-initWithContentsOfFile:对于NSMutableArray

Question

我将图片存储在NSMutableArray中，现在我正在尝试让它们显示在viewDidLoad中。我试着给initWithContentsOfFile打电话，但似乎不起作用。代码是这样的：imageView.image = [[UIImage alloc] initWithContentsOfFile:[self.array objectAtIndex:0]];

我不确定我应该使用什么来代替initWithContentsOfFile来加载保存的图像，我甚至不确定我是否可以通过用户默认设置将图像保存在plist中。我已经研究了一段时间了，但一无所获。任何帮助都非常感谢，谢谢！

编辑:以下是附加代码：

- (IBAction)grabImage {
    self.imgPicker = [[UIImagePickerController alloc] init];
    self.imgPicker.delegate = self;
    self.imgPicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;

    if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad) {
        _popover = [[UIPopoverController alloc] initWithContentViewController:imgPicker];
        [_popover presentPopoverFromRect:self.imageView.bounds inView:self.imageView permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];
    } 

    else {
        [self presentModalViewController:imgPicker animated:YES];
    }
    [self.imgPicker resignFirstResponder];
}
// Sets the image in the UIImageView
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)img editingInfo:(NSDictionary *)editInfo {
    if (imageView.image == nil) {
        imageView.image = img;

        [self.array addObject:imageView.image];

        [picker dismissModalViewControllerAnimated:YES];
        [self.popover dismissPopoverAnimated:YES];
        return;

    }

    if (imageView2.image == nil) {
        imageView2.image = img;
        NSLog(@"The image is a %@", imageView);
        [self.array addObject:imageView2.image];

        [picker dismissModalViewControllerAnimated:YES];
        [self.popover dismissPopoverAnimated:YES];
        return;
    }

    if (imageView3.image == nil) {
        imageView3.image = img;

        [self.array addObject:imageView3.image];

        [picker dismissModalViewControllerAnimated:YES];
        [self.popover dismissPopoverAnimated:YES];
        return;
    }
}

- (void)applicationDidEnterBackground:(UIApplication*)application {
    NSLog(@"Image on didenterbackground: %@", imageView);

   [self.array addObject:imageView.image];
    [self.array addObject:imageView2.image];
     [self.array addObject:imageView3.image];


            [self.user setObject:self.array forKey:@"images"];
    [user synchronize];

            }

- (void)viewDidLoad
    {
        self.user = [NSUserDefaults standardUserDefaults];
        NSLog(@"It is %@", self.user);
        self.array = [[self.user objectForKey:@"images"]mutableCopy];
        imageView.image = [[UIImage alloc] initWithContentsOfFile:[self.array objectAtIndex:0]];
        imageView2.image = [[UIImage alloc] initWithContentsOfFile:[self.array objectAtIndex:1]];
        imageView3.image = [[UIImage alloc] initWithContentsOfFile:[self.array objectAtIndex:2]];




        UIApplication *app = [UIApplication sharedApplication];
        [[NSNotificationCenter defaultCenter] addObserver:self
                                                 selector:@selector(applicationDidEnterBackground:)
                                                     name:UIApplicationDidEnterBackgroundNotification
                                                   object:app];

        backToGalleryButton.hidden = YES;
        tapToDeleteLabel.hidden = YES;
        deleteButton1.hidden = YES;
        [super viewDidLoad];

    }

编辑:这就是我如何标记图像，并根据它们的标记删除它们：

- (IBAction)deleteButtonPressed:(id)sender {
    NSLog(@"Sender is %@", sender);
    UIAlertView *deleteAlertView = [[UIAlertView alloc] initWithTitle:@"Delete"
                                                              message:@"Are you sure you want to delete this photo?"
                                                             delegate:self
                                                    cancelButtonTitle:@"No"
                                                    otherButtonTitles:@"Yes", nil];
    [deleteAlertView show];

    int imageIndex = ((UIButton *)sender).tag;
    deleteAlertView.tag = imageIndex;
}

- (UIImageView *)viewForTag:(NSInteger)tag {
    UIImageView *found = nil;
    for (UIImageView *view in self.array) {
        if (tag == view.tag) {
            found = view;
            break;
        }
    }
    return found;
}

- (void)alertView: (UIAlertView *) alertView 
clickedButtonAtIndex: (NSInteger) buttonIndex
{


    if (buttonIndex != [alertView cancelButtonIndex]) {
        NSLog(@"User Clicked Yes. Deleting index %d of %d", alertView.tag, [array count]);
        NSLog(@"The tag is %i", alertView.tag);

        UIImageView *view = [self viewForTag:alertView.tag];
        if (view) {
            [self.array removeObject:view];
        }

        NSLog(@"After deleting item, array count  = %d", [array count]);
    NSLog(@"Returned view is :%@, in view: %@", [self.view viewWithTag:alertView.tag], self.view);
        ((UIImageView *)[self.view viewWithTag:alertView.tag]).image =nil;
    }

    [self.user setObject:self.array forKey:@"images"];
}

Answer 1

问题是，您不能将图像存储在属性列表中，而当您将其保存在用户默认设置中时，您就会尝试这样做。您需要使用归档程序将图像转换为可以存储的NSData对象。

Answer 2

看起来您没有将有效的图像路径传递给初始化器方法。确保路径正确，并且包含图像扩展名。

不过，在这种情况下，你真的不应该调用initWithContentsOfFile:，因为UIImageView的image属性在你设置图像时会保留图像。这通常会导致内存泄漏(除非你正在使用自动引用计数)。请改用一个静态初始化器，比如imageNamed:，它的额外好处是使用系统缓存，并根据设备的特征自动加载正确版本的图像(例如，如果设备有视网膜显示器，它将加载图像的更高分辨率变体)。