Kivy - 在 .py 文件中的另一个屏幕中使用来自一个屏幕的 TextInput 的文本

Question

我的第一个屏幕上有一个 TextInput，我想在第二个屏幕的标签中使用接收到的文本。我怎样才能做到这一点？由于可以有不同的玩家，我创建了一个类 Players ，它为每个玩家存储一个名字和他/她的分数。在第二个屏幕中，我还尝试创建一个可以编辑点（标签文本）的按钮，但是当我单击它时，什么也没有发生。 （我也是新手。）

在下面的代码中，我标记了相关的行。

所以概述：

• 第一个屏幕：使用 textInput 提取用户名 + 使用 Player 类创建播放器实例

• 第二个屏幕：在标签中使用玩家名称 + 在标签中使用玩家点 + 创建 2 个按钮，从这个“点”标签中添加/减去点

我知道这里有类似的情况，但它对我的 .py 文件没有帮助：How to ref a TextInput from one screen in another screen in Kivy/Python?

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.textinput import TextInput
from kivy.uix.gridlayout import GridLayout
from kivy.uix.button import Button
from kivy.uix.label import Label
from kivy.properties import ObjectProperty, NumericProperty


class Player:
    def __init__(self, name):
        self.name = name
        self.points = 0

    def reset_points(self):
        self.points = 0

    def add_point(self, *args):
        self.points += 1

    def subtract_point(self, *args):
        self.points -= 1


class WelcomeWindow(Screen):
    # Introduce names of the 4 players

    def __init__(self, **kwargs):
        super(WelcomeWindow, self).__init__(**kwargs)
        self.name = "welcomewindow"
        self.layout = "layout_welcome_window"

        global_layout = GridLayout(rows=3)
        self.add_widget(global_layout)

        label_player_i = Label(text="Name Player ")
        global_layout.add_widget(label_player_i)

        name_input_player_i = TextInput(id="player ", text="player", multiline=False) # <--- user inputs name here
        global_layout.add_widget(name_input_player_i)

        self.player1 = Player(name_input_player_i.text) # <--- name is assigned to player here

        # Create button to go to next screen
        go_further_button = Button(text="Go to first round")
        go_further_button.bind(on_release=self.go_further)
        global_layout.add_widget(go_further_button)

    def go_further(self, *args):
        self.manager.current = "firstround"
        self.manager.transition.direction = "left"

class FirstRound(Screen):
    #Give explanation of first round + option to add points for every player

    def __init__(self, **kwargs):
        super(FirstRound, self).__init__(**kwargs)
        self.name = "firstround"
        self.layout = "layout_first_round"

        #Create layout
        global_layout = GridLayout(rows=4)
        self.add_widget(global_layout)

        #Create Labels
        label_player_name_i = Label(text=WelcomeWindow().player1.name) # <--- Label should get the name of the player here
        global_layout.add_widget(label_player_name_i)

        label_player_points_i = Label(text=str(WelcomeWindow().player1.points)) # <--- Label should get points of player
        global_layout.add_widget((label_player_points_i))

        #Create Buttons
        button_minus = Button(text="-", font_size=100, id="minus_button")
        button_minus.bind(on_release=WelcomeWindow().player1.subtract_point) # <--- When button pushed: should subtract point
        global_layout.add_widget(button_minus)

        button_plus = Button(text="+", font_size=100, id="plus_button")
        button_plus.bind(on_release=WelcomeWindow().player1.add_point) # <--- When button pushed: should add point
        global_layout.add_widget(button_plus)


WindowManager = ScreenManager()
WindowManager.add_widget(WelcomeWindow())
WindowManager.add_widget(FirstRound())

class KingenApp(App):

    def build(self):
        return WindowManager

if __name__ == "__main__":
    KingenApp().run()

