UITextView字数限制

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{
    if ([text isEqualToString:@""] && range.length > 0) {
        //删除字符肯定是安全的
        return YES;
    }
    else {
        if (textView.text.length - range.length + text.length > 300) {
            [FXAlertTool alertWithMessage:@"超出字数限制" target:self];
            return NO;
        }
        else {
            return YES;
        }
    }
}

- (void)textViewDidChange:(UITextView *)textView {
    int maxLimit = 300;
    NSString *lang = [[textView textInputMode] 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
        UITextRange *selectedRange = [textView markedTextRange];
        //获取高亮部分
        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 (textView.text.length > maxLimit) {
                textView.text = [textView.text substringToIndex:maxLimit];
                [FXAlertTool alertWithMessage:@"超出字数限制" target:self];
            }
        } 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 (textView.text.length > maxLimit) {
            textView.text = [textView.text substringToIndex:maxLimit];
            [FXAlertTool alertWithMessage:@"超出字数限制" target:self];
        }
    }
}

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text {
    int maxLimit = 300;
    if ([self isText:textView beyondLimit:maxLimit] && [text length] > 0) {
        return NO;
    }
    return YES;
}

- (BOOL)isText:(UITextView *)tv beyondLimit:(int)maxLimit{
    NSString *lang = [[tv textInputMode] primaryLanguage];
    if ([lang isEqualToString:@"zh-Hans"]) {
        UITextRange *selectedRange = [tv markedTextRange];
        UITextPosition *position = [tv positionFromPosition:selectedRange.start offset:0];
        if (!position) {
            if (tv.text.length > maxLimit) {
                return YES;
            }
        }
    } else {
        if (tv.text.length > maxLimit) {
            return YES;
        }
    }
    
    return NO;
}