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android/activity: Add Application.ActivityLifecycleCallbacks helpers (kivy#2669)
The `Application.ActivityLifecycleCallbacks` interface is used to register a class that can receive callbacks on Activity lifecycle changes. Add a `PythonJavaClass` implementing the interface and helper functions to register python callbacks with it. This can be used to perform actions in the python app when the activity changes lifecycle states.
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‎doc/source/apis.rst

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@@ -190,6 +190,51 @@ Example::
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# ...
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Activity lifecycle handling
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~~~~~~~~~~~~~~~~~~~~~~~~~~~
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.. module:: android.activity
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The Android ``Application`` class provides the `ActivityLifecycleCallbacks
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<https://developer.android.com/reference/android/app/Application.ActivityLifecycleCallbacks>`_
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interface where callbacks can be registered corresponding to `activity
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lifecycle
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<https://developer.android.com/guide/components/activities/activity-lifecycle>`_
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changes. These callbacks can be used to implement logic in the Python app when
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the activity changes lifecycle states.
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Note that some of the callbacks are not useful in the Python app. For example,
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an `onActivityCreated` callback will never be run since the the activity's
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`onCreate` callback will complete before the Python app is running. Similarly,
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saving instance state in an `onActivitySaveInstanceState` callback will not be
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helpful since the Python app doesn't have access to the restored instance
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state.
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.. function:: register_activity_lifecycle_callbacks(callbackname=callback, ...)
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This allows you to bind a callbacks to Activity lifecycle state changes.
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The callback names correspond to ``ActivityLifecycleCallbacks`` method
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names such as ``onActivityStarted``. See the `ActivityLifecycleCallbacks
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<https://developer.android.com/reference/android/app/Application.ActivityLifecycleCallbacks>`_
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documentation for names and function signatures for the callbacks.
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.. function:: unregister_activity_lifecycle_callbacks(instance)
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Unregister a ``ActivityLifecycleCallbacks`` instance previously registered
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with :func:`register_activity_lifecycle_callbacks`.
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Example::
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from android.activity import register_activity_lifecycle_callbacks
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def on_activity_stopped(activity):
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print('Activity is stopping')
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register_activity_lifecycle_callbacks(
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onActivityStopped=on_activity_stopped,
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)
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Receiving Broadcast message
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~~~~~~~~~~~~~~~~~~~~~~~~~~~
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‎pythonforandroid/recipes/android/src/android/activity.py

