objective-c - 为什么我有内存问题？

Question

我从 XCode 得到这个错误:

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

我用谷歌搜索，发现这与内存有关。但我不知道我哪行代码出错了，有什么想法吗？在模拟器中启动我的应用程序后，它会提示一秒钟，除上述错误外，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

这是一个额外的释放(如果你没有分配它，不要释放它)。几行下来:

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 View 并导致崩溃(它将释放消息发送到已经释放的对象/已经释放的内存)。相反，请尝试:

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