UITextView谷歌输入法输入中文时限制字数问题

谷歌输入在输入中文时，输入框中会先显示中文的拼音。例如限制字数为5个时，你想输入"我是中国人",当你输入woshiz就会提示字数超限了，下面的代码就是解决这个问题

#define MAXSTRINGLENGTH 15    //限定输入长度
- (void)textViewDidChange:(UITextView *)textView{
   NSString *lang = [[[UITextInputMode activeInputModes] firstObject] primaryLanguage];
    if ([lang isEqualToString:@"zh-Hans"]){
        UITextRange *range = [textView markedTextRange];
        UITextPosition *start = range.start;
        UITextPosition*end = range.end;
        NSInteger selectLength = [textView offsetFromPosition:start toPosition:end];
        NSInteger contentLength = textView.text.length - selectLength;
        if (contentLength > MAXSTRINGLENGTH){
            
            textView.text = [textView.text substringToIndex:MAXSTRINGLENGTH];
            [[[UIAlertView alloc] initWithTitle:@"提示" message:@"最长限制15个字" delegate:nil cancelButtonTitle:@"确定" otherButtonTitles: nil] show];
            
        }
        
        if (contentLength < MAXSTRINGLENGTH){
            
            textCountlabel.text = [NSString stringWithFormat:@"还剩%ld个字", MAXSTRINGLENGTH - contentLength];
        
        }else{
            
            textCountlabel.text = @"还剩0个字";
        
        }}else{
        if (textView.text.length > MAXSTRINGLENGTH){
            
            textView.text = [textView.text substringToIndex:MAXSTRINGLENGTH];
            [[[UIAlertView alloc] initWithTitle:@"提示" message:@"最长限制15个字" delegate:nil cancelButtonTitle:@"确定" otherButtonTitles: nil] show];
            
        }
        textCountlabel.text = [NSString stringWithFormat:@"还剩%ld个字", MAXSTRINGLENGTH-textView.text.length];
         }
}