在很多情況下都會(huì)要求限制輸入框的字?jǐn)?shù)長(zhǎng)度，在非中文情況下簡(jiǎn)單的處理下即可，但在系統(tǒng)自帶的中文輸入發(fā)現(xiàn)你會(huì)發(fā)現(xiàn)，即使輸入拼音也會(huì)被限制。我們需要對(duì)中文輸入法進(jìn)行單獨(dú)的設(shè)置：
1.給UITextField綁定一個(gè)方法：
[_summaryField addTarget:self action:@selector(editChange:) forControlEvents:UIControlEventEditingChanged];
2.實(shí)現(xiàn)方法
//最多輸入6個(gè)字

#define kMaxLength 6

 - (void)editChange:(UITextField*)textfield {
       NSString *toBeString = textfield.text;
       NSString *lang = [[UIApplication sharedApplication]textInputMode].primaryLanguage; // 鍵盤(pán)輸入模
       if ([lang isEqualToString:@"zh-Hans"]) { // 簡(jiǎn)體中文輸入，包括簡(jiǎn)體拼音，健體五筆，簡(jiǎn)體手寫(xiě)
             UITextRange *selectedRange = [textfield markedTextRange];
            //獲取高亮部分
             UITextPosition *position = [textfield positionFromPosition:selectedRange.start offset:0];
            // 沒(méi)有高亮選擇的字，則對(duì)已輸入的文字進(jìn)行字?jǐn)?shù)統(tǒng)計(jì)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];
                    }
                }
            }
        }
// 中文輸入法以外的直接對(duì)其統(tǒng)計(jì)限制即可，不考慮其他語(yǔ)種情況
        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];
                    }
                }
}```