从 Kivy 中的多点触摸类继承时确定触摸执行层次

Question

我正在尝试结合 KivyMD MDCardSwipe 和 kivy_garden drag_n_drop 的功能。 MDCardSwipe 允许您将卡片滑动到一边以显示底层小部件——在我的例子中带有垃圾桶图标和删除功能——并且 drag_n_drop 允许您四处拖动小部件以在布局中重新排序它们。理想情况下，我想要可以通过拖动重新排列的可滑动卡片。

我创建了一个 class DragCard，如下所示，它继承自 MDCardSwipe 和 DraggableObjectBehavior。当我以这种方式订购时，MDCardSwipe 功能起作用，但 DraggableObjectBehavior 不起作用。当我颠倒顺序时，MDCardSwipe 不再起作用，但 DraggableObjectBehavior 起作用。

MDCardSwipe 有一个相对较小的区域，滑动必须在该区域内开始。我希望 MDCardSwipe 在该区域内接收触摸，如果触摸在所述区域外，则将触摸传递给 DraggableObjectBehavior。

如有任何帮助，我们将不胜感激！

.py 文件：

from kivy.lang import Builder
from kivymd.app import MDApp
from kivy.core.window import Window
from kivy.uix.label import Label
from kivy.uix.boxlayout import BoxLayout
from kivymd.uix.card import MDCardSwipe
from kivy.uix.widget import Widget
from kivy_garden.drag_n_drop import DraggableLayoutBehavior, DraggableObjectBehavior
from kivy.properties import StringProperty


class DraggableBoxLayout(DraggableLayoutBehavior, BoxLayout):
    def __init__(self, **kwargs):
        super().__init__(
            spacer_widget = MySpacer(),
            spacer_props = {'size_hint_y': None, 'height' : 150 },
             **kwargs)
        

    def compare_pos_to_widget(self, widget, pos):
        if self.orientation == 'vertical':
            return 'before' if pos[1] >= widget.center_y else 'after'
        return 'before' if pos[0] < widget.center_x else 'after'

    def handle_drag_release(self, index, drag_widget):
        self.add_widget(drag_widget, index)


class DragCard(MDCardSwipe, DraggableObjectBehavior):
    text = StringProperty()

    def initiate_drag(self):
        # during a drag, we remove the widget from the original location
        self.parent.remove_widget(self)
        

class MySpacer(Widget):
    """Widget inserted at the location where the dragged widget may be
    dropped to show where it'll be dropped.
    """
    pass

 
class MainApp(MDApp): 
    
    def build(self):
        self.theme_cls.theme_style = 'Dark'
        self.theme_cls.primary_palette = "Cyan"
        Window.size = (375, 740)
        

        return Builder.load_file("drag.kv")

    def on_start(self):
        pass

if __name__ == '__main__':
    MainApp().run()

.kv 文件：

#:kivy 2.0.0

BoxLayout:
    orientation: 'vertical'

    DraggableBoxLayout:
        drag_classes: ['card']
        orientation: 'vertical'

        DragCard:
            text: 'A'
            drag_cls: 'card'
        DragCard:
            text: 'B'
            drag_cls: 'card'
        DragCard:
            text: 'C'
            drag_cls: 'card'
        DragCard:
            text: 'D'
            drag_cls: 'card'
        DragCard:
            text: 'E'
            drag_cls: 'card'
        DragCard:
            text: 'F'
            drag_cls: 'card'
        DragCard:
            text: 'G'
            drag_cls: 'card'
        DragCard:
            text: 'H'
            drag_cls: 'card'


<DragCard>:
    size_hint_y: None
    height: 150


    MDCardSwipeLayerBox:
        padding: "8dp"

        MDIconButton:
            icon: "trash-can"
            pos_hint: {"center_y": .5}
            # on_release: root.delete_template()

    MDCardSwipeFrontBox:

        Label:
            text: root.text
            pos_hint: {'center_x': .5, 'center_y': .5}
            halign: 'center'
            valign: 'center'
            font_style: 'H3'

<MySpacer>:
    canvas:
        Color:
            rgba: [.95, .57, .26, 1]
        Rectangle:
            size: self.size
            pos: self.pos

Answer 1

以下代码似乎可以执行您想要的操作。 DragCard 的 on_touch_down() 方法根据 touch 在 DragCard 上的位置调用 DraggableObjectBehavior 或 MDCardSwipe 的 on_touch_down() 方法].其他touch方法根据touch（由DraggableObjectBehavior设置）的grab_current属性决定调用哪个方法：

class DragCard(DraggableObjectBehavior, MDCardSwipe):
    text = StringProperty()

    def initiate_drag(self):
        # during a drag, we remove the widget from the original location
        self.parent.remove_widget(self)
        
    def on_touch_down(self, touch):
        if self.collide_point(*touch.pos):
            if touch.x > self.center_x:
                return DraggableObjectBehavior.on_touch_down(self, touch)
            else:
                return MDCardSwipe.on_touch_down(self, touch)

    def on_touch_up(self, touch):
        if touch.grab_current == self:
            return DraggableObjectBehavior.on_touch_up(self, touch)
        else:
            return MDCardSwipe.on_touch_up(self, touch)

    def on_touch_move(self, touch):
        if touch.grab_current == self:
            return DraggableObjectBehavior.on_touch_move(self, touch)
        else:
            return MDCardSwipe.on_touch_move(self, touch)

从 Kivy 中的多点触摸类继承时确定触摸执行层次

Determining touch execution hierarchy when inheriting from multiple touch classes in Kivy

python

kivy

kivy-language

kivymd

从 Kivy 中的多点触摸 类 继承时确定触摸执行层次

Determining touch execution hierarchy when inheriting from multiple touch classes in Kivy

python

kivy

kivy-language

kivymd

从 Kivy 中的多点触摸类继承时确定触摸执行层次