Fix window with one active widget closing on pressing button.

gui/core/ugui.py

@@ -261,6 +261,8 @@ class Screen:
                 if isinstance(cs_old, Window):
                     raise ValueError('Windows are modal.')
                 new_screen = cls_new_screen(*args, **kwargs)
+                if not len(new_screen.lstactive):
+                    raise ValueError("Screen has no active widgets.")
             else:
                 raise ValueError('Must pass Screen class or subclass (not instance)')
             new_screen.parent = cs_old
@@ -411,10 +413,10 @@ class Screen:
                         lo.show()  # Re-display with new status
                     co.enter()  # Tell object it has currency
                     co.show()
-                elif isinstance(self, Window):
+                #elif isinstance(self, Window):
                     # Special case of Window with one object: leave
                     # without making changes (Dropdown in particular)
-                    Screen.back()
+                    #Screen.back()
                 done = True
 
     # Move currency to a specific control.
@@ -488,7 +490,8 @@ class Window(Screen):
             cls._value = val
         return cls._value
 
-    def __init__(self, row, col, height, width, *, draw_border=True, bgcolor=None, fgcolor=None):
+    def __init__(self, row, col, height, width, *, draw_border=True,
+                 bgcolor=None, fgcolor=None):
         Screen.__init__(self)
         self.row = row
         self.col = col

gui/widgets/listbox.py

@@ -1,7 +1,7 @@
 # listbox.py Extension to ugui providing the Listbox class
 
 # Released under the MIT License (MIT). See LICENSE.
-# Copyright (c) 2021 Peter Hinch
+# Copyright (c) 2021-2022 Peter Hinch
 
 # 12 Sep 21 Support for scrolling.
 
@@ -18,7 +18,7 @@ class Listbox(Widget):
     ON_MOVE = 1  # Also run whenever the currency moves.
     ON_LEAVE = 2  # Also run on exit from the control.
 
-    # This is used by dropdown.py
+    # This is used by dropdown.py and menu.py
     @staticmethod
     def dimensions(writer, elements, dlines):
         # Height of a single entry in list.

gui/widgets/menu.py

@@ -26,7 +26,7 @@ class SubMenu(Window):
         # depends on number and length of elements.
         te = [x[0] for x in elements]  # Text part
         self.elements = elements
-        entry_height, lb_height, textwidth = Listbox.dimensions(wri, te)
+        entry_height, lb_height, _, textwidth = Listbox.dimensions(wri, te, None)
         lb_width = textwidth + 2
         # Calculate Window dimensions
         ap_height = lb_height + 6  # Allow for listbox border

hardware_setup.py

@@ -51,4 +51,4 @@ sel = Pin(16, Pin.IN, Pin.PULL_UP)  # Operate current control
 prev = Pin(18, Pin.IN, Pin.PULL_UP)  # Move to previous control
 increase = Pin(20, Pin.IN, Pin.PULL_UP)  # Increase control's value
 decrease = Pin(17, Pin.IN, Pin.PULL_UP)  # Decrease control's value
-display = Display(ssd, nxt, sel, prev, increase, decrease, 5)
+display = Display(ssd, nxt, sel, prev, increase, decrease) #, 5)