blocks|key|1481400|text|尝试按下面的方式调用becomeFirstResponder|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|1481401|[txtAddNew+performSelector:@selector(becomeFirstResponder)+withObject:nil+afterDelay:0];|code-block|syntax|javascript|1481402|按照苹果的说法，|1481403|只有当当前响应者可以辞职第一响应者状态(canResignFirstResponder)并且新的响应者可以成为第一响应者时，响应对象才会成为第一响应者。
您可以调用此方法使响应器对象(如视图)成为第一个响应程序。但是，只有当该视图是视图层次结构的一部分时，才应该对其进行调用。如果视图的window属性包含一个UIWindow对象，则它已安装在视图层次结构中；如果它返回零，则该视图将与任何层次结构分离。|blockquote|1481404|1481405|entityMap^0|A|K|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|W|8|@]|D|@]|E|$]]|$1|M|3|N|5|O|7|X|8|@]|D|@]|E|$]]|$1|P|3|-4|5|6|7|Y|8|@]|D|@]|E|$]]|$1|Q|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|R|$]]

Try calling becomeFirstResponder like below

<pre><code>[txtAddNew performSelector:@selector(becomeFirstResponder) withObject:nil afterDelay:0];
</code></pre>

As per Apple,

<blockquote>
 A responder object only becomes the first responder if the current
 responder can resign first-responder status (canResignFirstResponder)
 and the new responder can become first responder.
 
 You may call this method to make a responder object such as a view the
 first responder. However, you should only call it on that view if it
 is part of a view hierarchy. If the view’s window property holds a
 UIWindow object, it has been installed in a view hierarchy; if it
 returns nil, the view is detached from any hierarchy.
</blockquote>

blocks|key|1481452|text|Swift+3|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|1481453|这是被接受的答案的快速3版本。为了让它开始工作，我还得加点时间。|1481454|txtAddNew.perform(
++++#selector(becomeFirstResponder),+
++++with:+nil,+
++++afterDelay:+0.1
)|code-block|syntax|javascript|1481455|entityMap^0|0|7|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|R|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|S|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

Swift 3

Here is the swift 3 version of the accepted answer. For me to get it to work I also had to add a delay.

<pre><code>txtAddNew.perform(
 #selector(becomeFirstResponder), 
 with: nil, 
 afterDelay: 0.1
)
</code></pre>

blocks|key|2252114|text|我想你错过了addsubview+the+txtAddNew+to+the+Mainview|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2252115|+++txtAddNew.tag+=+15;
+++[self.view+addsubview:txtAddNew];++

+++//+Open+keyboard
++[txtAddNew+becomeFirstResponder];|code-block|syntax|javascript|2252116|entityMap^0|6|A|L|9|12|8|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|U|8|@]|D|@]|E|$]]]|L|$]]

I think you missed the <code>addsubview</code> the <code>txtAddNew</code> to the <code>Mainview</code>

<pre><code> txtAddNew.tag = 15;
 [self.view addsubview:txtAddNew]; 

 // Open keyboard
 [txtAddNew becomeFirstResponder];
</code></pre>

blocks|key|2677209|text|在代码中添加这一行。我希望它能起作用|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2677210|[txtAddNew+performSelectorOnMainThread:@selector(becomeFirstResponder)+withObject:nil+afterDelay:0.0];|code-block|syntax|javascript|2677211|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

add this line in your code . i hope it will work 

<pre><code>[txtAddNew performSelectorOnMainThread:@selector(becomeFirstResponder) withObject:nil afterDelay:0.0];
</code></pre>

blocks|key|1481467|text|Swift+4和iOS+11|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1481468|在我的情况下，无论我尝试了什么，我都无法设置第一个响应，直到我尝试了这个。|1481469|func+tableView(_+tableView:+UITableView,+willDisplay+cell:+UITableViewCell,+forRowAt+indexPath:+IndexPath)+{
++++if+cell.isKind(of:+YOURTABLEVIEWCELL.self)+{
++++++++if+let+yourCell+=+cell+as?+YOURTABLEVIEWCELL{
++++++++++++yourCell.yourUiTextField.becomeFirstResponder()
++++++++}
++++}
}|code-block|syntax|javascript|1481470|希望这能帮助那些陷入同样问题的人。|1481471|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|O|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Swift 4 and iOS 11

In my case, no mater what I tried, I was not able to set first responder until I tried this.

