ios 如何快速打开和关闭手电筒？

How to turn flashlight ON and OFF in swift?

提问by Lachtan

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

我想在 Swift 中为我的应用程序添加手电筒功能。我该怎么做呢？

回答by Lyndsey Scott

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

更新＃1： （torchActive没有返回预期值，这或许是因为它已经修改）

Update #2:For Swift 2.0

更新 #2：对于 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:

要将闪光灯从开切换到关（不仅仅是疯猪的回答中的“开”），您可以使用以下方法：

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.

我使用嵌套的 do-catch 块来实现来自评论的 Awesomeness 的建议。这样，即使try device.setTorchModeOnWithLevel(1.0)失败，设备也能正确解锁以进行配置。

Update #3:For Swift 4:

更新 #3：对于 Swift 4：

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

（我根据个人口味对代码进行了一些编辑）

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:

原答案：

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

要将闪光灯从开切换到关（不仅仅是疯猪的回答中的“开”），您可以使用以下方法：

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by Joshua Dance

Updated Swift 4 Answer:

更新 Swift 4 答案：

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.

然后要实际打开或关闭它，请调用该函数并传入 true 或 false 布尔值。

toggleTorch(on: true)of toggleTorch(on: false)

toggleTorch(on: true)的 toggleTorch(on: false)

I got this answer from Hacking with Swift, however their example had an error in it.

我从Hacking with Swift得到了这个答案，但是他们的例子中有一个错误。

They used AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)but this produces an error saying defaultDevicedoesn't exist. So I changed it to AVCaptureDevice.default(for: AVMediaType.video)

他们使用了，AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)但这会产生一个错误defaultDevice，说不存在。所以我把它改成AVCaptureDevice.default(for: AVMediaType.video)

回答by gpichler

I've updated @Lyndsey Scott's great answer for Swift 2.0

我已经更新了@Lyndsey Scott 对 Swift 2.0 的精彩回答

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by Chuy47

For swift 3

快速 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by mad pig

Like so:

像这样：

 func turnTorchOn(){

    let device = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
    if device.hasTorch {
        device.lockForConfiguration(nil)
        device.setTorchModeOnWithLevel(1.0, error: nil)
        device.unlockForConfiguration()
    }


}

回答by Lance

For xcode 9.1, swift 4 (updated to not crash if no torch):

对于 xcode 9.1，swift 4（更新为如果没有火炬则不会崩溃）：

   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by Alessandro Francucci

Swift 5

斯威夫特 5

The solution was already written by many, but I want to propose also the more concise one I came up in my project:

该解决方案已经由许多人编写，但我还想提出我在项目中提出的更简洁的解决方案：

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 device.setTorchModeOn(level: AVCaptureDevice.maxAvailableTorchLevel.significand) }
        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.

正如评论中提到的，您还可以在打开时更改手电筒级别，我觉得这非常方便。

Also import AVFoundation to use torch.

同时导入 AVFoundation 以使用火炬。

回答by Anup Gupta

Solution For Swift 4With Condition torchis available or not

Swift 4With Condition手电筒的解决方案是否可用

 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 DanceAnd @Lance

解决方案是@Joshua Dance和@Lance 的组合

回答by christopher saez

Swift 4.2

斯威夫特 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by Mauricio Caro

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)
            }
        }
    }