Swift - whose view is not in the window hierarchy 问题解决方法

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问题现象: 想在页面初始化的时候,使用self.presentViewController方法弹出个告警提示框UIAlertController。但行后报了个如下告警,同时告警框也出不来。
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2015 - 03 10 09 : 55 34.197 Test[ 1140 29622 ] Warning: Attempt to present <UIAlertController: 0x7c95ca20 > on <Test.ViewController: 0x7a6afc60 > whose view is not in the window hierarchy!

@H_404_59@解决办法: 原来的调用代码是写在viewDidLoad方法中,这个表示视图加载完毕。我们应该把方法调用放到viewDidApper中,这个是UIViewController对象的视图已经加入到窗口时调用
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import UIKit
class ViewController : UIViewController , UIActionSheetDelegate {
override func viewDidLoad() {
super .viewDidLoad()
}
viewDidAppear(animated: Bool ){
.viewDidAppear(animated)
var alertController = UIAlertController (title: "系统提示" message: "您确定要离开hangge.com吗?" UIAlertControllerStyle . Alert )
cancelAction = UIAlertAction "取消" UIAlertActionStyle Cancel nil )
okAction = "好的" Default )
alertController.addAction(cancelAction)
alertController.addAction(okAction)
self .presentViewController(alertController,animated: true )
}
didReceiveMemoryWarning() {
.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}

原文出自: www.hangge.com 转载请保留原文链接 http://www.hangge.com/blog/cache/detail_652.html

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