Implement two listboxes with j/k navigation and switching between them

App.py

@@ -1,4 +1,29 @@
 import urwid
+from concurrent.futures import ThreadPoolExecutor
+
+
+class Items(urwid.ListBox):
+    def __init__(self, items):
+        super().__init__(self)
+        walker = urwid.SimpleListWalker([urwid.AttrMap(item, None, 'reveal focus') for item in items])
+        self.body = walker
+
+    def keypress(self, size, key):
+        if key in ("j", "down"):
+            item_size = len(self.body)
+            focus_widget, idx = self.get_focus()
+            if idx < item_size - 1:
+                idx = idx + 1
+                self.set_focus(idx)
+            return
+        elif key in ("k", "up"):
+            focus_widget, idx = self.get_focus()
+            if idx > 0:
+                idx = idx - 1
+                self.set_focus(idx)
+            return
+
+        return super().keypress(size, key)
 
 
 class TUI(urwid.Frame):
@@ -12,17 +37,21 @@ class TUI(urwid.Frame):
             tui,
             palette,
             event_loop=urwid.AsyncioEventLoop(),
+            unhandled_input=tui.unhandled_input,
         )
         tui.loop = loop
 
         return tui
 
     def __init__(self):
+        self.executor = ThreadPoolExecutor(max_workers=1)
         self.loop = None
-        self.items = [urwid.Text("Feed# " + str(i)) for i in range(0, 15)]
-        walker = urwid.SimpleListWalker([urwid.AttrMap(item, None, 'reveal focus') for item in self.items])
-        self.lb = urwid.ListBox(walker)
-        self.body = self.lb
+        self.feedItems = [urwid.Text("Feed# " + str(i)) for i in range(0, 15)]
+        self.articleItems = [urwid.Text("Article# " + str(i)) for i in range(0, 10)]
+        self.feeds = Items(self.feedItems)
+        self.articles = Items(self.articleItems)
+        self.container = urwid.Columns([urwid.LineBox(self.feeds, title="Feeds"), urwid.LineBox(self.articles, title="Articles")])
+        self.body = self.container
 
         super().__init__(self.body)
 
@@ -30,23 +59,11 @@ class TUI(urwid.Frame):
         self.loop.run()
         self.executor.shutdown(wait=False)
 
-    def keypress(self, size, key):
-        if key in ("j", "down"):
-            item_size = len(self.lb.body)
-            focus_widget, idx = self.lb.get_focus()
-            if idx < item_size - 1:
-                idx = idx + 1
-                self.lb.set_focus(idx)
-        elif key in ("k", "up"):
-            focus_widget, idx = self.lb.get_focus()
-            if idx > 0:
-                idx = idx - 1
-                self.lb.set_focus(idx)
-        elif key == "a":
-            self.lb.body.append(urwid.AttrMap(urwid.Text("XXX"), None, 'reveal focus'))
-        else:
-            self.lb.keypress(size, key)
-            del self.lb.body[3]
+    def unhandled_input(self, key):
+        if key == "tab":
+            self.container.set_focus(1)
+        elif key == "q":
+            raise urwid.ExitMainLoop()
 
 
 tui = TUI.create()