如何组合多个 TUI 表单来编写更复杂的应用程序？
How do you combine multiple TUI forms to write more complex applications?
我想用 Text-based User I[=27= 编写一个程序]界面（TUI），由多种形式组成。
- 第一个表格包含一个"list"。每个列表元素代表一个按钮。
- 如果按下相应的按钮，将出现另一个表格，您可以在其中输入列表条目的数据。
- 然后第一个表单再次显示（更新列表条目）。
这是我的尝试，它使用库 npyscreen 但没有 return 第一种形式。该代码也不包含更改列表项的逻辑。
#! /usr/bin/env python3
# coding:utf8
import npyscreen
# content
headers = ["column 1", "column 2", "column 3", "column 4"]
entries = [["a1", "a2", "a3", "a4"],
["b1", "b2", "b3", "b4"],
["c1", "c2", "c3", "c4"],
["d1", "d2", "d3", "d4"],
["e1", "e2", "e3", "e4"]]
# returns a string in which the segments are padded with spaces.
def format_entry(entry):
return "{:10} | {:10} | {:10} | {:10}".format(entry[0], entry[1] , entry[2], entry[3])
class SecondForm(npyscreen.Form):
def on_ok(self):
self.parentApp.switchFormPrevious()
# add the widgets of the second form
def create(self):
self.col1 = self.add(npyscreen.TitleText, name="column 1:")
self.col2 = self.add(npyscreen.TitleText, name="column 2:")
self.col3 = self.add(npyscreen.TitleText, name="column 3:")
self.col4 = self.add(npyscreen.TitleText, name="column 4:")
class MainForm(npyscreen.Form):
def on_ok(self):
self.parentApp.switchForm(None)
def changeToSecondForm(self):
self.parentApp.change_form("SECOND")
# add the widgets of the main form
def create(self):
self.add(npyscreen.FixedText, value=format_entry(headers), editable=False, name="header")
for i, entry in enumerate(entries):
self.add(npyscreen.ButtonPress, when_pressed_function=self.changeToSecondForm, name=format_entry(entry))
class TestTUI(npyscreen.NPSAppManaged):
def onStart(self):
self.addForm("MAIN", MainForm)
self.addForm("SECOND", SecondForm, name="Edit row")
def onCleanExit(self):
npyscreen.notify_wait("Goodbye!")
def change_form(self, name):
self.switchForm(name)
if __name__ == "__main__":
tui = TestTUI()
tui.run()
下面是我对这个问题的看法，它可以描述为控制台的 master-detail user interface 实现。
这使用 urwid library, building some custom widgets 来实现所描述的 UI，它有两种模式：主视图（其中主要小部件是一堆记录）和详细视图（一个重叠的对话框，主视图在后面）。
有很多地方可以改进，包括让它看起来更漂亮。 :)
代码如下：
#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Sample program demonstrating how to implement widgets for a master-detail UI
for a list of records using the urwid library (http://urwid.org)
"""
from __future__ import print_function, absolute_import, division
from functools import partial
import urwid
PALETTE = [
('bold', 'bold', ''),
('reveal focus', 'black', 'dark cyan', 'standout'),
]
def show_or_exit(key):
if key in ('q', 'Q', 'esc'):
raise urwid.ExitMainLoop()
HEADERS = ["Field 1", "Field 2", "Field 3", "Field 4"]
ENTRIES = [
["a1", "a2", "a3", "a4"],
["b1", "b2", "b3", "b4"],
["c1", "c2", "c3", "c4"],
["d1", "d2", "d3", "d4"],
["e1", "e2", "e3", "e4"],
["e1", "e2", "e3", "e4"],
["f1", "f2", "f3", "f4"],
["g1", "g2", "g3", "g4"],
["h1", "h2", "h3", "h4"],
]
class SelectableRow(urwid.WidgetWrap):
def __init__(self, contents, on_select=None):
self.on_select = on_select
self.contents = contents
self._columns = urwid.Columns([urwid.Text(c) for c in contents])
self._focusable_columns = urwid.AttrMap(self._columns, '', 'reveal focus')
super(SelectableRow, self).__init__(self._focusable_columns)
def selectable(self):
return True
def update_contents(self, contents):
