Add app-level dialogs.

android/src/toga_android/app.py

@@ -11,6 +11,7 @@
 from org.beeware.android import IPythonApp, MainActivity
 
 from toga.command import Command, Group, Separator
+from toga.dialogs import InfoDialog
 from toga.handlers import simple_handler
 
 from .libs import events
@@ -280,8 +281,16 @@ def show_about_dialog(self):
             message_parts.append(f"Author: {self.interface.author}")
         if self.interface.description is not None:
             message_parts.append(f"\n{self.interface.description}")
-        self.interface.main_window.info_dialog(
-            f"About {self.interface.formal_name}", "\n".join(message_parts)
+
+        # Create and show an info dialog as the about dialog.
+        # We don't care about the response.
+        asyncio.create_task(
+            self.interface.dialog(
+                InfoDialog(
+                    f"About {self.interface.formal_name}",
+                    "\n".join(message_parts),
+                )
+            )
         )
 
     ######################################################################

android/src/toga_android/dialogs.py

@@ -1,10 +1,10 @@
-from abc import ABC
-
 from android import R
 from android.app import AlertDialog
 from android.content import DialogInterface
 from java import dynamic_proxy
 
+import toga
+
 
 class OnClickListener(dynamic_proxy(DialogInterface.OnClickListener)):
     def __init__(self, fn=None, value=None):
@@ -16,25 +16,31 @@ def onClick(self, _dialog, _which):
         self._fn(self._value)
 
 
-class BaseDialog(ABC):
-    def __init__(self, interface):
-        self.interface = interface
-        self.interface._impl = self
+class BaseDialog:
+    def show(self, host_window, future):
+        self.future = future
+
+        if self.native:
+            # Show the dialog. Don't differentiate between app and window modal dialogs.
+            self.native.show()
+        else:
+            # Dialog doesn't have an implementation. This can't be covered, as
+            # the testbed shortcuts the test before showing the dialog.
+            self.future.set_result(None)  # pragma: no cover
 
 
 class TextDialog(BaseDialog):
     def __init__(
         self,
-        interface,
         title,
         message,
         positive_text,
         negative_text=None,
         icon=None,
     ):
-        super().__init__(interface=interface)
+        super().__init__()
 
-        self.native = AlertDialog.Builder(interface.window._impl.app.native)
+        self.native = AlertDialog.Builder(toga.App.app.current_window._impl.app.native)
         self.native.setCancelable(False)
         self.native.setTitle(title)
         self.native.setMessage(message)
@@ -52,26 +58,23 @@ def __init__(
             self.native.setNegativeButton(
                 negative_text, OnClickListener(self.completion_handler, False)
             )
-        self.native.show()
 
     def completion_handler(self, return_value: bool) -> None:
-        self.interface.set_result(return_value)
+        self.future.set_result(return_value)
 
 
 class InfoDialog(TextDialog):
-    def __init__(self, interface, title, message):
+    def __init__(self, title, message):
         super().__init__(
-            interface=interface,
             title=title,
             message=message,
             positive_text="OK",
         )
 
 
 class QuestionDialog(TextDialog):
-    def __init__(self, interface, title, message):
+    def __init__(self, title, message):
         super().__init__(
-            interface=interface,
             title=title,
             message=message,
             positive_text="Yes",
@@ -80,9 +83,8 @@ def __init__(self, interface, title, message):
 
 
 class ConfirmDialog(TextDialog):
-    def __init__(self, interface, title, message):
+    def __init__(self, title, message):
         super().__init__(
-            interface=interface,
             title=title,
             message=message,
             positive_text="OK",
@@ -91,9 +93,8 @@ def __init__(self, interface, title, message):
 
