CODEWITHSUNDEEP
iosiphoneswift
Denys Triasunov
Denys Triasunov

Reputation: 569

How to turn on iPhone's flash for 1 second?

In the settings for my app, there is a switch allowing the user to turn iPhone's flash on or off (flash is used to indicate certain points in app logic while it's running). What I want to implement is this: when the user toggles this switch on, I want it to, well, flash for a split second to indicate its 'ON' state.

Now, I know how to set torchMode on or off - this is implemented in the app itself, but I'm not sure how to correctly make it 'blink' for settings purpose. One of the ways I thought of is to use following code (toggleFlash() is a static method for toggling torchMode implemented in main code):

UIView.animate(withDuration: 1.0, animations: {
    ViewController.toggleFlash(on: true)
}, completion: { (_) in
    ViewController.toggleFlash(on: false)
})

This does make it 'blink', but only for a moment - not 1 second. Besides, I'm not so sure if it's at all correct to use animate for this purpose. Another idea is to use Thread.sleep, but this looks like an even worse practice.

Can someone recommend better solutions?

Upvotes: 0

Views: 84

Answers (2)

Lachezar Todorov
Lachezar Todorov

Reputation: 923

Probably something like this:

func flash() {
    ViewController.toggleFlash(on: true)
    let time = DispatchWallTime.now() + DispatchTimeInterval.seconds(1)
    DispatchQueue.main.asyncAfter(wallDeadline: time) {
        ViewController.toggleFlash(on: false)
    }
}

wallDeadline is reliable and the solution is packed in one function.

Upvotes: 2

adamfowlerphoto
adamfowlerphoto

Reputation: 2751

You could use a timer.

func flashForOneSecond() {
    ViewController.toggleFlash(on: true)
    flashOffTimer = Timer.scheduledTimer(timeInterval:1, target:self, selector:#selector(self.switchFlashOff), userInfo:nil, repeats:false)
}

@objc func switchFlashOff() {
    ViewController.toggleFlash(on: false)
}

Upvotes: 2

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