python - 如何在 .kv 文件中使用 if 语句

Question

我想加载一个特定的图像，在这种情况下，我希望我的游戏显示钢铁侠的图像，但只有当变量“char”设置为钢铁侠时，玩家选择玩时才会设置和他一样。

<Game2>:
    name: "Avengers Tower"
    FloatLayout:
        Image:
            source: "avengerstower.png"

下面的图像代码是当 char 是钢铁侠时我要运行的代码

        Image:
            source: "ironmanhover.png" 
            pos_hint: {"x": .6, "y": .05}
            size_hint: .4, .7

        Label:
            text: "You are in the Avengers Tower!"
            pos_hint: {"x": .45, "y": .6}
            font_size: "20dp"
            color: (0,0,0,1)
            size_hint: None, None

        Button:
            text: "North"
            pos_hint: {"x": .45, "y": .85}
            size_hint: None, None
            height: 50
            on_press:
                root.manager.current = "AvengersCourtyard"

下面这段代码是设置 char 值的地方。

<Game>:
    name: "main"
    FloatLayout:
        Image:
            source: "choosecharacter.png"

        Image:
            source: "choosechar.png" 
            pos_hint: {"x": .3, "y": .25}
            size_hint: .4, .8

        Button:
            text: "<- Back"
            font_size: "15dp"
            pos: 40, 510
            size_hint: None, None
            height: 50
            on_press:
                root.manager.current = "Title"

        ToggleButton:
            text: "Iron Man"
            font_size: "15dp"
            pos: 200, 150
            size_hint: None, None
            height: 80
            group: "character"
            on_press:
                char = "Iron Man"

        ToggleButton:
            text: "Thor"
            font_size: "15dp"
            pos: 350, 150
            size_hint: None, None
            height: 80
            group: "character"
            on_press:
                char = "Thor"

        ToggleButton:
            text: "Scarlett Witch"
            font_size: "15dp"
            pos: 500, 150
            size_hint: None, None
            height: 80
            group: "character"
            on_press:
                char = "Scarlett Witch"

        Button:
            text: "Play!"
            height: 50
            font_size: "15dp"
            pos: 650, 60
            size_hint: None, None
            on_press:
                root.manager.current = "Avengers Tower"

这些是上面的按钮 ^^

Answer 1

ToggleButton 没有 on_press 事件。它有 on_state 事件。

Kivy » ToggleButton

The ToggleButton widget acts like a checkbox. When you touch or click it, the state toggles between ‘normal’ and ‘down’ (as opposed to a Button that is only ‘down’ as long as it is pressed).

Toggle buttons can also be grouped to make radio buttons - only one button in a group can be in a ‘down’ state.

片段

    ToggleButton:
        text: "Iron Man"
        font_size: "15dp"
        pos: 200, 150
        size_hint: None, None
        height: 80
        group: "character"
        #on_press:
        on_state:
            if self.state == "down": \
            print(self.text); \
            root.manager.current = "Avengers Tower"

    ToggleButton:
        text: "Thor"
        font_size: "15dp"
        pos: 350, 150
        size_hint: None, None
        height: 80
        group: "character"
        #on_press:
        on_state:
            if self.state == "down": \
            print(self.text); \
            root.manager.current = "Thor"

    ToggleButton:
        text: "Scarlett Witch"
        font_size: "15dp"
        pos: 500, 150
        size_hint: None, None
        height: 80
        group: "character"
        #on_press:
        on_state:
            if self.state == "down": \
            print(self.text); \
            root.manager.current = "Scarlett Witch"