单击“TextInput”对象后在 Kivy 中重新获得键盘焦点

Question

以下代码创建一个Kivy 应用程序，该应用程序只有一个屏幕MainScreen，显示Label 和TextInput 对象。

如果您在应用首次加载时提供了一些键盘输入，它会在控制台中打印有关按下哪个键的信息。但是，如果您随后单击 TextInput 对象，键盘将重新聚焦，以便您可以键入 TextInput 对象。但是，一旦您单击退出 TextInput 对象，例如在标签或背景上，按更多键，不执行相同的控制台打印操作；似乎键盘没有从TextInput 对象“散焦”。

点击TextInput 对象后如何重新获得键盘焦点？

from kivy.app import App
from kivy.lang import Builder
from kivy.core.window import Window
from kivy.uix.screenmanager import Screen, ScreenManager
from kivy.uix.textinput import TextInput

kv = '''ScreenManagement:
    MainScreen:

<MainScreen>:
    name: "main"
    BoxLayout:
        Label:
            text: "Label"
            font_size: 20
            size_hint: 0.2,0.1
        TextInput
            input_filter: 'float'
            font_size: 20
            hint_text: "Input Text"
            size_hint: 0.2,0.1'''

class MainScreen(Screen):

    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self._keyboard = Window.request_keyboard(self._keyboard_closed, self)
        self._keyboard.bind(on_key_down=self._on_keyboard_down)

    def _keyboard_closed(self):
        self._keyboard.unbind(on_key_down=self._on_keyboard_down)
        self._keyboard = None

    def _on_keyboard_down(self, keyboard, keycode, text, modifiers):
        print('INFO: The key', keycode, 'has been pressed')

        return True # return True to accept the key. Otherwise, it will be used by the system.

class ScreenManagement(ScreenManager):
    pass

class MainApp(App):
    def build(self):
        return Builder.load_string(kv)

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

Answer 1

一种可能的解决方案是使用on_touch_down 事件并在您按下不包含TextInput 的部分时重新配置键盘：

class MainScreen(Screen):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self.config_keyboard()

    def on_touch_down(self, touch):
        self.isTextInput = False

        def filter(widget):
            for child in widget.children:
                filter(child)
            if isinstance(widget, TextInput) and widget.collide_point(*touch.pos):
                self.isTextInput = True
                widget.on_touch_down(touch)

        filter(self)

        if not self.isTextInput and self._keyboard is None:
            self.config_keyboard()

    def config_keyboard(self):
        self._keyboard = Window.request_keyboard(self._keyboard_closed, self)
        self._keyboard.bind(on_key_down=self._on_keyboard_down)

    def _keyboard_closed(self):
        self._keyboard.unbind(on_key_down=self._on_keyboard_down)
        self._keyboard = None

    def _on_keyboard_down(self, keyboard, keycode, text, modifiers):
        print('INFO: The key', keycode, 'has been pressed')

        return True # return True to accept the key. Otherwise, it will be used by the system.