如何拖动UIView元素并更改位置？

Question

我正在开发一个iOS应用程序，允许用户创建表格。 窗体具有堆叠在UIScrollView中的许多UIView元素。 就编辑而言，UIView应该可以更改顺序。

我该如何实现？ 我想拖动任何UIView组件并将其移动到窗体中的任何位置。 例如。 持有第三个元素将激活自己移动。 将其移动到第二个元素将替换其位置。 我正在使用平移手势来移动UIViews。 现在我如何知道是否在任何UIView顶部都到达了轻击视图？

Answer 1

据我了解您的要求，您希望用户能够移动/重新定位某些UIView，例如在父视图中拖放。

我建议您使用启用了交互式运动的collectionView 。 如果要使用某些库，则可以尝试https://github.com/ra1028/RAReorderableLayout

或者对于UIView拖放实现，您可以查看以下https://blog.apoorvmote.com/uipangesturerecognizer-to-make-draggable-uiview-in-ios-swift/

Answer 2

UICollectionViewController的几个简单选项可以通过canMoveItemAt委托方法轻松处理，如果您有视图控制器，则可以通过以下方式尝试：

import UIKit

class LoveProfileEditViewViewController: BaseViewController {
    fileprivate var longPressGesture:UILongPressGestureRecognizer!
    @IBOutlet var theCollectionView:UICollectionView!
    public var items:[String]!

    override func viewDidLoad() {
        super.viewDidLoad()
        let horizontalLayout = UICollectionViewFlowLayout()
        horizontalLayout.scrollDirection = .horizontal
        self.theCollectionView.collectionViewLayout = horizontalLayout
        self.theCollectionView.register(UINib(nibName: "SomeNibName", bundle: nil), forCellWithReuseIdentifier: "Some Identifier")
        self.longPressGesture = UILongPressGestureRecognizer(target: self, action: #selector(self.handleLongGesture(gesture:)))
        self.theCollectionView.addGestureRecognizer(longPressGesture)
    }

    fileprivate func moveDataItem(_ sIndex: Int, _ dIndex: Int) {
        let item = self.items.remove(at: sIndex)
        self.items.insert(item, at:dIndex)
        self.theCollectionView.reloadData()
    }

    @objc private func handleLongGesture(gesture: UILongPressGestureRecognizer) {
        switch(gesture.state) {
        case UIGestureRecognizerState.began:
            guard let selectedIndexPath = self.theCollectionView.indexPathForItem(at: gesture.location(in: self.theCollectionView)) else {
                break
            }
            self.theCollectionView.beginInteractiveMovementForItem(at: selectedIndexPath)

        case UIGestureRecognizerState.changed:
            guard let selectedIndexPath = self.theCollectionView.indexPathForItem(at: gesture.location(in: self.theCollectionView)) else {
                break
            }
            self.theCollectionView?.updateInteractiveMovementTargetPosition(gesture.location(in: gesture.view!))

        case UIGestureRecognizerState.ended:
            self.theCollectionView.endInteractiveMovement()
        default:
            self.theCollectionView.cancelInteractiveMovement()
        }
    }

}

// MARK: - UICollectionViewDelegateFlowLayout
extension LoveProfileEditViewViewController: UICollectionViewDelegateFlowLayout {

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        return CGSize(width: 88.0, height: collectionView.bounds.size.height)
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
        return UIEdgeInsetsMake(0.0, 5.0, 0.0, 5.0)
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return 10.0
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
        return 10.0
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize {
        return .zero
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForFooterInSection section: Int) -> CGSize {
        return .zero
    }
}

// MARK: - UICollectionViewDataSource
extension LoveProfileEditViewViewController: UICollectionViewDataSource {
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return self.items.count
    }

    func collectionView(_ collectionView: UICollectionView, canMoveItemAt indexPath: IndexPath) -> Bool {
        //set boolean as per your need
        return true
    }

    func collectionView(_ collectionView: UICollectionView, moveItemAt sourceIndexPath: IndexPath, to destinationIndexPath: IndexPath) {
        if sourceIndexPath.row > 0 && destinationIndexPath.row > 0 {
            self.moveDataItem(sourceIndexPath.row, destinationIndexPath.row)
        }
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Some Identifier", for: indexPath) as! SomeNibName
        cell.textLabel.text = self.items[indexPath.row]
        return cell
    }
}

Answer 3

UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
[button addTarget:self action:@selector(imageTouch:withEvent:) 
forControlEvents:UIControlEventTouchDown];
[button addTarget:self action:@selector(imageMoved:withEvent:) 
forControlEvents:UIControlEventTouchDragInside];
[button setImage:[UIImage imageNamed:@"vehicle.png"] 
forState:UIControlStateNormal];
[self.view addSubview:button];

然后，您可以通过响应UIControlEventTouchDragInside事件，将车辆移动到所需的位置，例如：

 - (IBAction) imageMoved:(id) sender withEvent:(UIEvent *) event
 {
CGPoint point = [[[event allTouches] anyObject] locationInView:self.view];
UIControl *control = sender;
control.center = point;
}