Project goal: Creat a simple python 3 library for creating menu driven interfaces on 128x64 OLED displays and the
The interface can be navigated with two buttons, one to move to the next menu item and one to select the currently
This library allows you to quickly create menu driven interfaces for the Raspberry Pi and SSD1306 compatible 128x64 OLED displays using the SPI bus and at least two button.
(The GPIO pins for the buttons and SPI bus can be configured from within globalsetting.py)
How it work: The menu system consists of a number of "screens".
Each screen is defined by creating a file menu.XX in the folder specified in MENU_FOLDER in globalsetting.py
The library will read in each menu file in alphabetical order with the first menu file read being screen0.
example; menu.00 - Screen0 menu.01 - Screen1 -- snip menu.99 - Screen99
Each menu file has a very simple CSV file structure which defines the text/menus displayed on the screen.
Each menu file should not contain more than either 8 items or lines of text. The structure of the file is as such; Text,Flag,Type
Text is the line of text to be displayed. This string should not be longer than would be displayed on one line of the OLED screen. How many charecters will depend on the font size selected.
Flag is an integer which either points to the screen which would be selected if the execute button was pushed. For example for the screen loaded in Screen1 you would set this value to 1.
Flag can also be set to one of several special values which tell the menu system to treat this line differently.
Currently to special flags exist, flag 999 tells the menu system that this line is purely for informational display and is not a selectable menu option.
The second is flag 998 which tells the menu system that this item is not a link to another menu screen but should execute and python function which we can declare in myFunction.py.
Type should be set to the string "Menu" unless flag 998 is also used in which case it should contain the name of the function defined in myFunctions.py
Here is a simple example of a simple set of menus;
#menu.00 - Screen0 "Player",1,"Menu" "Help",2,"Menu"
#menu.01 - Screen1 "Stop",998,"stopPlayer" "Start",998,"startPlayer" "Forward 30 sec",998,"forward30" "Backwards 30 sec",998,"backwards30" "Back",0,"Menu"
#menu.02 - Screen2 "This is the",999,"Menu" "help page....",999,"Menu" "More info",3,"Menu" "Back",0,"Menu"
#menu.03 - Screen3 "This is a",999,"Menu" "sub menu...",999,"Menu" "Back",2,"Menu"
On startup the first menu loaded (Screen0) will be loaded and displayed.
This will display two menu items which can be skipped through by pressing button 1 and selected with button 2.
If the first menu item on Screen0 is selected the flag value is checked and the screen is changed to the screen with the same value, in this example, 1, so screen1 is selected.
On screen1 the first 4 items are not links to other screens but have flag 998 set which denotes these are function handlers which will call the function named in the type feild.
These function are defined in the myFunction.py file and will be covered later.
The final item on Screen1 is a link back to the start page, Screen0.
Screen2 shows use of the 999 flag which denotes that the first two lines of text are just to be displayed on the screen with no link or associated function handler.
myFunctions.py contains function definitions for each function handlers and a python dictionary named functionHandlersDictionary which contains one item for each function handler.
Example myFunctions.py;
def myFunction1(): print("This is myFunction1")
def myFunction2(): print("This is myFunction2")
functionHandlersDictionary = { "myFunction1": [myFunction1, "My function 1"], "myFunction2": [myFunction2, "My Function 2"]}
and the coresponding menu file to call these functions when selected with button 2 #menu.XX "Execute myFunction1",998,"myFunction1" "Execute myFunction2",998,"myFunction2"
Usage: Copy the folders and source files in to your project directory and rename menusystem-example.py and extend with your own additional features.
Edit the variables in globalsetting.py to match the GPIO pins you've used for the OLED SPI bus and your connected buttons.
You'll also need to set the MENU_FOLDER variable to point to the directory containing your menu/screen definitions.
Update myFunction.py to declare your function handlers and update the functionHandlersDictionary with a entry for each function.
Update myClasses.py to add button handlers for any additional buttons you require over the madatory next and select buttons by defining new button handlers in the myButton class.
if you do add aditional buttons in myClasses.py myButton you will also need to update the following list object in myClasses.py by adding additional myButton objects to the list myButtonsList;
myButtonsList = [myButton(5,"Button1", myButton.button1Handler),myButton(6, "Button2", myButton.button2Handler)]
The myButton object takes 3 arguments, the gpio pin the button is connected to, the lable for the button and then finaly the name of the handler function added to the myButton class in myClasses.py.
Example