CODEWITHSUNDEEP
iosiphoneswift
Greg
Greg

Reputation: 427

How to detect the first launch of an app

I have been researching this for 2 hours and I found a very similar question that was answered by Zaid Pathan. Unfortunately, when I used the code that Zaid shared in my own app, I do not get the result I expect. Here is the code:

     override func viewDidLoad() {
    super.viewDidLoad()

    println("Launched")

    func isAppAlreadyLaunchedOnce()->Bool{
        let defaults = NSUserDefaults.standardUserDefaults()

        if let isAppAlreadyLaunchedOnce = defaults.stringForKey("isAppAlreadyLaunchedOnce"){
            println("App already launched")
            return true
        }else{
            defaults.setBool(true, forKey: "isAppAlreadyLaunchedOnce")
            println("App launched first time")
            return false
        }
    }

I added the println("Launched") so I could see in the log that the code had executed. That works. However, the println("App already launched") and/or println("App launched first time") do not execute. Any suggestions?

Upvotes: 0

Views: 1265

Answers (3)

Hitesh Surani
Hitesh Surani

Reputation: 13537

You can identified weather application luanch first time or not using below method.

For Objective C 

    if ([self isFirstLuanch]) {
        NSLog(@"First lunch");
    }else{
        NSLog(@"No a first lunch");
    }

    -(BOOL) isFirstLuanch{
        if (![[NSUserDefaults standardUserDefaults] boolForKey:@"HasLaunchedOnce"]){
            return NO;
        }else{
            [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"HasLaunchedOnce"];
            [[NSUserDefaults standardUserDefaults] synchronize];
            return YES;
        }
    }

For swift 4.0

if isFirstLuanch(){
       print("First lunch")
}else{
       print("No a first lunch")
}

func isFirstLuanch()-> Bool{
    if UserDefaults.standard.bool(forKey: "isAppAlreadyLaunchedOnce") {
        return false
    }else{
        UserDefaults.standard.set(true, forKey: "isAppAlreadyLaunchedOnce")
        return true
    }
}

Upvotes: 1

Wellbin Huang
Wellbin Huang

Reputation: 783

You should call the synchronize() to save data to userdefaults.

defaults.setBool(true, forKey: "isAppAlreadyLaunchedOnce")
defaults.synchronize()

Upvotes: 1

MirekE
MirekE

Reputation: 11555

Yo created function in function. Either move the isAlreadyLaunchedOnce in the scope (to the same level as viewDidLoad) and call it from viewDidLoad or modify the code like this:

override func viewDidLoad() {
super.viewDidLoad()

println("Launched")

let defaults = NSUserDefaults.standardUserDefaults()
if let isAppAlreadyLaunchedOnce = defaults.stringForKey("isAppAlreadyLaunchedOnce"){
    println("App already launched")
    // do something
} else {
    defaults.setBool(true, forKey: "isAppAlreadyLaunchedOnce")
    println("App launched first time")
    // do something
}

}

Upvotes: 2

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