objective-c – 使用UIImagePickerController保存的图像进行内存管理

我正在编写一个应用程序,用户自己拍摄照片,然后通过一系列视图使用导航控制器调整图像.如果用户使用前置摄像头拍摄照片(在支持它的设备上设置为默认设置),这种方法非常好,但是当我重复这个过程时,我会大约一半时间,并在发出内存警告后崩溃. @H_874_2@在使用仪器进行分析后,我发现当使用较低分辨率的前置摄像头图像时,我的应用程序内存占用大约保持在20-25 MB,但使用后置摄像头时,每次视图更改都会增加33 MB左右,直到崩溃大约350 MB(在一个4S)

@H_874_2@下面是我用来处理将照片保存到文档目录,然后读取该文件位置以将图像设置为UIImageView的代码.此代码的“读取”部分通过多个视图控制器(viewDidLoad)进行回收,以便将我保存的图像设置为每个视图中的背景图像.

@H_874_2@我删除了所有的图像修改代码,将其剥离到试图隔离问题的最小值,我似乎无法找到它.就目前而言,所有应用程序都会在第一个视图中拍摄照片,然后将该照片用作大约10个以上视图的背景图像,并在用户浏览视图堆栈时进行分配.

@H_874_2@现在显然更高分辨率的照片会占用更多内存,但我不明白的是,为什么低分辨率照片似乎没有使用越来越多的内存,而高分辨率照片不断使用越来越多直到崩溃.

@H_874_2@我如何保存和阅读图像：

- (void) imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    UIImage *image = [info objectForKey:@"UIImagePickerControllerOriginalImage"];    
    jpgData = UIImageJPEGRepresentation(image,1);

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);  
    NSString *documentsPath = [paths objectATindex:0];
    filePath = [documentsPath StringByAppendingPathComponent:@"image.jpeg"];
    [jpgData writeToFile:filePath atomically:YES];    

    [self dismissModalViewControllerAnimated:YES];
    [disableNextButton setEnabled:YES];

    jpgData = [NSData dataWithContentsOfFile:filePath];
    UIImage *image2 = [UIImage imageWithData:jpgData];
    [imageView setImage:image2];
}

@H_874_2@现在我知道我可以在保存之前尝试缩放图像,我计划在接下来查看,但我不明白为什么这不起作用.也许我错误地认为ARC在离开堆栈顶部时会自动释放视图及其子视图.

@H_874_2@任何人都可以解释为什么我要存储我的设备内存？ (希望简单的事情,我完全忽略了)我是不是设法把ARC抛到窗外？

@H_874_2@编辑：我如何在其他视图中调用图像

- (void)loadBACkground
{
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,YES);  
    NSString *documentsPath = [paths objectATindex:0];
    NSString *filePath = [documentsPath StringByAppendingPathComponent:@"image.jpeg"];
    UIImage *image = [UIImage imageWithContentsOfFile:filePath];
    [BACkgroundImageView setImage:image];

}

@H_874_2@如何建立视图控制器之间的导航：

@H_874_2@编辑2：

@H_874_2@我的基本声明是什么样的：

#import <UIKit/UIKit.h>
#import <AVFoundation/AVFoundation.h>
@interface PhotoPickerViewController : UIViewController <UIImagePickerControllerDelegate,UINavigationControllerDelegate>
{
    IBOutlet UIImageView *imageView;
    NSData *jpgData;
    NSString *filePath;
    UIImagePickerController *imagePicker;
    IBOutlet UIBarButtonItem *disableNextButton;
}


@end

@H_874_2@如果相关,我如何调用我的图像选择器：

- (void)callCameraPicker
{


    if ([UIImagePickerController issourceTypeAvailable:UIImagePickerControllersourceTypeCamera] == YES)
    {
        NSLog(@"Camera is available and ready");

        imagePicker.sourCEType =  UIImagePickerControllersourceTypeCamera;
        imagePicker.delegate = self;
        imagePicker.allowsEdiTing = NO;
        imagePicker.cameraCaptureMode = UIImagePickerControllerCameraCaptureModePhoto;

        NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo]; for (AVCaptureDevice *device in devices) 
        {
            if([[UIScreen mainScreen] respondsToSELEctor:@SELEctor(scalE)] && [[UIScreen mainScreen] scale] == 2.0) 
            {
                imagePicker.cameraDevice = UIImagePickerControllerCameraDeviceFront;


            }
        }


        imagePicker.modalTransitionStyle = UIModalTransitionStyleCoverVertical;

        [self presentModalViewController:imagePicker animated:YES];

    }


    else
    {
        NSLog(@"Camera is not available");
        UIAlertView *cameraAlert = [[UIAlertView alloc] initWithtitle:@"Error" 
                                                              message:@"Your device doesn't seem to have a camera!" 
                                                             delegate:self cancelButtontitle:@"Dismiss" 
                                                    otherButtontitles:nil];
        [cameraAlert show];

    }
}

@H_874_2@编辑3：我记录了viewDidUnload,它实际上没有被调用,所以我现在在viewWillAppear中调用loadBACkground并在viewDidDisappear中使我的BACkgroundImageView为nil.我希望这会有所帮助,但没有任何区别.

- (void)viewWillAppear:(BOOL)animated
{
    [self loadBACkground];
}


- (void)viewDidDisappear:(BOOL)animated
{
    NSLog(@"ViewDidDisappear");
    BACkgroundImageView = nil;
}