Fixed Android backend

android/src/toga_android/window.py

@@ -145,7 +145,11 @@ def get_visible(self):
     ######################################################################
 
     def get_window_state(self):
-        # Windows are always full screen
+        # window.state is called in _close(), which itself sometimes
+        # is called during early stages of app startup, during which
+        # the app attribute may not exist. In such cases, return NORMAL.
+        if getattr(self, "app", None) is None:
+            return WindowState.NORMAL
         decor_view = self.app.native.getWindow().getDecorView()
         system_ui_flags = decor_view.getSystemUiVisibility()
         if system_ui_flags & (
@@ -162,33 +166,49 @@ def get_window_state(self):
     def set_window_state(self, state):
         current_state = self.get_window_state()
         decor_view = self.app.native.getWindow().getDecorView()
-        # On Android Maximized state is same as the Normal state
-        if state in {WindowState.NORMAL, WindowState.MAXIMIZED}:
-            if current_state in {
-                WindowState.FULLSCREEN,
-                WindowState.PRESENTATION,
-            }:
-                decor_view.setSystemUiVisibility(0)
-                if current_state == WindowState.PRESENTATION:
-                    # Marking this as no branch, since the testbed can't create a simple
-                    # window, so we can't test the other branch.
-                    if self._actionbar_shown_by_default:  # pragma: no branch
-                        self.app.native.getSupportActionBar().show()
-                    self._is_presentation_mode = False
-        else:
+        if (
+            current_state != WindowState.NORMAL
+            and state != WindowState.NORMAL
+            and (getattr(self, "_pending_window_state_transition", None) is None)
+        ):
+            # Set Window state to NORMAL before changing to other states as some
+            # states block changing window state without first exiting them or
+            # can even cause rendering glitches.
+            self._pending_window_state_transition = state
             self.set_window_state(WindowState.NORMAL)
-            if state in {WindowState.FULLSCREEN, WindowState.PRESENTATION}:
-                decor_view.setSystemUiVisibility(
-                    decor_view.SYSTEM_UI_FLAG_FULLSCREEN
-                    | decor_view.SYSTEM_UI_FLAG_HIDE_NAVIGATION
-                    | decor_view.SYSTEM_UI_FLAG_IMMERSIVE
-                )
-                if state == WindowState.PRESENTATION:
-                    # Marking this as no branch, since the testbed can't create a simple
-                    # window, so we can't test the other branch.
-                    if self._actionbar_shown_by_default:  # pragma: no branch
-                        self.app.native.getSupportActionBar().hide()
-                    self._is_presentation_mode = True
+
+        elif state in {WindowState.FULLSCREEN, WindowState.PRESENTATION}:
+            decor_view.setSystemUiVisibility(
+                decor_view.SYSTEM_UI_FLAG_FULLSCREEN
+                | decor_view.SYSTEM_UI_FLAG_HIDE_NAVIGATION
+                | decor_view.SYSTEM_UI_FLAG_IMMERSIVE
+            )
+            if state == WindowState.PRESENTATION:
+                # Marking this as no branch, since the testbed can't create a simple
+                # window, so we can't test the other branch.
+                if self._actionbar_shown_by_default:  # pragma: no branch
+                    self.app.native.getSupportActionBar().hide()
+                self._is_presentation_mode = True
+
+        else:
+            # On Android Maximized state is same as the Normal state
+            if state in {WindowState.NORMAL, WindowState.MAXIMIZED}:
+                if current_state in {
+                    WindowState.FULLSCREEN,
+                    WindowState.PRESENTATION,
+                }:
+                    decor_view.setSystemUiVisibility(0)
+                    if current_state == WindowState.PRESENTATION:
+                        # Marking this as no branch, since the testbed can't create a simple
+                        # window, so we can't test the other branch.
+                        if self._actionbar_shown_by_default:  # pragma: no branch
+                            self.app.native.getSupportActionBar().show()
+                        self._is_presentation_mode = False
+
+                # Complete any pending window state transition.
+                if getattr(self, "_pending_window_state_transition", None) is not None:
+                    self.set_window_state(self._pending_window_state_transition)
+                    del self._pending_window_state_transition
 
