覆盖窗口关闭行为

Question

我想捕获所有关闭某些特定现有 Cocoa 窗口并添加一些自己的处理程序的尝试（这可能确实会关闭它或执行不同的操作）。

我想到了不同的解决方案来做到这一点。一是：

我想在运行时用自己的关闭小部件替换现有 Cocoa 窗口的窗口关闭按钮，我可以在其中添加一些自己的代码。

现在，我有这段代码：

import objc
_NSThemeCloseWidget = objc.lookUpClass("_NSThemeCloseWidget")

def find_close_widget(window):
    contentView = window.contentView()
    grayFrame = contentView.superview()
    for i in range(len(grayFrame.subviews())):
        v = grayFrame.subviews()[i]
        if isinstance(v, _NSThemeCloseWidget):
            return v, i, grayFrame

class CustomCloseWidget(_NSThemeCloseWidget):
    pass

def replace_close_widget(window, clazz=CustomCloseWidget):
    v, i, grayFrame = find_close_widget(window)
    newv = clazz.alloc().init()
    grayFrame.subviews()[i] = newv

但是，这似乎不太正确。 （它崩溃了。）

Answer 1

关闭小部件并不是关闭窗口的唯一方法。有一个公共 API 可以获取该小部件，因此您无需仔细检查框架视图的子视图，但无论如何这是错误的路径。

正确的方法是让一个对象成为窗口的委托，并且 干扰窗口关闭 那里。理想情况下，您应该在创建窗口和订购窗口之间设置窗口的委托。

Answer 2

我现在要走另一条路。这部分与 Chrome 相关，但它可以很容易地在其他地方采用。我想尽早捕获关闭窗口的几个操作，以避免任何其他清理或其他导致窗口处于奇怪状态的操作。

def check_close_callback(obj):
    # check ...
    return True # or:
    return False

import objc
BrowserWindowController = objc.lookUpClass("BrowserWindowController")

# copied from objc.signature to avoid warning
def my_signature(signature, **kw):
    from objc._objc import selector
    kw['signature'] = signature
    def makeSignature(func):
        return selector(func, **kw)
    return makeSignature

windowWillCloseSig = "c12@0:4@8" # BrowserWindowController.windowWillClose_.signature
commandDispatchSig = "v12@0:4@8"
class BrowserWindowController(objc.Category(BrowserWindowController)):
    @my_signature(windowWillCloseSig)
    def myWindowShouldClose_(self, sender):
        print "myWindowShouldClose", self, sender
        if not check_close_callback(self): return objc.NO
        return self.myWindowShouldClose_(sender) # this is no recursion when we exchanged the methods

    @my_signature(commandDispatchSig)
    def myCommandDispatch_(self, cmd):
        try: print "myCommandDispatch_", self, cmd
        except: pass # like <type 'exceptions.UnicodeEncodeError'>: 'ascii' codec can't encode character u'\u2026' in position 37: ordinal not in range(128)
        if cmd.tag() == 34015: # IDC_CLOSE_TAB
            if not check_close_callback(self): return           
        self.myCommandDispatch_(cmd)

from ctypes import *
capi = pythonapi

# id objc_getClass(const char *name)
capi.objc_getClass.restype = c_void_p
capi.objc_getClass.argtypes = [c_char_p]

# SEL sel_registerName(const char *str)
capi.sel_registerName.restype = c_void_p
capi.sel_registerName.argtypes = [c_char_p]

def capi_get_selector(name):
    return c_void_p(capi.sel_registerName(name))

# Method class_getInstanceMethod(Class aClass, SEL aSelector)
# Will also search superclass for implementations.
capi.class_getInstanceMethod.restype = c_void_p
capi.class_getInstanceMethod.argtypes = [c_void_p, c_void_p]

# void method_exchangeImplementations(Method m1, Method m2)
capi.method_exchangeImplementations.restype = None
capi.method_exchangeImplementations.argtypes = [c_void_p, c_void_p]

def method_exchange(className, origSelName, newSelName):
    clazz = capi.objc_getClass(className)
    origMethod = capi.class_getInstanceMethod(clazz, capi_get_selector(origSelName))
    newMethod = capi.class_getInstanceMethod(clazz, capi_get_selector(newSelName))
    capi.method_exchangeImplementations(origMethod, newMethod)

def hook_into_windowShouldClose():
    method_exchange("BrowserWindowController", "windowShouldClose:", "myWindowShouldClose:")

def hook_into_commandDispatch():
    method_exchange("BrowserWindowController", "commandDispatch:", "myCommandDispatch:")

此代码来自此处和这里。