blocks|key|3276752|text|在文本字段实际更改其文本之前，-shouldChangeCharactersInRange被调用为，这就是为什么您将获得旧的文本值。要在更新后获取文本，请使用以下命令：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|BOLD|entityRanges|data|3276753|[textField2+setText:[textField1.text+stringByReplacingCharactersInRange:range+withString:string]];|code-block|syntax|javascript|3276754|entityMap^0|F|U|1D|Z|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]|$9|Q|A|R|B|D]]|E|@]|F|$]]|$1|G|3|H|5|I|7|S|8|@]|E|@]|F|$J|K]]|$1|L|3|-4|5|6|7|T|8|@]|E|@]|F|$]]]|M|$]]

<code>-shouldChangeCharactersInRange</code> gets called before text field actually changes its text, that's why you're getting old text value. To get the text after update use:

<pre><code>[textField2 setText:[textField1.text stringByReplacingCharactersInRange:range withString:string]];
</code></pre>

blocks|key|3276774|text|尝试使用UITextField的"Editing+Changed"事件，而不是使用UITextFieldDelegate。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3276775|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/388237/getting-the-value-of-a-uitextfield-as-keystrokes-are-entered^0|G|H|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

Instead of using the UITextFieldDelegate, try to use <a href="https://stackoverflow.com/questions/388237/getting-the-value-of-a-uitextfield-as-keystrokes-are-entered">"Editing Changed"</a> event of UITextField.

blocks|key|317315|text|这就是你需要的代码|type|unstyled|depth|inlineStyleRanges|entityRanges|data|317316|if+([textField+isEqual:self.textField1])
++textField2.text+=+[textField1.text+stringByReplacingCharactersInRange:range+withString:string];|code-block|syntax|javascript|317317|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|$]]

This is the code you need,

<pre><code>if ([textField isEqual:self.textField1])
 textField2.text = [textField1.text stringByReplacingCharactersInRange:range withString:string];
</code></pre>

blocks|key|315266|text|-(BOOL)textField:(UITextField+*)textField+shouldChangeCharactersInRange:(NSRange)range+replacementString:(NSString+*)string
{
++++NSString+*+searchStr+=+[textField.text+stringByReplacingCharactersInRange:range+withString:string];

++++NSLog(@"%25@",searchStr);
++++return+YES;
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|315267|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
 NSString * searchStr = [textField.text stringByReplacingCharactersInRange:range withString:string];

 NSLog(@"%@",searchStr);
 return YES;
}
</code></pre>

blocks|key|315280|text|我的解决方案是使用UITextFieldTextDidChangeNotification。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|315281|[[NSNotificationCenter+defaultCenter]+addObserver:self+selector:@selector(copyText:)+name:UITextFieldTextDidChangeNotification+object:nil];|code-block|syntax|javascript|315282|别忘了在dealloc方法中调用[[NSNotificationCenter+defaultCenter]+removeObserver:self];。|315283|entityMap^0|9|10|0|0|4|7|G|1N|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|X|8|@]|D|@]|E|$]]]|N|$]]

My solution is to use <code>UITextFieldTextDidChangeNotification</code>.

<pre><code>[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(copyText:) name:UITextFieldTextDidChangeNotification object:nil];
</code></pre>

Don't forget to call <code>[[NSNotificationCenter defaultCenter] removeObserver:self];</code> in <code>dealloc</code> method.

blocks|key|3063830|text|它的Swift版本:|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|3063831|func+textField(textField:+UITextField,+shouldChangeCharactersInRange+range:+NSRange,+replacementString+string:+String)+->+Bool+{

++++if+string+==+"+"+{
++++++++return+false
++++}

++++let+userEnteredString+=+textField.text

++++var+newString+=+(userEnteredString!+as+NSString).stringByReplacingCharactersInRange(range,+withString:+string)+as+NSString

++++print(newString)

++++return+true
}|code-block|syntax|javascript|3063832|entityMap^0|2|8|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

Swift version for it :

