如何在Swift 4中设置设备的闪存模式？

Question

我调用一个函数试图打开设备的闪光灯：

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");
    }

}

将device.flashMode设置为AVCaptureDevice.FlashMode.auto将显示警告"'flashMode‘在iOS 10.0中被废弃:使用AVCapturePhotoSettings.flashMode代替。“尽管这只是一个警告，但它在测试我的应用程序时不启用闪存，所以我将该行更改为：

device.flashMode = AVCaptureDevice.FlashMode.auto

所以我设定了这条线，就像它所暗示的：

AVCapturePhotoSettings.flashMode = AVCaptureDevice.FlashMode.auto

我得到错误“实例成员'flashMode‘不能在’AVCapturePhotoSettings‘类型上使用

因此，我不知道如何使用SWIFT4.0在Xcode版本9中设置闪存。我在Stack溢出中找到的所有答案都是针对早期版本的。

Answer 1

我也面临着同样的问题。不幸的是，许多有用的方法在iOS10和11中被废弃了。

AVCapturePhotoSettings对象是唯一的，不能重用，因此每次使用此方法都需要获得新的设置：

/// 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
}

如您所见，不需要lockConfiguration。

然后在拍摄照片时使用它：

 @IBAction func captureButtonPressed(_ sender: UIButton) {
    let settings = getSettings(camera: camera, flashMode: flashMode)
    photoOutput.capturePhoto(with: settings, delegate: self)
}

希望能帮上忙。

Answer 2

关于目标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];
        }
    }
 }