ios8 to validate urlField? [duplicate] - ios

Question

Help me to write the code like "if my string is a valid URL do smth"
Is it possible to write this in a couple strings of code?

Answer 1

I will assume that by URL, you are referring to a string identifying a internet resource location.
If you have an idea about the format of the input string , then why not manually check if the string starts with http://, https:// or any other scheme you need. If you expect other protocols, you can also add them to the check list (e.g. ftp://, mailto://, etc)
if ([myString hasPrefix:#"http://"] || [myString hasPrefix:#"https://"])
{
// do something
}
If you are looking for a more solid solution and detect any kind of URL scheme, then you should use a regular expression.
As a side note, the NSURL class is designed to express any kind of resource location (not just internet resources). That is why, strings like img/demo.jpg or file://bla/bla/bla/demo.jpg can be transformed into NSURL objects.
However, according to the documentation the [NSURL URLWithString] should return nil if the input string is not a valid internet resource string. In practice it doesn't.

Answer 2

+ (BOOL)validateUrlString:(NSString*)urlString
{
if (!urlString)
{
return NO;
}
NSDataDetector *linkDetector = [NSDataDetector dataDetectorWithTypes:NSTextCheckingTypeLink error:nil];
NSRange urlStringRange = NSMakeRange(0, [urlString length]);
NSMatchingOptions matchingOptions = 0;
if (1 != [linkDetector numberOfMatchesInString:urlString options:matchingOptions range:urlStringRange])
{
return NO;
}
NSTextCheckingResult *checkingResult = [linkDetector firstMatchInString:urlString options:matchingOptions range:urlStringRange];
return checkingResult.resultType == NSTextCheckingTypeLink
&& NSEqualRanges(checkingResult.range, urlStringRange);
}

Answer 3

I used this solution which is apparently a better and less complex check than a Regex check -
- (BOOL)isURL:(NSString *)inputString
{
NSURL *candidateURL = [NSURL URLWithString:inputString];
return candidateURL && candidateURL.scheme && candidateURL.host;
}

Answer 4

Try to create NSUrl with it, and see if it returns non-nil result.

Answer 5

if ([NSURL URLWithString:text]) {
// valid URL
}
else {
// invalid URL
}