如何让uitextview仅接受退格键和删除键

Question

我希望UItextView在TextView.contentSize.height增长超出特定限制后不再接受任何字符。但可以删除内容。如何实现这一点。任何建议？

Answer 1

使用textfield和textview的委托和数据源。

例如文本字段委托方法

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{ if (textField == self.txtContact) { 
      if ([DebugLog isEqualToString:@"1"]) { 
       NSLog(@"%@",textField.text); 
      } 
      char *x = (char*)[string UTF8String]; 
      if([string isEqualToString:@"-"] || [string isEqualToString:@"("] || [string isEqualToString:@")"] || [string isEqualToString:@"0"] || [string isEqualToString:@"1"] || [string isEqualToString:@"2"] || [string isEqualToString:@"3"] || [string isEqualToString:@"4"] || [string isEqualToString:@"5"] || [string isEqualToString:@"6"] || [string isEqualToString:@"7"] || [string isEqualToString:@"8"] || [string isEqualToString:@"9"] || x[0]==0 || [string isEqualToString:@" "]) { 
        if ([DebugLog isEqualToString:@"1"]) { 
         NSLog(@"%d",[string length]); 
        } 
       NSUInteger newLength = [textField.text length] + [string length]; 
       if (!CheckDigit) { 
        if ([textField.text length] == 4) { 
         textField.text =[NSString stringWithFormat:@"%@-",textField.text]; 
         CheckDigit=TRUE; 
        } 


       } 
       if (!CheckDigit1) { 
        if ([textField.text length] == 9) { 
         textField.text =[NSString stringWithFormat:@"%@-",textField.text]; 
         CheckDigit1=TRUE; 
        } 


       } 
       if ([textField.text length]<=4) { 
        CheckDigit=FALSE; 
       } 
       if ([textField.text length]<=9 && [textField.text length]>=4) { 
        CheckDigit1=FALSE; 
       } 

       return (newLength > 11) ? NO : YES; 

      } else { 
       return NO; 
      } 

} 

Answer 2

的下面有一个在所述UITextFieldDelegate协议。
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string是你的朋友。

Answer 3

用户以下的委托方法，以避免用户输入任何内容

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string 
    { 

    return 0;/// Dont allow user to type 

return 1; ///Allow user to type 

    }