向循环中的按钮添加 on_release 操作

Question

class WidgetFiscal(Screen):
    box = ObjectProperty(None)

    def on_box(self, *args):
        fiscal = ['Elzab Mera TE FV', 'Posnet Thermal XL', 'Posnet HD', 'Elzab Sigma', 'Novitus Delio Prime E', 'Elzab D10', 'Posnet Trio', 'Epson TM-T801FV']
        for i in fiscal:
            self.box.add_widget(Button(text=str(i), background_color=[1,2,1,1]))

我的 .kv 文件：

<FiscalPrinter>:
    name: 'fiscal_printer'

    BoxLayout:
        size: root.size
        spacing: 20
        padding: 10,10,10,10
        orientation: 'vertical'

        Label:
            text: 'Choose fiscal printer which you want to rent'
            size: root.width, root.height / 10
            size_hint: None, None

        WidgetFiscal:

        Button:
            text: 'GO BACK'
            size: root.width, root.height / 10
            size_hint: None, None
            on_release: app.root.current = "rent_device"

<WidgetFiscal>:
    box: box

    GridLayout:
        background_color: 1,2,1,1
        cols: 3
        id: box

Answer 1

正在向 Button 小部件添加 on_release 事件。

self.box.add_widget(Button(..., on_release=self.mycallback))

备注

Kivy » Touch event basics

By default, touch events are dispatched to all currently displayed widgets. This means widgets receive the touch event whether it occurs within their physical area or not.

...

In order to provide the maximum flexibility, Kivy dispatches the events to all the widgets and lets them decide how to react to them. If you only want to respond to touch events inside the widget, you simply check:

def on_touch_down(self, touch):
    if self.collide_point(*touch.pos):
        # The touch has occurred inside the widgets area. Do stuff!
        pass

解决方案

因此您想定义 class PrinterButton 并继承 Button 小部件并实现 on_touch_down 方法以仅响应 Button 触摸的触摸事件。

片段

class PrinterButton(Button):
    def on_touch_down(self, touch):
        if self.collide_point(*touch.pos):
            print(f"\nPrinterButton.on_touch_down: text={self.text}")
            self.dispatch('on_release')
            return True    # consumed on_touch_down & stop propagation / bubbling
        return super(PrinterButton, self).on_touch_down(touch)

class WidgetFiscal(Screen): 
    box = ObjectProperty(None)

    def on_box(self, *args):
        fiscal = ['Elzab Mera TE FV', 'Posnet Thermal XL', 'Posnet HD', 'Elzab Sigma', 'Novitus Delio Prime E', 'Elzab D10', 'Posnet Trio', 'Epson TM-T801FV']
        for i in fiscal:
            self.box.add_widget(PrinterButton(text=str(i), background_color=[1,2,1,1], on_release=self.mycallback))

    def mycallback(self, instance):
        print(f"mycallback: Button.text={instance.text}")

输出