demos: add few states demo

demos/few_states/demo.py

@@ -0,0 +1,85 @@
+"""The bot is designed to demonstrate how to work with multiple states."""
+
+from hammett.core import Application, Button
+from hammett.core.constants import DEFAULT_STATE, RenderConfig, SourcesTypes
+from hammett.core.handlers import register_typing_handler
+from hammett.core.screen import RouteMixin, Screen, StartScreen
+
+ANOTHER_STATE = 'another_state'
+
+
+class MainMenu(StartScreen):
+    """The screen that will be registered in the DEFAULT_STATE."""
+
+    description = (
+        'This is the screen that is registered in DEFAULT_STATE\n'
+        '\n'
+        'In this state the text input handler will not work, you can try to write something. '
+        'Spoiler: nothing will happen'
+    )
+
+    def setup_keyboard(self):
+        """Sets up the keyboard for the screen."""
+
+        return [[
+            Button(
+                'Move to another state',
+                AnotherScreen,
+                source_type=SourcesTypes.SGOTO_SOURCE_TYPE,
+            )
+        ]]
+
+
+class AnotherScreen(RouteMixin, Screen):
+    """The screen that will be registered in the ANOTHER_STATE."""
+
+    routes = (
+        ({DEFAULT_STATE}, ANOTHER_STATE),
+    )
+
+    description = (
+        'This is the screen that is registered in ANOTHER_STATE.\n'
+        '\n'
+        'Write something here, the text input handler will be called and return to the '
+        'previous state.'
+    )
+
+    @register_typing_handler
+    async def handle_text_input(self, update, context):
+        """Handles text input and returns to DEFAULT_STATE."""
+
+        text = update.message.text
+        keyboard = [[
+            Button(
+                'Try again',
+                AnotherScreen,
+                source_type=SourcesTypes.SGOTO_SOURCE_TYPE,
+            )
+        ]]
+
+        config = RenderConfig(
+            as_new_message=True,
+            description=f"Hi, {text}, I'm Dad!",
+            keyboard=keyboard,
+        )
+        await self.render(update, context, config=config)
+        return DEFAULT_STATE
+
+
+def main():
+    """Runs the bot."""
+
+    name = 'few_states'
+    app = Application(
+        name,
+        entry_point=MainMenu,
+        states={
+            DEFAULT_STATE: [MainMenu],
+            ANOTHER_STATE: [AnotherScreen]
+        },
+    )
+    app.run()
+
+
+if __name__ == '__main__':
+    main()

demos/few_states/settings.py

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+import os
+
+TOKEN = os.getenv('TOKEN', '')