像本机相机应用程序一样执行闪光（灯光）

Question

我如何像本机相机应用一样执行闪光？ 我发现以下代码可以打开灯，但是我需要拍摄快照。

if(self.videoDevice.hasTorch) {
    [self.videoDevice lockForConfiguration:nil];
    [self.videoDevice setTorchModeOnWithLevel: 1.0 error: nil];
    [self.videoDevice unlockForConfiguration];
}

Answer 1

试试这个。 似乎与您期望的一样

http://iosdevelopertips.com/camera/flashlight-application-using-the-iphone-led.html

Answer 2

您必须将TorchLevel设置在0.0到1.0之间，然后在非常小的间隔内再次设置为0.0。

- (BOOL)setTorchModeOnWithLevel:(float)torchLevel error:(NSError **)outError

Answer 3

试试这个代码：

- (void)turnOnCamerFlash
{
    if (NSClassFromString(@"AVCaptureDevice") != nil)
    {
        AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

        if ([device hasTorch])
        {
            [device lockForConfiguration:nil];
            [device setTorchMode:AVCaptureTorchModeOn];
            [device unlockForConfiguration];
        }       
    }
}

Answer 4

它接缝那里没有闪光灯功能，所以执行闪光灯的（唯一的？）可能性是使用计时器。

    - (IBAction)doFlash:(id)sender {
        if(self.videoDevice.hasTorch) {
            flashCounter = 0;
            [NSTimer scheduledTimerWithTimeInterval: 0.1
                                             target:self
                                           selector:@selector(flashLightTicker:)
                                           userInfo:nil
                                            repeats: YES];
        }
    }

    - (void)flashLightTicker:(id)sender {
        [self.videoDevice lockForConfiguration:nil];
        if(flashCounter == 0) {
            [self.videoDevice setTorchModeOnWithLevel: 0.1 error: nil];
        }
        if(flashCounter == 5) {
            [self.videoDevice setTorchMode: AVCaptureTorchModeOff];
        }
        if(flashCounter == 7) {
            [self.videoDevice setTorchModeOnWithLevel: AVCaptureMaxAvailableTorchLevel error: nil];
        }
        if(flashCounter >= 10) {
            [self.videoDevice setTorchMode: AVCaptureTorchModeOff];
            [sender invalidate];
        }
        [self.videoDevice unlockForConfiguration];
        flashCounter++;
    }