First time launch / segue swift

Question

what i am trying to accomplish is once the app is launched it will check for first time use. if it is the first time use it will take you to a view controller to enter credentials, else it will take you to to the main menu of the app. this is what i have so far but every time i launch it will give me a blank page with the error message of "A segue must either have a performHandler or it must override -perform. " i have both segues linked on storyboard. can any one please steer me in the right direction.

    let defaults = UserDefaults.standard
    if defaults.string(forKey: "isAppAlreadyLaunchedOnce") != nil{
        print("first time")
        self.performSegue(withIdentifier: "toToken", sender: nil)
    }else{
        defaults.set(true, forKey: "isAppAlreadyLaunchedOne")
        defaults.synchronize()
        print("not first")
        self.performSegue(withIdentifier: "toMainMenu", sender: nil)
    }

As a side note, you probably mixed up the logic — `defaults.set(true, forKey: "isAppAlreadyLaunchedOne")` is supposed to be called on first launch. — 0xNSHuman, Apr 05 '17 at 19:01
Now on topic: what type of segue did you create in Storyboard? Is it a Custom one? — 0xNSHuman, Apr 05 '17 at 19:04
Why are you setting a `Bool` and retrieving `String` from `UserDefaults`? — Losiowaty, Apr 05 '17 at 19:14

0xNSHuman · Answer 1 · 2017-04-06T08:41:13.887

1

If your segue type is set to be Custom in Storyboard — you have to subclass UIStoryboardSegue with your own logic in order for it to work.

class MySegue: UIStoryboardSegue {
    override func perform() {
        // your custom transition logic
    }
}

Otherwise just use one of the existing presets from iOS SDK.

edited Apr 06 '17 at 08:41

answered Apr 05 '17 at 19:10

0xNSHuman

638
5
8

thank you. it did solve that error but it gave me another error, but its a start. thanks. – guichonator19 Apr 05 '17 at 19:15
@LuisMartinez You're welcome. Accepting answer that you find helpful is always appreciated on StackOverflow. – 0xNSHuman Apr 05 '17 at 19:17
thanks for the help. as soon as that error was clear it was very easy to solve the next one. now it is working. thanks – guichonator19 Apr 05 '17 at 19:24

Cyril · Answer 2 · 2017-11-12T08:29:20.510

0

Your method is very confusing. The way I go about this problem is shown below.

override viewDidLoad() {
super.viewDidLoad

let checkForFirstTimeLaunch = Userdefaults.standard.string(forKey: "Flag")

if checkForFirstTimeLaunch == false {
print("First time launch")

//if user launches app for the first time, it will go here

} else {
//otherwise, it will go here

}

}

edited Nov 12 '17 at 08:29

answered Apr 06 '17 at 01:20

Cyril

2,783
1
24
35

First time launch / segue swift

2 Answers2