration: 1, delay: 0, usingSpringWithDamping: 1, initialSpringVelocity: 1, options: .curveEaseOut, animations: {

            self.dragingText.transform = CGAffineTransform(translationX: 0, y: translation.y)

        }, completion: nil)
    default:
        ()
    }
}

Answer 1

CGAffine转换对于您的任务不是必需的。试试：

情况已更改： textview.center = CGPoint（x：textview.x + translation.x，                 y：textview.y + translation.y）

Answer 2

解决了一个问题

 @objc func handlePan(gesture: UIPanGestureRecognizer) {
    let translation = gesture.translation(in: nil)

    switch gesture.state {
    case .changed:

        dragingText.center = CGPoint(x: dragingText.center.x + translation.x, y: dragingText.center.y + translation.y )
        gesture.setTranslation(CGPoint.zero, in: nil)

    case .ended:

        let isInside = isInsideDragableAres()

        if isInside.0 {
            UIView.animate(withDuration: 0.7, delay: 0, usingSpringWithDamping: 0.4, initialSpringVelocity: 0.7, options: .curveEaseOut, animations: {
                self.dragingText.center = CGPoint(x: self.view.center.x, y: self.dragingText.center.y + translation.y )
            }, completion: nil)
        }
        else{
            UIView.animate(withDuration: 0.7, delay: 0, usingSpringWithDamping: 0.4, initialSpringVelocity: 0.7, options: .curveEaseOut, animations: {
                self.dragingText.center = CGPoint(x: self.view.center.x, y: isInside.1! )
            }, completion: nil)
        }

    default:
        ()
    }
}