Question

我试图保存行的选定状态，以便当tableview加载所选行时会出现相应的复选标记。我在viewDidAppear中尝试过以下方法，但它无效。

override func viewDidAppear(animated: Bool) {

super.viewDidAppear(true)
let checkMarkToDisplay = NSUserDefaults.standardUserDefaults().valueForKey("lastSelection") as! Int
lastSelection = NSIndexPath(forRow: checkMarkToDisplay, inSection: 0)
self.tableView.cellForRowAtIndexPath(lastSelection)?.accessoryType = .Checkmark

}

var lastSelection: NSIndexPath!

override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {

if self.lastSelection != nil
{

    self.tableView.cellForRowAtIndexPath(self.lastSelection)?.accessoryType = .None
}

if indexPath.row > 0
{
    self.tableView.cellForRowAtIndexPath(indexPath)?.accessoryType = .Checkmark

    self.lastSelection = indexPath

    self.tableView.deselectRowAtIndexPath(indexPath, animated: true)
}      

NSUserDefaults.standardUserDefaults().setObject(indexPath.row, forKey: "lastSelection")

Answer 1

请在cellForRowAtIndexPath中实现您的逻辑，并从viewDidAppear中删除您的复选标记代码。

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
     let checkMarkToDisplay  =   NSUserDefaults.standardUserDefaults().valueForKey("lastSelection") as! Int

    if checkMarkToDisplay == indexPath.row{
        cell?.accessoryType = .Checkmark
    }
    else{
        cell?.accessoryType = .None
    }
}

Answer 2

将其移至viewDidLoad（）

lastSelection = NSIndexPath(forRow: checkMarkToDisplay, inSection: 0)

并删除此

self.tableView.cellForRowAtIndexPath(lastSelection)?.accessoryType = .Checkmark

然后将其添加到

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    //create the cell
    //then
    cell.accessoryType = lastSelection == indexPath ? .Checkmark : .None

    //other cell configuration

    return cell
}

将UITableView中的选定行保存到NSUserDefaults

2 个答案: