ios - Segue 可选值 nil
<p><pre><code>func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let newuser = users
let usernname = newuser.name! as String
print(usernname)
print(keys)
let destinationViewController = ChatViewController()
destinationViewController.toUid = keys
destinationViewController.topBar.title = usernname
performSegue(withIdentifier: "toChatView", sender: self)
}
</code></pre>
<p>keys 工作正常，但用户名有错误。它说</p>
<pre><code>fatal error: unexpectedly found nil while unwrapping an Optional value
</code></pre>
<p>但是当我打印我的 <code>username</code> 变量时，它会打印出来</p></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p>你需要检查用户名是否为 nil </p>
<pre><code>let usernname = newuser.name! as String
let destinationViewController = ChatViewController()
destinationViewController.toUid = keys
if username != nil { // check if this is nil or not
print(usernname)
print(keys)
destinationViewController.topBar.title = usernname
performSegue(withIdentifier: "toChatView", sender: self)
}
</code></pre></p>
<p style="font-size: 20px;">关于ios - Segue 可选值 nil，我们在Stack Overflow上找到一个类似的问题：
<a href="https://stackoverflow.com/questions/39848319/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/39848319/
</a>
</p>
页:
[1]