objective-c - cocoa 异常: _createMenuRef called with existing principal MenuRef already associated with menu

Question

这是Python代码:

#!/usr/bin/python

import os
import sys

from Foundation import *
from AppKit import *
import objc

def setupWindowMenu(app):
    windowMenu = NSMenu.alloc().initWithTitle_('Window')
    windowMenu.retain()
    menuItem = NSMenuItem.alloc().initWithTitle_action_keyEquivalent_('Minimize', 'performMiniaturize:', 'm')
    windowMenu.addItem_(menuItem)
    windowMenuItem = NSMenuItem.alloc().initWithTitle_action_keyEquivalent_('Window', None, '')
    windowMenuItem.setSubmenu_(windowMenu)
    app.mainMenu().addItem_(windowMenuItem)
    app.setWindowsMenu_(windowMenu)

app = NSApplication.sharedApplication()

mainMenu = NSMenu.alloc().init()
app.setMainMenu_(mainMenu)
setupWindowMenu(app)

app.finishLaunching()
app.updateWindows()
app.activateIgnoringOtherApps_(True)

app.run()

我得到这个输出:

$ python pyobjcdemo.py
2011-09-11 23:22:40.470 Python[21409:1507] _createMenuRef called with existing principal MenuRef already associated with menu
2011-09-11 23:22:40.471 Python[21409:1507] (
    0   CoreFoundation                      0x00007fff93acb986 __exceptionPreprocess + 198
    1   libobjc.A.dylib                     0x00007fff8f3b4d5e objc_exception_throw + 43
    2   CoreFoundation                      0x00007fff93acb7ba +[NSException raise:format:arguments:] + 106
    3   CoreFoundation                      0x00007fff93acb744 +[NSException raise:format:] + 116
    4   AppKit                              0x00007fff8a8841fb -[NSCarbonMenuImpl _createMenuRef] + 64
    5   AppKit                              0x00007fff8a883ae6 -[NSCarbonMenuImpl _instantiateCarbonMenu] + 148
    6   AppKit                              0x00007fff8a8588e9 -[NSApplication finishLaunching] + 878
    7   AppKit                              0x00007fff8a85827d -[NSApplication run] + 118
    8   libffi.dylib                        0x00007fff8cf29e7c ffi_call_unix64 + 76
    9   ???                                 0x00007fbd1b480d10 0x0 + 140450183253264
)

为什么？

这是什么意思？

为什么这个简单的 PyObjC 代码有任何 Carbon 依赖项？

Answer 1

错误是对 finishLaunching 的调用。只需将其删除，就可以消除错误。

关于为什么在 Cocoa 中看到 Carbon 类型，这只是代码层的问题。 Carbon 和 Cocoa 并不是两个完全独立的系统，它们是同一系统的 API。 (尽管较低的“碳”层通常被称为“核心”技术，例如 Core Graphics。)