* Available for iOS 7
* Group path is different in iOS 7 and 8
ios7:file:///private/var/mobile/Containers/Shared/AppGroup/xxx
ios8:file:///private/var/mobile/Containers/xxx
* Userdeafults can't share in iOS7, but it won't raise any error.
* Enable App Groups will add *.entitlements in proj
* Delete all app relate to the App Groups, system will delete the dir in AppGroup either, next time install the app will use another UUID
- (IBAction)doSet:(id)sender{ NSUserDefaults *def = [[NSUserDefaults alloc] initWithSuiteName:@"group.myappgroup"]; NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"]; NSString *s = [dateFormatter stringFromDate:[NSDate date]]; NSLog(@"set value:%@",s); [def setValue:s forKey:@"dt"]; [def synchronize]; } - (IBAction)doGet:(id)sender{ NSUserDefaults *def = [[NSUserDefaults alloc] initWithSuiteName:@"group.myappgroup"]; NSLog(@"%@", [def valueForKey:@"dt"]); self.title = [def valueForKey:@"dt"]; } - (IBAction)doWrite:(id)sender{ NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"]; NSString *s = [dateFormatter stringFromDate:[NSDate date]]; NSURL *url = [[NSFileManager defaultManager] containerURLForSecurityApplicationGroupIdentifier:@"group.myappgroup"]; url = [url URLByAppendingPathComponent:@"a.dat"]; NSLog(@"%@",url.absoluteString); NSError *err = NULL; [s writeToURL:url atomically:YES encoding:NSUTF8StringEncoding error:&err]; if(err){ NSLog(@"err:%@",err.description); } } - (IBAction)doReadFile:(id)sender{ NSURL *url = [[NSFileManager defaultManager] containerURLForSecurityApplicationGroupIdentifier:@"group.myappgroup"]; url = [url URLByAppendingPathComponent:@"a.dat"]; NSLog(@"%@",url.absoluteString); NSError *err = NULL; NSString *s = [NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncoding error:&err]; if(!err){ NSLog(@"%@",s); self.title = s; }else{ NSLog(@"err:%@",err.description); } }