iOS 判断字符串是否为空字符串 && 判断字符串包含那个字符

- (BOOL) isBlankString:(NSString *)string {    if (string == nil || string == NULL) {        return YES;    }    if ([string isKindOfClass:[NSNull class]]) {        return YES;    }    if ([[string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]] length]==0) {        return YES;    }    return NO;} 

//判断roadTitleLab.text 是否含有qingjoin if([roadTitleLab.text rangeOfString:@"qingjoin"].location !=NSNotFound)//_roaldSearchText   {                NSLog(@"yes");   }            else    {                NSLog(@"no");   }