折腾：
［已解决］swift编辑和删除UICollectionViewCell
之后，加了：
else if selectedContactItem.id == removePersonId { self.isRemoveMode = !self.isRemoveMode print("self.isRemoveMode=\(self.isRemoveMode)") self.collectionView.reloadData() } |
然后重新让cell绘图，结果cell出现重叠内容：
1.尝试了：
// let cell:UICollectionViewCell = collectionView.dequeueReusableCellWithReuseIdentifier(StrIdConversationManageCollectionViewCell, forIndexPath: indexPath) let cell:UICollectionViewCell = UICollectionViewCell() |
不行，会出错：
Assertion failure in -[UICollectionView _createPreparedCellForItemAtIndexPath:withLayoutAttributes:applyAttributes:isFocused:], /BuildRoot/Library/Caches/com.apple.xbs/Sources/UIKit_Sim/UIKit-3512.30.14/UICollectionView.m:1520 2015-12-25 14:02:41.755 JianDao[28445:1291040] *** Terminating app due to uncaught exception ‘NSInternalInconsistencyException’, reason: ‘the cell returned from -collectionView:cellForItemAtIndexPath: does not have a reuseIdentifier – cells must be retrieved by calling -dequeueReusableCellWithReuseIdentifier:forIndexPath:’ |
2.试了试：
调整布局，把之前的，手动计算frame的，都换成constraint的：
if let contactItem = getContactItem(indexPath) { let contactImage = contactItem.headerImageLarge let contactImageView:UIImageView = UIImageView(image: contactImage) // contactImageView.center.x = cell.contentView.center.x cell.contentView.addSubview(contactImageView) // cell.addSubview(contactImageView) constrain(contactImageView, cell) { contactImageView, cell in contactImageView.top == cell.top contactImageView.centerX == cell.centerX } if !isSperialItem(contactItem) { // let nameLabelFrame = CGRectMake(0, contactImage.size.height + collectionViewCellPaddingY, contactImage.size.width, collectionViewCellNameLabelHeight) // let nameLabel:UILabel = UILabel(frame: nameLabelFrame) let nameLabel:UILabel = UILabel() nameLabel.text = contactItem.name nameLabel.textAlignment = NSTextAlignment.Center nameLabel.font = UIFont.systemFontOfSize(12) cell.contentView.addSubview(nameLabel) constrain(nameLabel, cell) { nameLabel, cell in nameLabel.bottom == cell.bottom nameLabel.centerX == cell.centerX } if isRemoveMode { //here is got reusable cell, not draw it again, just need add extra delete button let removeBadgeButton:UIButton = UIButton() removeBadgeButton.setBackgroundImage(UIImage(named: "remove_badge"), forState: UIControlState.Normal) removeBadgeButton.tag = indexPath.row removeBadgeButton.addTarget(self, action: Selector("removeSelectedPerson:"), forControlEvents: UIControlEvents.TouchUpInside) cell.contentView.addSubview(removeBadgeButton) constrain(removeBadgeButton, cell) { removeBadgeButton, cell in removeBadgeButton.left == cell.right – 10 removeBadgeButton.top == cell.top – 5 } } } } |
结果问题依旧。
3.把字视图都加到cell，而不是cell.contentView上：
cell.contentView.addSubview(removeBadgeButton) |
都换成：
cell.addSubview(removeBadgeButton) |
也还是不行。
4.此时已经意识到了：
是由于用了：
let cell:UICollectionViewCell = collectionView.dequeueReusableCellWithReuseIdentifier(StrIdConversationManageCollectionViewCell, forIndexPath: indexPath) |
的dequeueReusableCellWithReuseIdentifier
所以cell都是复用了
－》之前已经存在的cell，会被随机获得拿来复用
－》导致之前的cell中还有头像图片，还有nameLabel
－》所以此处要去删除掉已有的字视图，再重新绘制，即可：
5.后来再去优化，解决，当已经处于remove模式时，点击减号，结果之前加的remove button，却还保留，的问题。
6.最终代码是：
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell { print("ConversationManageViewController cellForItemAtIndexPath") let cell:UICollectionViewCell = collectionView.dequeueReusableCellWithReuseIdentifier(StrIdConversationManageCollectionViewCell, forIndexPath: indexPath) // if isRemoveMode { //remove previous added subview // isRemoveMode==true: header image, name label // isRemoveMode==false: header image, name label, remove button //otherwise will cause overlapp namelabel let prevAddedSubViews = cell.contentView.subviews // print("prevAddedSubViews=\(prevAddedSubViews)") for eachPreAddedSubView in prevAddedSubViews { eachPreAddedSubView.removeFromSuperview() } // } if let contactItem = getContactItem(indexPath) { let contactImage = contactItem.headerImageLarge let contactImageView:UIImageView = UIImageView(image: contactImage) cell.contentView.addSubview(contactImageView) constrain(contactImageView, cell) { contactImageView, cell in contactImageView.top == cell.top contactImageView.centerX == cell.centerX } if !isSperialItem(contactItem) { let nameLabel:UILabel = UILabel() nameLabel.text = contactItem.name nameLabel.textAlignment = NSTextAlignment.Center nameLabel.font = UIFont.systemFontOfSize(12) cell.contentView.addSubview(nameLabel) constrain(nameLabel, cell) { nameLabel, cell in nameLabel.bottom == cell.bottom nameLabel.centerX == cell.centerX } constrain(nameLabel, contactImageView) { nameLabel, contactImageView in nameLabel.top == contactImageView.bottom + collectionViewCellPaddingY } // constrain(nameLabel, contactImageView) { nameLabel, contactImageView in // distribute(by: 10, vertically: nameLabel, contactImageView) // } if isRemoveMode { //here is got reusable cell, not draw it again, just need add extra delete button let removeBadgeButton:UIButton = UIButton() removeBadgeButton.setBackgroundImage(UIImage(named: "remove_badge"), forState: UIControlState.Normal) removeBadgeButton.tag = indexPath.row removeBadgeButton.addTarget(self, action: Selector("removeSelectedPerson:"), forControlEvents: UIControlEvents.TouchUpInside) cell.contentView.addSubview(removeBadgeButton) constrain(removeBadgeButton, cell) { removeBadgeButton, cell in removeBadgeButton.left == cell.right – 10 removeBadgeButton.top == cell.top – 5 } } } } return cell } … … dispatch_async(dispatch_get_main_queue(), { () -> Void in self.deleteContactItem(indexPath) self.collectionView.deleteItemsAtIndexPaths([indexPath]) }) } |
效果是：
再去点击减号，即可还原：
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