Question

我试图在Widget类中使用ScrollView但是当我放入on_touch_down方法时它不起作用。有什么问题？怎么解决这个？

这是一段代码：

from kivy.app import App
from kivy.core.window import Window
from kivy.uix.button import Button
from kivy.uix.gridlayout import GridLayout
from kivy.uix.scrollview import ScrollView
from kivy.uix.widget import Widget

Window.size = (520, 960)


class GameManager(Widget):

    def __init__(self, **kwargs):
        super(GameManager, self).__init__(**kwargs)
        layout = GridLayout(cols=1, spacing=10, size_hint_y=None)
        layout.bind(minimum_height=layout.setter('height'))
        for i in range(100):
            btn = Button(text=str(i), size_hint_y=None, height=40)
            layout.add_widget(btn)
        root = ScrollView(size_hint=(1, None), size=(Window.width/2, Window.height*3/4))
        root.add_widget(layout)
        self.add_widget(root)

    #When I delete this method everything is fine
    def on_touch_down(self, touch): 
        if self.collide_point(*touch.pos):
             pass


class ScrollViewApp(App):
    game = GameManager()

Answer 1

touch_down事件沿窗口小部件树传播，首先传递给根窗口小部件，然后让每个窗口小部件将触摸传递给其子窗口。问题是，你覆盖了on_touch_down方法并且事件没有传播，连续你的ScrollView没有响应这个事件。

您应该只调用父项的on_touch_downd方法以允许事件传播：

    def on_touch_down(self, touch):
        if self.collide_point(*touch.pos):
             pass

        super(GameManager, self).on_touch_down(touch)

Kivy ScrollView不适用于on_touch_down方法

1 个答案: