Detect Android Application Resume and Pause state

Issue

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?

Solution

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>

Answered By - Son Truong