     ######################################################################
     # Window capabilities

android/tests_backend/window.py

@@ -23,18 +23,14 @@ def content_size(self):
         )
 
     def get_window_state(self):
-        # Windows are always full screen
         decor_view = self.native.getWindow().getDecorView()
         system_ui_flags = decor_view.getSystemUiVisibility()
-        if (
-            system_ui_flags
-            & (
-                decor_view.SYSTEM_UI_FLAG_FULLSCREEN
-                | decor_view.SYSTEM_UI_FLAG_HIDE_NAVIGATION
-                | decor_view.SYSTEM_UI_FLAG_IMMERSIVE
-            )
-        ) != 0:
-            if not self.native.getSupportActionBar().isShowing():
+        if system_ui_flags & (
+            decor_view.SYSTEM_UI_FLAG_FULLSCREEN
+            | decor_view.SYSTEM_UI_FLAG_HIDE_NAVIGATION
+            | decor_view.SYSTEM_UI_FLAG_IMMERSIVE
+        ):
+            if self.window._impl._is_presentation_mode:
                 current_state = WindowState.PRESENTATION
             else:
                 current_state = WindowState.FULLSCREEN

testbed/tests/app/test_desktop.py

@@ -346,9 +346,15 @@ async def test_presentation_mode_with_excess_windows_list(app, app_probe):
     ],
 )
 async def test_presentation_mode_exit_on_window_state_change(
-    app, app_probe, new_window_state
+    app, app_probe, main_window_probe, new_window_state
 ):
     """Changing window state exits presentation mode and sets the new state."""
+    if (
+        new_window_state == WindowState.MINIMIZED
+        and not main_window_probe.supports_minimize
+    ):
+        pytest.xfail("This backend doesn't reliably support minimized window state.")
+
     try:
         window1 = toga.MainWindow(
             title="Test Window 1", position=(150, 150), size=(200, 200)

testbed/tests/window/test_window.py

@@ -217,6 +217,50 @@ async def test_window_state_presentation(main_window, main_window_probe):
         assert main_window_probe.get_window_state() != WindowState.PRESENTATION
         assert main_window_probe.get_window_state() == WindowState.NORMAL
 
+    @pytest.mark.parametrize(
+        "initial_state, final_state",
+        [
+            # Direct switch from FULLSCREEN:
+            (WindowState.FULLSCREEN, WindowState.PRESENTATION),
+            # Direct switch from PRESENTATION:
+            (WindowState.PRESENTATION, WindowState.FULLSCREEN),
+        ],
+    )
+    async def test_window_state_direct_change(
+        app, initial_state, final_state, main_window, main_window_probe
+    ):
+        assert main_window_probe.get_window_state() == WindowState.NORMAL
+        assert main_window_probe.get_window_state() != initial_state
+        assert main_window_probe.get_window_state() != final_state
+        try:
+            # Set to initial state
+            main_window.state = initial_state
+            await main_window_probe.wait_for_window(
+                f"Main window is in {initial_state}"
+            )
+
+            assert main_window_probe.get_window_state() != WindowState.NORMAL
+            assert main_window_probe.get_window_state() == initial_state
+            assert main_window_probe.get_window_state() != final_state
+
+            # Set to final state
+            main_window.state = final_state
+            await main_window_probe.wait_for_window(f"Main window is in {final_state}")
+
+            assert main_window_probe.get_window_state() != WindowState.NORMAL
+            assert main_window_probe.get_window_state() == final_state
+            assert main_window_probe.get_window_state() != initial_state
+        finally:
+            # Set to NORMAL state
+            main_window.state = WindowState.NORMAL
+            await main_window_probe.wait_for_window(
+                "Main window is in WindowState.NORMAL"
+            )
+
+            assert main_window_probe.get_window_state() == WindowState.NORMAL
+            assert main_window_probe.get_window_state() != final_state
+            assert main_window_probe.get_window_state() != initial_state
+
     async def test_screen(main_window, main_window_probe):
         """The window can be relocated to another screen, using both absolute and relative screen positions."""
         assert main_window.screen.origin == (0, 0)
@@ -820,6 +864,14 @@ async def test_window_state_presentation(second_window, second_window_probe):
     async def test_window_state_direct_change(
         app, initial_state, final_state, second_window, second_window_probe
     ):
+        if (
+            WindowState.MINIMIZED in {initial_state, final_state}
+            and not second_window_probe.supports_minimize
+        ):
+            pytest.xfail(
+                "This backend doesn't reliably support minimized window state."
+            )
+
         second_window.toolbar.add(app.cmd1)
         second_window.content = toga.Box(style=Pack(background_color=CORNFLOWERBLUE))
         second_window.show()