如何更新 kivy 标签颜色，即数据在运行时存储在主应用程序 class 的变量中

Question

这是我的py文件

class ImportSetting:
    with open('settings.txt') as json_file:
        save_data = json.load(json_file)

class MainApp(App):
    height = Window.height
    spacing = dp(2)
    def sp(self, a):
        self.spacing = a
    # Button Colors #################################
    button_color_square = ImportSetting.save_data['bcs']
    def bcs(self, val):
        self.button_color_square = val

    button_text_color_square = ImportSetting.save_data['bcs_t']
    def bcs_t(self, val):
        self.button_text_color_square = val

    button_color_top_bar = ImportSetting.save_data['bct']
    def bct(self, val):
        self.button_color_top_bar = val

    button_text_color_top_bar = ImportSetting.save_data['bct_t']
    def bct_t(self, val):
        self.button_text_color_top_bar = val

    button_color_side_bar = ImportSetting.save_data['bcr']
    def bcr(self, val):
        self.button_color_side_bar = val

    button_text_color_side_bar = ImportSetting.save_data['bcr_t']
    def bcr_t(self, val):
        self.button_text_color_side_bar = val

    # Background Color
    text_background_color = ImportSetting.save_data["text_bc"]
    def text_bc(self, val):
        self.text_background_color = val

    button_background_color = ImportSetting.save_data["button_bc"]
    def button_bc(self, val):
        self.button_background_color = val

    history_background_color = ImportSetting.save_data["history_bc"]
    def history_bc(self, val):
        self.history_background_color = val

    # Text color
    text_color_main = ImportSetting.save_data["main_tc"]
    def tc(self, val):
        self.text_color_main = val
        print(self.text_color_main)

    text_color_history = ImportSetting.save_data["history_tc"]
    def htc(self, val):
        self.text_color_history = val

    # Button press color
    press_color = ImportSetting.save_data["on_button_press_color"]
    # Font Size
    font_size_main = ImportSetting.save_data["fsm"]
    font_size_history = ImportSetting.save_data["fsh"]

    font_size_button_square = ImportSetting.save_data["fsbs"]
    font_size_button_top_bar = ImportSetting.save_data["fsbtb"]
    font_size_button_side_bar = ImportSetting.save_data["fsbsb"]

    def build(self):
        kv = Builder.load_file("main.kv")
        return kv


if __name__ == "__main__":
    MainApp().run()
    save_data = {'bcs': MainApp.button_color_square, 'bcs_t': MainApp.button_text_color_square,
                 'bct': MainApp.button_color_top_bar, 'bct_t': MainApp.button_text_color_top_bar,
                 'bcr': MainApp.button_color_side_bar, 'bcr_t': MainApp.button_text_color_side_bar,
                 "text_bc": MainApp.text_background_color, "button_bc": MainApp.button_background_color,
                 "history_bc": MainApp.history_background_color, "main_tc": MainApp.text_color_main,
                 "history_tc": MainApp.text_color_history, "on_button_press_color": MainApp.press_color,
                 "fsm": MainApp.font_size_main, "fsh": MainApp.font_size_history, "fsbs": MainApp.font_size_button_square,
                 "fsbtb": MainApp.font_size_button_top_bar, "fsbsb": MainApp.font_size_button_side_bar}

    with open('settings.txt', "w") as outfile:
        json.dump(save_data, outfile)

然后是我的kv文件

                    BoxLayout:
                        spacing: sp
                        Button:
                            text: "C"
                            on_press: root.clear()
                            font_size: dp(app.font_size_button_top_bar)
                            background_normal: ""
                            background_down: ""
                            color: app.button_text_color_top_bar
                            on_press: self.background_color = app.press_color
                            on_release: self.background_color = app.button_color_top_bar
                            background_color: app.button_color_top_bar
                        Button:
                            text: "+/-"
                            on_press: root.switch()
                            font_size: dp(app.font_size_button_top_bar)
                            background_normal: ""
                            background_down: ""
                            color: app.button_text_color_top_bar
                            on_press: self.background_color = app.press_color
                            on_release: self.background_color = app.button_color_top_bar
                            background_color: app.button_color_top_bar
                        Button:
                            text: "%"
                            on_press: root.percent()
                            font_size: dp(app.font_size_button_top_bar)
                            background_normal: ""
                            background_down: ""
                            color: app.button_text_color_top_bar
                            on_press: self.background_color = app.press_color
                            on_release: self.background_color = app.button_color_top_bar
                            background_color: app.button_color_top_bar
                        Button:
                            text: "÷"
                            on_press: root.divide()
                            font_size: dp(app.font_size_button_side_bar)
                            background_normal: ""
                            background_down: ""
                            color: app.button_text_color_side_bar
                            on_press: self.background_color = app.press_color
                            on_release: self.background_color = app.button_color_side_bar
                            background_color: app.button_color_side_bar

# Button Row 2
                    BoxLayout:
                        spacing: sp
                        Button:
                            text: "7"
                            on_press: root.add_int(self)
                            font_size: dp(app.font_size_button_square)
                            background_normal: ""
                            background_down: ""
                            color: app.button_text_color_square
                            on_press: self.background_color = app.press_color
                            on_release: self.background_color = app.button_color_square
                            background_color: app.button_color_square
                        Button:
                            text: "8"
                            on_press: root.add_int(self)
                            font_size: dp(app.font_size_button_square)
                            background_normal: ""
                            background_down: ""
                            color: app.button_text_color_square
                            on_press: self.background_color = app.press_color
                            on_release: self.background_color = app.button_color_square
                            background_color: app.button_color_square
                        Button:
                            text: "9"
                            on_press: root.add_int(self)
                            font_size: dp(app.font_size_button_square)
                            background_normal: ""
                            background_down: ""
                            color: app.button_text_color_square
                            on_press: self.background_color = app.press_color
                            on_release: self.background_color = app.button_color_square
                            background_color: app.button_color_square
                        Button:
                            text: "x"
                            on_press: root.multiply()
                            font_size: dp(app.font_size_button_side_bar)
                            background_normal: ""
                            background_down: ""
                            color: app.button_text_color_side_bar
                            on_press: self.background_color = app.press_color
                            on_release: self.background_color = app.button_color_side_bar
                            background_color: app.button_color_side_bar

