ios - 在我的相机应用程序 ios (xcode) 上，当我拍照时，我按下一个按钮来查看图像，但是当我按下一个按钮返回相机时，她卡住了

Question

这是我的viewcontroller.m

#import "ViewController.h"
#import <AVFoundation/AVFoundation.h>
#import "ShowPhotoViewController.h"
@interface ViewController ()

@end

@implementation ViewController
AVCaptureSession *session;
AVCaptureStillImageOutput *stillImageOutput;

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

}

-(void)viewWillAppear:(BOOL)animated{
    session = [[AVCaptureSession alloc]init];
    [session setSessionPreset:AVCaptureSessionPresetPhoto];

    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.frameForCapture.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];
}




- (IBAction)takePhoto:(id)sender {
   // ShowPhotoViewController* showPhotoCtrl = segue.destinationViewController;
    AVCaptureConnection *videoConnection = nil;
    for (AVCaptureConnection *connection in stillImageOutput.connections) {
      for (AVCaptureInputPort *port in [connection inputPorts]) {
          if ([[port mediaType] isEqual:AVMediaTypeVideo]) {
              videoConnection = connection;
              break;
          }
      }
        if (videoConnection) {
            break;
        }
    }
    [stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) {
        if (imageDataSampleBuffer != NULL) {
            NSData *imageDate = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer];
            UIImage *image = [UIImage imageWithData:imageDate];
            self.imageView.image = image;


        }
    }];
}
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
    //openSecondScreen

    if([segue.identifier isEqualToString:@"goToShow"]){
    ShowPhotoViewController* showPhotoCtrl = segue.destinationViewController;
       showPhotoCtrl.image = self.imageView.image;

    }
}

-(IBAction)backToFirstScreen:(UIStoryboardSegue*)sender{

}


@end

我的 ShowPhotoViewController.m

#import "ShowPhotoViewController.h"

@interface ShowPhotoViewController ()

@end

@implementation ShowPhotoViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.showPhoto.image = self.image;
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/

@end

所以当我拍照并按下显示按钮时，他会带我到 ShowPhotoViewController然后在 ShowPhotoViewController 中我按回他带我到 ViewController 但相机卡住

有人有什么建议吗？

谢谢你!

Answer 1

这可能是由于您从 ShowPhotoViewController 弹出时重新分配和设置，因为初始化设置已写入-(void)viewWillAppear:(BOOL)animated 方法。因为只要 View 出现，就会调用此方法。因此，最好通过使用一些标志(如 isFirstTime)来管理初始化方法只工作一次。