iOS輸入漢字時限制字數

添加通知

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textLengDidChange:) name:UITextViewTextDidChangeNotification object:self.textView];

在通知方法裏添加如下代碼

- (void)titleTextChange:(NSNotification *)notification {

    UITextView *textView = (UITextView *)notification.object;
    NSInteger count = 0;
    if(textView == self.titleTextView){

        count = [kUserDefaults integerForKey:APP_ENVVAR_MAGAZINE_TITLE_TEXT_MAXSIZE];

    }

    UITextInputMode *inputMode = [[UITextInputMode activeInputModes] firstObject];
    if([inputMode.primaryLanguage isEqualToString:@"zh-Hans"]){

        UITextRange *selectedRange = [textView markedTextRange];
        UITextPosition *position = [textView positionFromPosition:selectedRange.start offset:0];
        if(!position){
            textView.text = [textView.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
            if(textView.text.length > count){
                textView.text = [textView.text substringToIndex:count];

            }
        }
    }else{
        textView.text = [textView.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
        if(textView.text.length > count){
            textView.text = [textView.text substringToIndex:count];

        }
    }
}