# update the list record inplace...
self.contents[:] = contents
# ... and update the displayed items
for t, (w, _) in zip(contents, self._columns.contents):
w.set_text(t)
def keypress(self, size, key):
if self.on_select and key in ('enter',):
self.on_select(self)
return key
def __repr__(self):
return '%s(contents=%r)' % (self.__class__.__name__, self.contents)
class CancelableEdit(urwid.Edit):
def __init__(self, *args, **kwargs):
self.on_cancel = kwargs.pop('on_cancel', None)
super(CancelableEdit, self).__init__(*args, **kwargs)
def keypress(self, size, key):
if key == 'esc':
self.on_cancel(self)
else:
return super(CancelableEdit, self).keypress(size, key)
def build_dialog(title, contents, background, on_save=None, on_cancel=None):
buttons = urwid.Columns([
urwid.Button('Save', on_press=on_save),
urwid.Button('Cancel', on_press=on_cancel),
])
pile = urwid.Pile(
[urwid.Text(title), urwid.Divider('-')]
+ contents
+ [urwid.Divider(' '), buttons]
)
return urwid.Overlay(
urwid.Filler(urwid.LineBox(pile)),
urwid.Filler(background),
'center',
('relative', 80),
'middle',
('relative', 80),
)
class App(object):
def __init__(self, entries):
self.entries = entries
self.header = urwid.Text('Welcome to the Master Detail Urwid Sample!')
self.footer = urwid.Text('Status: ready')
contents = [
SelectableRow(row, on_select=self.show_detail_view)
for row in entries
]
listbox = urwid.ListBox(urwid.SimpleFocusListWalker(contents))
# TODO: cap to screen size
size = len(entries)
self.master_pile = urwid.Pile([
self.header,
urwid.Divider(u'─'),
urwid.BoxAdapter(listbox, size),
urwid.Divider(u'─'),
self.footer,
])
self.widget = urwid.Filler(self.master_pile, 'top')
self.loop = urwid.MainLoop(self.widget, PALETTE, unhandled_input=show_or_exit)
def show_detail_view(self, row):
self._edits = [
CancelableEdit('%s: ' % key, value, on_cancel=self.close_dialog)
for key, value in zip(HEADERS, row.contents)
]
self.loop.widget = build_dialog(
title='Editing',
contents=self._edits,
background=self.master_pile,
on_save=partial(self.save_and_close_dialog, row),
on_cancel=self.close_dialog,
)
self.show_status('Detail: %r' % row)
def save_and_close_dialog(self, row, btn):
new_content = [e.edit_text for e in self._edits]
row.update_contents(new_content)
self.show_status('Updated')
self.loop.widget = self.widget
def close_dialog(self, btn):
self.loop.widget = self.widget
def show_status(self, mesg):
self.footer.set_text(str(mesg))
def start(self):
self.loop.run()
if __name__ == '__main__':
app = App(ENTRIES)
app.start()
Appclass 保存应用程序的状态，跟踪主要小部件并包含在用户操作（如点击按钮）时调用的方法 save/cancel。
记录在 SelectableRow 小部件的方法 update_contents 中就地更新，表示在主列表中显示的记录。
CancelableEdit 小部件的存在只是为了能够对对话框 window.
