Add alpha (undocumented) Menu widget.

gui/demos/menu.py

@@ -0,0 +1,33 @@
+# menu.py micro-gui demo of Menu class
+
+# Released under the MIT License (MIT). See LICENSE.
+# Copyright (c) 2021 Peter Hinch
+
+import hardware_setup  # Create a display instance
+from gui.core.ugui import Screen, ssd
+import gui.fonts.freesans20 as freesans20
+from gui.core.writer import CWriter
+
+from gui.widgets.menu import Menu
+from gui.widgets.buttons import CloseButton
+from gui.core.colors import *
+
+class BaseScreen(Screen):
+
+    def __init__(self):
+        def cb(button, n):
+            print('Top level callback', n)
+
+        def cb_sm(lb, n):
+            print('Submenu callback', lb.value(), lb.textvalue(), n)
+
+        super().__init__()
+        mnu = (('Gas', cb_sm, (0,), ('Argon','Neon','Xenon','Radon')),
+               ('Metal', cb_sm, (1,), ('Caesium', 'Lithium', 'Sodium', 'Potassium')),
+               ('View', cb, (2,)))
+        wri = CWriter(ssd, freesans20, GREEN, BLACK, verbose=False)
+        Menu(wri, bgcolor=BLUE, textcolor=WHITE, args = mnu)
+        CloseButton(wri)
+
+
+Screen.change(BaseScreen)

gui/widgets/dropdown.py

@@ -14,26 +14,24 @@ dolittle = lambda *_ : None
 # handled by Screen .move bound method
 class _ListDialog(Window):
 
-    def __init__(self, writer, row, col, dropdown, textwidth):
+    def __init__(self, writer, row, col, dd):  # dd is parent dropdown
-        dd = dropdown
-        elements = dd.elements
         # Need to determine Window dimensions from size of Listbox, which
         # depends on number and length of elements.
-        entry_height, lb_height, textwidth = Listbox.dimensions(writer, elements)
+        entry_height, lb_height, textwidth = Listbox.dimensions(writer, dd.elements)
         lb_width = textwidth + 2
         # Calculate Window dimensions
         ap_height = lb_height + 6  # Allow for listbox border
         ap_width = lb_width + 6
         super().__init__(row, col, ap_height, ap_width)
-        self.listbox = Listbox(writer, row + 3, col + 3, elements = elements, width = lb_width,
+        self.listbox = Listbox(writer, row + 3, col + 3, elements = dd.elements, width = lb_width,
                                fgcolor = dd.fgcolor, bgcolor = dd.bgcolor, bdcolor=False, 
                                fontcolor = dd.fontcolor, select_color = dd.select_color,
                                value = dd.value(), callback = self.callback)
-        self.dropdown = dd
+        self.dd = dd
 
     def callback(self, obj_listbox):
         Screen.back()
-        self.dropdown.value(obj_listbox.value()) # Update it
+        self.dd.value(obj_listbox.value()) # Update it
 
 
 class Dropdown(Widget):
@@ -88,5 +86,5 @@ class Dropdown(Widget):
 
     def do_sel(self):  # Select was pushed
         if len(self.elements) > 1:
-            args = (self.writer, self.row - 2, self.col - 2, self, self.textwidth)
+            args = (self.writer, self.row - 2, self.col - 2, self)
             Screen.change(_ListDialog, args = args)

gui/widgets/menu.py

@@ -0,0 +1,66 @@
+# menu.py Extension to micro-gui providing the Menu class
+
+# Released under the MIT License (MIT). See LICENSE.
+# Copyright (c) 2021 Peter Hinch
+
+# Usage:
+# from gui.widgets.menu import Menu
+
+from gui.core.ugui import Window, Screen
+from gui.widgets.buttons import Button
+from gui.widgets.listbox import Listbox
+from gui.core.colors import *
+
+# Next and Prev close the listbox without running the callback. This is
+# handled by Screen .move bound method
+# A SubMenu is a Window containing a Listbox
+class SubMenu(Window):
+
+    def __init__(self, menu, button, elements, cb, args):  # menu is parent Menu
+        wri = menu.writer
+        row = 10
+        col = button.col + 4 # Drop down below top level menu button
+        # Need to determine Window dimensions from size of Listbox, which
+        # depends on number and length of elements.
+        entry_height, lb_height, textwidth = Listbox.dimensions(wri, elements)
+        lb_width = textwidth + 2
+        # Calculate Window dimensions
+        ap_height = lb_height + 6  # Allow for listbox border
+        ap_width = lb_width + 6
+        super().__init__(row, col, ap_height, ap_width)
+        self.listbox = Listbox(wri, row + 3, col + 3, elements = elements, width = lb_width,
+                               fgcolor = button.fgcolor, bgcolor = button.bgcolor, bdcolor=False, 
+                               fontcolor = button.textcolor, select_color = menu.select_color,
+                               callback = self.callback)
+        self.cb = cb
+        self.args = args
+
+    def callback(self, obj_listbox):
+        Screen.back()
+        self.cb(obj_listbox, *self.args) # CB can access obj_listbox.value() or .textvalue()
+
+class Menu:
+
+    def __init__(self, writer, *, height=25, bgcolor=None, fgcolor=None, textcolor=None, select_color=DARKBLUE, args):   # ((text, cb, (args,)),(text, cb, (args,), (elements,)), ...)
+        self.writer = writer
+        self.select_color = select_color
+        row = 2
+        col = 2
+        btn = {'bgcolor' : bgcolor,
+               'fgcolor' : fgcolor,
+               'height' : height,
+               'textcolor' : textcolor, }
+        for arg in args:
+            if len(arg) == 4:  # Handle submenu
+                # txt, cb, (cbargs,), (elements,) = arg
+                b = Button(writer, row, col, text=arg[0],
+                           callback=self.cb, args=arg, **btn)
+            else:
+                txt, cb, cbargs = arg
+                b = Button(writer, row, col, text=txt,
+                           callback=cb, args=cbargs, **btn)
+            col = b.mcol
+
+    def cb(self, button, txt, user_cb, args, elements):  # Button pushed which calls submenu
+        args = (self, button, elements, user_cb, args)
+        Screen.change(SubMenu, args = args)