所以接下来是我对这个问题的看法，它可以描述为控制台的主从用户界面的实现。
这使用了urwid 库，构建了一些自定义小部件来实现所描述的 UI，它有两种模式：主视图（主小部件是一堆记录）和详细视图（叠加对话框，主视图在后面）。
有很多事情可以改进，包括让它看起来更漂亮。:)
这是代码：
#!/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()
该类App保存应用程序的状态，跟踪主要小部件并包含在用户操作（如点击保存/取消按钮）时调用的方法。
记录在 SelectableRow 小部件的方法中就地更新update_contents，它表示主列表中显示的记录。
小CancelableEdit部件的存在只是为了能够esc从对话窗口做出反应。
随意提出任何进一步澄清的问题，我尝试使用体面的名称并保持代码或多或少的可读性，但我知道这里还有很多事情要做，我不确定需要详细解释什么。
这是一个有趣的练习，谢谢你给了我这样做的借口！=)
