Detect when an iOS app is launched for the first time?
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];
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")