# Button Row 3
                    BoxLayout:
                        spacing: sp
                        Button:
                            text: "4"
                            on_press: root.add_int(self)
                            font_size: dp(app.font_size_button_square)
                            background_normal: ""
                            background_down: ""
                            color: app.button_text_color_square
                            on_press: self.background_color = app.press_color
                            on_release: self.background_color = app.button_color_square
                            background_color: app.button_color_square
                        Button:
                            text: "5"
                            on_press: root.add_int(self)
                            font_size: dp(app.font_size_button_square)
                            background_normal: ""
                            background_down: ""
                            color: app.button_text_color_square
                            on_press: self.background_color = app.press_color
                            on_release: self.background_color = app.button_color_square
                            background_color: app.button_color_square
                        Button:
                            text: "6"
                            on_press: root.add_int(self)
                            font_size: dp(app.font_size_button_square)
                            background_normal: ""
                            background_down: ""
                            color: app.button_text_color_square
                            on_press: self.background_color = app.press_color
                            on_release: self.background_color = app.button_color_square
                            background_color: app.button_color_square
                        Button:
                            text: "-"
                            on_press: root.subtract()
                            font_size: dp(app.font_size_button_side_bar)
                            background_normal: ""
                            background_down: ""
                            color: app.button_text_color_side_bar
                            on_press: self.background_color = app.press_color
                            on_release: self.background_color = app.button_color_side_bar
                            background_color: app.button_color_side_bar

# Button Row 4
                    BoxLayout:
                        spacing: sp
                        Button:
                            text: "1"
                            on_press: root.add_int(self)
                            font_size: dp(app.font_size_button_square)
                            background_normal: ""
                            background_down: ""
                            color: app.button_text_color_square
                            on_press: self.background_color = app.press_color
                            on_release: self.background_color = app.button_color_square
                            background_color: app.button_color_square
                        Button:
                            text: "2"
                            on_press: root.add_int(self)
                            font_size: dp(app.font_size_button_square)
                            background_normal: ""
                            background_down: ""
                            color: app.button_text_color_square
                            on_press: self.background_color = app.press_color
                            on_release: self.background_color = app.button_color_square
                            background_color: app.button_color_square
                        Button:
                            text: "3"
                            on_press: root.add_int(self)
                            font_size: dp(app.font_size_button_square)
                            background_normal: ""
                            background_down: ""
                            color: app.button_text_color_square
                            on_press: self.background_color = app.press_color
                            on_release: self.background_color = app.button_color_square
                            background_color: app.button_color_square
                        Button:
                            text: "+"
                            on_press: root.add()
                            font_size: dp(app.font_size_button_side_bar)
                            background_normal: ""
                            background_down: ""
                            color: app.button_text_color_side_bar
                            on_press: self.background_color = app.press_color
                            on_release: self.background_color = app.button_color_side_bar
                            background_color: app.button_color_side_bar
# Button Row 5
                    BoxLayout:
                        spacing: sp
                        Button:
                            text: "0"
                            size_hint: 2, 1
                            on_press: root.add_int(self)
                            font_size: dp(app.font_size_button_square)
                            background_normal: ""
                            background_down: ""
                            color: app.button_text_color_square
                            on_press: self.background_color = app.press_color
                            on_release: self.background_color = app.button_color_square
                            background_color: app.button_color_square
                        Button:
                            text: "."
                            on_press: root.decimal()
                            font_size: dp(app.font_size_button_square)
                            background_normal: ""
                            background_down: ""
                            color: app.button_text_color_square
                            on_press: self.background_color = app.press_color
                            on_release: self.background_color = app.button_color_square
                            background_color: app.button_color_square
                        Button:
                            text: "="
                            on_press: root.calculate()
                            font_size: dp(app.font_size_button_side_bar)
                            background_normal: ""
                            background_down: ""
                            color: app.button_text_color_side_bar
                            on_press: self.background_color = app.press_color
                            on_release: self.background_color = app.button_color_side_bar
                            background_color: app.button_color_side_bar

如您所见，我在我的主应用程序中创建了几个包含颜色数据的变量，然后我将我的 kivy 按钮的颜色属性分配给变量，然后将所有变量保存在字典中使用 json，然后在我的代码开头创建一个导入 class 并导入字典，然后我将每个变量分配给代表该变量的字典键。现在每次我启动我的应用程序时，每次关闭它时都会保存颜色设置，我通过将变量重新分配给颜色然后运行应用程序来修改其中一种变量颜色来验证这一点，然后我关闭它并再次删除重新分配和运行并更新颜色，但是当我尝试在运行时通过函数更新颜色时，变量更新但不是按钮颜色。顺便提醒一下，我刚刚开始学习 python 和 kivy 以及一般编程，这是我的第一个应用程序。

Answer 1

在 App 之后更改变量的值运行不会影响小部件的颜色，即使您从该变量分配了小部件的颜色。评估 kv 时，颜色设置为该变量的值。例外情况是该变量是 Property。如果您从 kv 中的 Property 分配小部件颜色，则当 Property 更改时，该小部件颜色将更改。因此，您只需将变量更改为 Properties.

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