Question

我从XCode那里得到了这个错误：

objc[8422]: FREED(id): message release sent to freed object=0x3b120c0

我用谷歌搜索，发现这与记忆有关。但是我不知道哪个代码出错了，有什么想法吗？在模拟器中启动我的应用程序后，它会提示第二个，除了上面的错误之外没有其他错误。

@implementation MyAppDelegate

@synthesize window;
@synthesize viewController;


- (void)applicationDidFinishLaunching:(UIApplication *)application {    

    // Override point for customization after app launch    
    [window addSubview:viewController.view];
    [window makeKeyAndVisible];

    [self changeScene:[MainGameMenuScene class]];
}


- (void)dealloc {
    [viewController release];
    [window release];
    [super dealloc];
}

- (void) changeScene: (Class) scene
{
    BOOL animateTransition = true;

    if(animateTransition){
        [UIView beginAnimations:nil context:NULL];
        [UIView setAnimationDuration:0.5];
        [UIView setAnimationTransition:UIViewAnimationTransitionFlipFromLeft forView:window cache:YES]; //does nothing without this line.
    }

    if( viewController.view != nil ) {
        [viewController.view removeFromSuperview]; //remove view from window's subviews.
        [viewController.view release]; //release gamestate 
    }

    viewController.view = [[scene alloc] initWithFrame:CGRectMake(0, 0, IPHONE_WIDTH, IPHONE_HEIGHT) andManager:self];

        //now set our view as visible
    [window addSubview:viewController.view];
    [window makeKeyAndVisible];

    if(animateTransition){
        [UIView commitAnimations];  
    }   
}

Answer 1

[viewController.view release]; //release gamestate

这是一个额外的版本（如果你没有分配它，不要发布它）。几条线：

viewController.view = [[scene alloc] initWithFrame:CGRectMake(0, 0, IPHONE_WIDTH, IPHONE_HEIGHT) andManager:self];

将在保留新值之前再次释放viewController.view，这将过度释放视图并导致崩溃（它将释放消息发送到已经被释放的对象/已经释放的内存）。相反，尝试：

scene *view = [[scene alloc] initWithFrame:CGRectMake(0, 0, IPHONE_WIDTH, IPHONE_HEIGHT) andManager:self];
viewController.view = view; // setView will release the old/retain the new
[view release];             // so you don't need to worry about releasing it later

Answer 2

得到解决方案：

- (void) changeScene: (Class) scene
{
    BOOL animateTransition = true;

    if(animateTransition){
        [UIView beginAnimations:nil context:NULL];
        [UIView setAnimationDuration:0.5];
        [UIView setAnimationTransition:UIViewAnimationTransitionFlipFromLeft forView:window cache:YES]; //does nothing without this line.
    }

    if( viewController.view != nil ) {
        [viewController.view retain]; //retain the view.
        [viewController.view removeFromSuperview]; //remove view from window's subviews.
        [viewController.view release]; //release gamestate 
    }

    viewController.view = [[scene alloc] initWithFrame:CGRectMake(0, 0, IPHONE_WIDTH, IPHONE_HEIGHT) andManager:self];

        //now set our view as visible
    [window addSubview:viewController.view];
    [window makeKeyAndVisible];

    if(animateTransition){
        [UIView commitAnimations];  
    }   
}

我需要保留视图，但我不知道为什么这是必要的。

Answer 3

这一行：

[viewController.view release];

很可能是你的问题。除了类dealloc方法之外，永远不要将释放发送到对象的属性。视图控制器视图属性访问器将为您处理保留和释放。

为什么我有记忆问题？

3 个答案: