iOS 判斷App是否第一次啓動

#define LAST_RUN_VERSION_KEY @"last_run_version_of_application"
- (BOOL) isFirstLoad{
NSString *currentVersion = [[[NSBundle mainBundle] infoDictionary]
objectForKey:@"CFBundleShortVersionString"];

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];

NSString *lastRunVersion = [defaults objectForKey:LAST_RUN_VERSION_KEY];

if (!lastRunVersion) {
[defaults setObject:currentVersion forKey:LAST_RUN_VERSION_KEY];
return YES;
}
else if (![lastRunVersion isEqualToString:currentVersion]) {
[defaults setObject:currentVersion forKey:LAST_RUN_VERSION_KEY];
return YES;
}
return NO;
}