Update PythonNative Page

owenthcarey · owenthcarey · commit c4e263984b44 · 2023-07-08T12:41:14.000-07:00
diff --git a/apps/android_pythonnative_3/app/src/main/python/app/main_3.py b/apps/android_pythonnative_3/app/src/main/python/app/main_3.py
@@ -2,12 +2,17 @@
 
 
 class MainPage(pn.Page):
-    def __init__(self, context):
-        super().__init__()
-        self.context = context
+    def __init__(self, native_instance):
+        super().__init__(native_instance)
 
     def on_create(self):
         super().on_create()
+        stack_view = pn.StackView(self.native_instance)
+        button = pn.Button(self.native_instance, "Button")
+        label = pn.Label(self.native_instance, "Label")
+        stack_view.add_view(button)
+        stack_view.add_view(label)
+        self.set_root_view(stack_view)
 
     def on_start(self):
         super().on_start()
diff --git a/apps/pythonnative_demo/app/main.py b/apps/pythonnative_demo/app/main.py
@@ -17,7 +17,7 @@ def main():
     stack_view.add_view(label)
 
     # Set the layout
-    page.set_layout(stack_view)
+    page.set_root_view(stack_view)
 
     # Display the page
     page.show()
diff --git a/libs/pythonnative/pythonnative/page.py b/libs/pythonnative/pythonnative/page.py
@@ -1,3 +1,34 @@
+"""
+Your current approach, which involves creating an Android Activity in Kotlin
+and then passing it to Python, is necessary due to the restrictions inherent
+in Android's lifecycle. You are correctly following the Android way of managing
+Activities. In Android, the system is in control of when and how Activities are
+created and destroyed. It is not possible to directly create an instance of an
+Activity from Python because that would bypass Android's lifecycle management,
+leading to unpredictable results.
+
+Your Button example works because Button is a View, not an Activity. View
+instances in Android can be created and managed directly by your code. This is
+why you are able to create an instance of Button from Python.
+
+Remember that Activities in Android are not just containers for your UI like a
+ViewGroup, they are also the main entry points into your app and are closely
+tied to the app's lifecycle. Therefore, Android needs to maintain tight control
+over them. Activities aren't something you instantiate whenever you need them;
+they are created in response to a specific intent and their lifecycle is
+managed by Android.
+
+So, to answer your question: Yes, you need to follow this approach for
+Activities in Android. You cannot instantiate an Activity from Python like you
+do for Views.
+
+On the other hand, for iOS, you can instantiate a UIViewController directly
+from Python. The example code you provided for this is correct.
+
+Just ensure that your PythonNative UI framework is aware of these platform
+differences and handles them appropriately.
+"""
+
 from abc import ABC, abstractmethod
 from .utils import IS_ANDROID
 from .view import ViewBase
@@ -11,54 +42,45 @@ class PageBase(ABC):
     @abstractmethod
     def __init__(self) -> None:
         super().__init__()
-        self.layout = None
-
-    @abstractmethod
-    def add_view(self, view) -> None:
-        pass
 
     @abstractmethod
-    def set_layout(self, layout) -> None:
+    def set_root_view(self, view) -> None:
         pass
 
     @abstractmethod
-    def show(self) -> None:
+    def on_create(self) -> None:
         pass
 
     @abstractmethod
-    def on_create(self):
+    def on_start(self) -> None:
         pass
 
     @abstractmethod
-    def on_start(self):
+    def on_resume(self) -> None:
         pass
 
     @abstractmethod
-    def on_resume(self):
+    def on_pause(self) -> None:
         pass
 
     @abstractmethod
-    def on_pause(self):
+    def on_stop(self) -> None:
         pass
 
     @abstractmethod
-    def on_stop(self):
+    def on_destroy(self) -> None:
         pass
 
     @abstractmethod
-    def on_destroy(self):
+    def on_restart(self) -> None:
         pass
 
     @abstractmethod
-    def on_restart(self):
+    def on_save_instance_state(self) -> None:
         pass
 
