Check when app is in forground/background (api 14+)

AppBackgroundChecker.java

public class AppBackgroundChecker implements Application.ActivityLifecycleCallbacks, ComponentCallbacks2 {

    private boolean isBackground;

    public void register(Application application) {
        application.registerActivityLifecycleCallbacks(this);
        application.registerComponentCallbacks(this);
    }

    @Override
    public void onTrimMemory(int level) {
        if (level == TRIM_MEMORY_UI_HIDDEN) {
            isBackground = true;
            // Do anything for background
        }
    }

    @Override
    public void onConfigurationChanged(Configuration configuration) {

    }

    @Override
    public void onLowMemory() {

    }

    @Override
    public void onActivityCreated(Activity activity, Bundle bundle) {

    }

    @Override
    public void onActivityStarted(Activity activity) {

    }

    @Override
    public void onActivityResumed(Activity activity) {
        if (isBackground) {
            isBackground = false;
            // Do what you need for foreground
        }
    }

    @Override
    public void onActivityPaused(Activity activity) {

    }

    @Override
    public void onActivityStopped(Activity activity) {

    }

    @Override
    public void onActivitySaveInstanceState(Activity activity, Bundle bundle) {

    }

    @Override
    public void onActivityDestroyed(Activity activity) {

    }
}

MainApp.java

public class MainApp extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
        new AppBackgroundChecker().register(this);
    }
}