现在UIViewController

Question

我知道这是非常愚蠢的。

我有一个扫描QR码的视图控制器。我在AppDelegate（didFinishLaunchingWithOptions）中创建了它，并且我还将我的AppDelegate设置为视图控制器的代理，该视图控制器将在完成代码扫描时调用方法。在该方法中，我在AppDelegate中实施了我想提供的UINavigationController。问题是它不显示我的导航控制器。这是我的代码：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions 
{ 
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; 
    // Override point for customization after application launch. 
    reader=[ZBarReaderViewController new]; 
    reader.readerDelegate=self; 
    reader.supportedOrientationsMask=ZBarOrientationMaskAll; 
    ZBarImageScanner *scanner=reader.scanner; 
    [scanner setSymbology:ZBAR_I25 config:ZBAR_CFG_ENABLE to:0]; 


    [self.window addSubview:reader.view]; 
    [self.window makeKeyAndVisible]; 
    return YES; 
} 

-(void) imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info 
{ 
    RootViewController *rootViewController=[[RootViewController alloc] init ]; //create root view controller 

    UINavigationController *navigationController=[[UINavigationController alloc] initWithRootViewController:rootViewController]; // create and init navigation controller with viewController 
    [navigationController setValue:[[GradientBar alloc] init] forKey:@"navigationBar"]; 

    rootViewController.title=@"mTLU"; 
    [reader presentModalViewController:navigationController animated:NO]; 

} 

Answer 1

好像你忘了设置在self.window.rootViewControllerdidFinishLaunchingWithOptions:

尝试：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions 
{ 
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; 
    // Override point for customization after application launch. 
    self.reader=[ZBarReaderViewController new]; 
    self.reader.readerDelegate=self; 
    self.reader.supportedOrientationsMask=ZBarOrientationMaskAll; 
    ZBarImageScanner *scanner=reader.scanner; 
    [scanner setSymbology:ZBAR_I25 config:ZBAR_CFG_ENABLE to:0]; 

    self.window.rootViewController = self.reader; 

    [self.window addSubview:reader.view]; 
    [self.window makeKeyAndVisible]; 
    return YES; 
} 

此代码假定reader是AppDelegateproperty。如果它只是iVar您应该省略self.（或考虑将其设置为property）。