UITextField限制输入文字的个数详解手机开发

static constNSInteger Max_Character_Num =4;

 - (IBAction)onTextFieldEditingChanged:(id)sender 

 NSString *lang = [[UITextInputMode currentInputMode] primaryLanguage]; 

 if ([lang isEqualToString:@"zh-Hans"]) { 

 UITextRange *selectedRange = [self.tagNameTextField markedTextRange]; 

 UITextPosition *position = [self.tagNameTextField positionFromPosition:selectedRange.start offset:0]; 

 if (!position) { 

 if (self.tagNameTextField.text.length Max_Character_Num) { 

 self.tagNameTextField.text = [self.tagNameTextField.text substringFrom:0 to:Max_Character_Num]; 

 }else{ 

 if (self.tagNameTextField.text.length Max_Character_Num) { 

 self.tagNameTextField.text = [self.tagNameTextField.text substringFrom:0 to:Max_Character_Num]; 

 } 

来自：http://blog.csdn.net/wang_lichun/article/details/45251217

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