Kivy 日期选择器小部件

我遇到了障碍，不知道如何继续.我想添加一种方法，以便在单击 date_labels 时，它们将 self.date 设置为具有该日期部分的日期对象.

I've hit a road block and can't work out how to continue. I want to add a method such that when the date_labels are clicked, they set self.date to a date object with that day part.

我试过添加

self.date_label.bind(on_touch_down = self.set_date(date_cursor.day)) 

但只有最大递归错误.

import kivy

kivy.require('1.4.0')

from kivy.uix.gridlayout import GridLayout
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.label import Label
from kivy.uix.button import Button

from kivy.app import App

from datetime import date, timedelta

from functools import partial

class DatePicker(BoxLayout):

    def __init__(self, *args, **kwargs):
        super(DatePicker, self).__init__(**kwargs)
        self.date = date.today()
        self.orientation = "vertical"
        self.month_names = ('January',
                            'February', 
                            'March', 
                            'April', 
                            'May', 
                            'June', 
                            'July', 
                            'August', 
                            'September', 
                            'October',
                            'November',
                            'December')
        if kwargs.has_key("month_names"):
            self.month_names = kwargs['month_names']
        self.header = BoxLayout(orientation = 'horizontal', 
                                size_hint = (1, 0.2))
        self.body = GridLayout(cols = 7)
        self.add_widget(self.header)
        self.add_widget(self.body)

        self.populate_body()
        self.populate_header()

    def populate_header(self, *args, **kwargs):
        self.header.clear_widgets()
        previous_month = Button(text = "<")
        previous_month.bind(on_press=partial(self.move_previous_month))
        next_month = Button(text = ">", on_press = self.move_next_month)
        next_month.bind(on_press=partial(self.move_next_month))
        month_year_text = self.month_names[self.date.month -1] + ' ' + str(self.date.year)
        current_month = Label(text=month_year_text, size_hint = (2, 1))

        self.header.add_widget(previous_month)
        self.header.add_widget(current_month)
        self.header.add_widget(next_month)

    def populate_body(self, *args, **kwargs):
        self.body.clear_widgets()
        date_cursor = date(self.date.year, self.date.month, 1)
        for filler in range(date_cursor.isoweekday()-1):
            self.body.add_widget(Label(text=""))
        while date_cursor.month == self.date.month:
            date_label = Button(text = str(date_cursor.day))
            date_label.bind(on_press=partial(self.set_date, 
                                                  day=date_cursor.day))
            if self.date.day == date_cursor.day:
                date_label.background_normal, date_label.background_down = date_label.background_down, date_label.background_normal
            self.body.add_widget(date_label)
            date_cursor += timedelta(days = 1)

    def set_date(self, *args, **kwargs):
        self.date = date(self.date.year, self.date.month, kwargs['day'])
        self.populate_body()
        self.populate_header()

    def move_next_month(self, *args, **kwargs):
        if self.date.month == 12:
            self.date = date(self.date.year + 1, 1, self.date.day)
        else:
            self.date = date(self.date.year, self.date.month + 1, self.date.day)
        self.populate_header()
        self.populate_body()

    def move_previous_month(self, *args, **kwargs):
        if self.date.month == 1:
            self.date = date(self.date.year - 1, 12, self.date.day)
        else:
            self.date = date(self.date.year, self.date.month -1, self.date.day)
        self.populate_header()
        self.populate_body()



class MyApp(App):

    def build(self):
        return DatePicker()

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

推荐答案

你在绑定中犯了一个小错误，你调用方法而不是传递它(因此，你传递了 self.set_date(date_cursor.day) 的结果，但是调用 self.set_date 也会调用 self.populate_body，所以你得到在无限递归中，只被python递归限制停止.

you do a small mistake in your binding, you call the method instead of passing it (thus, you pass the result of self.set_date(date_cursor.day), but calling self.set_date calls self.populate_body too, so you get in an infinite recursion, only stopped by python recursion limit.

你想要做的是绑定方法，但使用 date_cursor.day 作为第一个参数，对于这个 partial 函数，来自 functools 完美.

What you want to do is bind the method but with date_cursor.day as a first parameter, for this the partial function, from functools is perfect.