python - 如何将字典值传递给回调函数？

Question

我有一个标题字典，其值代表 3 个字母缩写。

我有一个带有标题的按钮列表，我需要 on_click 来返回缩写。

我现在返回的是标题(按钮文本)，但我不知道如何传递整个字典条目，或者只是传递值。

from kivy.uix.modalview import ModalView
from kivy.uix.listview import ListView
from kivy.uix.gridlayout import GridLayout
from kivy.lang import Builder
from kivy.app import App
import citylists
import cat_dict

from kivy.uix.screenmanager import ScreenManager, Screen, FadeTransition
from kivy.storage.jsonstore import JsonStore

store = JsonStore('data.json')

Builder.load_string("""
#:import ListItemButton kivy.uix.listview.ListItemButton
#:import ListAdapter kivy.adapters.listadapter.ListAdapter


<ListViewModal>:
    ListView:
        size_hint: .8, .8
        adapter:
            ListAdapter(
            data=[i for i in root.categories],
            args_converter=lambda row_index, rec: \
            {'text': rec, 'on_press': root.callback, 'size_hint_y': None, 'height': 25},
            cls=ListItemButton)

""")




class ListViewModal(ModalView):
    categories = sorted(cat_dict.SECTION_DICT)

    def __init__(self, **kwargs):
        super(ListViewModal, self).__init__(**kwargs)

    def callback(self, instance):
        print "HI" + str(instance)


class MainView(GridLayout):

    def __init__(self, **kwargs):
        kwargs['cols'] = 1
        super(MainView, self).__init__(**kwargs)

        listview_modal = ListViewModal()

        self.add_widget(listview_modal)

class MainScreen(Screen):
    pass


mainscreen=MainScreen()
mainlayout = MainView()
mainscreen.add_widget(mainlayout)

sm = ScreenManager()
sm.add_widget(mainscreen)

class CARApp(App):

    def build(self):
       return sm


if __name__ == '__main__':
     CARApp().run()

cat_dict.py

EECTION_DICT = {
    "accounting+finance": "acc",
    "admin / office": "ofc",
    "arch / engineering": "egr",
    'art / media / design': 'med',
    'biotech / science': 'sci',
    'business / mgmt': 'bus',
    'customer management': 'csr',
    'education': 'edu',....

Answer 1

看起来您实际上不需要向回调传递任何内容。看起来以下内容满足了您的要求:

class ListViewModal(ModalView):
    section_dict = cat_dict.SECTION_DICT
    categories = sorted(section_dict)

    def __init__(self, **kwargs):
        super(ListViewModal, self).__init__(**kwargs)

    def callback(self, instance):
        print "HI" + str(instance)
        # Print abbreviation from dictionary lookup
        print ListViewModal.section_dict[instance.text]

哪些输出:

HI<ListItemButton text=accounting+finance>acc

But one way to pass extra arguments to your callback would be to change

'on_press': root.callback
# to
'on_press': lambda inst: root.callback(inst, 'some arg')

然后更改

def callback(self, instance):
# to
def callback(self, instance, arg):

The docs除了使用 lambda 函数之外，还列出了使用 itertools.partial 作为选项。