Question

我遇到了与UIImageView相关的内存问题。将此视图添加到我的UIScrollView后，如果我尝试释放UIImageView，应用程序崩溃。根据堆栈跟踪，调用[UIImageView dealloc]后会调用[UIImageView stopAnimating]。但是，如果我不释放视图，则内存永远不会被释放，并且我已经确认在解除分配后视图上仍有一个额外的保留调用...这导致我的总分配快速攀升并最终导致应用程序崩溃多次加载视图后。我不确定我在这里做错了什么......我不知道在它发布之后是什么试图访问UIImageView。我已经在下面包含了相关的头文件和实现代码（我正在使用Three20框架，如果它与它有任何关系......另外，AppScrollView只是一个UIScrollView，它将touchesEnded事件转发给下一个响应者）： / p>

部首：

@interface PhotoHiResPreviewController : TTViewController <UIScrollViewDelegate> {

    NSString* imageURL;
    UIImage* hiResImage;
    UIImageView* imageView;
    UIView* mainView;
    AppScrollView* mainScrollView;
}

@property (nonatomic, retain) NSString* imageURL;
@property (nonatomic, retain) NSString* imageShortURL;
@property (nonatomic, retain) UIImage* hiResImage;
@property (nonatomic, retain) UIImageView* imageView;

- (id)initWithImageURL:(NSString*)imageTTURL;

实现：

@implementation PhotoHiResPreviewController

@synthesize imageURL, hiResImage, imageView;


- (id)initWithImageURL:(NSString*)imageTTURL {

    if (self = [super init]) {

        hiResImage = nil;

        NSString *documentsDirectory = [NSString stringWithString:[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject]];
        [self setImageURL:[NSString stringWithFormat:@"%@/%@.jpg", documentsDirectory, imageTTURL]];
    }
    return self;
}

- (void)loadView {

    [super loadView];

    // Initialize the scroll view   
    hiResImage = [UIImage imageWithContentsOfFile:self.imageURL];
    CGSize photoSize = [hiResImage size];
    mainScrollView = [[AppScrollView alloc] initWithFrame:[UIScreen mainScreen].bounds];
    mainScrollView.autoresizingMask = ( UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight);
    mainScrollView.backgroundColor = [UIColor blackColor];
    mainScrollView.contentSize = photoSize;
    mainScrollView.contentMode = UIViewContentModeScaleAspectFit;
    mainScrollView.delegate = self;

    // Create the image view and add it to the scrollview.
    UIImageView *tempImageView = [[UIImageView alloc] initWithFrame:CGRectMake(0.0, 0.0, photoSize.width, photoSize.height)];
    tempImageView.contentMode = UIViewContentModeCenter;
    [tempImageView setImage:hiResImage];
    self.imageView = tempImageView;
    [tempImageView release];    
    [mainScrollView addSubview:imageView];

    // Configure zooming.
    CGSize screenSize = [[UIScreen mainScreen] bounds].size;
    CGFloat widthRatio = screenSize.width / photoSize.width;
    CGFloat heightRatio = screenSize.height / photoSize.height;
    CGFloat initialZoom = (widthRatio > heightRatio) ? heightRatio : widthRatio;
    mainScrollView.maximumZoomScale = 3.0;
    mainScrollView.minimumZoomScale = initialZoom;
    mainScrollView.zoomScale = initialZoom;
    mainScrollView.bouncesZoom = YES;

    mainView = [[UIView alloc] initWithFrame:[UIScreen mainScreen].bounds];
    mainView.autoresizingMask = ( UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight);
    mainView.backgroundColor = [UIColor blackColor];
    mainView.contentMode = UIViewContentModeScaleAspectFit;
    [mainView addSubview:mainScrollView];   

    // Add to view  
    self.view = mainView;
    [imageView release];
    [mainScrollView release];   
    [mainView release];
}

- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
    return imageView;
}

- (void)dealloc {

    mainScrollView.delegate = nil;
    TT_RELEASE_SAFELY(imageURL);
    TT_RELEASE_SAFELY(hiResImage);
    [super dealloc];
}

我不知道如何解决这个问题。如果我在loadView方法结束时删除对[imageView release]的调用，一切正常......但我有大量的分配，很快就会爬到一个突破点。但是，如果我发布它，则会在取消分配视图后发生[UIImageView stopAnimating]调用，导致应用程序崩溃。

感谢您的帮助！几天来，我一直在抨击这个。 :-P

干杯，约西亚

Answer 1

在设置它之前移动imageView的版本。这样，在更改imageView指针指向的位置之前释放对象：

// Create the image view and add it to the scrollview.
UIImageView *tempImageView = [[UIImageView alloc] initWithFrame:CGRectMake(0.0, 0.0, photoSize.width, photoSize.height)];
tempImageView.contentMode = UIViewContentModeCenter;
[tempImageView setImage:hiResImage];
// release old object
[imageView release];
// set the pointer to point at a new object
self.imageView = tempImageView;
[tempImageView release];    
[mainScrollView addSubview:imageView];

然后在您释放其他对象的方法的底部，删除以下行：

[imageView release];

Answer 2

理想情况下，类级变量应该在类'dealloc（）方法

中发布

看起来imgView是一个类级变量，你在方法调用结束时释放它。

如果你想在方法结束时发布一个变量 - 它应该是一个方法级变量。因此，在您的情况下，尝试使imgView成为方法级变量。然后你应该能够在方法结束时释放它而没有任何问题

Answer 3

为什么要创建临时视图？你不止一次打电话给loadView吗？

self.imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0.0, 0.0, photoSize.width, photoSize.height)];
[self.imageView setContentMode:UIViewContentModeCenter];
[self.imageView setImage:hiResImage];
[mainScrollView addSubview:self.imageView];
[self.imageView release]

或者在dealloc中释放它，因为它是一个实例变量？ addSubview保留你的UIImageView，所以如果因为对象不存在而崩溃会很奇怪。你试过设置断点吗？

添加到UIScrollView后发布UIImageView时出现问题

3 个答案: