How to turn the iPhone camera flash on/off swift 2?

问题

I was looking how to turn on/off the iPhone's camera flash and I found this:

@IBAction func didTouchFlashButton(sender: AnyObject) {
    let avDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)

// check if the device has torch
if avDevice.hasTorch {
    // lock your device for configuration
    avDevice.lockForConfiguration(nil)
    // check if your torchMode is on or off. If on turns it off otherwise turns it on
    if avDevice.torchActive {
        avDevice.torchMode = AVCaptureTorchMode.Off
    } else {
        // sets the torch intensity to 100%
        avDevice.setTorchModeOnWithLevel(1.0, error: nil)
    }
    // unlock your device
    avDevice.unlockForConfiguration()
    }
}

I do get 2 issues, one on the line:

avDevice.lockForConfiguration(nil)

and the other on the line:

avDevice.setTorchModeOnWithLevel(1.0, error:nil)

both of them are related to exception handling but I don't know how to resolve them.

回答1:

@IBAction func didTouchFlashButton(sender: UIButton) {
    let avDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)

    // check if the device has torch
    if avDevice.hasTorch {
        // lock your device for configuration
        do {
            let abv = try avDevice.lockForConfiguration()
        } catch {
            print("aaaa")
        }

        // check if your torchMode is on or off. If on turns it off otherwise turns it on
        if avDevice.torchActive {
            avDevice.torchMode = AVCaptureTorchMode.Off
        } else {
            // sets the torch intensity to 100%
            do {
                let abv = try avDevice.setTorchModeOnWithLevel(1.0)
            } catch {
                print("bbb")
            }
        //    avDevice.setTorchModeOnWithLevel(1.0, error: nil)
        }
        // unlock your device
        avDevice.unlockForConfiguration()
    }
}

回答2:

Swift 4 version, adapted from Ivan Slavov's answer. "TorchMode.auto" is also an option if you want to get fancy.

    @IBAction func didTouchFlashButton(_ sender: Any) {
    if let avDevice = AVCaptureDevice.default(for: AVMediaType.video) {
        if (avDevice.hasTorch) {
            do {
                try avDevice.lockForConfiguration()
            } catch {
                print("aaaa")
            }

            if avDevice.isTorchActive {
                avDevice.torchMode = AVCaptureDevice.TorchMode.off
            } else {
                avDevice.torchMode = AVCaptureDevice.TorchMode.on
            }
        }
        // unlock your device
        avDevice.unlockForConfiguration()
    }
}

回答3:

for some reason "avDevice.torchActive" is always false, even when the torch is on, making it impossible to turn off but I fixed it by declaring a boolean initially set to false and every time the flash turns on, the boolean is set to true.

var on: Bool = false    

@IBAction func didTouchFlashButton(sender: UIButton) {
let avDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)

// check if the device has torch
if avDevice.hasTorch {
    // lock your device for configuration
    do {
        let abv = try avDevice.lockForConfiguration()
    } catch {
        print("aaaa")
    }

    // check if your torchMode is on or off. If on turns it off otherwise turns it on
    if on == true {
        avDevice.torchMode = AVCaptureTorchMode.Off
        on = false
    } else {
        // sets the torch intensity to 100%
        do {
            let abv = try avDevice.setTorchModeOnWithLevel(1.0)
            on = true
        } catch {
            print("bbb")
        }
    //    avDevice.setTorchModeOnWithLevel(1.0, error: nil)
    }
    // unlock your device
    avDevice.unlockForConfiguration()
}

}

回答4:

import AVFoundation

var videoDeviceInput: AVCaptureDeviceInput?
var movieFileOutput: AVCaptureMovieFileOutput?
var stillImageOutput: AVCaptureStillImageOutput?

Add a class method to ViewController.

class func setFlashMode(flashMode: AVCaptureFlashMode, device: AVCaptureDevice){

        if device.hasFlash && device.isFlashModeSupported(flashMode) {
            var error: NSError? = nil
            do {
                try device.lockForConfiguration()
                device.flashMode = flashMode
                device.unlockForConfiguration()
            } catch let error1 as NSError {
                error = error1
                print(error)
            }
        }

    }

Check the flashmode status.

// Flash set to Auto/Off for Still Capture
                print("flashMode.rawValue : \(self.videoDeviceInput!.device.flashMode.rawValue)")
                if(self.videoDeviceInput!.device.flashMode.rawValue == 1)
                {
                    CameraViewController.setFlashMode(AVCaptureFlashMode.On, device: self.videoDeviceInput!.device)
                }
                else if (self.videoDeviceInput!.device.flashMode.rawValue == 2)
                {
                    CameraViewController.setFlashMode(AVCaptureFlashMode.Auto, device: self.videoDeviceInput!.device)
                }
                else
                {
                    CameraViewController.setFlashMode(AVCaptureFlashMode.Off, device: self.videoDeviceInput!.device)
                }

来源：https://stackoverflow.com/questions/33585353/how-to-turn-the-iphone-camera-flash-on-off-swift-2