Added quitting a menu functionality (actually quitting the run()'s infinite internal loop)

README.md

@@ -13,7 +13,7 @@ This project is the completely rewritten successor of my old (and now archived)
 - [x] a reliable order of the menu items
 - [x] good documentation for all of this (maybe through examples)
 - [x] show an exit screen when a specific exit code is returned by a callback function
-- [ ] make the menu itself exitable (to enable stuff like submenus, etc.)
+- [x] make the menu itself exitable (to enable stuff like submenus, etc.)
 - [x] make the project a valid python package 
 
 

__init__.py

@@ -23,9 +23,8 @@ class lcdMenu:
     # cycle:             bool    - if true, start again with the first menu entry after the last one (and show the last before the first)
     # hide_menu_name:    bool    - OPTIONAL - if true, hide the menu's name (won't work in combination with a vertical scrolling direction)
     # name:              str     - OPTIONAL - a string with the name of the menu (can be hidden under certain circumstances)
-    # default_selection: int     - OPTIONAL - the index of the item selected by default (starting with 0) - DON'T USE NEGATIVE INDEXES
     # debounce_time:     float   - OPTIONAL - the debounce time used by the library to debounce button presses
-    def __init__(self, lcd, buttons: dict, menu_items: list, scroll_direction: bool, cycle: bool, hide_menu_name: bool = False, name: str = "CHOOSE", default_selection: int = 0, debounce_time: float = 0.15):
+    def __init__(self, lcd, buttons: dict, scroll_direction: bool, cycle: bool, hide_menu_name: bool = False, name: str = "CHOOSE", debounce_time: float = 0.15):
         # save the argument variables
         self.lcd = lcd
         if "prev_btn" in buttons.keys():
@@ -34,22 +33,30 @@ class lcdMenu:
             self.prev_btn = None
         self.next_btn = buttons["next_btn"]
         self.ok_btn = buttons["ok_btn"]
-        self.menu_items = menu_items
         self.scroll_direction = scroll_direction
         self.cycle = cycle
         self.hide_menu_name = hide_menu_name
         self.name = name
-        self.current_selection = default_selection
         self.debounce_time = debounce_time
         
+        self.current_selection = 0  # set a standard value (can/most of the time will be changed directly after __init__ by a call to self.setup())
+        self.menu_items = []  # set a standard empty (can/most of the time will be changed directly after __init__ by a call to self.setup())
+        
         # variables that are very unlikely the user want's to set them (but can be set via <lcdMenuObject>.<attribute_name>, of course)
         self.start_execution_msg = "Selected..."  # the string displayed when an menu item is selected
         self.end_execution_msg = "Closing..."  # the string displayed when the callback function of a selected menu item returns        self.end_execution_wait = 1  # the time (in seconds) to wait after the callback function of a selected menu item returns
         self.start_execution_wait = 0.5  # the time (in seconds) to wait before the callback function of a selected menu item is called
         self.end_execution_wait = 1  # the time (in seconds) to wait after the callback function of a selected menu item returns
         self.fill_char = '-'  # the character used to fill up space (used only on 4x20 displays); MUST BE 1 character long
-    
-    
+
+
+    # menu_items:       list  - a list (-> maintains order!) containing tuples with the following format: (<ENTRY_NAME>,<CALLBACK FUNCTION>)
+    # start_selection:  int   - OPTIONAL - the index of the item selected by default (starting with 0) - DON'T USE NEGATIVE INDEXES
+    def setup(self, menu_items: list, start_selection: int = 0):
+        self.menu_items = menu_items
+        self.current_selection = start_selection
+
+
     def show_selection(self):
         # some checks:
         # 1. if you scrolling vertically, I found no elegant way to hide the name (there just need's to be something up there!)
@@ -58,7 +65,6 @@ class lcdMenu:
         # 2. if there are no menu items to display...
         if len(self.menu_items) == 0:
             raise TypeError("Can't show empty menus! Maybe you forgot calling self.setup() after initializing me?")
-
         
