收到内存警告然后'丢失与iPhone的连接'。

Question

我使用以下代码段打开相机，点击照片并使用照片（当出现两个选项重新拍摄和使用照片时）。

- (IBAction)openCamera
{
    @autoreleasepool {
        [imageSpinner stopAnimating];
        [imageSpinner removeFromSuperview];
        [cameralabel setText:@""];
        if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
        {
            UIImagePickerController *imagePicker =
            [[UIImagePickerController alloc] init];
            imagePicker.delegate = self;
            imagePicker.sourceType =
            UIImagePickerControllerSourceTypeCamera;
            imagePicker.allowsEditing = NO;
            [self presentViewController:imagePicker animated:NO completion:nil];
            imagePicker=nil;
        }
    }
}

-(void)setImageSpinner
{
    @autoreleasepool {
        imageSpinner = nil;
        imageSpinner = [[UIActivityIndicatorView alloc]initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
        imageSpinner.center = self.view.center;
        [imageSpinner startAnimating];
        [self.view addSubview:imageSpinner];
        [self.view bringSubviewToFront:imageSpinner];
    }
}

- (void)viewDidLoad
{
    [self openCamera];
    [super viewDidLoad];
}

- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];
}

-(void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    [self.navigationController setToolbarHidden:YES];
    self.navigationItem.hidesBackButton = NO;
}

-(void)viewWillDisappear:(BOOL)animated
{
    [super viewWillDisappear:animated];
}

-(void)viewDidDisappear:(BOOL)animated
{
    [super viewDidDisappear:animated];
}

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
    NSString *savedImagePath;
    @autoreleasepool {
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        NSString *documentsDirectory = [paths objectAtIndex:0];
       savedImagePath = [documentsDirectory stringByAppendingPathComponent:@"Image 1.jpeg"];
        paths=nil;
        documentsDirectory=nil;
        [picker dismissViewControllerAnimated:NO completion:NULL];
        [cameralabel setText:@"Please wait"];
        [self setImageSpinner];
    }
    @autoreleasepool {
        ManifestDocumentViewController *manifestVC = [self.storyboard instantiateViewControllerWithIdentifier:@"manifestImage"];
        manifestVC.getTempFilePath = savedImagePath;
       if ([screenName isEqualToString:@"Retake"])
        {
            manifestVC.screenName = @"Retake";
            manifestVC.retakeFileID = retakeFileID;
            manifestVC.retakeFilePath = retakeFilePath;
            NSData *data = [NSData dataWithContentsOfFile:savedImagePath];
            [data writeToFile:retakeFilePath atomically:YES];
            data=nil;
        }
        else
        {
            manifestVC.screenName = @"Camera";
            UIImage *image = info[UIImagePickerControllerOriginalImage];
           NSData *imageData = [NSData dataWithData:UIImageJPEGRepresentation(image, 1.0f)];
            [imageData writeToFile:savedImagePath atomically:NO];
            image=nil;
            imageData=nil;
        }
        savedImagePath=nil;
       [self.navigationController pushViewController:manifestVC animated:YES];
    }
}

- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
{
    [picker dismissViewControllerAnimated:YES completion:NULL];
    picker.delegate=nil;
    picker=nil;
}

- (UIStatusBarStyle)preferredStatusBarStyle
{
    return UIStatusBarStyleLightContent;
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    [[NSURLCache sharedURLCache] removeAllCachedResponses];
}

在iPhone 4s上的调试会话期间，内存会突然增加，如调试导航器下的内存使用情况所示。附带的是Memory Usage比较的屏幕截图。 “其他流程”的加薪是一个值得关注的问题。

收到的内存警告也会出现在显示的日志中。在运行代码多次后应用程序崩溃（消息“丢失与iPhone的连接”）。这相当于内存中的峰值和完全消耗的“Free”内存。

可以尽可能优化上述代码，以确保尽可能减少内存使用量。