Add window states API

android/src/toga_android/app.py

@@ -12,6 +12,7 @@
 
 import toga
 from toga.command import Command, Group, Separator
+from toga.constants import WindowState
 from toga.dialogs import InfoDialog
 from toga.handlers import simple_handler
 
@@ -321,14 +322,19 @@ def set_current_window(self, window):
         pass
 
     ######################################################################
-    # Full screen control
+    # Presentation mode controls
     ######################################################################
 
-    def enter_full_screen(self, windows):
-        pass
+    def enter_presentation_mode(self, screen_window_dict):
+        for screen, window in screen_window_dict.items():
+            window._impl._before_presentation_mode_screen = window.screen
+            window.screen = screen
+            window._impl.set_window_state(WindowState.PRESENTATION)
 
-    def exit_full_screen(self, windows):
-        pass
+    def exit_presentation_mode(self):
+        for window in self.interface.windows:
+            if window.state == WindowState.PRESENTATION:
+                window._impl.set_window_state(WindowState.NORMAL)
 
     ######################################################################
     # Platform-specific APIs

android/src/toga_android/window.py

@@ -10,6 +10,7 @@
 from java import dynamic_proxy
 from java.io import ByteArrayOutputStream
 
+from toga.constants import WindowState
 from toga.types import Position, Size
 
 from .container import Container
@@ -31,11 +32,17 @@ def onGlobalLayout(self):
 
 
 class Window(Container):
+    # ActionBar is always hidden on Window.
+    _actionbar_shown_by_default = False
+
     def __init__(self, interface, title, position, size):
         super().__init__()
         self.interface = interface
         self.interface._impl = self
         self._initial_title = title
+        # Use a shadow variable since the presence of ActionBar is not
+        # a reliable indicator for confirmation of presentation mode.
+        self._in_presentation_mode = False
 
     ######################################################################
     # Window properties
@@ -137,8 +144,73 @@ def get_visible(self):
     # Window state
     ######################################################################
 
-    def set_full_screen(self, is_full_screen):
-        self.interface.factory.not_implemented("Window.set_full_screen()")
+    def get_window_state(self):
+        # 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 & (
+            decor_view.SYSTEM_UI_FLAG_FULLSCREEN
+            | decor_view.SYSTEM_UI_FLAG_HIDE_NAVIGATION
+            | decor_view.SYSTEM_UI_FLAG_IMMERSIVE
+        ):
+            if self._in_presentation_mode:
+                return WindowState.PRESENTATION
+            else:
+                return WindowState.FULLSCREEN
+        return WindowState.NORMAL
+
+    def set_window_state(self, state):
+        current_state = self.get_window_state()
+        if current_state == state:
+            return
+        decor_view = self.app.native.getWindow().getDecorView()
+        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)
+
+        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._in_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._in_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
@@ -160,6 +232,9 @@ def get_image_data(self):
 
 
 class MainWindow(Window):
+    # ActionBar is always hidden on MainWindow.
+    _actionbar_shown_by_default = True
+
     def configure_titlebar(self):
         # Display the titlebar on a MainWindow.
         pass

android/tests_backend/window.py

@@ -1,5 +1,7 @@
 from androidx.appcompat import R as appcompat_R
 
+from toga.constants import WindowState
+
 from .dialogs import DialogsMixin
 from .probe import BaseProbe
 
@@ -20,6 +22,22 @@ def content_size(self):
             self.root_view.getHeight() / self.scale_factor,
         )
 
+    def get_window_state(self):
+        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
+        ):
+            if self.window._impl._in_presentation_mode:
+                current_state = WindowState.PRESENTATION
+            else:
+                current_state = WindowState.FULLSCREEN
+        else:
+            current_state = WindowState.NORMAL
+        return current_state
+
     def _native_menu(self):
         return self.native.findViewById(appcompat_R.id.action_bar).getMenu()
 

changes/1857.feature.rst

@@ -0,0 +1 @@
+Toga apps can now detect and set their window states including maximized, minimized, normal, full screen and presentation states.

changes/1857.removal.rst

@@ -0,0 +1 @@
+"Full screen mode" on an app has been renamed "Presentation mode" to avoid the ambiguity with "full screen mode" on a window. The ``toga.App.enter_full_screen`` and ``toga.App.exit_full_screen`` APIs have been renamed ``toga.App.enter_presentation_mode`` and ``toga.App.exit_presentation_mode``, respectively. ```

cocoa/src/toga_cocoa/app.py

@@ -17,6 +17,7 @@
 import toga
 from toga.app import overridden
 from toga.command import Command, Separator
+from toga.constants import WindowState
 from toga.handlers import NativeHandler, simple_handler
 
 from .keys import cocoa_key
@@ -491,33 +492,47 @@ def set_current_window(self, window):
         window._impl.native.makeKeyAndOrderFront(window._impl.native)
 
     ######################################################################
-    # Full screen control
+    # Presentation mode controls
     ######################################################################
 
-    def enter_full_screen(self, windows):
+    def enter_presentation_mode(self, screen_window_dict):
         opts = NSMutableDictionary.alloc().init()
         opts.setObject(
             NSNumber.numberWithBool(True), forKey="NSFullScreenModeAllScreens"
         )
-
-        for window, screen in zip(windows, NSScreen.screens):
-            window.content._impl.native.enterFullScreenMode(screen, withOptions=opts)
-            # Going full screen causes the window content to be re-homed
-            # in a NSFullScreenWindow; teach the new parent window
-            # about its Toga representations.
+        for screen, window in screen_window_dict.items():
+            window.content._impl.native.enterFullScreenMode(
+                screen._impl.native, withOptions=opts
+            )
+            # Going presentation mode causes the window content to be re-homed
+            # in a NSFullScreenWindow; teach the new parent window about its
+            # Toga representations.
             window.content._impl.native.window._impl = window._impl
             window.content._impl.native.window.interface = window
             window.content.refresh()
 
-    def exit_full_screen(self, windows):
+            # Process any pending window state.
+            if (
+                window._impl._pending_state_transition
+                and window._impl._pending_state_transition != WindowState.PRESENTATION
+            ):
+                window._impl._apply_state(WindowState.NORMAL)
+            else:
+                window._impl._pending_state_transition = None
+
+    def exit_presentation_mode(self):
         opts = NSMutableDictionary.alloc().init()
         opts.setObject(
             NSNumber.numberWithBool(True), forKey="NSFullScreenModeAllScreens"
         )
 
-        for window in windows:
-            window.content._impl.native.exitFullScreenModeWithOptions(opts)
-            window.content.refresh()
+        for window in self.interface.windows:
+            if window.state == WindowState.PRESENTATION:
+                window.content._impl.native.exitFullScreenModeWithOptions(opts)
+                window.content.refresh()
+
+                # Process any pending window state.
+                window._impl._apply_state(window._impl._pending_state_transition)
 
 
 class DocumentApp(App):  # pragma: no cover