在SWIFT中滚动时，我的表视图重用所选单元格 [英] my table view reuse the selected cells when scroll -- in SWIFT

问题描述

早上好

我的问题是当我向下和向上滚动时，我的表视图重用了所选的单元格...我的意思是当我从上面选择一个单元格时向下滚动，我没有选择的一些单元格被选中，当我再次向上滚动时，一些选中的单元格也没有被选中，当发生这种情况时，我再次选择苹果，不仅仅选择一个不允许的单元格。我想提一下，我试图从'didSelectRowAtIndexPath'保存旧的索引路径，我在'CellForRowAtIndexPath'中检查它，但它不起作用：

my problem is that my table view reuse the selected cell when i scroll down and up again .. i mean when i select one cell from up then scroll down, some cells which i didnt select are shown selected, also some selected cells from up are not showed selected when i scroll up again, and when that happened i am apple again to select more than just one cell which must be not allowed .. i want to mention that i tried to save the old index path from 'didSelectRowAtIndexPath'and i checked it like this in the 'CellForRowAtIndexPath'but it doesnt work :

if (old == indexpath)
{
        cell?.backgroundColor = UIColor.redColor()
        cell?.textLabel?.backgroundColor = UIColor.whiteColor() //to change only the thumbnail color and keep the cell color 
}

else {
        cell?.backgroundColor = UIColor.whiteColor()
}

现在这里是我的代码

 func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    var cell = myTable.dequeueReusableCellWithIdentifier("WorkCell") as UITableViewCell
    cell.tag = (indexPath.row) + 1
    cell.textLabel?.text = Berufs[indexPath.row]
    var img = UIImageView(frame: CGRect(x: 10, y: 3, width: 40 , height: 40))
    cell.selectionStyle = UITableViewCellSelectionStyle.None
    img.image = UIImage(named: "transparent.png")
    cell.indentationLevel = 1
    cell.indentationWidth = 45
    cell.addSubview(img)
    return cell
}

var old = 1000

func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath)
{
    let indexPath = tableView.indexPathForSelectedRow()
    let cell = tableView.cellForRowAtIndexPath(indexPath!)
    var tmpCell = view.viewWithTag(old)
    var rowNum = (cell?.tag)! - 1

    if (cell?.backgroundColor == UIColor.redColor())
    {
        cell?.backgroundColor = UIColor.whiteColor()
    }
    else if (cell?.backgroundColor != UIColor.redColor())
    {
        tmpCell?.backgroundColor = UIColor.whiteColor()
        cell?.backgroundColor = UIColor.redColor()
        cell?.textLabel?.backgroundColor = UIColor.whiteColor()

        println("du interssiert dich für \(Berufs[rowNum])")
    }

    old = rowNum + 1

}

推荐答案

您当前将选择状态存储在backgroundColor中。这不是一个好主意，因为出于性能原因，tableView将重用单元格。

You currently store the selection state in the backgroundColor. That's not a good idea because for performance reasons cells will be reused by the tableView.

您应该将选定的indexPath保存在数据模型中。如果要允许多个选择，可以将选定的indexPath存储在NSMutableSet中。

You should save the selected indexPaths in the data model. If you want to allow multiple selection you can store the selected indexPaths in a NSMutableSet.

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as UITableViewCell
    cell.selectionStyle = .None
    configure(cell, forRowAtIndexPath: indexPath)
    return cell
}

var selectedIndexPaths = NSMutableSet()

func configure(cell: UITableViewCell, forRowAtIndexPath indexPath: NSIndexPath) {
    cell.textLabel!.text = "Row \(indexPath.row)"
    if selectedIndexPaths.containsObject(indexPath) {
        // selected
        cell.backgroundColor = UIColor.redColor()
    }
    else {
        // not selected
        cell.backgroundColor = UIColor.whiteColor()
    }
}


override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
    if selectedIndexPaths.containsObject(indexPath) {
        // deselect
        selectedIndexPaths.removeObject(indexPath)
    }
    else {
        // select
        selectedIndexPaths.addObject(indexPath)
    }
    let cell = tableView.cellForRowAtIndexPath(indexPath)!
    configure(cell, forRowAtIndexPath: indexPath)
}

如果你只需要单选，你应该在NSIndexPath中保存选定的indexPath？实例变量

If you only need single selection you should save the selected indexPath in an NSIndexPath? instance variable

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as UITableViewCell
    cell.selectionStyle = .None
    configure(cell, forRowAtIndexPath: indexPath)
    return cell
}

var selectedIndexPath: NSIndexPath?

func configure(cell: UITableViewCell, forRowAtIndexPath indexPath: NSIndexPath) {
    cell.textLabel!.text = "Row \(indexPath.row)"
    if selectedIndexPath == indexPath {
        // selected
        cell.backgroundColor = UIColor.redColor()
    }
    else {
        // not selected
        cell.backgroundColor = UIColor.whiteColor()
    }
}

override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
    if selectedIndexPath == indexPath {
        // selected same cell -> deselect all
        selectedIndexPath = nil
    }
    else {
        // select different cell
        let oldSelectedIndexPath = selectedIndexPath
        selectedIndexPath = indexPath

        // refresh old cell to clear old selection indicators
        var previousSelectedCell: UITableViewCell?
        if let previousSelectedIndexPath = oldSelectedIndexPath {
            if let previousSelectedCell = tableView.cellForRowAtIndexPath(previousSelectedIndexPath) {
                configure(previousSelectedCell, forRowAtIndexPath: previousSelectedIndexPath)
            }
        }
    }
    let selectedCell = tableView.cellForRowAtIndexPath(indexPath)!
    configure(selectedCell, forRowAtIndexPath: indexPath)
}

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