<pre><code>func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -&gt; Bool {

 if string == " " {
 return false
 }

 let userEnteredString = textField.text

 var newString = (userEnteredString! as NSString).stringByReplacingCharactersInRange(range, withString: string) as NSString

 print(newString)

 return true
}
</code></pre>

blocks|key|317368|text|使用防护|type|unstyled|depth|inlineStyleRanges|entityRanges|data|317369|func+textField(textField:+UITextField,+shouldChangeCharactersInRange+range:+NSRange,+replacementString+string:+String)+->+Bool+{
++++++++guard+case+let+textFieldString+as+NSString+=+textField.text+where
++++++++++++textFieldString.stringByReplacingCharactersInRange(range,+withString:+string).length+<=+maxLength+else+{
++++++++++++++++return+false
++++++++}
++++++++return+true
++++}|code-block|syntax|javascript|317370|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|$]]

use guard 

<pre><code>func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -&gt; Bool {
 guard case let textFieldString as NSString = textField.text where
 textFieldString.stringByReplacingCharactersInRange(range, withString: string).length &lt;= maxLength else {
 return false
 }
 return true
 }
</code></pre>

blocks|key|3063880|text|Swift+3|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3063881|根据接受的答案，以下内容应适用于Swift+3|offset|length|style|BOLD|3063882|func+textField(_+textField:+UITextField,+shouldChangeCharactersIn+range:+NSRange,+replacementString+string:+String)+->+Bool+{

++++let+newString+=+NSString(string:+textField.text!).replacingCharacters(in:+range,+with:+string)

++++return+true
}|code-block|syntax|javascript|3063883|备注|3063884|String和NSString都有名为replacingCharacters:inRange:withString的方法。但是，不出所料，前者需要一个Range实例，而后者需要一个NSRange实例。textField委托方法使用NSRange实例，因此在本例中使用NSString。|CODE|3063885|entityMap^0|0|G|7|0|0|0|0|6|7|8|J|12|23|5|2I|7|2S|9|37|7|3P|8|0^^$0|@$1|2|3|4|5|6|7|T|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|U|8|@$D|V|E|W|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|X|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|Y|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|Z|8|@$D|10|E|11|F|Q]|$D|12|E|13|F|Q]|$D|14|E|15|F|Q]|$D|16|E|17|F|Q]|$D|18|E|19|F|Q]|$D|1A|E|1B|F|Q]|$D|1C|E|1D|F|Q]|$D|1E|E|1F|F|Q]]|9|@]|A|$]]|$1|R|3|-4|5|6|7|1G|8|@]|9|@]|A|$]]]|S|$]]

<h1>Swift 3</h1>

Based on the accepted answer, the following should work in Swift 3:

<pre><code>func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -&gt; Bool {

 let newString = NSString(string: textField.text!).replacingCharacters(in: range, with: string)

 return true
}
</code></pre>

<h2>Note</h2>

Both <code>String</code> and <code>NSString</code> have methods called <code>replacingCharacters:inRange:withString</code>. However, as expected, the former expects an instance of <code>Range</code>, while the latter expects an instance of <code>NSRange</code>. The <code>textField</code> delegate method uses an <code>NSRange</code> instance, thus the use of <code>NSString</code> in this case.

blocks|key|318369|text|如果您需要用以下内容替换文本字段文本，您可以使用my+solution+(Swift+3)：https://gist.github.com/Blackjacx/2198d86442ec9b9b05c0801f4e392047|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|318370|替换之后，您只需让textField.text检索合成的文本即可。|style|CODE|318371|entityMap|0|LINK|mutability|MUTABLE|url|https://gist.github.com/Blackjacx/2198d86442ec9b9b05c0801f4e392047^0|1A|1U|0|0|9|E|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@$A|Q|B|R|1|S]]|C|$]]|$1|D|3|E|5|6|7|T|8|@$A|U|B|V|F|G]]|9|@]|C|$]]|$1|H|3|-4|5|6|7|W|8|@]|9|@]|C|$]]]|I|$J|$5|K|L|M|C|$N|O]]]]

