popToRootViewControllerAnimated 后程序崩溃

Question

我在 MainMenuViewController 类中有一个 navigationController 。当我将 FirstViewController 推入 navigationController 时，我进入第二个场景（FirstViewController），一切正常。但是，当我想返回根控制器（MainMenuViewController）时，我的程序在 main.m 中崩溃，并出现错误线程 1：程序收到信号：“EXC_BAD_ACCESS”。你能帮助我吗？

int main(int argc, char *argv[]) {

    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
    int retVal = UIApplicationMain(argc, argv, nil, nil);  // CRASH
    [pool release]; 
    return retVal;
}

ProjectAppDelegate.h：

@interface ProjectAppDelegate: NSObject <UIApplicationDelegate> {
    UIWindow *window;
    MainMenuViewController *mainVC;
    UINavigationController *navigationController;
}

@property (nonatomic, retain) IBOutlet UIWindow *window;
@property (nonatomic, retain) IBOutlet MainMenuViewController *mainVC;
@property (nonatomic, retain) UINavigationController *navigationController;

+(ProjectAppDelegate.h*)getInstance;
@end

ProjectAppDelegate.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    
    ProjectAppDelegateInstance = self;
    self.navigationController = [[UINavigationController alloc] initWithRootViewController:mainVC];
    [self.navigationController setNavigationBarHidden:TRUE];
    [self.window addSubview:self.navigationController.view];
    [self.window makeKeyAndVisible];
    return YES;
}

MainMenuViewController.m

- (IBAction)actonFirst:(id)sender 
{
    FirstViewController *firstVC = [[[FirstViewController alloc] initWithPageNum:1] autorelease];
    [[ProjectAppDelegate getInstance].mainVC.navigationController pushViewController:firstVC animated:TRUE];
}

FirstViewController.m

- (IBAction)actonHome:(id)sender 
{
    [[ProjectAppDelegate getInstance].mainVC.navigationController popToRootViewControllerAnimated:TRUE];
}

Answer 1

为什么你要把recipeVC推到分配firstVC的地方。

FirstViewController *firstVC = [[FirstViewController alloc] initWithPageNum:1];

[[ProjectAppDelegate getInstance].mainVC.navigationController 
pushViewController:recipeVC animated:TRUE];

Answer 2

actionFirst 方法中的recipeVC 是什么？首先检查一下..
我在我的一个项目中也遇到了这种问题。make firstVC 是 MainMenuViewController 和 MainMenuViewController 的属性。在 dealloc() 中释放它。
尝试一下对我有用的。

Answer 3

您为什么要将您的应用程序代表类命名为ProjectAppdelegate.h？删除“ .h”。

@interface ProjectAppDelegate : NSObject <UIApplicationDelegate> {
    UIWindow *window;
    MainMenuViewController *mainVC;
    UINavigationController *navigationController;
}

@property (nonatomic, retain) IBOutlet UIWindow *window;
@property (nonatomic, retain) IBOutlet MainMenuViewController *mainVC;
@property (nonatomic, retain) UINavigationController *navigationController;

+(ProjectAppDelegate*)getInstance;
@end

另一个良好的编码实践是手动释放第一个VC，而不是进行自动释放。这种方法要好得多。

- (IBAction)actonFirst:(id)sender 
{
    FirstViewController *firstVC = [[FirstViewController alloc] initWithPageNum:1];
    [[ProjectAppDelegate getInstance].mainVC.navigationController pushViewController:firstVC animated:TRUE];
    [firstVc release];
}