iphone - iOS 内存泄漏导致更改 View Controller 时崩溃

Question

我创建了两个 View Controller ，其中有 UIImage 动画。它经常崩溃并在 xcode 工具中显示内存泄漏。

我的 Controller 代码-

- (void)viewDidLoad {
     NSArray *firstArray;
     firstArray = [NSArray arrayWithObjects:    
                    [UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"up0001" ofType:@"png"]],
                    [UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"up0002" ofType:@"png"]],
                                      ::
                                      ::
                   [UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"up0035" ofType:@"png"]], nil];


     imgView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 1024, 768)];

     imgView = UIViewContentModeScaleToFill;

     [imgView setAnimationImages:firstArray];

     imgView.animationDuration = 1.75;

     imgView.animationRepeatCount = 0;

     [imgView startAnimating];

     [self.view addSubview: imgView];
}
- (void)dealloc {
    [super dealloc];
    [imgView release]; 
    imgView = nil;
}

我正在通过获取 appdelegate 对象并在我的 Appdelegate.m 中调用以下 appdelegate 函数来将 viewcontrollers 更改为我的 rootviewcontroller(请提出任何好的方法)

- (void)changeRootViewController:(NSString *)controllerName
{

    if(self.viewController){
        [self.viewController.view removeFromSuperview];
        self.viewController=nil;
    }

    if (controllerName == @"ViewController") {
        ViewController *lviewController =[[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];
        self.viewController =  (RootViewController *)lviewController;
        [lviewController release];
        lviewController.view = nil;
        [self.window setRootViewController:self.viewController]; //LEAKS 100%
    } else if (controllerName == @"MainViewController") {
        // Use a different VC as roowViewController
        MainViewController *lviewController =[[MainViewController alloc] initWithNibName:@"MainViewController" bundle:nil];
        self.viewController =  (RootViewController *)lviewController;
        [lviewController release];
        lviewController.view = nil;
        [self.window setRootViewController:self.viewController]; //LEAKS 100%
    } else if (controllerName == @"SecondViewController") {
        // Use a different VC as roowViewController
        SecondViewController *lviewController =[[SecondViewController alloc] initWithNibName:@"SecondViewController" bundle:nil];
        self.viewController =  (RootViewController *)lviewController;
        [lviewController release];
        lviewController.view = nil;
        [self.window setRootViewController:self.viewController];  //LEAKS 100%
    }

    [self.window makeKeyAndVisible];
}

并在我各自的 Controller 按钮中调用它 -

AppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
[appDelegate changeRootViewController:@"ViewController"];

或

 AppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
[appDelegate changeRootViewController:@"MainViewController"];

我想从我的主 Controller 管理 View Controller ，在没有导航栏的情况下交换 Controller 。请帮助我找出最佳方法并避免泄漏。

Answer 1

看这段代码:

if (controllerName == @"ViewController") {
        ViewController *lviewController =[[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];
        self.viewController =  (RootViewController *)lviewController;
        [lviewController release];
        lviewController.view = nil;
        [self.window setRootViewController:self.viewController]; //LEAKS 100%
    }

当您分配“lviewController”时，它的保留计数为 1；当你执行“self.viewController”时，我认为 viewController 是一个保留属性，然后 lviewController 保留计数增加到 2；然后你释放它，平衡之前的分配，并且保留计数返回到 1；最后你将它分配给 rootViewController，这是一个保留属性，所以 lviewController 保留计数再次为 2；最后，当您在窗口中“交换” View Controller 时，lviewController 被释放，因此它的保留计数变为 1。如您所见，它永远不会被释放。这意味着每次调用此函数时，都会发生泄漏。