NSDictionary 内存泄漏
我的代码有一个问题，我一生都无法弄清楚，即使这里之前的所有线程也无法解决。 我正在从 JSON 源中提取数据并将其放入 NSDictionary 中，如教程和 SO 中所述。在分析应用程序时，我注意到此 NSDictionary 引起的内存泄漏，但在此函数结束时释放它会导致应用程序崩溃。有什么建议吗？ （顺便说一句：我对 Obj-C 和一般编程都很陌生，所以这段代码主要是从各种来源挑选出来的。）
- (void)fetchedData:(NSData *)responseData {
//parse JSON for empty return
if([responseData length] != 0){
NSError* error = nil;
//Convert JSON data to Obj-C
NSDictionary* allShotData = [NSJSONSerialization JSONObjectWithData:responseData options:kNilOptions error:&error];
NSString *player = [[allShotData objectForKey:@"player"] objectForKey:@"name"];
NSString *shotDribbblePage = [allShotData objectForKey:@"url"];
NSString *shotTitle = [allShotData objectForKey:@"title"];
NSURL *imageURL = [NSURL URLWithString:[allShotData objectForKey:@"image_url"]];
shotPageURL = [shotDribbblePage retain];
//***********************
// Setup a-sync loading of shot
//***********************
NSOperationQueue *queue = [NSOperationQueue new];
NSInvocationOperation *operation = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(loadImage:) object:imageURL];
[queue addOperation:operation];
[operation release];
[queue release];
}
else{
airballCount++;
if (airballCount <= 20) {
[self getDribbbleData];
}
else{
NSLog(@"Too many airballs. Bailing out");
[self showNoConnectionModal];
}
}
}
I have a problem with my code that for the life of me I can't figure out, not even with all previous threads here on SO.
I'm pulling data from a JSON source and putting it in an NSDictionary as stated in tutorials and on SO. When profiling the app, I notice a memory leak caused by this NSDictionary but releasing it at the end of this function crashes the app. Any suggestions?
(By the way: I'm new to Obj-C and programming in general, so this code is mostly cherrypicked from various sources.)
- (void)fetchedData:(NSData *)responseData {
//parse JSON for empty return
if([responseData length] != 0){
NSError* error = nil;
//Convert JSON data to Obj-C
NSDictionary* allShotData = [NSJSONSerialization JSONObjectWithData:responseData options:kNilOptions error:&error];
NSString *player = [[allShotData objectForKey:@"player"] objectForKey:@"name"];
NSString *shotDribbblePage = [allShotData objectForKey:@"url"];
NSString *shotTitle = [allShotData objectForKey:@"title"];
NSURL *imageURL = [NSURL URLWithString:[allShotData objectForKey:@"image_url"]];
shotPageURL = [shotDribbblePage retain];
//***********************
// Setup a-sync loading of shot
//***********************
NSOperationQueue *queue = [NSOperationQueue new];
NSInvocationOperation *operation = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(loadImage:) object:imageURL];
[queue addOperation:operation];
[operation release];
[queue release];
}
else{
airballCount++;
if (airballCount <= 20) {
[self getDribbbleData];
}
else{
NSLog(@"Too many airballs. Bailing out");
[self showNoConnectionModal];
}
}
}
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这里：
您可能应该使用访问器：
我应该真的强调您应该在任何地方使用访问器，因为它们会为您进行引用计数（例外：不在初始化器和dealloc中）。正如 beryllium 还指出的那样，如果没有访问器，您可以手动进行引用计数。这采用基本形式：
如果是返回的字典的内容泄漏，那么这就是您在读取时使用/引用内容的方式（过度保留）。
如果您在并发上下文中使用您的类，那么您通常需要锁。
如果您正在从辅助线程加载
UIImage或以其他方式与 UIKit 对象进行交互，那就不好了。Here:
you should probably use the accessor:
I should really emphasize that you should use your accessors everywhere since they do your ref counting for you (exception: not in initializers and dealloc). As beryllium also notes, you could do your ref counting manually if there is no accessor. That takes the basic form:
If it's the contents of the returned dictionary that are leaking, then it's how you have used/referenced the contents when read (over-retain).
If you're using your class in a concurrent context, then you will usually need a lock.
If you're loading a
UIImageor otherwise interacting with UIKit objects from a secondary thread -- that's not good.