轉載：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]; // 鍵盤輸入模式
if ([lang isEqualToString:@"zh-Hans"]) { // 簡體中文輸入，包括簡體拼音，健體五筆，簡體手寫
//獲取高亮部分
UITextRange *selectedRange = [textView markedTextRange];
UITextPosition *position = [textView positionFromPosition:selectedRange.start offset:0];
// 沒有高亮選擇的字，則對已輸入的文字進行字數統計和限制
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{//有高亮選擇的字符串，則暫不對文字進行統計和限制
}
}else {// 中文輸入法以外的直接對其統計限制即可，不考慮其他語種情況
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];
}
}
}
}