将函数绑定到kivy中的多个动态创建的按钮？

Question

问题

我想创建多个按钮并将它们绑定到一个函数。问题是，每当我单击一个按钮时，都会多次调用该函数。似乎是事件连接的问题。当我查看按下按钮时调用该函数的实例时，似乎该函数被一次从每个按钮调用？！

KV代码：

...
# This is the button that I'am using
<ProjectSelectButton>:
height: 35
background_color: 0,0,1,1
on_touch_down: self.click_on_button(args[0], args[1])

...

# The buttons are added to this grid
ButtonsPlacedHere@GridLayout:
    id: active_projects
    cols: 1
    size_hint_y: None
    height: self.minimum_height
    spacing: 1
...

Python 代码：

...
class ProjectSelectButton(Button):
    def click_on_button(self, instance, touch, *args):
        print(instance)
        if touch.button == 'right':
            print(self.id, "right mouse clicked")
        else touch.buttom == 'left':
            print(self.id, "left mouse clicked")

...

# The part of my programm that creates the buttons
# projects is a dictionary
for key, project in data_manager.resource_pool.projects.items():
    print(project.project_name)
    button= ProjectSelectButton(text=project.project_name, id=key, size_hint_y=None)
    # Bind without KV-File (same result)
    # label.bind(on_touch_up=self.click_on_button)
    ids.active_projects.add_widget(button)

示例输出：

当我点击一个按钮时，我得到了什么！

<guiMain.ProjectSelectButton object at 0x0BA34260>
ID01 right mouse clicked
<guiMain.ProjectSelectButton object at 0x0BA34260>
ID01 right mouse clicked
<guiMain.ProjectSelectButton object at 0x0BA28F10>
ID02 right mouse clicked
<guiMain.ProjectSelectButton object at 0x0BA28F10>
ID02 right mouse clicked
<guiMain.ProjectSelectButton object at 0x0BA22C00>
ID03 right mouse clicked
<guiMain.ProjectSelectButton object at 0x0BA22C00>
ID03 right mouse clicked

当我按下 ID 为 01 的按钮时我想要什么：

<guiMain.ProjectSelectButton object at 0x0BA34260>
ID01 right mouse clicked

问题

如何创建多个按钮，当它们被按下时会调用一个函数？

Answer 1

Programming Guide » Input management » Touch events

默认情况下，触摸事件被调度到所有当前显示的小部件。这意味着无论是否发生在其物理区域内，小部件都会接收到触摸事件。

为了提供最大的灵活性，Kivy 调度 所有小部件的事件，并让它们决定如何对它们做出反应。 如果您只想响应小部件内的触摸事件，您 简单检查一下。

解决方案

在click_on_button 方法中使用self.collide_point 方法。当它碰撞时，你应该只得到一个按钮。详情请参考我的例子。

片段

class ProjectSelectButton(Button):
    def click_on_button(self, instance, touch, *args):
        print(instance)
        if self.collide_point(*touch.pos):
            if touch.button == 'right':
                print(self.id, "right mouse clicked")
            elif touch.buttom == 'left':
                print(self.id, "left mouse clicked")
            return True
        return super(ProjectSelectButton, self).on_touch_down(touch)

示例

main.py

​​>

from kivy.app import App
from kivy.uix.gridlayout import GridLayout
from kivy.uix.button import Button


class CreateButton(Button):

    def on_touch_down(self, touch):
        if self.collide_point(*touch.pos):
            if touch.button == "right":
                print(self.id, "right mouse clicked")
            elif touch.button == "left":
                print(self.id, "left mouse clicked")
            else:
                print(self.id)
            return True
        return super(CreateButton, self).on_touch_down(touch)


class OnTouchDownDemo(GridLayout):

    def __init__(self, **kwargs):
        super(OnTouchDownDemo, self).__init__(**kwargs)
        self.build_board()

    def build_board(self):
        # make 9 buttons in a grid
        for i in range(0, 9):
            button = CreateButton(id=str(i))
            self.add_widget(button)


class OnTouchDownApp(App):

    def build(self):
        return OnTouchDownDemo()


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

ontouchdown.kv

#:kivy 1.10.0

<CreateButton>:
    font_size: 50
    on_touch_down: self.on_touch_down

<OnTouchDownDemo>:
    rows: 3
    cols: 3
    row_force_default: True
    row_default_height: 150
    col_force_default: True
    col_default_width: 150
    padding: [10]
    spacing: [10]