ios 使用`textField:shouldChangeCharactersInRange:`，如何获取包含当前输入字符的文本？
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Using `textField:shouldChangeCharactersInRange:`, how do I get the text including the current typed character?
提问by user265961
I'm using the code below to try and have textField2's text content get updated to match textField1's whenever the user types in textField1.
我正在使用下面的代码尝试textField2更新 的文本内容以匹配textField1每当用户输入textField1.
- (BOOL) textField: (UITextField *)theTextField shouldChangeCharactersInRange: (NSRange)range replacementString: (NSString *)string {
if (theTextField == textField1){
[textField2 setText:[textField1 text]];
}
}
However, the output I observe is that...
但是，我观察到的输出是......
textField2 is "12", when textField1 is "123"
textField2 is "123", when textField1 is "1234"
textField2 为“12”，当 textField1 为“123”时
textField2 为“123”，当 textField1 为“1234”时
... when what I want is:
...当我想要的是：
textField2 is "123", when textField1 is "123"
textField2 is "1234", when textField1 is "1234"
textField2 为“123”，当 textField1 为“123”时
当 textField1 为“1234”时，textField2 为“1234”
What am I doing wrong?
我究竟做错了什么？
回答by Vladimir
-shouldChangeCharactersInRangegets called beforetext field actually changes its text, that's why you're getting old text value. To get the text after update use:
-shouldChangeCharactersInRange在文本字段实际更改其文本之前被调用，这就是您获得旧文本值的原因。要在更新后获取文本，请使用：
[textField2 setText:[textField1.text stringByReplacingCharactersInRange:range withString:string]];
回答by btmanikandan
-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
NSString * searchStr = [textField.text stringByReplacingCharactersInRange:range withString:string];
NSLog(@"%@",searchStr);
return YES;
}
回答by focorner
Swift 3
斯威夫特 3
Based on the accepted answer, the following should work in Swift 3:
根据接受的答案，以下内容应该适用于Swift 3：
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let newString = NSString(string: textField.text!).replacingCharacters(in: range, with: string)
return true
}
Note
笔记
Both Stringand NSStringhave methods called replacingCharacters:inRange:withString. However, as expected, the former expects an instance of Range, while the latter expects an instance of NSRange. The textFielddelegate method uses an NSRangeinstance, thus the use of NSStringin this case.
双方String并NSString有方法叫replacingCharacters:inRange:withString。然而，正如预期的那样，前者期望 的实例Range，而后者期望 的实例NSRange。的textField委托方法使用一个NSRange实例，因此，使用NSString在这种情况下。
回答by tomute
Instead of using the UITextFieldDelegate, try to use "Editing Changed"event of UITextField.
不要使用 UITextFieldDelegate，而是尝试使用 UITextField 的“Editing Changed”事件。
回答by bauerMusic
In Swift(4), without NSString(pure Swift):
在 Swift(4) 中，没有NSString（纯 Swift）：
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
}
As an extension:
作为扩展：
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
}
回答by ioopl
Swift version for it :
Swift 版本：
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
}
回答by Deepak Danduprolu
This is the code you need,
这是你需要的代码
if ([textField isEqual:self.textField1])
textField2.text = [textField1.text stringByReplacingCharactersInRange:range withString:string];
回答by ober
use guard
使用警卫
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
}
回答by blackjacx
If you need to replace the textfield text with this you can use my solution (Swift 3): https://gist.github.com/Blackjacx/2198d86442ec9b9b05c0801f4e392047
如果您需要用这个替换文本字段文本，您可以使用我的解决方案（Swift 3）：https: //gist.github.com/Blackjacx/2198d86442ec9b9b05c0801f4e392047
After the replacement you can just get textField.textto retrieve the composed text.
替换后，您可以textField.text检索组合文本。
回答by boweidmann
My solution is to use UITextFieldTextDidChangeNotification.
我的解决方案是使用UITextFieldTextDidChangeNotification.
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(copyText:) name:UITextFieldTextDidChangeNotification object:nil];
Don't forget to call [[NSNotificationCenter defaultCenter] removeObserver:self];in deallocmethod.
不要忘记调用[[NSNotificationCenter defaultCenter] removeObserver:self];的dealloc方法。
