Issue when differentiating metadata for UILabel? - ios

Question

I am fetching meta data for the radio streams that currently being played in my iOS app, (Artist Name, track name). However this meta data comes in one piece i.e = "FRANK SINATRA - THEME FROM NEW YORK, NEW YORK".
While this is okay, It would look much nice if I had 2 different labels styled differently one saying "FRANK SINATRA" while the other would read "THEME FROM NEW YORK, NEW YORK".
To do this, I have to get rid of the hyphen,
_metaData = infoString; // THIS IS THE OLD 1- LABEL FOR DATA ALL WAY
// THIS IS THE CODE I AM IMPLEMENTING TO GET RID OF THE HYPHEN
NSUInteger xxx = [_metaData rangeOfString:#"-"].location;
NSUInteger xxxPlustTwo = xxx + 2;
NSString *xxxx = [_metaData substringToIndex:xxx];
self.artistName.text=xxxx;
NSString *trackInformation = [_trackName substringFromIndex:xxxPlustTwo];
self.soundInfoMeta.text = trackInformation;
And just like that I am able to break the 2 apart, problem is that when the station goes to commercial my app immediately crashes. The following is the error I receive on Xcode:
***Terminating app due to uncaught exception ‘NSRangeException’, reason: ‘***-[__NSCFString substringToIndex:]: Index 2147483647 out of bounds; string length 17’
What can be causing this problem?
Update: I tried changing the NSUInteger to double but this did not fix the problem, here is the latest crash log:
xxxx NSString * nil 0x00000000
NSObject NSObject
isa Class 0x0
xxx double 2147483647 2147483647
xplus double 2147483649 2147483649
_trackName __NSCFString * #"http://www.181.fm" 0x16d8a890
NSObject NSObject
isa Class __NSCFString 0x39d9a8f8

Answer 1

You're probably getting input that has no hyphen, so the location of the the hyphen is NSNotFound which is defined to be NSIntegerMax, I believe. Your code needs to be robust to this.
This is a bit different from how you're doing it now, but it should work on more types of input:
NSString *infoString = #"ARTIST - TRACK";
NSArray *infoStringComponents = [infoString componentsSeparatedByString:#" - "];
__block NSString *artistString = #"";
__block NSString *trackInfoString = #"";
if ([infoStringComponents count] == 0) {
// This case should only happen when there's no info string at all
artistString = #"Unknown Artist";
trackInfoString = #"Unknown Song";
}
else if ([infoStringComponents count] == 1) {
// If no hyphens just display the whole string as the track info
trackInfoString = infoStringComponents[0];
}
else {
[infoStringComponents enumerateObjectsUsingBlock:^(NSString *component, NSUInteger index, BOOL *stop) {
NSString *trimmedComponent = [component stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
if (index == 0) {
artistString = trimmedComponent;
}
else {
NSString *buffer = #"";
if ([trackInfoString length] > 0) {
buffer = #" - ";
}
trackInfoString = [trackInfoString stringByAppendingFormat:#"%#%#",buffer,trimmedComponent];
}
}];
}
You could also check if the location property of the range you derive is equal to NSNotFound and then just assume you can't derive an artist out of it and display your _metaData variable in an appropriate label. For example:
NSRange hyphenRange = [infoString rangeOfString:#"-"];
if (hyphenRange.location == NSNotFound) {
// Display only infoString to the user, unformatted into artist / song info
}
else {
// Try the same technique you're attempting now
}