<pre><code>func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
 if cell.isKind(of: YOURTABLEVIEWCELL.self) {
 if let yourCell = cell as? YOURTABLEVIEWCELL{
 yourCell.yourUiTextField.becomeFirstResponder()
 }
 }
}
</code></pre>

Hope this helps someone stuck with the same problem.

blocks|key|1481421|text|有时，第一次辞职第一应答器会有所帮助：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1481422|var+tapGesture+=+UITapGestureRecognizer()
tapGesture.rac_gestureSignal().subscribeNext+{+[weak+self]+(_)+->+Void+in
++++self?.inputTextField.resignFirstResponder()
++++self?.inputTextField.becomeFirstResponder()
}

self.charViewsContainer.addGestureRecognizer(tapGesture)|code-block|syntax|javascript|1481423|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Sometimes it helps to first resign the first responder:

<pre><code>var tapGesture = UITapGestureRecognizer()
tapGesture.rac_gestureSignal().subscribeNext { [weak self] (_) -&gt; Void in
 self?.inputTextField.resignFirstResponder()
 self?.inputTextField.becomeFirstResponder()
}

self.charViewsContainer.addGestureRecognizer(tapGesture)
</code></pre>

blocks|key|1481430|text|对于iOS+9.3，以下内容适用于我：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1481431|+private+var+searchTextFieldShouldReturn+=+false

++++override+func+viewWillAppear(animated:+Bool)+{
++++++++++++super.viewWillAppear(animated)

++++++++++++self.searchTextFieldShouldReturn+=+false
++++++++++++self.searchTextField.becomeFirstResponder()
++++++++}
++++override+func+viewWillDisappear(animated:+Bool)+{
++++++++super.viewWillDisappear(animated)

++++++++self.searchTextFieldShouldReturn+=+true
++++++++self.searchTextField.resignFirstResponder()
++++}

++++func+textFieldShouldReturn(textField:+UITextField)+->+Bool+{
++++++++++++self.searchTextFieldShouldReturn+=+true
++++++++++++textField.resignFirstResponder()

++++++++++++return+true
++++++++}

++++func+textFieldShouldEndEditing(textField:+UITextField)+->+Bool+{

++++++++++++return+self.searchTextFieldShouldReturn
++++++++}|code-block|syntax|javascript|1481432|，因此您需要确保您也实现了textFieldShouldEndEditing委托.|offset|length|style|BOLD|1481433|entityMap^0|0|0|0|15|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

For iOS 9.3, the following worked for me:

<pre><code> private var searchTextFieldShouldReturn = false

 override func viewWillAppear(animated: Bool) {
 super.viewWillAppear(animated)

 self.searchTextFieldShouldReturn = false
 self.searchTextField.becomeFirstResponder()
 }
 override func viewWillDisappear(animated: Bool) {
 super.viewWillDisappear(animated)

 self.searchTextFieldShouldReturn = true
 self.searchTextField.resignFirstResponder()
 }

 func textFieldShouldReturn(textField: UITextField) -&gt; Bool {
 self.searchTextFieldShouldReturn = true
 textField.resignFirstResponder()

 return true
 }

 func textFieldShouldEndEditing(textField: UITextField) -&gt; Bool {

 return self.searchTextFieldShouldReturn
 }
</code></pre>

So You need to make sure You also implement the textFieldShouldEndEditing delegate.

blocks|key|2677332|text|万一其他人和我有同样的问题：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2677333|我有一个IBOutlet连接到我的UITextField。错误地，我在我的viewDidLoad方法中初始化它。就是，[[textField+alloc]+init];。我把这个拆了，一切又恢复了。|offset|length|style|CODE|2677334|entityMap^0|0|4|8|H|B|11|B|1N|P|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]|$D|N|E|O|F|G]|$D|P|E|Q|F|G]|$D|R|E|S|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|I|$]]

Just in case others have the same issue as me:

I had an <code>IBOutlet</code> connected to my <code>UITextField</code>. Erroneously I was initializing this in my <code>viewDidLoad</code> method. That is, <code>[[textField alloc] init];</code>. I removed this and everything worked again.

I am using UITextField's method becomeFirstResponder to show the keyboard.
This is working in iOS 7. But in iOS 8 this method doesn't show the keyboard.

<pre><code> UITextField *txtAddNew = [[UITextField alloc] initWithFrame:CGRectMake(10,10,240, 21)];
 txtAddNew.font = [UIFont fontWithName:@"Helvetica" size:16];
 txtAddNew.clearButtonMode = UITextFieldViewModeWhileEditing;
 txtAddNew.returnKeyType = UIReturnKeyDone;
 txtAddNew.delegate = self;
 txtAddNew.autocorrectionType = UITextAutocorrectionTypeNo;
 txtAddNew.tag = 15;

 // Open keyboard
 [txtAddNew becomeFirstResponder];
</code></pre>

Is there any way to do it in iOS 8?

becomeFirstResponder not working in iOS 8

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我正在使用UITextField的方法becomeFirstResponder来显示键盘。这在iOS 7中是可行的，但在iOS 8中，这种方法没有显示键盘。 UITextField *txtAddNew = [[UITextField alloc] initWithFrame:CGRectMake(10,10,240, 21)]; txtAddNew.font = [UIFont fontWith

问becomeFirstResponder不在iOS 8工作
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