Merge pull request #9 from relic-se/usb-errors

Improve return value of `BootMouse.update`

Author: FoamyGuy

README.rst

@@ -134,7 +134,7 @@ Usage Example
         out_str = f"{mouse.x},{mouse.y}"
 
         # add pressed buttons to out str
-        if pressed_btns is not None:
+        if pressed_btns is not None and len(pressed_btns) > 0:
             out_str += f" {" ".join(pressed_btns)}"
 
         # update the text label with the new coordinates

adafruit_usb_host_mouse.py

@@ -186,8 +186,9 @@ def update(self):
         Read data from the USB mouse and update the location of the visible cursor
         and check if any buttons are pressed.
 
-        :return: a List containing one or more of the strings "left", "right", "middle"
-          indicating which buttons are pressed.
+        :return: a tuple containing one or more of the strings "left", "right", "middle"
+          indicating which buttons are pressed. If no buttons are pressed, the tuple will be empty.
+          If a error occurred while trying to read from the usb device, `None` will be returned.
         """
         try:
             # attempt to read data from the mouse
@@ -226,5 +227,4 @@ def update(self):
                 # it is being clicked.
                 pressed_btns.append(button)
 
-        if len(pressed_btns) > 0:
-            return pressed_btns
+        return tuple(pressed_btns)

examples/usb_host_mouse_simpletest.py

@@ -46,7 +46,7 @@
     out_str = f"{mouse.x},{mouse.y}"
 
     # add pressed buttons to out str
-    if pressed_btns is not None:
+    if pressed_btns is not None and len(pressed_btns) > 0:
         out_str += f" {" ".join(pressed_btns)}"
 
     # update the text label with the new coordinates