How do you set a device's flash mode in Swift 4? - ios

Question

I'm calling a function to attempt to turn on my device's flash:
private func flashOn(device:AVCaptureDevice)
{
print("flashOn called");
do {
try device.lockForConfiguration()
// line below returns warning 'flashMode' was deprecated in iOS 10.0: Use AVCapturePhotoSettings.flashMode instead.
device.flashMode = AVCaptureDevice.FlashMode.auto
device.unlockForConfiguration()
} catch {
// handle error
print("flash on error");
}
}
Setting device.flashMode to AVCaptureDevice.FlashMode.auto brings up the warning "'flashMode' was deprecated in iOS 10.0: Use AVCapturePhotoSettings.flashMode instead.". Even though it is just a warning, it does not enable the flash when testing my app, so I change that line to:
device.flashMode = AVCaptureDevice.FlashMode.auto
So I set the line to this, like it suggests:
AVCapturePhotoSettings.flashMode = AVCaptureDevice.FlashMode.auto
And I get the error "Instance member 'flashMode' cannot be used on type 'AVCapturePhotoSettings'"
So I have no idea how to set the flash in Xcode version 9 using Swift 4.0. All the answers I've found in Stack Overflow have been for previous versions.

Answer 1

I've been facing the same problem. Unfortunately, many useful methods got deprecated in iOS10 and 11. Here is how I managed to resolve it:
AVCapturePhotoSettings object is unique and cannot be reused, so you need to get new settings every time using this method:
/// the current flash mode
private var flashMode: AVCaptureDevice.FlashMode = .auto
/// Get settings
///
/// - Parameters:
/// - camera: the camera
/// - flashMode: the current flash mode
/// - Returns: AVCapturePhotoSettings
private func getSettings(camera: AVCaptureDevice, flashMode: AVCaptureDevice.FlashMode) -> AVCapturePhotoSettings {
let settings = AVCapturePhotoSettings()
if camera.hasFlash {
settings.flashMode = flashMode
}
return settings
}
As you can see, lockConfiguration is not needed.
Then simply use it while capturing photo:
#IBAction func captureButtonPressed(_ sender: UIButton) {
let settings = getSettings(camera: camera, flashMode: flashMode)
photoOutput.capturePhoto(with: settings, delegate: self)
}
Hope it will help.

Answer 2

For objective C:
- (IBAction)turnTorchOn: (UIButton *) sender {
sender.selected = !sender.selected;
BOOL on;
if (sender.selected) {
on = true;
} else {
on = false;
}
// check if flashlight available
Class captureDeviceClass = NSClassFromString(#"AVCaptureDevice");
if (captureDeviceClass != nil) {
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
AVCapturePhotoSettings *photosettings = [AVCapturePhotoSettings photoSettings];
if ([device hasTorch] && [device hasFlash]) {
[device lockForConfiguration:nil];
if (on) {
[device setTorchMode:AVCaptureTorchModeOn];
photosettings.flashMode = AVCaptureFlashModeOn;
//torchIsOn = YES; //define as a variable/property if you need to know status
} else {
[device setTorchMode:AVCaptureTorchModeOff];
photosettings.flashMode = AVCaptureFlashModeOn;
//torchIsOn = NO;
}
[device unlockForConfiguration];
}
}
}