问题
I'd like to add flashlight functionality to my app in Swift. How can I go about doing that?
回答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()
}
}
回答2:
I've updated @Lyndsey Scott's great answer for Swift 2.0
let device = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
if (device.hasTorch) {
do {
try device.lockForConfiguration()
if (device.torchMode == AVCaptureTorchMode.On) {
device.torchMode = AVCaptureTorchMode.Off
} else {
try device.setTorchModeOnWithLevel(1.0)
}
device.unlockForConfiguration()
} catch {
print(error)
}
}
回答3:
Updated Swift 4 Answer:
func toggleTorch(on: Bool) {
guard
let device = AVCaptureDevice.default(for: AVMediaType.video),
device.hasTorch
else { return }
do {
try device.lockForConfiguration()
device.torchMode = on ? .on : .off
device.unlockForConfiguration()
} catch {
print("Torch could not be used")
}
}
Then to actually turn it on or off, call the function and pass in a true or false boolean.
toggleTorch(on: true) of toggleTorch(on: false)
I got this answer from Hacking with Swift, however their example had an error in it.
They used AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo) but this produces an error saying defaultDevice doesn't exist. So I changed it to AVCaptureDevice.default(for: AVMediaType.video)
回答4:
For swift 3
func toggleFlash() {
if let device = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo), device.hasTorch {
do {
try device.lockForConfiguration()
let torchOn = !device.isTorchActive
try device.setTorchModeOnWithLevel(1.0)
device.torchMode = torchOn ? .on : .off
device.unlockForConfiguration()
} catch {
print("error")
}
}
}
回答5:
Like so:
func turnTorchOn(){
let device = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
if device.hasTorch {
device.lockForConfiguration(nil)
device.setTorchModeOnWithLevel(1.0, error: nil)
device.unlockForConfiguration()
}
}
回答6:
For xcode 9.1, swift 4 (updated to not crash if no torch):
func toggleFlash() {
let device = AVCaptureDevice.default(for: AVMediaType.video)
if (device != nil) {
if (device!.hasTorch) {
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)
}
}
}
}
回答7:
Solution For Swift 4 With Condition torch is available or not
func flashlight() {
guard let device = AVCaptureDevice.default(for: AVMediaType.video) else{
return
}
if (device.hasTorch) {
do {
try device.lockForConfiguration()
if (device.torchMode == .on) {
device.torchMode = .off
} else {
device.torchMode = .on
}
device.unlockForConfiguration()
} catch {
print("Torch could not be used")
print(error)
}
}
else{
print("Torch is not available")
}
}
The Solution is Combination of @Joshua Dance And @Lance
回答8:
Swift 4.2
if let device = AVCaptureDevice.default(for: AVMediaType.video) {
if (device.hasTorch) {
do {
try device.lockForConfiguration()
let torchOn = !device.isTorchActive
try device.setTorchModeOn(level: 1.0)
device.torchMode = torchOn ? AVCaptureDevice.TorchMode.on : AVCaptureDevice.TorchMode.off
device.unlockForConfiguration()
} catch {
print(error.localizedDescription)
}
}
}
回答9:
Swift 5
The solution was already written by many, but I want to propose also the more concise one I came up in my project:
func toggleTorch(on: Bool) {
guard let device = AVCaptureDevice.default(for: AVMediaType.video) else { return }
guard device.hasTorch else { print("Torch isn't available"); return }
do {
try device.lockForConfiguration()
device.torchMode = on ? .on : .off
// Optional thing you may want when the torch it's on, is to manipulate the level of the torch
if on { try captureDevice.setTorchModeOn(level: AVCaptureDevice.maxAvailableTorchLevel) }
device.unlockForConfiguration()
} catch {
print("Torch can't be used")
}
}
As mentioned in the comment, you can also change the torch level when it's on, which I find quite handy.
回答10:
Swift 4.1
@objc func Flash() {
let device = AVCaptureDevice.default(for: AVMediaType.video)
if (device?.hasTorch)! {
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)
}
}
}
来源：https://stackoverflow.com/questions/27207278/how-to-turn-flashlight-on-and-off-in-swift