問題描述

我正在嘗試制作一個主菜單，讓我在單擊按鈕時切換屏幕，但我不知道如何從按鈕中引用管理器.

I'm trying to make a main menu that lets me switch Screens when I click a button, but I can't figure out how to reference the manager from the button.

我有一個主菜單頁面的設置(在 kv 文件中):

I have a setup for a main menu page (in kv file):

<MainMenu>:  #AnchorLayout
     BoxLayout:
         Button:
             text: "button 1"
         Button:
             text: "change screen"
             on_release: root.manager.current = "OtherPage"

<MainWidget>:
    screen_manger: screen_manager
    ScreenManger:
        id: screen_manger
        Screen:
            name: "MainMenu"
            MainMenu
        Screen:
            name: "OtherPage"
            OtherPage    #this is defined in the kv file, just lazy to type it.

當我點擊按鈕 Change Screen 時，我得到:

When I click on the Button Change Screen, i get:

AttributeError: 'MainMenu' object has no attribute 'manager'

老實說，這并不讓我感到驚訝.我想我可以通過在 python 代碼中編寫所有布局并在 BoxLayout 或 MainMenu 小部件中添加對屏幕管理器的引用來解決這個問題，但我不知道如何在 kv 文件中執行此操作.

which, in all honesty doesn't supprise me. I figure I can work around this by writing all the layout in python code and adding a reference to the screen manager in the BoxLayout or MainMenu widgets, but I have no idea how to do this in the kv file.

推薦答案

更好理解問題后重新做答案:

Re-doing the answer after understanding the issue better:

您的 MainWidget 實例不知道 screen_manager 引用，它沒有傳遞給它(并且在其規則中 root 引用 MainWidget 實例，而不是 ScreenManager 一個.

Your MainWidget instance doesn't know about the screen_manager reference, it's not passed to it (and in its rule root refer to the MainWidget instance, not the ScreenManager one.

如果您將 manager: screen_manager 放在 MainWidget 實例的聲明下(第 15 行)，然后將 manager ObjectProperty 添加到 pythonMainWidget 的聲明，那么您的綁定將起作用.

If you put manager: screen_manager under the declaration of MainWidget instance (line 15), and you add a manager ObjectProperty to the python declaration of MainWidget, then your binding will work.

蟒蛇:

class MainWidget(Widget):
    manager = ObjectProperty(None)

kv:

<MainWidget>:
    screen_manger: screen_manager
    ScreenManger:
        id: screen_manger
        Screen:
            name: "MainMenu"
            MainMenu:
                manager: screen_manager
        Screen:
            name: "OtherPage"

那么它應該可以按您的意愿工作.

then it should work as you want it.

另外，qua-non 的這個 wiki 條目可能會有所幫助 https://github.com/kivy/kivy/wiki/Linking-ScreenManager-to-a-different-Widget

edit: also, this wiki entry by qua-non could be helpful https://github.com/kivy/kivy/wiki/Linking-ScreenManager-to-a-different-Widget

這篇關于kv 語言中的 Kivy 屏幕管理器參考的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！