cocoa - 如何使用 AVCaptureFlashMode

Question

我正在制作一个应用程序，可以将图像拼接成全景场景。我希望能够以编程方式打开 iPhone 4 上的闪光灯 LED。

我该怎么做？

我阅读了文档，发现我需要使用 AVCaptureFlashMode

但我不知道2如何使用它？

如有任何帮助，我们将不胜感激。

<小时/>

更新了下面的代码。感谢 SIF!

NSError* error = nil;    NSLog(@"Setting up LED");    if([captDevice hasTorch] == NO)    {        NSLog(@"Error: This device doesnt have a torch");    }    if([captDevice isTorchModeSupported:AVCaptureTorchModeOn] == NO)    {        NSLog(@"Error: This device doesnt support AVCaptureTorchModeOn");    }    AVCaptureSession* captureSession = [[AVCaptureSession alloc] init];    AVCaptureDeviceInput* videoInput = [[AVCaptureDeviceInput alloc] initWithDevice:captDevice error:&error];    AVCaptureVideoDataOutput* videoOutput = [[AVCaptureVideoDataOutput alloc] init];    if (videoInput && videoOutput)     {        [captureSession addInput:videoInput];        [captureSession addOutput:videoOutput];        if([captDevice lockForConfiguration:&error])        {            if (flag == YES) {                captDevice.torchMode = AVCaptureTorchModeOn;            } else {                captDevice.torchMode = AVCaptureTorchModeOff;            }                       [captDevice unlockForConfiguration];        }        else         {            NSLog(@"Could not lock device for config error: %@", error);        }        [captureSession startRunning];    }    else     {        NSLog(@"Error: %@", error);    }

如何关闭它？

Answer 1

AVCaptureDevice* d = nil;

// find a device by position
NSArray* allDevices = [AVCaptureDevice devices];
for (AVCaptureDevice* currentDevice in allDevices) {
  if (currentDevice.position == AVCaptureDevicePositionBack) {
    d = currentDevice;
  }
}

// at this point, d may still be nil, assuming we found something we like....

NSError* err = nil;
BOOL lockAcquired = [d lockForConfiguration:&err];

if (!lockAcquired) {
   // log err and handle...
} else {
   // flip on the flash mode
   if ([d hasFlash] && [d isFlashModeSupported:AVCaptureFlashModeOn] ) {
      [d setFlashMode:AVCaptureFlashModeOn];
   }

   [d unlockForConfiguration];
}