textView控制输入字数的限制

转载：http://www.jianshu.com/p/2d1c06f2dfa4

 

#define MAX_STARWORDS_LENGTH 30

- (void)textViewDidChange:(UITextView *)textView{

//    NSString  * nsTextContent=textView.text;

//    NSInteger   existTextNum=[nsTextContent length];

//    NSLog(@"剩余：%ld",30-existTextNum);

    

    NSString *toBeString = textView.text;

    NSArray *current = [UITextInputMode activeInputModes];

    UITextInputMode *currentInputMode = [current firstObject];

    NSString *lang = [currentInputMode primaryLanguage]; // 键盘输入模式

    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

        //获取高亮部分

        UITextRange *selectedRange = [textView markedTextRange];

        UITextPosition *position = [textView 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 > MAX_STARWORDS_LENGTH)

            {

                NSRange rangeIndex = [toBeString rangeOfComposedCharacterSequenceAtIndex:MAX_STARWORDS_LENGTH];

                if (rangeIndex.length == 1){

                    textView.text = [toBeString substringToIndex:MAX_STARWORDS_LENGTH];

                }else{

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

                    textView.text = [toBeString substringWithRange:rangeRange];

                }

            }

        }else{//有高亮选择的字符串，则暂不对文字进行统计和限制

            

        }

    }else {// 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

        if (toBeString.length > MAX_STARWORDS_LENGTH){

            NSRange rangeIndex = [toBeString rangeOfComposedCharacterSequenceAtIndex:MAX_STARWORDS_LENGTH];

            if (rangeIndex.length == 1){

                textView.text = [toBeString substringToIndex:MAX_STARWORDS_LENGTH];

            }else{

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

                textView.text = [toBeString substringWithRange:rangeRange];

            }

        }

    }

}