我的表格有一个拖放功能(下面的代码)，效果很好。除了，我无法将单元格拖到屏幕上/ View 中未显示的位置。
换句话说，我还没有弄清楚如何让它自动滚动。
是否有人能够查看我的代码并知道在何处添加代码以在用户将单元格拖动到 View 的顶部或底部时启用自动滚动？
func animateCellDrag (gestureRecognizer: UIGestureRecognizer, tableView: UITableView, whichList: String) {
let longPress = gestureRecognizer as! UILongPressGestureRecognizer
let state = longPress.state
var locationInView = longPress.locationInView(tableView)
var indexPath = tableView.indexPathForRowAtPoint(locationInView)
var count = 0
struct My {
static var cellSnapshot : UIView? = nil
}
struct Path {
static var initialIndexPath : NSIndexPath? = nil
}
if indexPath != nil {
//Steps to take a cell snapshot. Function to be called in switch statement
func snapshotOfCell(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
}
switch state {
case UIGestureRecognizerState.Began:
//Calls above function to take snapshot of held cell, animate pop out
//Run when a long-press gesture begins on a cell
if indexPath != nil {
Path.initialIndexPath = indexPath
let cell = tableView.cellForRowAtIndexPath(indexPath!) as UITableViewCell!
My.cellSnapshot = snapshotOfCell(cell)
var center = cell.center
My.cellSnapshot!.center = center
My.cellSnapshot!.alpha = 0.0
tableView.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:
if My.cellSnapshot != nil || indexPath != nil {
//Runs when the user "lets go" of the cell
//Sets CG Y-Coordinate of snapshot cell to center of current location in table (snaps into place)
var center = My.cellSnapshot!.center
center.y = locationInView.y
My.cellSnapshot!.center = center
let appDel: AppDelegate = (UIApplication.sharedApplication().delegate as! AppDelegate)
let context: NSManagedObjectContext = appDel.managedObjectContext!
let fetchRequest = NSFetchRequest(entityName: whichList)
let sortDescriptor = NSSortDescriptor(key: "displayOrder", ascending: true )
fetchRequest.sortDescriptors = [ sortDescriptor ]
//If the indexPath is not 0 AND is not the same as it began (didn't move): Update array and table row order
if ((indexPath != nil) && (indexPath != Path.initialIndexPath) && (indexPath?.row < taskList_Cntxt.count)) {
switch whichList {
case "TodayTask", "TomTask", "TBDTask", "FinTask":
swap(&taskList_Cntxt[indexPath!.row], &taskList_Cntxt[Path.initialIndexPath!.row])
tableView.moveRowAtIndexPath(Path.initialIndexPath!, toIndexPath: indexPath!)
toolBox.updateDisplayOrder()
default:
swap(&curLifeList_Context[indexPath!.row], &curLifeList_Context[Path.initialIndexPath!.row])
tableView.moveRowAtIndexPath(Path.initialIndexPath!, toIndexPath: indexPath!)
toolBox.llvc_updateDisplayOrder()
}
do {
try context.save()
} catch _ { print("Drag and drop error. State: Changed")}
Path.initialIndexPath = indexPath
}
}
default:
if My.cellSnapshot != nil || indexPath != nil {
//Runs continuously while a long press is recognized / Animates cell movement
let cell = tableView.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 {
//Completion block removes snapshot of cell, cleans everything up
Path.initialIndexPath = nil
My.cellSnapshot!.removeFromSuperview()
My.cellSnapshot = nil
}
})//End of competion block & end of animation
}//End of 'if nil'
}//End of switch
}//End of longPress if-nil
}//End of longPressGestureRecognized
最佳答案
我能够使用这段代码解决它:
if locationOnScreen.y < 200 && indexPath!.row > 1 {
let indexPath = NSIndexPath(forRow: indexPath!.row-1, inSection: 0)
tableView.scrollToRowAtIndexPath(indexPath, atScrollPosition: UITableViewScrollPosition.Top, animated: false)
} else if locationOnScreen.y > 550 && indexPath!.row < listCount {
let indexPath = NSIndexPath(forRow: indexPath!.row+1, inSection: 0)
tableView.scrollToRowAtIndexPath(indexPath, atScrollPosition: UITableViewScrollPosition.Bottom, animated: false)
}
地点:
var locationOnScreen = longPress.locationInView(tableView.superview)
listCount = listArrayOrContext.count
插入开关盒:
case UIGestureRecognizerState.Changed:
我将 animate 设置为 false，否则我会得到非常不稳定、困惑的滚动。如果有人知道如何获得缓慢、渐进的滚动，请发布。
关于ios - 拖放工作 - 自动滚动不，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/35130028/