If you need to replace the textfield text with this you can use my solution (Swift 3): <a href="https://gist.github.com/Blackjacx/2198d86442ec9b9b05c0801f4e392047" rel="nofollow noreferrer">https://gist.github.com/Blackjacx/2198d86442ec9b9b05c0801f4e392047</a>

After the replacement you can just get <code>textField.text</code> to retrieve the composed text.

blocks|key|3276981|text|在Swift(4)中，没有NSString+(纯Swift)：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3276982|func+textField(_+textField:+UITextField,+shouldChangeCharactersIn+range:+NSRange,+replacementString+string:+String)+->+Bool+{

++++if+let+textFieldString+=+textField.text,+let+swtRange+=+Range(range,+in:+textFieldString)+{

++++++++let+fullString+=+textFieldString.replacingCharacters(in:+swtRange,+with:+string)

++++++++print("FullString:+\(fullString)")
++++}

++++return+true
}|code-block|syntax|javascript|3276983|作为扩展：|3276984|extension+UITextField+{

++++func+fullTextWith(range:+NSRange,+replacementString:+String)+->+String?+{

++++++++if+let+fullSearchString+=+self.text,+let+swtRange+=+Range(range,+in:+fullSearchString)+{

++++++++++++return+fullSearchString.replacingCharacters(in:+swtRange,+with:+replacementString)
++++++++}

++++++++return+nil
++++}
}

//+Usage:

func+textField(_+textField:+UITextField,+shouldChangeCharactersIn+range:+NSRange,+replacementString+string:+String)+->+Bool+{

++++if+let+textFieldString+=+textField.fullTextWith(range:+range,+replacementString:+string)+{
++++++++print("FullString:+\(textFieldString)")
++++}

++++return+true
}|3276985|entityMap^0|D|8|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|O|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|P|$]]

In Swift(4), without <code>NSString</code> (pure Swift):

<pre><code>func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -&gt; Bool {

 if let textFieldString = textField.text, let swtRange = Range(range, in: textFieldString) {

 let fullString = textFieldString.replacingCharacters(in: swtRange, with: string)

 print("FullString: \(fullString)")
 }

 return true
}
</code></pre>

As an extension:

<pre><code>extension UITextField {

 func fullTextWith(range: NSRange, replacementString: String) -&gt; String? {

 if let fullSearchString = self.text, let swtRange = Range(range, in: fullSearchString) {

 return fullSearchString.replacingCharacters(in: swtRange, with: replacementString)
 }

 return nil
 }
}

// Usage:

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -&gt; Bool {

 if let textFieldString = textField.fullTextWith(range: range, replacementString: string) {
 print("FullString: \(textFieldString)")
 }

 return true
}
</code></pre>

I'm using the code below to try and have <code>textField2</code>'s text content get updated to match <code>textField1</code>'s whenever the user types in <code>textField1</code>.

<pre><code>- (BOOL) textField: (UITextField *)theTextField shouldChangeCharactersInRange: (NSRange)range replacementString: (NSString *)string { 
 if (theTextField == textField1){ 
 [textField2 setText:[textField1 text]]; 
 }
}
</code></pre>

However, the output I observe is that...

<blockquote>
 textField2 is "12", when textField1 is "123"
 
 textField2 is "123", when textField1 is "1234"
</blockquote>

... when what I want is:

<blockquote>
 textField2 is "123", when textField1 is "123"
 
 textField2 is "1234", when textField1 is "1234"
</blockquote>

What am I doing wrong?

Using `textField:shouldChangeCharactersInRange:`, how do I get the text including the current typed character?

Swift

我正在使用下面的代码来尝试让textField2的文本内容在用户输入textField1时更新为与textField1的文本内容相匹配。- (BOOL) textField: (UITextField *)theTextField shouldChangeCharactersInRange: (NSRange)rang...

问使用` `textField:shouldChangeCharactersInRange:`，如何获取包含当前键入字符的文本？
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问使用` `textField:shouldChangeCharactersInRange:`，如何获取包含当前键入字符的文本？
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