快速简单的应用程序总是在模拟器上崩溃

Question

我的应用程序基本上是一个web浏览器和本地存储的web应用程序。

为了支持URL的方案映射，我呼吁viewDidLoad以下功能，订阅UIApplicationDidBecomeActiveNotification，然后当我得到这样的消息，我打开一个web应用到UIWebView：

/** 
* Setup the observer to get notifications about app activation 
*/ 

func initObserver() { 
    NSNotificationCenter.defaultCenter().addObserver(
     self, 
     selector: "initWebApp", 
     name: UIApplicationDidBecomeActiveNotification, 
     object: nil); 
} 

/** 
* Launches the WebApp, this is called from the observer, 
* and appDelegate.appParameters has possible parameters to the webapp 
*/ 

func initWebApp() { 
    var appDelegate=UIApplication.sharedApplication().delegate as AppDelegate; 
    println ("- Launch Parameters: "+appDelegate.initParameters); 
    let path=appDelegate.initParameters, 
     url=NSURL(string: URL_BASE + "?" + (path ?? "")), 
     requestObj=NSURLRequest(URL: url!); 
    mWebView.loadRequest(requestObj); 

} 

然而，当我以这种方式初始化webview（来自观察处理程序）时，只要单击窗口上的任何位置，模拟器就会始终与下面包含的堆栈跟踪一起崩溃。

相反，如果我不同意的情况下，并调用initWebApp()从viewDidLoad()，一切工作正常（显然URL方案的映射不工作，但我的意思是的WebView及其应用工作100％没有崩溃）

