Downloading a zip file in iOS - ios

Question

Try to download a zip file from the given URL, since the zip file Gets updated daily I wrote the codes in ApplicationDidFinishLunching method but it doesn't work. anything wrong with my code?
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
// Override point for customization after application launch.
NSString *stringURL = #"http://webspace.apiit.edu.my/intake-timetable/download_timetable/timetableXML.zip";
NSURL *url = [NSURL URLWithString:stringURL];
NSData *urlData = [NSData dataWithContentsOfURL:url];
//Find a cache directory. You could consider using documenets dir instead (depends on the data you are fetching)
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
NSString *path = [paths objectAtIndex:0];
//Save the data
NSString *dataPath = [path stringByAppendingPathComponent:#"timetableXML.zip"];
dataPath = [dataPath stringByStandardizingPath];
[urlData writeToFile:dataPath atomically:YES];
return YES;
}

Answer 1

Try this instead as it will download the zip file in the background. Even though the file is only a few kb the download can take some time and as the download is performed on the main thread this will prevent the app from launching!
dispatch_queue_t queue = dispatch_get_global_queue(0,0);
dispatch_async(queue, ^{
NSLog(#"Beginning download");
NSString *stringURL = #"http://webspace.apiit.edu.my/intake-timetable/download_timetable/timetableXML.zip";
NSURL *url = [NSURL URLWithString:stringURL];
NSData *urlData = [NSData dataWithContentsOfURL:url];
//Find a cache directory. You could consider using documenets dir instead (depends on the data you are fetching)
NSLog(#"Got the data!");
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
NSString *path = [paths objectAtIndex:0];
//Save the data
NSLog(#"Saving");
NSString *dataPath = [path stringByAppendingPathComponent:#"timetableXML.zip"];
dataPath = [dataPath stringByStandardizingPath];
[urlData writeToFile:dataPath atomically:YES];
});
You should never download anything on the main thread as it will "block" your application. It should however be noted that there are better ways than this to download data. Read for example this.