好吧,我被卡住了。我遇到了一个棘手的问题,要让我的自定义表视图单元格分段到Master-Detail应用程序的"details"部分,而另一篇StackOverflow帖子通过调用prepareForSegue函数解决了这个问题。我仍然没有得到预期的结果,我发现了一个大问题:将单元格的属性传递到详细信息部分需要选择一个单元格,而该帖子中的代码会在segue之前取消选择该单元格。这似乎是一个简单的修复方法,但当我删除那一行时,当我点击一个单元格时,程序崩溃了。我真的不知道在这里该怎么办(我的iOS体验100%来自过去48小时),我希望这里有人能帮忙。
涉及代码:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "showDetail" {
if let indexPath = self.tableView.indexPathForSelectedRow {
let object = objects[indexPath.row]
let controller = (segue.destinationViewController as! UINavigationController).topViewController as! DetailViewController
controller.detailItem = object
controller.navigationItem.leftBarButtonItem = self.splitViewController?.displayModeButtonItem()
controller.navigationItem.leftItemsSupplementBackButton = true
}
}
}
override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
let cell = tableView.cellForRowAtIndexPath(indexPath)
tableView.deselectRowAtIndexPath(indexPath, animated: false) // What appears to be the problem
performSegueWithIdentifier("showDetail", sender: cell)
}
错误(当我删除取消选择行时):
fatal error: unexpectedly found nil while unwrapping an Optional value (lldb)
(在编辑器中弹出:THREAD 1:EXC_BREAKPOINT)
感谢所有的帮助。
您可以尝试这样放置代码:
override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
let cell = tableView.cellForRowAtIndexPath(indexPath)
performSegueWithIdentifier("showDetail", sender: cell)
tableView.deselectRowAtIndexPath(indexPath, animated: false) // What appears to be the problem
}
但我认为最好是在didSelectRowAtIndexpath
中获得要发送到下一个屏幕的对象,并将其传递给performSegue
,如下所示:
override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
let object = objects[indexPath.row]
performSegueWithIdentifier("showDetail", sender: object)
tableView.deselectRowAtIndexPath(indexPath, animated: false)
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "showDetail" {
if let object = sender as! "type of object" {
let controller = (segue.destinationViewController as! UINavigationController).topViewController as! DetailViewController
controller.detailItem = object
controller.navigationItem.leftBarButtonItem = self.splitViewController?.displayModeButtonItem()
controller.navigationItem.leftItemsSupplementBackButton = true
}
}
}
希望得到帮助!