Detect when an iOS app is launched for the first time? [closed]

Question

How do I detect when an iOS app is launched for the first time?

Answer 1

Pretty much what Marc and Chris said, though I prefer to change the value when the app quits in case there're multiple areas of the application that need to know about it. In code:

Objective-C

// -applicationDidFinishLaunching: [[NSUserDefaults standardUserDefaults] registerDefaults:[NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:YES],@"firstLaunch",nil]]; // to check it: [[NSUserDefaults standardUserDefaults] boolForKey:@"firstLaunch"]; // -applicationWillTerminate: [[NSUserDefaults standardUserDefaults] setBool:NO forKey:@"firstLaunch"]; 

Swift 5.0

// -applicationDidFinishLaunching: UserDefaults.standard.register(defaults: ["firstLaunch":true]) // to check it: UserDefaults.standard.bool(forKey: "firstLaunch") // -applicationWillTerminate: UserDefaults.standard.set(false, forKey: "firstLaunch") 

Answer 2

I realize this question is quite old, but I used it to come up with one method of detecting the first startup after a "fresh install" (vs. first startup after an upgrade/downgrade) and thought I'd share the code here for future viewers in case it's helpful.

// Get current version ("Bundle Version") from the default Info.plist file NSString *currentVersion = (NSString*)[[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleVersion"]; NSArray *prevStartupVersions = [[NSUserDefaults standardUserDefaults] arrayForKey:@"prevStartupVersions"]; if (prevStartupVersions == nil)  {     // Starting up for first time with NO pre-existing installs (e.g., fresh      // install of some version)     [self firstStartAfterFreshInstall];     [[NSUserDefaults standardUserDefaults] setObject:[NSArray arrayWithObject:currentVersion] forKey:@"prevStartupVersions"]; } else {     if (![prevStartupVersions containsObject:currentVersion])      {         // Starting up for first time with this version of the app. This         // means a different version of the app was alread installed once          // and started.         [self firstStartAfterUpgradeDowngrade];         NSMutableArray *updatedPrevStartVersions = [NSMutableArray arrayWithArray:prevStartupVersions];         [updatedPrevStartVersions addObject:currentVersion];         [[NSUserDefaults standardUserDefaults] setObject:updatedPrevStartVersions forKey:@"prevStartupVersions"];     } }  // Save changes to disk [[NSUserDefaults standardUserDefaults] synchronize];