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On Mac OS X the trackpad has support for several gestures, one is the two fingered swipe to scroll up, down, left, or right on a page. wxPython has a panel to help create scrolled widgets wx.lib.scrolledpanel. However it does not have support for gestures which is a real pain.

I have tried to modify the NSView, as it is done if it were a normal Objective C application, however the NSEvents use methods (touchesBeganWithEvent:, etc) that are subclassed to be used as a notification and handling of an event. This is unlike the Bind calls in wxPython. This would be fine however if Objective C allowed monkey patching... eg

def handleTouchBegin(event):
    print "Hey a touch event has begun!"

view.touchBeganWithEvent_ = handleTouchBegin

but as you can guess PyObj C errors (because Objective C doesn't support monkey patching or not in any clean and nice fashion) and I get the following error

TypeError: cannot change a method

Ok well I could do what apple says and subclass it, but the object is already created, so how can I still capture the events. Of course there is also 

NSEvent addGlobalMonitorForEventsMatchingMask: 
and
NSEvent addLocalMonitorForEventsMatchingMask:

but those also disappoint in that they either don't even deal with the application (global deals with all the others) or doesn't deal with a single NSView's events (or does it and I am misinformed).

So how should I do this? Am I missing another option, I know I read something about NSResponder but from what I gathered that is what NSView is, an event responder and you don't add one to a NSView.

Are there observers like in QTKit such as for monitoring the load state changing ( https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/QTKitApplicationProgrammingGuide/AnatomyoftheQTKFramework/AnatomyoftheQTKFramework.html#//apple_ref/doc/uid/TP40008156-CH109-SW11 )?

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ObjC 不支持 Python 风格的猴子补丁……但它确实支持一些类似的功能，如方法调配、类构成、类别插入等。PyObjC 可以做所有这些事情。

在我的脑海中，来自 PyObjC 的 swizzling 应该是这样的：

def swizzle(cls, sel, func):
    oldimp = cls.instanceMethodForSelector_(sel)
    def wrapper(self, *args, **kwargs):
        return func(self, oldimp, *args, **kwargs)
    newmethod = objc.selector(wrapper, 
                              selector=oldimp.selector, signature=oldimp.signature)
    objc.classAddMethod(cls, sel, newmethod)
    return wrapper
于 2013-08-09T01:24:33.247 回答