任何人都可以看看这个堆栈跟踪（它总是相同的），并给我任何指针？

从事件处理程序操作UIWebView等UI对象是否是一种不好的做法？ （我来自Android的，你经常要更改线程在类似情况下）

2015-04-06 02:49:34.907 FunqTV[14285:518122] -[NSURL _effectiveStatusBarStyleViewController]: unrecognized selector sent to instance 0x7ae1cac0 
2015-04-06 02:49:34.919 FunqTV[14285:518122] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSURL _effectiveStatusBarStyleViewController]: unrecognized selector sent to instance 0x7ae1cac0' 
*** First throw call stack: 
*** First throw call stack: 
(
    0 CoreFoundation      0x00648466 __exceptionPreprocess + 182 
    1 libobjc.A.dylib      0x02037a97 objc_exception_throw + 44 
    2 CoreFoundation      0x006502c5 -[NSObject(NSObject) doesNotRecognizeSelector:] + 277 
    3 CoreFoundation      0x00598bc7 ___forwarding___ + 1047 
    4 CoreFoundation      0x0059878e _CF_forwarding_prep_0 + 14 
    5 UIKit        0x00fd3fa8 +[UIViewController _currentStatusBarStyleViewController] + 75 
    6 UIKit        0x00e63c81 -[UIApplication _updateCurrentStatusBarViewControllerAppearance] + 59 
    7 UIKit        0x00eb06ea -[UIWindow _updateContextOrderingAndSetLayerHidden:] + 548 
    8 UIKit        0x00eade74 -[UIWindow _initWithFrame:debugName:scene:attached:] + 336 
    9 UIKit        0x00eadd1e -[UIWindow _initWithFrame:debugName:attached:] + 79 
    10 UIKit        0x00eadc7f -[UIWindow _initWithFrame:attached:] + 71 
    11 UIKit        0x011e6f27 -[UIAutoRotatingWindow _initWithFrame:attached:] + 80 
    12 UIKit        0x00eadc33 -[UIWindow initWithFrame:] + 63 
    13 UIKit        0x011e6eba -[UIAutoRotatingWindow initWithFrame:] + 72 
    14 UIKit        0x011e4e2a -[UITextEffectsWindow initWithFrame:] + 72 
    15 UIKit        0x00eae09a -[UIWindow initWithContentRect:] + 164 
    16 UIKit        0x011e4b12 -[UITextEffectsWindow(UIObjectsForPerScreen) _basicInitWithScreen:options:] + 141 
    17 UIKit        0x011e4bcf -[UITextEffectsWindow(UIObjectsForPerScreen) _initWithScreen:options:] + 182 
    18 UIKit        0x016fcf8c +[_UIObjectPerScreen objectOfClass:forScreen:withOptions:createIfNecessary:] + 556 
    19 UIKit        0x011e645c +[UITextEffectsWindow _sharedTextEffectsWindowforScreen:aboveStatusBar:allowHosted:matchesStatusBarOrientationOnAccess:] + 416 
    20 UIKit        0x011e65b4 +[UITextEffectsWindow sharedTextEffectsWindowForScreen:] + 121 
    21 UIKit        0x013d173a -[UIPeripheralHost(UIKitInternal) containerWindow] + 156 
    22 UIKit        0x013d178a -[UIPeripheralHost(UIKitInternal) containerRootController] + 34 
    23 UIKit        0x013c6e15 -[UIPeripheralHost currentState] + 38 
    24 UIKit        0x013c6f10 -[UIPeripheralHost isOnScreen] + 35 
    25 UIKit        0x013d3a6a -[UIPeripheralHost(UIKitInternal) _isCoordinatingWithSystemGestures] + 82 
    26 UIKit        0x00e70da1 -[UIApplication _shouldDelayTouchesForControlCenter] + 56 
    27 UIKit        0x00ebd506 -[UIWindow _shouldDelayTouchForSystemGestures:] + 41 
    28 UIKit        0x0128f8e8 -[_UISystemGestureGateGestureRecognizer touchesBegan:withEvent:] + 498 
    29 UIKit        0x00eb3946 -[UIWindow _sendGesturesForEvent:] + 567 
    30 UIKit        0x00eb4abf -[UIWindow sendEvent:] + 769 
    31 UIKit        0x00e79bb1 -[UIApplication sendEvent:] + 242 
    32 UIKit        0x00e89bf6 _UIApplicationHandleEventFromQueueEvent + 21066 
    33 UIKit        0x00e5dbc7 _UIApplicationHandleEventQueue + 2300 
    34 CoreFoundation      0x0056b98f __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 15 
    35 CoreFoundation      0x0056149d __CFRunLoopDoSources0 + 253 
    36 CoreFoundation      0x005609f8 __CFRunLoopRun + 952 
    37 CoreFoundation      0x0056037b CFRunLoopRunSpecific + 443 
    38 CoreFoundation      0x005601ab CFRunLoopRunInMode + 123 
    39 GraphicsServices     0x040152c1 GSEventRunModal + 192 
    40 GraphicsServices     0x040150fe GSEventRun + 104 
    41 UIKit        0x00e619b6 UIApplicationMain + 1526 
    42 FunqTV        0x0007dfbe top_level_code + 78 
    43 FunqTV        0x0007dffb main + 43 
    44 libdyld.dylib      0x027a5ac9 start + 1 
    45 ???         0x00000001 0x0 + 1 
) 
libc++abi.dylib: terminating with uncaught exception of type NSException 

Answer 1

如果我换调用initWebApp（）成dispatch_async（）块，它的工作原理：

/** 
    * Setup the observer to get notifications about app activation 
    */ 

    func initObserver() { 
     NSNotificationCenter.defaultCenter().addObserver(
      self, 
      selector: "requestInitWebApp", 
      name: UIApplicationDidBecomeActiveNotification, 
      object: nil); 
    } 

    /** 
    * Called from the observer. It now dispatches async a call to the init 
    * function rather than calling it directly from the observer thread. 
    */ 

    func requestInitWebApp() { 
     println ("Dispatching async call to init webview"); 
     dispatch_async(dispatch_get_main_queue()) { 
      self.initWebApp(); 
     } 
    }