objective c - Check string containing URL for "http://" -

i trying check url entered user, fighting against errors , 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 :

nsstring may not respond -rangewithstring
unused variable urladdress in condition "if … else" (for both)
urladdress undeclared : in urlrequest

does have idea do?

nsstring responds rangeofstring:, not rangewithstring:.

the variable urladdress declared both in if statement, , in else statement. means lives in scope. once leave if/else statement, variable gone.

for url it's best if begins scheme (like "http://"), , code gladly accept apple.http://.com being valid.

you can use hasprefix: method instead, 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];