     @abstractmethod
-    def on_save_instance_state(self):
-        pass
-
-    @abstractmethod
-    def on_restore_instance_state(self):
+    def on_restore_instance_state(self) -> None:
         pass
 
 
@@ -70,49 +92,40 @@ def on_restore_instance_state(self):
     from java import jclass
 
     class Page(PageBase, ViewBase):
-        def __init__(self):
+        def __init__(self, native_instance) -> None:
             super().__init__()
             self.native_class = jclass("android.app.Activity")
+            self.native_instance = native_instance
             # self.native_instance = self.native_class()
 
-        def add_view(self, view):
-            if self.layout is None:
-                raise ValueError("You must set a layout before adding views.")
-            self.layout.add_view(view)
-
-        def set_layout(self, layout):
-            self.layout = layout
-            self.native_instance.setContentView(layout.native_instance)
-
-        def show(self):
-            # This method should contain code to start the Activity
-            pass
+        def set_root_view(self, view) -> None:
+            self.native_instance.setContentView(view.native_instance)
 
-        def on_create(self):
+        def on_create(self) -> None:
             print("Android on_create() called")
 
-        def on_start(self):
+        def on_start(self) -> None:
             print("Android on_start() called")
 
-        def on_resume(self):
+        def on_resume(self) -> None:
             print("Android on_resume() called")
 
-        def on_pause(self):
+        def on_pause(self) -> None:
             print("Android on_pause() called")
 
-        def on_stop(self):
+        def on_stop(self) -> None:
             print("Android on_stop() called")
 
-        def on_destroy(self):
+        def on_destroy(self) -> None:
             print("Android on_destroy() called")
 
-        def on_restart(self):
+        def on_restart(self) -> None:
             print("Android on_restart() called")
 
-        def on_save_instance_state(self):
+        def on_save_instance_state(self) -> None:
             print("Android on_save_instance_state() called")
 
-        def on_restore_instance_state(self):
+        def on_restore_instance_state(self) -> None:
             print("Android on_restore_instance_state() called")
 
 else:
@@ -123,47 +136,38 @@ def on_restore_instance_state(self):
     from rubicon.objc import ObjCClass
 
     class Page(PageBase, ViewBase):
-        def __init__(self):
+        def __init__(self, native_instance) -> None:
             super().__init__()
             self.native_class = ObjCClass("UIViewController")
+            self.native_instance = native_instance
             # self.native_instance = self.native_class.alloc().init()
 
-        def add_view(self, view):
-            if self.layout is None:
-                raise ValueError("You must set a layout before adding views.")
-            self.layout.add_view(view)
-
-        def set_layout(self, layout):
-            self.layout = layout
-            self.native_instance.view().addSubview_(layout.native_instance)
-
-        def show(self):
-            # This method should contain code to present the ViewController
-            pass
+        def set_root_view(self, view) -> None:
+            self.native_instance.view().addSubview_(view.native_instance)
 
-        def on_create(self):
+        def on_create(self) -> None:
             print("iOS on_create() called")
 
-        def on_start(self):
+        def on_start(self) -> None:
             print("iOS on_start() called")
 
-        def on_resume(self):
+        def on_resume(self) -> None:
             print("iOS on_resume() called")
 
-        def on_pause(self):
+        def on_pause(self) -> None:
             print("iOS on_pause() called")
 
-        def on_stop(self):
+        def on_stop(self) -> None:
             print("iOS on_stop() called")
 
-        def on_destroy(self):
+        def on_destroy(self) -> None:
             print("iOS on_destroy() called")
 
-        def on_restart(self):
+        def on_restart(self) -> None:
             print("iOS on_restart() called")
 
-        def on_save_instance_state(self):
+        def on_save_instance_state(self) -> None:
             print("iOS on_save_instance_state() called")
 
-        def on_restore_instance_state(self):
+        def on_restore_instance_state(self) -> None:
             print("iOS on_restore_instance_state() called")