 
 class ErrorDialog(TextDialog):
-    def __init__(self, interface, title, message):
+    def __init__(self, title, message):
         super().__init__(
-            interface=interface,
             title=title,
             message=message,
             positive_text="OK",
@@ -104,48 +105,52 @@ def __init__(self, interface, title, message):
 class StackTraceDialog(BaseDialog):
     def __init__(
         self,
-        interface,
         title,
         message,
         **kwargs,
     ):
-        super().__init__(interface=interface)
-        interface.window.factory.not_implemented("Window.stack_trace_dialog()")
+        super().__init__()
+
+        toga.App.app.factory.not_implemented("dialogs.StackTraceDialog()")
+        self.native = None
 
 
 class SaveFileDialog(BaseDialog):
     def __init__(
         self,
-        interface,
         title,
         filename,
         initial_directory,
         file_types=None,
     ):
-        super().__init__(interface=interface)
-        interface.window.factory.not_implemented("Window.save_file_dialog()")
+        super().__init__()
+
+        toga.App.app.factory.not_implemented("dialogs.SaveFileDialog()")
+        self.native = None
 
 
 class OpenFileDialog(BaseDialog):
     def __init__(
         self,
-        interface,
         title,
         initial_directory,
         file_types,
         multiple_select,
     ):
-        super().__init__(interface=interface)
-        interface.window.factory.not_implemented("Window.open_file_dialog()")
+        super().__init__()
+
+        toga.App.app.factory.not_implemented("dialogs.OpenFileDialog()")
+        self.native = None
 
 
 class SelectFolderDialog(BaseDialog):
     def __init__(
         self,
-        interface,
         title,
         initial_directory,
         multiple_select,
     ):
-        super().__init__(interface=interface)
-        interface.window.factory.not_implemented("Window.select_folder_dialog()")
+        super().__init__()
+
+        toga.App.app.factory.not_implemented("dialogs.SelectFolderDialog()")
+        self.native = None

android/tests_backend/app.py

@@ -6,11 +6,12 @@
 
 from toga import Group
 
+from .dialogs import DialogsMixin
 from .probe import BaseProbe
 from .window import WindowProbe
 
 
-class AppProbe(BaseProbe):
+class AppProbe(BaseProbe, DialogsMixin):
     supports_key = False
 
     def __init__(self, app):
@@ -73,7 +74,9 @@ def activate_menu_about(self):
         self._activate_menu_item(["About Toga Testbed"])
 
     async def close_about_dialog(self):
-        await self.main_window_probe.close_info_dialog(None)
+        about_dialog = self.get_dialog_view()
+        assert about_dialog is not None, "No about dialog displayed"
+        await self.press_dialog_button(about_dialog, "OK")
 
     def activate_menu_visit_homepage(self):
         xfail("This backend doesn't have a visit homepage command")

android/tests_backend/dialogs.py

@@ -0,0 +1,56 @@
+import asyncio
+
+import pytest
+
+
+class DialogsMixin:
+    def _setup_alert_dialog_result(self, dialog, buttons, selected_index):
+        # Install an overridden show method that invokes the original,
+        # but then closes the open dialog.
+        orig_show = dialog._impl.show
+
+        def automated_show(host_window, future):
+            orig_show(host_window, future)
+
+            async def _close_dialog():
+                # Inject a small pause without blocking the event loop
+                await asyncio.sleep(1.0 if self.app.run_slow else 0.2)
+                try:
+                    dialog_view = self.get_dialog_view()
+                    self.assert_dialog_buttons(dialog_view, buttons)
+                    await self.press_dialog_button(dialog_view, buttons[selected_index])
+                except Exception as e:
+                    # An error occurred closing the dialog; that means the dialog
+                    # isn't what as expected, so record that in the future.
+                    future.set_exception(e)
+
+            asyncio.ensure_future(_close_dialog())
+
+        dialog._impl.show = automated_show
+
+    def setup_info_dialog_result(self, dialog):
+        self._setup_alert_dialog_result(dialog, ["OK"], 0)
+
+    def setup_question_dialog_result(self, dialog, result):
+        self._setup_alert_dialog_result(dialog, ["No", "Yes"], 1 if result else 0)
+
+    def setup_confirm_dialog_result(self, dialog, result):
+        self._setup_alert_dialog_result(dialog, ["Cancel", "OK"], 1 if result else 0)
+
+    def setup_error_dialog_result(self, dialog):
+        self._setup_alert_dialog_result(dialog, ["OK"], 0)
+
+    def setup_stack_trace_dialog_result(self, dialog, result):
+        pytest.skip("Stack Trace dialog not implemented on Android")
+
+    def setup_save_file_dialog_result(self, dialog, result):
+        pytest.skip("Save File dialog not implemented on Android")
+
+    def setup_open_file_dialog_result(self, dialog, result, multiple_select):
+        pytest.skip("Open File dialog not implemented on Android")
+
+    def setup_select_folder_dialog_result(self, dialog, result, multiple_select):
+        pytest.skip("Select Folder dialog not implemented on Android")
+
+    def is_modal_dialog(self, dialog):
+        return True