         # get some often used values into local variables
         selection_name = self.menu_items[self.current_selection][0]
@@ -101,7 +107,7 @@ class lcdMenu:
                 # maybe the following could be done with a crazy math formula - but I want to keep it simpler!
                 # as there aren't enough menu items after the current selection to fill the display, we have to...
                 # ... calculate where to place the current selection, how many items there are before it and how many after it
-                menu_items_cut = self.menu_items[:lines_for_display:-1][::-1]  # cut the menu_items list to the relevant last n ones maintaining order (n = number of lines for display)
+                menu_items_cut = self.menu_items[::-1][:lines_for_display][::-1]  # cut the menu_items list to the relevant last n ones maintaining order (n = number of lines for display)
                 current_pos_in_cut = -len(self.menu_items) + self.current_selection + lines_for_display  # calculate the current index of the selection in the new cut
                 # draw all the lines
                 for i in range(lines_for_display):
@@ -219,11 +225,17 @@ class lcdMenu:
             while self.ok_btn.value() == 1: sleep(self.debounce_time) # wait till release
             self.execute_selection()
         
-        
+    def stop(self):  # here to act as a callback for a menu entry (if the user wants to ofc!)
+        self.running = False
+        return True
+    
     def run(self):
         # show the selection first
         self.show_selection()
+        self.running = True
         
         # then listen on button presses in a loop...
-        while True:
+        while self.running:
             self.loop()
+            
+        return True  # to prevent a "Closing menu ..." in submenu-situations

example_quittable.py

@@ -0,0 +1,36 @@
+from lcdMenu import lcdMenu
+from machine import Pin, I2C
+from PCF8574T import I2C_LCD
+
+prev_btn = Pin(13, Pin.IN, Pin.PULL_DOWN)  # input of the first btn
+next_btn = Pin(14, Pin.IN, Pin.PULL_DOWN)  # input of the second btn
+ok_btn   = Pin(15, Pin.IN, Pin.PULL_DOWN)  # input of switch
+
+LCD = I2C_LCD(I2C(0, sda=Pin(8), scl=Pin(9), freq=400000),0x27,2, 16)
+
+def first_callback():
+    print("first_callback() called!")
+def second_cb():
+    print("second_cb() called")
+def third_cb():
+    print("third_cb() called")
+    return True
+
+
+button_mappings = {"prev_btn":prev_btn, "next_btn": next_btn, "ok_btn": ok_btn}
+
+submenu = lcdMenu(LCD, button_mappings, scroll_direction=True, cycle=False, hide_menu_name=False, name="Submenu!")
+# the submenu.stop callback is a special callback specifically designed for use cases where the lcdMenu ist started with run()
+# submenu.stop breaks an infinite loop inside the run() method, essentially quitting the run() method and giving back flow to the caller context
+# so we can utilize this for us to quit a submenu (or a "main" menu if you want to, of course!)
+submenuItems = [("first item", first_callback),
+                ("second item", second_cb),
+                ("third item", third_cb),
+                ("back", submenu.stop)]  
+submenu.setup(submenuItems)
+
+mainmenu = lcdMenu(LCD, button_mappings, scroll_direction=False, cycle=True, hide_menu_name=False, name="Main menu!")
+mainmenu.setup([("Sub menu",submenu.run)])
+
+mainmenu.run()
+

example_simple.py

@@ -20,6 +20,8 @@ def third_cb():
 menuItems = [("first item", first_callback),
              ("second item", second_cb),
              ("third item", third_cb)]
-menu = lcdMenu(LCD, {"prev_btn":prev_btn, "next_btn": next_btn, "ok_btn": ok_btn}, menuItems, scroll_direction=False, cycle=False, hide_menu_name=True, name="Fullscreen!")
+menu = lcdMenu(LCD, {"prev_btn":prev_btn, "next_btn": next_btn, "ok_btn": ok_btn}, scroll_direction=False, cycle=False, hide_menu_name=True, name="Fullscreen!")
+menu.setup(menuItems)
 
 menu.run()
+

example_submenu.py

@@ -22,7 +22,11 @@ menuItems = [("first item", first_callback),
              ("third item", third_cb)]
 button_mappings = {"prev_btn":prev_btn, "next_btn": next_btn, "ok_btn": ok_btn}
 
-submenu = lcdMenu(LCD, button_mappings, menuItems, scroll_direction=True, cycle=False, hide_menu_name=False, name="Submenu!")
+submenu = lcdMenu(LCD, button_mappings, scroll_direction=True, cycle=False, hide_menu_name=False, name="Submenu!")
+submenu.setup(menuItems)
+
+mainmenu = lcdMenu(LCD, button_mappings, scroll_direction=False, cycle=True, hide_menu_name=False, name="Main menu!")
+mainmenu.setup([("Sub menu",submenu.run)])
 
-mainmenu = lcdMenu(LCD, button_mappings, [("Sub menu",submenu.run)], scroll_direction=False, cycle=True, hide_menu_name=False, name="Main menu!")
 mainmenu.run()
+