Is there a simple way in objective c to convert all special characters like ë,à,é,ä to the normal characters like e en a?
Yep, and it's pretty simple:
NSString *src = @"Convert special characters like ë,à,é,ä all to e,a,e,a? Objective C";
NSData *temp = [src dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
NSString *dst = [[[NSString alloc] initWithData:temp encoding:NSASCIIStringEncoding] autorelease];
NSLog(@"converted: %@", dst);
Running that on my machine produces:
EmptyFoundation[69299:a0f] converted: Convert special characters like e,a,e,a all to e,a,e,a? Objective C
Basically, we're asking the string to transform itself it an NSData (ie, a byte array) that represents the characters in the string in the ASCII character set. Since not all of the characters in the original string are in ASCII, we tell the string that it's OK to do a "lossy" conversion. In other words, it's OK to turn "é" into "e", and so on.
Once we've got our byte array, we simply turn it back into a string, and we're done! :)