android/tests_backend/window.py

@@ -1,10 +1,10 @@
-import pytest
 from androidx.appcompat import R as appcompat_R
 
+from .dialogs import DialogsMixin
 from .probe import BaseProbe
 
 
-class WindowProbe(BaseProbe):
+class WindowProbe(BaseProbe, DialogsMixin):
     def __init__(self, app, window):
         super().__init__(app)
         self.native = self.app._impl.native
@@ -20,38 +20,6 @@ def content_size(self):
             self.root_view.getHeight() / self.scale_factor,
         )
 
-    async def close_info_dialog(self, dialog):
-        dialog_view = self.get_dialog_view()
-        self.assert_dialog_buttons(dialog_view, ["OK"])
-        await self.press_dialog_button(dialog_view, "OK")
-
-    async def close_question_dialog(self, dialog, result):
-        dialog_view = self.get_dialog_view()
-        self.assert_dialog_buttons(dialog_view, ["No", "Yes"])
-        await self.press_dialog_button(dialog_view, "Yes" if result else "No")
-
-    async def close_confirm_dialog(self, dialog, result):
-        dialog_view = self.get_dialog_view()
-        self.assert_dialog_buttons(dialog_view, ["Cancel", "OK"])
-        await self.press_dialog_button(dialog_view, "OK" if result else "Cancel")
-
-    async def close_error_dialog(self, dialog):
-        dialog_view = self.get_dialog_view()
-        self.assert_dialog_buttons(dialog_view, ["OK"])
-        await self.press_dialog_button(dialog_view, "OK")
-
-    async def close_stack_trace_dialog(self, dialog, result):
-        pytest.skip("Stack Trace dialog not implemented on Android")
-
-    async def close_save_file_dialog(self, dialog, result):
-        pytest.skip("Save File dialog not implemented on Android")
-
-    async def close_open_file_dialog(self, dialog, result, multiple_select):
-        pytest.skip("Open File dialog not implemented on Android")
-
-    async def close_select_folder_dialog(self, dialog, result, multiple_select):
-        pytest.skip("Select Folder dialog not implemented on Android")
-
     def _native_menu(self):
         return self.native.findViewById(appcompat_R.id.action_bar).getMenu()
 
@@ -88,6 +56,3 @@ def assert_toolbar_item(self, index, label, tooltip, has_icon, enabled):
 
     def press_toolbar_button(self, index):
         self.native.onOptionsItemSelected(self._toolbar_items()[index])
-
-    def is_modal_dialog(self, dialog):
-        return True

changes/2669.feature.rst

@@ -0,0 +1 @@
+Dialogs can now be displayed relative to an app, in addition to be being modal to a window.

changes/2669.removal.rst

@@ -0,0 +1 @@
+The APIs on ``Window`` for displaying dialogs (``info_dialog()``, ``question_dialog()``, etc) have been deprecated. They can be replaced with creating an instance of a ``Dialog`` class (e.g., ``InfoDialog``), and passing that instance to ``window.dialog()``.