How to turn flashlight ON and OFF in swift?

Question

I'd like to add flashlight functionality to my app in Swift. How can I go about doing that?

Answer 1

Update #1: (torchActive isn't returning the expected value; perhaps because it's been modified)

Update #2: For Swift 2.0

To toggle the flash from on to off (not just "on" as in mad pig's answer), you can use the following method:

func toggleFlash() {
    let device = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
    if (device.hasTorch) {
        do {
            try device.lockForConfiguration()
            if (device.torchMode == AVCaptureTorchMode.On) {
                device.torchMode = AVCaptureTorchMode.Off
            } else {
                do {
                    try device.setTorchModeOnWithLevel(1.0)
                } catch {
                    print(error)
                }
            }
            device.unlockForConfiguration()
        } catch {
            print(error)
        }
    }
}

I used nested do-catch blocks to implement Awesomeness's suggestion from the comments. This way, even if try device.setTorchModeOnWithLevel(1.0) fails, the device is properly unlocked for configuration.

Update #3: For Swift 4:

(I edited the code a bit to my personal taste)

func toggleFlash() {
    guard let device = AVCaptureDevice.default(for: AVMediaType.video) else { return }
    guard device.hasTorch else { return }

    do {
        try device.lockForConfiguration()

        if (device.torchMode == AVCaptureDevice.TorchMode.on) {
            device.torchMode = AVCaptureDevice.TorchMode.off
        } else {
            do {
                try device.setTorchModeOn(level: 1.0)
            } catch {
                print(error)
            }
        }

        device.unlockForConfiguration()
    } catch {
        print(error)
    }
}

---

Original answer:

To toggle the flash from on to off (not just "on" as in mad pig's answer), you can use the following method:

func toggleFlash() {
    let device = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
    if (device.hasTorch) {
        device.lockForConfiguration(nil)
        let torchOn = !device.torchActive
        device.setTorchModeOnWithLevel(1.0, error: nil)
        device.torchMode = torchOn ? AVCaptureTorchMode.On : AVCaptureTorchMode.Off
        device.unlockForConfiguration()
    }
}