打开闪光灯的代码

1.比较常用，也比较简单，因此粘贴到这里

 1 - (void)onFlash:(UIButton *)sender{
 2
 3     AVCaptureDevice *avDevice = self.device;
 4     if (![avDevice hasFlash] || ![avDevice hasTorch]) {
 5         UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"" message:@"打开摄像头失败！请检测您的摄像头！" delegate:nil cancelButtonTitle:@"确定" otherButtonTitles: nil, nil];
 6         [alert show];
 7         return;
 8     }
 9
10     sender.selected = !sender.selected;
11     [self openFlashLight:sender];
12 }
13
14 - (void)openFlashLight:(UIButton *)sender
15 {
16     AVCaptureSession *avSession = self.captureSession;
17     AVCaptureDevice *avDevice = self.device;
18     if (sender.selected) {
19         if (avDevice.torchMode == AVCaptureTorchModeOff) {
20             [avSession beginConfiguration];
21             [avDevice lockForConfiguration:nil];
22             [avDevice setTorchMode:AVCaptureTorchModeOn];
23             [avDevice setFlashMode:AVCaptureFlashModeOn];
24             [avDevice unlockForConfiguration];
25         }
26     }
27     else
28     {
29         if (avDevice.torchMode == AVCaptureTorchModeOn) {
30             [avSession beginConfiguration];
31             [avDevice lockForConfiguration:nil];
32             [avDevice setTorchMode:AVCaptureTorchModeOff];
33             [avDevice setFlashMode:AVCaptureFlashModeOff];
34             [avDevice unlockForConfiguration];
35         }
36     }
37 }