make ScrollBarListBox decoration

subiquity/ui/views/installprogress.py

@@ -66,21 +66,24 @@ class ProgressView(BaseView):
 
         super().__init__(self.event_pile)
 
-    def add_event(self, text):
-        at_end = len(self.event_listwalker) == 0 or self.event_listbox.focus_position == len(self.event_listwalker) - 1
-        if len(self.event_listwalker) > 0:
-            self.event_listwalker[-1] = self.event_listwalker[-1][0]
-        self.event_listwalker.append(Columns([('pack', Text(text)), ('pack', self.spinner)], dividechars=1))
+    def _add_line(self, lb, line):
+        lb = lb.base_widget
+        walker = lb.body
+        at_end = len(walker) == 0 or lb.focus_position == len(walker) - 1
+        walker.append(line)
         if at_end:
-            self.event_listbox.set_focus(len(self.event_listwalker) - 1)
-            self.event_listbox.set_focus_valign('bottom')
+            lb.set_focus(len(walker) - 1)
+            lb.set_focus_valign('bottom')
+
+    def add_event(self, text):
+        walker = self.event_listwalker
+        if len(walker) > 0:
+            walker[-1] = walker[-1][0]
+        new = Columns([('pack', Text(text)), ('pack', self.spinner)], dividechars=1)
+        self._add_line(self.event_listbox, new)
 
     def add_log_line(self, text):
-        at_end = len(self.log_listwalker) == 0 or self.log_listbox.focus_position == len(self.log_listwalker) - 1
-        self.log_listwalker.append(Text(text))
-        if at_end:
-            self.log_listbox.set_focus(len(self.log_listwalker) - 1)
-            self.log_listbox.set_focus_valign('bottom')
+        self._add_line(self.log_listbox, Text(text))
 
     def set_status(self, text):
         self.event_linebox.set_title(text)

subiquity/ui/views/snaplist.py

@@ -19,15 +19,17 @@ from urwid import (
     BOX,
     CheckBox,
     LineBox,
+    ListBox as UrwidListBox,
     RadioButton,
     SelectableIcon,
+    SimpleFocusListWalker,
     Text,
     Widget,
     WidgetWrap,
     )
 
 from subiquitycore.ui.buttons import ok_btn, cancel_btn, other_btn
-from subiquitycore.ui.container import Columns, ListBox, Pile
+from subiquitycore.ui.container import Columns, ListBox, Pile, ScrollBarListBox
 from subiquitycore.ui.utils import button_pile, Color, Padding, screen
 from subiquitycore.view import BaseView
 
@@ -54,20 +56,9 @@ class StarRadioButton(RadioButton):
     reserve_columns = 3
 
 
-class NoTabCyclingListBox(ListBox):
-    # Carefully disable the TabCycling parts of our ListBox (but keep the scrollbar!)
-
-    def keypress(self, size, key):
-        if not key.startswith("enter") and self._command_map[key] in ('next selectable', 'prev selectable'):
-            return key
-        else:
-            return super().keypress(size, key)
-
-    def _select_first_selectable(self):
-        return
-
-    def _select_last_selectable(self):
-        return
+def NoTabCyclingListBox(body):
+    body = SimpleFocusListWalker(body)
+    return ScrollBarListBox(UrwidListBox(body))
 
 
 class SnapInfoView(Widget):

subiquitycore/ui/container.py

@@ -386,41 +386,46 @@ class FocusTrackingListBox(TabCyclingListBox):
 Columns = FocusTrackingColumns
 Pile = FocusTrackingPile
 
+class ScrollBarListBox(urwid.WidgetDecoration):
 
-class ScrollBarListBox(FocusTrackingListBox):
-
-    def __init__(self, walker=None):
+    def __init__(self, lb):
         def f(char, attr):
             return urwid.AttrMap(urwid.SolidFill(char), attr)
         self.boxes = [
-            urwid.AttrMap(urwid.SolidFill("\N{FULL BLOCK}"), 'scrollbar_bg'),
-            urwid.AttrMap(urwid.SolidFill("\N{FULL BLOCK}"), 'scrollbar_fg'),
+            f("\N{FULL BLOCK}", 'scrollbar_bg'),
+            f("\N{FULL BLOCK}", 'scrollbar_fg'),
             ]
         self.bar = Pile([
             ('weight', 1, f("\N{BOX DRAWINGS LIGHT VERTICAL}", 'scrollbar_bg')),
             ('weight', 1, self.boxes[0]),
             ('weight', 1, f("\N{BOX DRAWINGS LIGHT VERTICAL}", 'scrollbar_bg')),
             ])
-        super().__init__(walker)
+        super().__init__(lb)
+
+    def keypress(self, size, key):
+        visible = self.original_widget.ends_visible(size, True)
+        if len(visible) != 2:
+            size = (size[0]-1, size[1])
+        return self.original_widget.keypress(size, key)
 
     def render(self, size, focus=False):
-        visible = self.ends_visible(size, focus)
+        visible = self.original_widget.ends_visible(size, focus)
         if len(visible) == 2:
-            return super().render(size, focus)
+            return self.original_widget.render(size, focus)
         else:
             # This implementation assumes that the number of rows is
             # not too large (and in particular is finite). That's the
             # case for all the listboxes we have in subiquity today.
             maxcol, maxrow = size
 
-            offset, inset = self.get_focus_offset_inset((maxcol - 1, maxrow))
+            offset, inset = self.original_widget.get_focus_offset_inset((maxcol - 1, maxrow))
 
             seen_focus = False
             height = height_before_focus = 0
-            focus_widget, focus_pos = self.body.get_focus()
+            focus_widget, focus_pos = self.original_widget.body.get_focus()
             # Scan through the rows calculating total height and the
             # height of the rows before the focus widget.
-            for widget in self.body:
+            for widget in self.original_widget.body:
                 rows = widget.rows((maxcol - 1,))
                 if widget is focus_widget:
                     seen_focus = True
@@ -459,10 +464,15 @@ class ScrollBarListBox(FocusTrackingListBox):
                 (self.bar.contents[2][0], self.bar.options('weight', bottom)),
                 ]
             canvases = [
-                (super().render((maxcol - 1, maxrow), focus), self.focus_position, True, maxcol - 1),
+                (self.original_widget.render((maxcol - 1, maxrow), focus), self.original_widget.focus_position, True, maxcol - 1),
                 (self.bar.render((1, maxrow)), None, False, 1)
                 ]
             return urwid.CanvasJoin(canvases)
 
 
-ListBox = ScrollBarListBox
+def ListBox(body=None):
+    # urwid.ListBox converts an arbitrary sequence argument to a
+    # PollingListWalker, which doesn't work with our code.
+    if body is not None and getattr(body, 'get_focus', None) is None:
+        body = urwid.SimpleFocusListWalker(body)
+    return ScrollBarListBox(FocusTrackingListBox(body))