中的 esc 作出反应
随时提出任何进一步澄清的问题，我尝试使用体面的名称并或多或少地保持代码的可读性，但我知道这里还有很多事情要做，我不确定需要做什么详细解释。
这是一个有趣的练习，感谢您给我做这件事的借口！ =)
我发现自己在使用 Npyscreen，所以我发现了你的问题。如果您仍在使用此应用程序，这里是您的初始代码，但这次返回到主窗体：
#! /usr/bin/env python3
# coding:utf8
import npyscreen
# content
headers = ["column 1", "column 2", "column 3", "column 4"]
entries = [["a1", "a2", "a3", "a4"],
["b1", "b2", "b3", "b4"],
["c1", "c2", "c3", "c4"],
["d1", "d2", "d3", "d4"],
["e1", "e2", "e3", "e4"]]
# returns a string in which the segments are padded with spaces.
def format_entry(entry):
return "{:10} | {:10} | {:10} | {:10}".format(entry[0], entry[1] , entry[2], entry[3])
class SecondForm(npyscreen.Form):
def on_ok(self):
self.parentApp.switchFormPrevious()
# add the widgets of the second form
def create(self):
self.col1 = self.add(npyscreen.TitleText, name="column 1:")
self.col2 = self.add(npyscreen.TitleText, name="column 2:")
self.col3 = self.add(npyscreen.TitleText, name="column 3:")
self.col4 = self.add(npyscreen.TitleText, name="column 4:")
def afterEditing(self):
self.parentApp.setNextForm("MAIN")
class MainForm(npyscreen.Form):
def on_ok(self):
self.parentApp.switchForm(None)
def changeToSecondForm(self):
self.parentApp.change_form("SECOND")
# add the widgets of the main form
def create(self):
self.add(npyscreen.FixedText, value=format_entry(headers), editable=False, name="header")
for i, entry in enumerate(entries):
self.add(npyscreen.ButtonPress, when_pressed_function=self.changeToSecondForm, name=format_entry(entry))
class TestTUI(npyscreen.NPSAppManaged):
def onStart(self):
self.addForm("MAIN", MainForm)
self.addForm("SECOND", SecondForm, name="Edit row")
def onCleanExit(self):
npyscreen.notify_wait("Goodbye!")
def change_form(self, name):
self.switchForm(name)
if __name__ == "__main__":
tui = TestTUI()
tui.run()
我想用 Text-based User I[=27= 编写一个程序]界面（TUI），由多种形式组成。
- 第一个表格包含一个"list"。每个列表元素代表一个按钮。
- 如果按下相应的按钮，将出现另一个表格，您可以在其中输入列表条目的数据。
- 然后第一个表单再次显示（更新列表条目）。
这是我的尝试，它使用库 npyscreen 但没有 return 第一种形式。该代码也不包含更改列表项的逻辑。
#! /usr/bin/env python3
# coding:utf8
import npyscreen
# content
headers = ["column 1", "column 2", "column 3", "column 4"]
entries = [["a1", "a2", "a3", "a4"],
["b1", "b2", "b3", "b4"],
["c1", "c2", "c3", "c4"],
["d1", "d2", "d3", "d4"],
["e1", "e2", "e3", "e4"]]
# returns a string in which the segments are padded with spaces.
def format_entry(entry):
return "{:10} | {:10} | {:10} | {:10}".format(entry[0], entry[1] , entry[2], entry[3])
class SecondForm(npyscreen.Form):
def on_ok(self):
self.parentApp.switchFormPrevious()
# add the widgets of the second form
def create(self):
self.col1 = self.add(npyscreen.TitleText, name="column 1:")
self.col2 = self.add(npyscreen.TitleText, name="column 2:")
self.col3 = self.add(npyscreen.TitleText, name="column 3:")
self.col4 = self.add(npyscreen.TitleText, name="column 4:")
class MainForm(npyscreen.Form):
def on_ok(self):
self.parentApp.switchForm(None)
def changeToSecondForm(self):
self.parentApp.change_form("SECOND")
# add the widgets of the main form
def create(self):
self.add(npyscreen.FixedText, value=format_entry(headers), editable=False, name="header")
for i, entry in enumerate(entries):
self.add(npyscreen.ButtonPress, when_pressed_function=self.changeToSecondForm, name=format_entry(entry))
class TestTUI(npyscreen.NPSAppManaged):
def onStart(self):
self.addForm("MAIN", MainForm)
self.addForm("SECOND", SecondForm, name="Edit row")
def onCleanExit(self):
npyscreen.notify_wait("Goodbye!")
