Check string containing URL for "http://"

Question

I am trying to check the URL entered by the user, but I am fighting against some errors and warnings.

-(BOOL) textFieldShouldReturn:(UITextField *)textField {
    //check "http://"
    NSString *check = textField.text;
    NSString *searchString = @"http://";
    NSRange resultRange = [check rangeWithString:searchString];
    BOOL result = resultRange.location != NSNotFound;
    if (result) {
        NSURL *urlAddress = [NSURL URLWithString: textField.text];
    } else {
        NSString *good = [NSString stringWithFormat:@"http://%@", [textField text]];
        NSURL *urlAddress = [NSURL URLWithString: good];
    }
    // open url
    NSURLRequest *requestObject = [NSURLRequest requestWithURL:urlAddress];
}

They say:

NSString may not respond to -rangeWithString
Unused variable urlAddress in the condition "if … else" (for both)
urlAddress undeclared : in the URLRequest

Does anyone have any idea what to do?

Answer 1

NSString responds to rangeOfString:, not rangeWithString:.

The variable urlAddress is declared both in the if statement, and in the else statement. That means it only lives in that scope. Once you leave the if/else statement, the variable is gone.

For a URL it's best if it begins with the scheme (like "http://"), and your code will gladly accept apple.http://.com as being valid.

You can use the hasPrefix: method instead, like this:

BOOL result = [[check lowercaseString] hasPrefix:@"http://"];
NSURL *urlAddress = nil;

if (result) {  
    urlAddress = [NSURL URLWithString: textField.text];
}
else {
    NSString *good = [NSString stringWithFormat:@"http://%@", [textField text]];
    urlAddress = [NSURL URLWithString: good];
}

NSURLRequest *requestObject = [NSURLRequest requestWithURL:urlAddress];