限制输入长度

- (void)textFieldDidChange:(UITextField *)textField

{

UITextField * textfield = [_tableview viewWithTag:1000];

NSString *toBeString = textfield.text;

NSString *lang = [[UIApplication sharedApplication]textInputMode].primaryLanguage; // 键盘输入模

if ([lang isEqualToString:@"zh-Hans"]) { // 简体中文输入，包括简体拼音，健体五笔，简体手写

UITextRange *selectedRange = [textfield markedTextRange];

//获取高亮部分

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

// 没有高亮选择的字，则对已输入的文字进行字数统计和限制

if (!position) {

if (toBeString.length > kMaxLength)

{

NSRange rangeIndex = [toBeString rangeOfComposedCharacterSequenceAtIndex:kMaxLength];

if (rangeIndex.length == 1)

{

textfield.text = [toBeString substringToIndex:kMaxLength];

}

else

{

NSRange rangeRange = [toBeString rangeOfComposedCharacterSequencesForRange:NSMakeRange(0, kMaxLength)];

textfield.text = [toBeString substringWithRange:rangeRange];

}

}

}

}

// 中文输入法以外的直接对其统计限制即可，不考虑其他语种情况

else{

if (toBeString.length > kMaxLength)

{

NSRange rangeIndex = [toBeString rangeOfComposedCharacterSequenceAtIndex:kMaxLength];

if (rangeIndex.length == 1)

{

textfield.text = [toBeString substringToIndex:kMaxLength];

}

else

{

NSRange rangeRange = [toBeString rangeOfComposedCharacterSequencesForRange:NSMakeRange(0,kMaxLength)];

textfield.text = [toBeString substringWithRange:rangeRange];

}

}

}

}