在我的应用程序中,我正在使用一个名为 ThumbDownloader 的类来实现延迟加载
要开始图像下载,我的 UITableView cellForRowAtIndexPath 方法调用此方法:
- (void)startIconDownload:(Product *)product forIndexPath:(NSIndexPath *)indexPath
{
ThumbDownloader *thumbDownloader = [imageDownloadsInProgress objectForKey:indexPath];
if (thumbDownloader == nil)
{
thumbDownloader = [[ThumbDownloader alloc] init];
thumbDownloader.product = product;
thumbDownloader.imageSizeWidth = 87;
thumbDownloader.imageSizeHeight = 87;
thumbDownloader.indexPathInTableView = indexPath;
thumbDownloader.delegate = self;
[imageDownloadsInProgress setObject:thumbDownloader forKey:indexPath];
[thumbDownloader startDownload];
[thumbDownloader release];
}
}
thumbdownloader 类在完成图片下载后,会调用我的主类 (listingView) 中的一个方法:
- (void)appImageDidLoad:(NSIndexPath *)indexPath
问题是,如果我在图片下载时进入listingView并快速离开,应用程序会崩溃:
-[listingView appImageDidLoad:]: message sent to deallocated instance 0x3beed10
这是我的dealloc
- (void)dealloc
{
[myTable release], myTable = nil;
[imageDownloadsInProgress release], imageDownloadsInProgress = nil;
[spinView release], spinView = nil;
[mainView release], mainView = nil;
[tableView release], tableView = nil;
[myVs release], myVs = nil;
[filteredVs release], filteredVs = nil;
[toolBar release], toolBar = nil;
[super dealloc];
}
我试图遍历 imageDownloadsInProgress 中的 Thumbdownloader 实例以将它们的代表设置为 nil,但是当我尝试它也崩溃时......就像这样:
- (void)dealloc
{
for(ThumbDownloader *thumbDownloader in imageDownloadsInProgress)
if(thumbDownloader !=nil && thumbDownloader.delegate!=nil)
thumbDownloader.delegate = nil;
.....