python - 单击 `TextInput` 对象后在 Kivy 中重新捕获键盘焦点

Question

以下代码创建一个 Kivy具有单个屏幕的应用 MainScreen，显示 Label 和 TextInput 对象。

如果您在应用程序首次加载时提供一些键盘输入，它会在控制台中打印出有关按下哪个键的信息。但是，如果您随后单击 TextInput 对象，键盘会重新聚焦，以便您可以在 TextInput 对象中键入。但是，一旦您从 TextInput 对象中单击返回，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；键盘似乎没有从 TextInput 对象“散焦”。

如何在点击 TextInput 对象后重新获得键盘焦点？

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

一个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.