How to handle iOS app launching after update? - ios

Question

Is there any way to know that iOS app is launched after being updated?
I think i can save app current version every time i launch the application for example in NSUserDefaults and check this version every time i open the application.
And what about the case:
1) User installs app version 1.0 , but doesn't launch it.
2) User installs app version 2.0.
How to handle that case for example?
Thanks in advance.

Answer 1

If always done what you have suggested, saving the app version in the NSUserDefaults.
And about your other case, if the app does not start with version 1 then it does with version 2 you could just see it as a new install.
Since your app never started in the first place you can just treat it as a fresh install. If you doing this to track update in some kind of analytics tool you will have an issue. But you could use apple install/update reports to get the correct list of install/updates.
Just be sure that if you do any updates from any version you make you code in such a way that you can upgrade from any previous version. So installing verion 4 from 1 will preform any and all changes for version 2 and 3 as well.

Answer 2

I found the following note at this website from Apple.
When a user downloads an app update, iTunes installs the update in a new app directory. It then moves the user’s data files from the old installation over to the new app directory before deleting the old installation. Files in the following directories are guaranteed to be preserved during the update process:
/Documents
/Library
Although files in other user directories may also be moved over, you should not rely on them being present after an update.
In every version you release, you can put a txt file with a unique name (unique for every version) in one of these update-persistent directories and check for the previous version txt file(s) at initial launch of application. This should work even in the case where your application was not launched between the download and an initial update.

Answer 3

Every time your application is launched, the following function in your appDelegate class gets called after the launching process is complete:
- (BOOL)application:(UIApplication *)application
didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
This is a point where you can check the version of the application, probably using somoething like:
[[[NSBundle mainBundle] infoDictionary] objectForKey:#"CFBundleShortVersionString"]

Answer 4

I'm a bit late to the party, but if this is still an issue, I use a saved Boolean to see if this is the app's first launch:
if (![[NSUserDefaults standardUserDefaults] boolForKey:#"HasLaunchedOnce"]) {
NSLog(#"First launch");
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setBool:YES forKey:#"HasLaunchedOnce"];
[defaults synchronize];
}
I can then deal with an install or update as you already mention in your question.

Answer 5

I think this could be useful: MTMigration manages blocks of code that need to run once on version updates in iOS apps. This could be anything from data normalization routines, "What's New In This Version" screens, or bug fixes.
It is available through CocoaPods: pod 'MTMigration'
Please take a look to MTMigration repository at GitHub (https://github.com/mysterioustrousers/MTMigration) for usage and examples.
[MTMigration applicationUpdateBlock:^{
/* This code run on every version change. */
}];
[MTMigration migrateToVersion:#"1.0" block:^{
/* This code only run once in version 1.0 */
}];
[MTMigration migrateToVersion:#"2.0" block:^{
/* This code only run once in version 2.0 */
}];
If a user was at version 1.0 , skipped 2.0 , and upgraded to 3.0 , then both the 1.0 and 2.0 blocks would run.