判断url

 NSString*judgeString [email protected]"^(http|https)://([\w-]+.)+[\w-]+(/[\w-./?%&=]*)?$";
NSPredicate * preddicate =[NSPredicate predicateWithFormat:@"SELF MATCHES %@",judgeString];
    BOOL isValiu =[preddicate evaluateWithObject:urlString];
    if (isValiu) {
NSString * judgeString = @"http://|https://";
    NSPredicate * preddicate =[NSPredicate predicateWithFormat:@"SELF MATCHES %@",urlString];
    NSError *error = NULL;
    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:judgeString options:NSRegularExpressionCaseInsensitive error:&error];
    NSTextCheckingResult *result = [regex firstMatchInString:string options:0 range:NSMakeRange(0, [string length])];
    NSString *imageBeforeText = nil;
    NSString *imageName = nil;
    while (result) {
        //http//
        imageName = [string substringWithRange:result.range];
        //获取http之前的文字
        imageBeforeText = [string substringToIndex:result.range.location];
        //获取url
        string = [string substringFromIndex:result.range.location + result.range.length];
        result = [regex firstMatchInString:string options:0 range:NSMakeRange(0, [string length])];
    }
    NSString * isUrlString = [NSString stringWithFormat:@"%@%@",imageName,string];