如何在pythonpromptoolkit中将pageup/pagedown键绑定添加到TextArea？

Question

让我们以calculator.py为例

要添加与鼠标滚轮配合使用的滚动条，您需要更改：

output_field = TextArea(style="class:output-field", text=help_text)

致：

output_field = TextArea(style="class:output-field", text=help_text, scrollbar=True)

但是，您会添加或更改什么来使用page up（向上翻页）和page down（向下翻页）键滚动文本区域

# The key bindings.
kb = KeyBindings()

@kb.add("pageup")
def _(event):
    # What goes here?
    pass

@kb.add("pagedown")
def _(event):
    # What goes here?
    pass

Answer 1

改变焦点

最简单的方法可能是导入focus_next（或focus_previous）

from prompt_toolkit.key_binding.bindings.focus import focus_next

并将其绑定到控制空间（或其他任何内容）

# The key bindings.
kb = KeyBindings()

kb.add("c-space")(focus_next)

集中注意力

您还可以将注意力集中在input_field，导入scroll_page_up和scroll_page_down

from prompt_toolkit.key_binding.bindings.page_navigation import scroll_page_up, scroll_page_down

然后将焦点切换到output_field，调用scroll_page_up/scroll_page_down，最后将焦点切换回input_field

# The key bindings.
kb = KeyBindings()

@kb.add("pageup")
def _(event):
    w = event.app.layout.current_window
    event.app.layout.focus(output_field.window)
    scroll_page_up(event)
    event.app.layout.focus(w)

@kb.add("pagedown")
def _(event):
    w = event.app.layout.current_window
    event.app.layout.focus(output_field.window)
    scroll_page_down(event)
    event.app.layout.focus(w)