Add support for user-defined New, Save, Save As and Save All commands

android/src/toga_android/app.py

@@ -186,6 +186,9 @@ def onPrepareOptionsMenu(self, menu):
 class App:
     # Android apps exit when the last window is closed
     CLOSE_ON_LAST_WINDOW = True
+    # Android doesn't have command line handling;
+    # but saying it does shortcuts the default handling
+    HANDLES_COMMAND_LINE = True
 
     def __init__(self, interface):
         self.interface = interface

changes/2209.feature.2.rst

@@ -0,0 +1 @@
+The API for Documents and document types has been finalized. Document handling behavior is now controlled by declaring document types as part of your ``toga.App`` definition.

changes/2209.feature.3.rst

@@ -0,0 +1 @@
+File management menu items (such as New, Open and Save) can now be overridden to install default menu items.

changes/2209.removal.rst

@@ -0,0 +1,11 @@
+The API for Documents and Document-based apps has been significantly modified. Unfortunately, these changes are not backwards compatible; any existing Document-based app will require modification.
+
+The ``DocumentApp`` base class is no longer required. Apps can subclass ``App``, providing the same arguments as before.
+
+The API for ``Document`` subclasses has also changed:
+
+* A path is no longer provided as an argument to the Document constructor;
+
+* The ``document_type`` is now specified as a class property; and
+
+* The ``can_close()`` handler is no longer honored. It should be converted into a normal ``on_close`` handler and explicitly installed on the document's ``main_window``.