【发布时间】：2015-03-08 17:04:48
【问题描述】：
我一直在尝试使用本指南创建拖放操作http://www.freshconsulting.com/create-drag-and-drop-uitableview-swift/
这是我在 viewdidload 中的代码
let longpress = UILongPressGestureRecognizer(target: self, action: "longPressGestureRecognized:")
longpress.minimumPressDuration = 1.0
table.addGestureRecognizer(longpress)
还有函数
func longPressGestureRecognized(gestureRecognizer: UILongPressGestureRecognizer) {
func snapshopOfCell(inputView: UIView) -> UIView {
UIGraphicsBeginImageContextWithOptions(inputView.bounds.size, false, 0.0)
inputView.layer.renderInContext(UIGraphicsGetCurrentContext())
let image = UIGraphicsGetImageFromCurrentImageContext() as UIImage
UIGraphicsEndImageContext()
let cellSnapshot : UIView = UIImageView(image: image)
cellSnapshot.layer.masksToBounds = false
cellSnapshot.layer.cornerRadius = 0.0
cellSnapshot.layer.shadowOffset = CGSizeMake(-5.0, 0.0)
cellSnapshot.layer.shadowRadius = 5.0
cellSnapshot.layer.shadowOpacity = 0.4
return cellSnapshot
}
let longPress = gestureRecognizer as UILongPressGestureRecognizer
let state = longPress.state
var locationInView = longPress.locationInView(table)
var indexPath = table.indexPathForRowAtPoint(locationInView)
struct My {
static var cellSnapshot : UIView? = nil
}
struct Path {
static var initialIndexPath : NSIndexPath? = nil
}
switch state {
case UIGestureRecognizerState.Began:
if indexPath != nil {
Path.initialIndexPath = indexPath
let cell = table.cellForRowAtIndexPath(indexPath!) as UITableViewCell!
My.cellSnapshot = snapshopOfCell(cell)
var center = cell.center
My.cellSnapshot!.center = center
My.cellSnapshot!.alpha = 0.0
table.addSubview(My.cellSnapshot!)
UIView.animateWithDuration(0.25, animations: { () -> Void in
center.y = locationInView.y
My.cellSnapshot!.center = center
My.cellSnapshot!.transform = CGAffineTransformMakeScale(1.05, 1.05)
My.cellSnapshot!.alpha = 0.98
cell.alpha = 0.0
}, completion: { (finished) -> Void in
if finished {
cell.hidden = true
}
})
}
case UIGestureRecognizerState.Changed:
var center = My.cellSnapshot!.center
center.y = locationInView.y
My.cellSnapshot!.center = center
if ((indexPath != nil) && (indexPath != Path.initialIndexPath)) {
swap(&cellContent[indexPath!.row], &cellContent[Path.initialIndexPath!.row])
table.moveRowAtIndexPath(Path.initialIndexPath!, toIndexPath: indexPath!)
Path.initialIndexPath = indexPath
}
default:
let cell = table.cellForRowAtIndexPath(Path.initialIndexPath!) as UITableViewCell!
cell.hidden = false
cell.alpha = 0.0
UIView.animateWithDuration(0.25, animations: { () -> Void in
My.cellSnapshot!.center = cell.center
My.cellSnapshot!.transform = CGAffineTransformIdentity
My.cellSnapshot!.alpha = 0.0
cell.alpha = 1.0
}, completion: { (finished) -> Void in
if finished {
Path.initialIndexPath = nil
My.cellSnapshot!.removeFromSuperview()
My.cellSnapshot = nil
}
})
}
}
问题是在单元格上长按时会崩溃。
错误代码：longPressGestureRecognized:]：无法识别的选择器发送到实例 0x79a3b110'
其他一切都很好，比如删除单元格内容等。
提前致谢！
【问题讨论】：
标签： swift drag-and-drop tableview cell