def change_form(self, name):
self.switchForm(name)
if __name__ == "__main__":
tui = TestTUI()
tui.run()
下面是我对这个问题的看法，它可以描述为控制台的 master-detail user interface 实现。
这使用 urwid library, building some custom widgets 来实现所描述的 UI，它有两种模式：主视图（其中主要小部件是一堆记录）和详细视图（一个重叠的对话框，主视图在后面）。
有很多地方可以改进，包括让它看起来更漂亮。 :)
代码如下：
#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Sample program demonstrating how to implement widgets for a master-detail UI
for a list of records using the urwid library (http://urwid.org)
"""
from __future__ import print_function, absolute_import, division
from functools import partial
import urwid
PALETTE = [
('bold', 'bold', ''),
('reveal focus', 'black', 'dark cyan', 'standout'),
]
def show_or_exit(key):
if key in ('q', 'Q', 'esc'):
raise urwid.ExitMainLoop()
HEADERS = ["Field 1", "Field 2", "Field 3", "Field 4"]
ENTRIES = [
["a1", "a2", "a3", "a4"],
["b1", "b2", "b3", "b4"],
["c1", "c2", "c3", "c4"],
["d1", "d2", "d3", "d4"],
["e1", "e2", "e3", "e4"],
["e1", "e2", "e3", "e4"],
["f1", "f2", "f3", "f4"],
["g1", "g2", "g3", "g4"],
["h1", "h2", "h3", "h4"],
]
class SelectableRow(urwid.WidgetWrap):
def __init__(self, contents, on_select=None):
self.on_select = on_select
self.contents = contents
self._columns = urwid.Columns([urwid.Text(c) for c in contents])
self._focusable_columns = urwid.AttrMap(self._columns, '', 'reveal focus')
super(SelectableRow, self).__init__(self._focusable_columns)
def selectable(self):
return True
def update_contents(self, contents):
# update the list record inplace...
self.contents[:] = contents
# ... and update the displayed items
for t, (w, _) in zip(contents, self._columns.contents):
w.set_text(t)
def keypress(self, size, key):
if self.on_select and key in ('enter',):
self.on_select(self)
return key
def __repr__(self):
return '%s(contents=%r)' % (self.__class__.__name__, self.contents)
class CancelableEdit(urwid.Edit):
def __init__(self, *args, **kwargs):
self.on_cancel = kwargs.pop('on_cancel', None)
super(CancelableEdit, self).__init__(*args, **kwargs)
def keypress(self, size, key):
if key == 'esc':
self.on_cancel(self)
else:
return super(CancelableEdit, self).keypress(size, key)
def build_dialog(title, contents, background, on_save=None, on_cancel=None):
buttons = urwid.Columns([
urwid.Button('Save', on_press=on_save),
urwid.Button('Cancel', on_press=on_cancel),
])
pile = urwid.Pile(
[urwid.Text(title), urwid.Divider('-')]
+ contents
+ [urwid.Divider(' '), buttons]
)
return urwid.Overlay(
urwid.Filler(urwid.LineBox(pile)),
urwid.Filler(background),
'center',
('relative', 80),
'middle',
('relative', 80),
)
class App(object):
def __init__(self, entries):
self.entries = entries
self.header = urwid.Text('Welcome to the Master Detail Urwid Sample!')
