Custom Camera View Not Working on iOS 8/Xcode 6

问题

So I had this code working on another app of mine to take photos on a custom camera view when I had iOS 7 on my phone and Xcode 5.1, now on iOS 8 and Xcode 6, the camera works but I can't see the live view of the camera in my leftVertical UIView. Here's my code, would appreciate any help Thanks!

#import <AVFoundation/AVFoundation.h>

session = [[AVCaptureSession alloc] init];
if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone)
    [session setSessionPreset:AVCaptureSessionPreset352x288];
else
    [session setSessionPreset:AVCaptureSessionPreset352x288];

AVCaptureDevice *inputDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
NSError *error;
AVCaptureDeviceInput *deviceInput = [AVCaptureDeviceInput deviceInputWithDevice:inputDevice error:&error];
if ([session canAddInput:deviceInput]) {
    [session addInput:deviceInput];
}

AVCaptureVideoPreviewLayer *previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
[previewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];

CALayer *rootLayer = [[self view] layer];
[rootLayer setMasksToBounds:YES];
CGRect frame = self.leftVertical.frame;

[previewLayer setFrame:frame];

[rootLayer insertSublayer:previewLayer atIndex:0];

//////////////////////////

stillImageOutput = [[AVCaptureStillImageOutput alloc] init];
NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys:AVVideoCodecJPEG, AVVideoCodecKey, nil];
[stillImageOutput setOutputSettings:outputSettings];

[session addOutput:stillImageOutput];

[session startRunning];

回答1:

try this...

In –viewWillAppear: start camera capture on main thread, like this..

dispatch_async(dispatch_get_main_queue(), ^{

if (![session isRunning])
    {              
            [session startRunning];
    }
});

来源：https://stackoverflow.com/questions/25986600/custom-camera-view-not-working-on-ios-8-xcode-6