Answer 1

你的代码有几个问题：

• 当您创建Widget 的实例时，将调用任何Widget 的__init__() 方法。所以FirstRound 的__init__() 方法在WindowManager.add_widget(FirstRound()) 行被调用。那时，WelcomeWindow 的TextInput 中无法输入任何文字 ，因此您无法获得当时的玩家名称。
• Player 实例 (self.player1 = Player(name_input_player_i.text)) 的创建会在用户有机会输入玩家姓名之前创建 Player 实例。
• 在FirstRound 的__init__() 方法中使用WelcomeWindow() 会创建一个与GUI 中的实例无关的WelcomeWindow 新实例。所以从那个实例中提取的任何信息都是没有用的。
• 在您的FirstRound 中，玩家积分标签在创建Label 时从Player 类实例中获取其数据。之后更改Player 的points 属性将不会影响Label。

第一个问题可以通过将大部分代码从FirstRound 的__init__() 方法中移出，并将其放入在显示Screen 时运行的on_enter() 方法中。

第二个问题可以通过将Player 实例的创建移到go_further() 方法中来处理，因为它在离开WelcomeWindow 时被执行。

第三个问题可以通过将WelcomeWindow() 的这些用法替换为self.manager.get_screen('welcomewindow') 来访问GUI 中WelcomeWindow 的实际实例。

这是您的代码的修改版本，它可以完成这三件事：

from kivy.app import App
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.textinput import TextInput
from kivy.uix.gridlayout import GridLayout
from kivy.uix.button import Button
from kivy.uix.label import Label


class Player:
    def __init__(self, name):
        self.name = name
        self.points = 0

    def reset_points(self):
        self.points = 0

    def add_point(self, *args):
        self.points += 1

    def subtract_point(self, *args):
        self.points -= 1


class WelcomeWindow(Screen):
    # Introduce names of the 4 players

    def __init__(self, **kwargs):
        super(WelcomeWindow, self).__init__(**kwargs)
        self.name = "welcomewindow"
        self.layout = "layout_welcome_window"

        global_layout = GridLayout(rows=3)
        self.add_widget(global_layout)

        label_player_i = Label(text="Name Player ")
        global_layout.add_widget(label_player_i)

        self.name_input_player_i = TextInput(id="player ", text="player", multiline=False) # <--- user inputs name here
        global_layout.add_widget(self.name_input_player_i)

        # Create button to go to next screen
        go_further_button = Button(text="Go to first round")
        go_further_button.bind(on_release=self.go_further)
        global_layout.add_widget(go_further_button)

    def go_further(self, *args):
        self.player1 = Player(self.name_input_player_i.text) # <--- name is assigned to player here
        self.manager.current = "firstround"
        self.manager.transition.direction = "left"


class FirstRound(Screen):
    #Give explanation of first round + option to add points for every player

    def __init__(self, **kwargs):
        super(FirstRound, self).__init__(**kwargs)
        self.name = "firstround"
        self.layout = "layout_first_round"

    def on_enter(self, *args):
        #Create layout
        global_layout = GridLayout(rows=4)
        self.add_widget(global_layout)

        #Create Labels
        welcome_window = self.manager.get_screen('welcomewindow')  # get a reference to the WelcomeWindow instance
        label_player_name_i = Label(text=welcome_window.player1.name) # <--- Label should get the name of the player here
        global_layout.add_widget(label_player_name_i)

        label_player_points_i = Label(text=str(welcome_window.player1.points)) # <--- Label should get points of player
        global_layout.add_widget((label_player_points_i))

        #Create Buttons
        button_minus = Button(text="-", font_size=100, id="minus_button")
        button_minus.bind(on_release=welcome_window.player1.subtract_point) # <--- When button pushed: should subtract point
        global_layout.add_widget(button_minus)

        button_plus = Button(text="+", font_size=100, id="plus_button")
        button_plus.bind(on_release=welcome_window.player1.add_point) # <--- When button pushed: should add point
        global_layout.add_widget(button_plus)


WindowManager = ScreenManager()
WindowManager.add_widget(WelcomeWindow())
WindowManager.add_widget(FirstRound())


class KingenApp(App):

    def build(self):
        return WindowManager


if __name__ == "__main__":
    KingenApp().run()

第四个问题值得自己提出一个问题，但可能涉及使用 kivy 语言。