contentViewController ((нуль)) или contentViewController.view равна нулю

Question

я получаю следующее сообщение об ошибке и StackTrace однако точка зрения не ноль (как показано журналирования вниз прямо перед ним)

StackTrace

2014-02-05 08:29:47.338 MenuTimer[74522:303] An uncaught exception was raised 
2014-02-05 08:29:47.338 MenuTimer[74522:303] The contentViewController ((null)) or contentViewController.view is nil. 
2014-02-05 08:29:47.340 MenuTimer[74522:303] (
    0 CoreFoundation      0x00007fff8e39341c __exceptionPreprocess + 172 
    1 libobjc.A.dylib      0x00007fff87b1ee75 objc_exception_throw + 43 
    2 CoreFoundation      0x00007fff8e3932cc +[NSException raise:format:] + 204 
    3 AppKit        0x00007fff8157e3da -[NSPopover showRelativeToRect:ofView:preferredEdge:] + 228 
    4 MenuTimer       0x0000000100002a72 -[MenuTimer onSetTime:] + 818 
    5 AppKit        0x00007fff814f83d0 -[NSApplication sendAction:to:from:] + 327 
    6 AppKit        0x00007fff81513348 -[NSMenuItem _corePerformAction] + 394 
    7 AppKit        0x00007fff81513084 -[NSCarbonMenuImpl performActionWithHighlightingForItemAtIndex:] + 117 
    8 AppKit        0x00007fff815624dd -[NSMenu _internalPerformActionForItemAtIndex:] + 35 
    9 AppKit        0x00007fff81562359 -[NSCarbonMenuImpl _carbonCommandProcessEvent:handlerCallRef:] + 104 
    10 AppKit        0x00007fff81509176 NSSLMMenuEventHandler + 716 
    11 HIToolbox       0x00007fff8acff6d4 _ZL23DispatchEventToHandlersP14EventTargetRecP14OpaqueEventRefP14HandlerCallRec + 892 
    12 HIToolbox       0x00007fff8acfec87 _ZL30SendEventToEventTargetInternalP14OpaqueEventRefP20OpaqueEventTargetRefP14HandlerCallRec + 385 
    13 HIToolbox       0x00007fff8ad12d90 SendEventToEventTarget + 40 
    14 HIToolbox       0x00007fff8ad48a30 _ZL18SendHICommandEventjPK9HICommandjjhPKvP20OpaqueEventTargetRefS5_PP14OpaqueEventRef + 420 
    15 HIToolbox       0x00007fff8ad7b618 SendMenuCommandWithContextAndModifiers + 59 
    16 HIToolbox       0x00007fff8ad7b5c4 SendMenuItemSelectedEvent + 178 
    17 HIToolbox       0x00007fff8ad7b4a5 _ZL19FinishMenuSelectionP13SelectionDataP10MenuResultS2_ + 94 
    18 HIToolbox       0x00007fff8ad5956e _ZL19PopUpMenuSelectCoreP8MenuData5PointdS1_tjPK4RecttjS4_S4_PK10__CFStringPP13OpaqueMenuRefPt + 1726 
    19 HIToolbox       0x00007fff8ad586c6 _HandlePopUpMenuSelection7 + 596 
    20 AppKit        0x00007fff81561221 _NSSLMPopUpCarbonMenu3 + 4153 
    21 AppKit        0x00007fff815601d6 _NSPopUpCarbonMenu3 + 39 
    22 AppKit        0x00007fff8155fe96 -[NSCarbonMenuImpl popUpMenu:atLocation:width:forView:withSelectedItem:withFont:withFlags:withOptions:] + 350 
    23 AppKit        0x00007fff81950959 +[NSStatusBarButtonCell popupStatusBarMenu:inRect:ofView:withEvent:] + 699 
    24 AppKit        0x00007fff81951ade -[NSStatusItem popUpStatusItemMenu:] + 173 
    25 MenuTimer       0x0000000100001779 -[StatusBarView mouseDown:] + 633 
    26 AppKit        0x00007fff814ded08 -[NSWindow sendEvent:] + 11296 
    27 AppKit        0x00007fff815da11b -[NSStatusBarWindow sendEvent:] + 247 
    28 AppKit        0x00007fff8147d744 -[NSApplication sendEvent:] + 2021 
    29 AppKit        0x00007fff812cda29 -[NSApplication run] + 646 
    30 MenuTimer       0x0000000100002500 -[MenuTimer init] + 2112 
    31 MenuTimer       0x00000001000031b5 main + 101 
    32 libdyld.dylib      0x00007fff87fcc5fd start + 1 
) 

Однако следующий код и вывод указывают по-разному. Это потому, что у меня нет явного контроллера?

Код

// create set time window 
    NSLog(@"Set Time..."); 
    NSLog(@"View %@", self.statusTime.view); 
    NSLog(@"Frame %@", self.statusTime.view.frame); 
    NSPopover *popover = [[NSPopover alloc] init]; 
    NSLog(@"Showing popover..."); 
    [popover showRelativeToRect:[self.statusTime.view frame] 
         ofView:self.statusTime.view 
        preferredEdge:NSMinYEdge]; 

Выход

2014-02-05 08:29:47.237 MenuTimer[74522:303] Set Time... 
2014-02-05 08:29:47.237 MenuTimer[74522:303] View <StatusBarView: 0x6080001b05a0> 
2014-02-05 08:29:47.238 MenuTimer[74522:303] Frame <StatusBarView: 0x6080001b05a0> 
2014-02-05 08:29:47.238 MenuTimer[74522:303] Showing popover... 

Answer 1

Вы должны установить contentViewController (что поповер на самом деле показ), прежде чем показывать его.

т.е.

NSViewController *viewController; // some view controller created programmatically or from a nib 

NSPopover *popover = [[NSPopover alloc] init]; 
popover.contentViewController = viewController; // Missing this. 
NSLog(@"Showing popover..."); 
[popover showRelativeToRect:[self.statusTime.view frame] 
        ofView:self.statusTime.view 
       preferredEdge:NSMinYEdge]; 

ofView: Параметр находится именно там, где поповер показывается с.