CODEWITHSUNDEEP
swifttimer
ZombieIK
ZombieIK

Reputation: 5

Swift 3 Timer in Timer

how does a timer in timer worked?

func startSequenz()
{
    for mainCell in mainTable {
        timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector:#selector(ViewController.run), userInfo: nil, repeats: true)
    }
}

func run ()
{
    for cell in table{
        timer2 = Timer.scheduledTimer(timeInterval: 1, target: self, selector:#selector(ViewController.run2), userInfo: nil, repeats: true)
    }
    timer!.invalidate()
}

func run2()
{
    currentSteps! += 1
    print("\(currentSteps!)")
    timer2!.invalidate()
}

Executing func run2() never stops. My target is, to delay the execute of run2 and sleep(1) freez the GUI.

UPDATE:

I´ve use Tom E answer and it worked partially. But the GUI refresh only once at the end of the execute.

func run ()
{
    for cell in table{

        DispatchQueue.global().asyncAfter(deadline: .now() + .seconds(2)) {
        // This code will be placed on a background queue and be executed a second later

            // i do my stuff   

            DispatchQueue.main.async {

                // Here you may update any GUI elements  
                self.currentCell = cell
                self.currentStep! += 1

                self.sectionHeaderText = "\(self.currentStep!) of \(self.totalSteps!)"
                self.tableView.reloadSections(IndexSet(integer: 0), with: .none)
            }
        }
    }
}

public override func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
    switch section {
      case 0  : return sectionHeaderText
      default : return nil
    }
}

Upvotes: 0

Views: 425

Answers (1)

Tom E
Tom E

Reputation: 1607

It doesn’t seem to make much sense to create a repeating timer which will immediately be invalidated upon the first time its action method is called.

If you seek for proper ways to delay the execution of code please have a look at Grand Central Dispatch. Here’s a sample of code with non-blocking, delayed background execution:

DispatchQueue.global().asyncAfter(deadline: .now() + .seconds(1)) {
    // This code will be placed on a background queue and be executed a second later

    DispatchQueue.main.async {
        // Here you may update any GUI elements
    }
}

Please make sure you don’t access any GUI elements from a background queue. For this reason the sample shows how to switch to the main thread for any GUI updates.

Upvotes: 1

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