[Pyobjc-dev] property progress

[Ronald O. <ron...@ma...>]

This now works on my machine:

import objc


NSObject = objc.lookUpClass('NSObject')
NSKeyValueObservingOptionNew = 0x01
NSKeyValueObservingOptionOld = 0x02



class Observer (NSObject):
    def init(self):
        self = super(Observer, self).init()
        self.keys = []
        return self

    def dealloc(self):
        for o, k in self.keys:
            o.removeObserver_forKeyPath_(self, k)

    def observeValueForKeyPath_ofObject_change_context_(self, path, object, change, context):
        print "===> %s\t\t%s"%(path, change)

    def register(self, object, keypath):
        object.addObserver_forKeyPath_options_context_(
                self, keypath, 
                NSKeyValueObservingOptionNew|NSKeyValueObservingOptionOld,
                0)
        self.keys.append((object, keypath))


class Person (NSObject):
    def _init(self):
        self = objc.super(Person, self).init()
        self.firstName = None
        self.lastName = None
        return self

    firstName = objc.object_property()
    lastName = objc.object_property()

    fullName = objc.object_property(read_only=True, ivar=objc.NULL)
    fullName.depends_on(u'firstName')
    fullName.depends_on(u'lastName')

    @fullName.getter
    def fullName(self):
        return "%s %s"%(self.firstName, self.lastName)

obs = Observer.alloc().init()
pers = Person.alloc().init()
obs.register(pers, "fullName")
obs.register(pers, "firstName")
obs.register(pers, "lastName")

pers.firstName = "Ronald"
pers.lastName = "Oussoren"

print "done"
print pers.fullName


That is,  I can define something that behaves like a python property for Python code, but is implemented  using ObjC-style getter/setter methods and therefore participates properly in key-value observations.

What makes me really happy is that adding some hooks to the bridge allowed me to write class objc_property in Python, which should make it a lot more convenient to add simular properties that represent an array or set.

I haven't committed this to the repository yet, I have to add unittests and documentation before I do that.

Ronald