self.footer = urwid.Text('Status: ready')
contents = [
SelectableRow(row, on_select=self.show_detail_view)
for row in entries
]
listbox = urwid.ListBox(urwid.SimpleFocusListWalker(contents))
# TODO: cap to screen size
size = len(entries)
self.master_pile = urwid.Pile([
self.header,
urwid.Divider(u'─'),
urwid.BoxAdapter(listbox, size),
urwid.Divider(u'─'),
self.footer,
])
self.widget = urwid.Filler(self.master_pile, 'top')
self.loop = urwid.MainLoop(self.widget, PALETTE, unhandled_input=show_or_exit)
def show_detail_view(self, row):
self._edits = [
CancelableEdit('%s: ' % key, value, on_cancel=self.close_dialog)
for key, value in zip(HEADERS, row.contents)
]
self.loop.widget = build_dialog(
title='Editing',
contents=self._edits,
background=self.master_pile,
on_save=partial(self.save_and_close_dialog, row),
on_cancel=self.close_dialog,
)
self.show_status('Detail: %r' % row)
def save_and_close_dialog(self, row, btn):
new_content = [e.edit_text for e in self._edits]
row.update_contents(new_content)
self.show_status('Updated')
self.loop.widget = self.widget
def close_dialog(self, btn):
self.loop.widget = self.widget
def show_status(self, mesg):
self.footer.set_text(str(mesg))
def start(self):
self.loop.run()
if __name__ == '__main__':
app = App(ENTRIES)
app.start()
Appclass 保存应用程序的状态，跟踪主要小部件并包含在用户操作（如点击按钮）时调用的方法 save/cancel。
记录在 SelectableRow 小部件的方法 update_contents 中就地更新，表示在主列表中显示的记录。
CancelableEdit 小部件的存在只是为了能够对对话框 window.
随时提出任何进一步澄清的问题，我尝试使用体面的名称并或多或少地保持代码的可读性，但我知道这里还有很多事情要做，我不确定需要做什么详细解释。
这是一个有趣的练习，感谢您给我做这件事的借口！ =)
我发现自己在使用 Npyscreen，所以我发现了你的问题。如果您仍在使用此应用程序，这里是您的初始代码，但这次返回到主窗体：
#! /usr/bin/env python3
# coding:utf8
import npyscreen
# content
headers = ["column 1", "column 2", "column 3", "column 4"]
entries = [["a1", "a2", "a3", "a4"],
["b1", "b2", "b3", "b4"],
["c1", "c2", "c3", "c4"],
["d1", "d2", "d3", "d4"],
["e1", "e2", "e3", "e4"]]
# returns a string in which the segments are padded with spaces.
def format_entry(entry):
return "{:10} | {:10} | {:10} | {:10}".format(entry[0], entry[1] , entry[2], entry[3])
class SecondForm(npyscreen.Form):
def on_ok(self):
self.parentApp.switchFormPrevious()
# add the widgets of the second form
def create(self):
self.col1 = self.add(npyscreen.TitleText, name="column 1:")
self.col2 = self.add(npyscreen.TitleText, name="column 2:")
self.col3 = self.add(npyscreen.TitleText, name="column 3:")
self.col4 = self.add(npyscreen.TitleText, name="column 4:")
def afterEditing(self):
self.parentApp.setNextForm("MAIN")
class MainForm(npyscreen.Form):
def on_ok(self):
self.parentApp.switchForm(None)
def changeToSecondForm(self):
self.parentApp.change_form("SECOND")
# add the widgets of the main form
def create(self):
self.add(npyscreen.FixedText, value=format_entry(headers), editable=False, name="header")
for i, entry in enumerate(entries):
self.add(npyscreen.ButtonPress, when_pressed_function=self.changeToSecondForm, name=format_entry(entry))
class TestTUI(npyscreen.NPSAppManaged):
def onStart(self):
self.addForm("MAIN", MainForm)
self.addForm("SECOND", SecondForm, name="Edit row")
def onCleanExit(self):
npyscreen.notify_wait("Goodbye!")
def change_form(self, name):
self.switchForm(name)
if __name__ == "__main__":
tui = TestTUI()
tui.run()