如何動態地將用python代碼創建的小部件添加到kv文件

Question

我是Kivy的新手，我遇到了將項目添加到gridLayout的問題。這些項目是在我的python類中創建的，我想在我的kv文件中填充我的gridlayout。它可以工作，但標籤被添加到同一個地方（這意味着它們不在列中 - 它們都在一個單元格中）。我試過here的解決方案，但我仍然不知道什麼是錯的。

KV文件：

#:kivy 1.9.1 

<Connected>: 

    BoxLayout: 
     orientation: 'vertical' 

     Label: 
      text: 'main window' 
      font_size: 32 

     BoxLayout: 
      orientation: 'vertical' 

      Label: 
       text: 'Flights' 
       font_size: 32 

      BoxLayout: 
       orientation: 'horizontal' 
       Label: 
        text: 'From' 
        font_size: 32 
       Label: 
        text: 'To' 
        font_size: 32 
       Label: 
        text: 'Company' 
        font_size: 32 
       Label: 
        text: 'Date' 
        font_size: 32 

      ScrollView: 
       size_hint_y: None 
       height: '200dp' 

       GridLayout: 
        id: flights_table 
        col: 4 
        size_hint_y: None 
        spacing: '1dp' 

      Button: 
       text: "Buy a ticket" 
       font_size: 32 
       on_press: root.order_flight() 

      Button: 
       text: "Logout" 
       font_size: 24 
       on_press: root.disconnect() 

Python代碼：

# coding: utf-8 
import json 
import requests 
from kivy.adapters.dictadapter import (
    DictAdapter, 
    ListAdapter, 
) 
from kivy.properties import (
    ListProperty, 
    ObjectProperty, 
) 
from kivy.uix.gridlayout import GridLayout 
from kivy.uix.label import Label 
from kivy.uix.screenmanager import (
    Screen, 
    SlideTransition, 
) 
from kivy.uix.listview import ListItemButton 


class Connected(Screen): 
    u"""Screen after login in.""" 

    flights = ListProperty() 

    def on_pre_enter(self, *args): 
     u"""Method that loads before the screen is loaded.""" 
     self.flights = self.get_flights() 

     for flight in self.flights: 
      for value in [flight.get('from_city'), flight.get('to_city'), flight.get('company'), flight.get('flight_date')]: 
       self.ids.flights_table.add_widget(Label(text=value)) 

    def disconnect(self): 
     u"""Logout method.""" 
     self.manager.transition = SlideTransition(direction="right") 
     self.manager.current = 'login' 
     self.manager.get_screen('login').resetForm() 

    def get_flights(self): 
     u"""Method that gets the flights from a rest api.""" 
     response = requests.get('http://127.0.0.1:8000/flights/', params={'format': 'json'}) 
     if response.status_code == 200: 
      data = None 
      try: 
       data = json.loads(response.content.decode('utf-8')) 
      except ValueError as err: 
       raise 
      return data 
     return list() 

Answer 1

我有我的問題解決了。我改變了構建網格佈局的方式。相反，在我的.kv文件中構建網格，我得到了我的ScrollView的id併爲其添加了一個網格佈局。從Kivy警告幫我一點點：

在0x7ff7ac893a60

[警告] kivy.uix.gridlayout.GridLayout對象都沒有的cols或設置行佈局不會被觸發。

此外Kivy documentation給了我一個提示。

所以我的代碼是現在這個樣子：

.kv文件：

#:kivy 1.9.1 

<Connected>: 

    BoxLayout: 
     orientation: 'vertical' 

     Label: 
      text: 'Main panel' 
      font_size: 32 

     BoxLayout: 
      orientation: 'vertical' 

      Label: 
       text: 'Flights' 
       font_size: 32 

      BoxLayout: 
       orientation: 'horizontal' 
       Label: 
        text: 'From' 
        font_size: 32 
       Label: 
        text: 'To' 
        font_size: 32 
       Label: 
        text: 'company' 
        font_size: 32 
       Label: 
        text: 'Data' 
        font_size: 32 

      ScrollView: 
       id: scroll_view 
       size_hint_y: None 
       height: '200dp' 


      Button: 
       text: "Order a ticket" 
       font_size: 32 
       on_press: root.order_flight() 

      Button: 
       text: "Logout" 
       font_size: 24 
       on_press: root.disconnect() 

Python代碼：

# coding: utf-8 
import json 
import requests 
from kivy.adapters.dictadapter import (
    DictAdapter, 
    ListAdapter, 
) 
from kivy.properties import (
    ListProperty, 
    ObjectProperty, 
) 
from kivy.uix.gridlayout import GridLayout 
from kivy.uix.label import Label 
from kivy.uix.screenmanager import (
    Screen, 
    SlideTransition, 
) 
from kivy.uix.listview import ListItemButton 
from requests.exceptions import ConnectionError 

class Connected(Screen): 
    u"""Screen after login in.""" 

    flights = ListProperty() 

    def on_pre_enter(self, *args): 
     u"""Method that loads before the screen is loaded.""" 
     self.flights = self.get_flights() 

     scroll = self.ids.scroll_view 
     scroll.clear_widgets() 
     grid = GridLayout(cols=4, size_hint_y=None, spacing='1dp') 
     # grid.bind(minimum_height=grid.setter('height')) 
     for flight in self.flights: 
      for value in [flight.get('from_city'), flight.get('to_city'), flight.get('company'), flight.get('flight_date')]: 
       grid.add_widget(Label(text=value)) 
     scroll.add_widget(grid) 

    def disconnect(self): 
     u"""Logout method.""" 
     self.manager.transition = SlideTransition(direction="right") 
     self.manager.current = 'login' 
     self.manager.get_screen('login').resetForm() 

    def get_flights(self): 
     u"""Method that gets the flights from a rest api.""" 
     try: 
      response = requests.get('http://127.0.0.1:8000/flights/', params={'format': 'json'}) 
     except ConnectionError: 
      raise 
     if response.status_code == 200: 
      data = None 
      try: 
       data = json.loads(response.content.decode('utf-8')) 
      except ValueError as err: 
       raise 
      return data 
     return list()