ios - UIAlert 中的 unwind segue 不起作用
<p><p>如果用户需要登录才能访问某个功能,我会尝试向用户显示警报,但是当我按下警报中的登录按钮时 <code>self.self.performSegueWithIdentifier("tryonToLogin", sender:self )</code> 似乎没有做任何事情。 </p>
<p><strong>LoginViewController</strong></p>
<pre><code>@IBAction func unwindToLogin(segue:UIStoryboardSegue){
}
</code></pre>
<p><strong>UIAlert</strong></p>
<pre><code> @IBAction func goToGallery(sender: UIButton){
if(isLoggedIn){
performSegueWithIdentifier("ShowGallery", sender: sender)
}else{
showMessage("You must login to view access this feature", sender:sender)
}
}
func showMessage(popUpMessageText : String, sender:UIButton){
let messageTitle = "Error"
print("prepreform segue")
performSegueWithIdentifier("unwindToLogin", sender:sender)
let refreshAlert = UIAlertController(title: messageTitle, message: popUpMessageText, preferredStyle: UIAlertControllerStyle.Alert)
refreshAlert.addAction( UIAlertAction(title: "Login", style: .Default, handler: { (action: UIAlertAction!) in
print("Handle Login redirect logic here")
self.performSegueWithIdentifier("unwindToLogin", sender: self)
print("after Handle Login redirect logic here")
}))
refreshAlert.addAction(UIAlertAction(title: "Cancel", style: .Default, handler: { (action: UIAlertAction!) in
print("Handle Cancel logic here")
}))
presentViewController(refreshAlert, animated: true, completion: nil)
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
// Get the new view controller using segue.destinationViewController.
// Pass the selected object to the new view controller.
print("prepare for segue called")
self.camera = nil
}
</code></pre>
<p>没有错误。它被调用,好像 ii 放入一个不存在的 id 我得到 no segue with specified identifier found 错误消息。
UIAlert 是否影响 <code>performSegueWithIdentifier()</code></p> 的调用
<p>下面的帖子使用了这种方法,所以我认为它应该可以工作。我错过了什么。</p>
<p>**IB 截图**</p>
<p> <a href="/image/0uaAW.png" rel="noreferrer noopener nofollow"><img src="/image/0uaAW.png" alt="screenshot 1"/></a> </p>
<p> <a href="/image/1iJw7.png" rel="noreferrer noopener nofollow"><img src="/image/1iJw7.png" alt="enter image description here"/></a> </p>
<p><strong>编辑</strong></p>
<p>我尝试移动 <code>self.performSegueWithIdentifier("unwindToLogin", sender:self)</code> 以查看确实出现了,但它仍然无法正常工作。</p></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p> block 内的 self 是 UIAlertController,而不是 UIViewController。创建对 UIViewController 的弱引用,并调用该对象的方法。</p>
<pre><code>weak var weakSelf = self
let refreshAlert = UIAlertController(title: messageTitle, message: popUpMessageText, preferredStyle: UIAlertControllerStyle.Alert)
refreshAlert.addAction( UIAlertAction(title: "Login", style: .Default, handler: { (action: UIAlertAction!) in
print("Handle Login redirect logic here")
dispatch_async(dispatch_get_main_queue()) {
weakSelf?.performSegueWithIdentifier("unwindToLogin", sender:self)
}
}))
</code></pre></p>
<p style="font-size: 20px;">关于ios - UIAlert 中的 unwind segue 不起作用,我们在Stack Overflow上找到一个类似的问题:
<a href="https://stackoverflow.com/questions/37571817/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/37571817/
</a>
</p>
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