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@@ -61,3 +61,154 @@ def unbind(**kwargs):
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_activity.unregisterNewIntentListener(listener)
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elif event == 'on_activity_result':
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_activity.unregisterActivityResultListener(listener)
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# Keep a reference to all the registered classes so that python doesn't
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# garbage collect them.
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_lifecycle_callbacks = set()
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class ActivityLifecycleCallbacks(PythonJavaClass):
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"""Callback class for handling PythonActivity lifecycle transitions"""
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__javainterfaces__ = ['android/app/Application$ActivityLifecycleCallbacks']
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def __init__(self, callbacks):
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super().__init__()
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# It would be nice to use keyword arguments, but PythonJavaClass
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# doesn't allow that in its __cinit__ method.
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if not isinstance(callbacks, dict):
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raise ValueError('callbacks must be a dict instance')
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self.callbacks = callbacks
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def _callback(self, name, *args):
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func = self.callbacks.get(name)
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if func:
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return func(*args)
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@java_method('(Landroid/app/Activity;Landroid/os/Bundle;)V')
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def onActivityCreated(self, activity, savedInstanceState):
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self._callback('onActivityCreated', activity, savedInstanceState)
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@java_method('(Landroid/app/Activity;)V')
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def onActivityDestroyed(self, activity):
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self._callback('onActivityDestroyed', activity)
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@java_method('(Landroid/app/Activity;)V')
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def onActivityPaused(self, activity):
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self._callback('onActivityPaused', activity)
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@java_method('(Landroid/app/Activity;Landroid/os/Bundle;)V')
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def onActivityPostCreated(self, activity, savedInstanceState):
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self._callback('onActivityPostCreated', activity, savedInstanceState)
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@java_method('(Landroid/app/Activity;)V')
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def onActivityPostDestroyed(self, activity):
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self._callback('onActivityPostDestroyed', activity)
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@java_method('(Landroid/app/Activity;)V')
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def onActivityPostPaused(self, activity):
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self._callback('onActivityPostPaused', activity)
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@java_method('(Landroid/app/Activity;)V')
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def onActivityPostResumed(self, activity):
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self._callback('onActivityPostResumed', activity)
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@java_method('(Landroid/app/Activity;Landroid/os/Bundle;)V')
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def onActivityPostSaveInstanceState(self, activity, outState):
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self._callback('onActivityPostSaveInstanceState', activity, outState)
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@java_method('(Landroid/app/Activity;)V')
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def onActivityPostStarted(self, activity):
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self._callback('onActivityPostStarted', activity)
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@java_method('(Landroid/app/Activity;)V')
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def onActivityPostStopped(self, activity):
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self._callback('onActivityPostStopped', activity)
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@java_method('(Landroid/app/Activity;Landroid/os/Bundle;)V')
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def onActivityPreCreated(self, activity, savedInstanceState):
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self._callback('onActivityPreCreated', activity, savedInstanceState)
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@java_method('(Landroid/app/Activity;)V')
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def onActivityPreDestroyed(self, activity):
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self._callback('onActivityPreDestroyed', activity)
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@java_method('(Landroid/app/Activity;)V')
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def onActivityPrePaused(self, activity):
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self._callback('onActivityPrePaused', activity)
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@java_method('(Landroid/app/Activity;)V')
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def onActivityPreResumed(self, activity):
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self._callback('onActivityPreResumed', activity)
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@java_method('(Landroid/app/Activity;Landroid/os/Bundle;)V')
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def onActivityPreSaveInstanceState(self, activity, outState):
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self._callback('onActivityPreSaveInstanceState', activity, outState)
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@java_method('(Landroid/app/Activity;)V')
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def onActivityPreStarted(self, activity):
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self._callback('onActivityPreStarted', activity)
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@java_method('(Landroid/app/Activity;)V')
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def onActivityPreStopped(self, activity):
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self._callback('onActivityPreStopped', activity)
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@java_method('(Landroid/app/Activity;)V')
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def onActivityResumed(self, activity):
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self._callback('onActivityResumed', activity)
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@java_method('(Landroid/app/Activity;Landroid/os/Bundle;)V')
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def onActivitySaveInstanceState(self, activity, outState):
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self._callback('onActivitySaveInstanceState', activity, outState)
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@java_method('(Landroid/app/Activity;)V')
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def onActivityStarted(self, activity):
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self._callback('onActivityStarted', activity)
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@java_method('(Landroid/app/Activity;)V')
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def onActivityStopped(self, activity):
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self._callback('onActivityStopped', activity)
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def register_activity_lifecycle_callbacks(**callbacks):
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"""Register ActivityLifecycleCallbacks instance
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The callbacks are supplied as keyword arguments corresponding to the
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Application.ActivityLifecycleCallbacks methods such as
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onActivityStarted. See the ActivityLifecycleCallbacks documentation
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for the signature of each method.
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The ActivityLifecycleCallbacks instance is returned so it can be
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supplied to unregister_activity_lifecycle_callbacks if needed.
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"""
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instance = ActivityLifecycleCallbacks(callbacks)
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_lifecycle_callbacks.add(instance)
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# Use the registerActivityLifecycleCallbacks method from the
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# Activity class if it's available (API 29) since it guarantees the
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# callbacks will only be run for that activity. Otherwise, fallback
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# to the method on the Application class (API 14). In practice there
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# should be no difference since p4a applications only have a single
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# activity.
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if hasattr(_activity, 'registerActivityLifecycleCallbacks'):
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_activity.registerActivityLifecycleCallbacks(instance)
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else:
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app = _activity.getApplication()
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app.registerActivityLifecycleCallbacks(instance)
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return instance
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def unregister_activity_lifecycle_callbacks(instance):
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"""Unregister ActivityLifecycleCallbacks instance"""
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if hasattr(_activity, 'unregisterActivityLifecycleCallbacks'):
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_activity.unregisterActivityLifecycleCallbacks(instance)
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else:
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app = _activity.getApplication()
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app.unregisterActivityLifecycleCallbacks(instance)
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try:
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_lifecycle_callbacks.remove(instance)
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except KeyError:
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pass

‎testapps/on_device_unit_tests/test_app/app_flask.py

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vibrate_with_pyjnius,
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get_android_python_activity,
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set_device_orientation,
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setup_lifecycle_callbacks,
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)
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app = Flask(__name__)
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setup_lifecycle_callbacks()
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service_running = False
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TESTS_TO_PERFORM = dict()
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NON_ANDROID_DEVICE_MSG = 'Not running from Android device'

‎testapps/on_device_unit_tests/test_app/app_kivy.py

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load_kv_from,
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raise_error,
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run_test_suites_into_buffer,
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setup_lifecycle_callbacks,
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vibrate_with_pyjnius,
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)
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from widgets import TestImage
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self.sm = Builder.load_string(screen_manager_app)
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return self.sm
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def on_start(self):
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setup_lifecycle_callbacks()
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def reset_unittests_results(self, refresh_ui=False):
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for img in get_images_with_extension():
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subprocess.call(["rm", "-r", img])

‎testapps/on_device_unit_tests/test_app/tools.py

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else:
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activity.setRequestedOrientation(
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ActivityInfo.SCREEN_ORIENTATION_PORTRAIT)
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@skip_if_not_running_from_android_device
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def setup_lifecycle_callbacks():
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"""
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Register example ActivityLifecycleCallbacks
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"""
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from android.activity import register_activity_lifecycle_callbacks
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register_activity_lifecycle_callbacks(
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onActivityStarted=lambda activity: print('onActivityStarted'),
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onActivityPaused=lambda activity: print('onActivityPaused'),
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onActivityResumed=lambda activity: print('onActivityResumed'),
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onActivityStopped=lambda activity: print('onActivityStopped'),
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onActivityDestroyed=lambda activity: print('onActivityDestroyed'),
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)

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