Detect Android Application Resume and Pause state

Question

I want to start ScheduledExecutorService on resume of application and want to stop on pause of application.

I only found solution by detecting acivities running status by maintaining count. Like in lib https://github.com/curioustechizen/android-app-pause/tree/master/android-app-pause .

Is there is any other solution to detect application pause and resume state?

Answer 1

You should use ProcessLifecycleOwner.

Class that provides lifecycle for the whole application process.

You can consider this LifecycleOwner as the composite of all of your Activities, except that ON_CREATE will be dispatched once and ON_DESTROY will never be dispatched. Other lifecycle events will be dispatched with following rules: ProcessLifecycleOwner will dispatch ON_START, ON_RESUME events, as a first activity moves through these events. ON_PAUSE, ON_STOP, events will be dispatched with a delay after a last activity passed through them. This delay is long enough to guarantee that ProcessLifecycleOwner won't send any events if activities are destroyed and recreated due to a configuration change.

It is useful for use cases where you would like to react on your app coming to the foreground or going to the background and you don't need a milliseconds accuracy in receiving lifecycle events.

Implementation

Step 1. Create a class named MyApp that extends from the Application class.

public class MyApp extends Application {

    @Override
    public void onCreate() {
        super.onCreate();
        ProcessLifecycleOwner.get()
                .getLifecycle()
                .addObserver(new ProcessLifecycleObserver());
    }

    private static final class ProcessLifecycleObserver implements LifecycleObserver {

        @OnLifecycleEvent(Lifecycle.Event.ON_RESUME)
        public void onApplicationResumed() {
            // Start ScheduledExecutorService here
        }

        @OnLifecycleEvent(Lifecycle.Event.ON_PAUSE)
        public void onApplicationPaused() {
            // Stop ScheduledExecutorService here
        }
    }
}

Step 2. Add the class into the AndroidManifest.xml file

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.kotlinapp">

    <application
        android:name=".MyApp"
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">

        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>