Attach a View as Foreground Service On Oreo

Question

I'm trying to update a foreground service where a layout appear in front of other apps like Facebook Messenger's talking head. It has no background service. The foreground service operates successfully without the setView(). When I set the view to the window manager I get

android.view.WindowManager$BadTokenException: Unable to add window -- token null is not valid; is your activity running?

I cannot figure out how to set the token to not be null. Any insight would be helpful.

Activity

 public class MainActivity extends AppCompatActivity {
    Button btnStartService, btnStopService;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btnStartService = findViewById(R.id.buttonStartService);
        btnStopService = findViewById(R.id.buttonStopService);
        btnStartService.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startService();
            }
        });
        btnStopService.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                stopService();
            }
        });
    }
    public void startService() {
        Intent serviceIntent = new Intent(this, ForegroundService.class);
        serviceIntent.putExtra("inputExtra", "Foreground Service Example in Android");
        ContextCompat.startForegroundService(this, serviceIntent);
    }
    public void stopService() {
        Intent serviceIntent = new Intent(this, ForegroundService.class);
        stopService(serviceIntent);
    }
}

Service

public class ForegroundService extends Service {

int LAYOUT_FLAG;
WindowManager windowManager;
View mFloatingView;

public static final String CHANNEL_ID = "ForegroundServiceChannel";

@Override
public void onCreate() {
    super.onCreate();
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    String input = intent.getStringExtra("inputExtra");
    createNotificationChannel();
    Intent notificationIntent = new Intent(this, MainActivity.class);
    PendingIntent pendingIntent = PendingIntent.getActivity(this,
            0, notificationIntent, PendingIntent.FLAG_IMMUTABLE);
    Notification notification = new NotificationCompat.Builder(this, CHANNEL_ID)
            .setContentTitle("Foreground Service")
            .setContentText(input)
            .setSmallIcon(R.drawable.ic_launcher_foreground)
            .setContentIntent(pendingIntent)
            .build();
    Toast.makeText(getApplicationContext(),"onStartCommand",Toast.LENGTH_SHORT).show();

    **makeWindow();**

    startForeground(1, notification);
    //do heavy work on a background thread
    //stopSelf();
    return START_NOT_STICKY;
}
**public void makeWindow(){**
    if(Build.VERSION.SDK_INT>= Build.VERSION_CODES.O){
        LAYOUT_FLAG = WindowManager.LayoutParams.TYPE_ACCESSIBILITY_OVERLAY;
    }else{
        LAYOUT_FLAG = WindowManager.LayoutParams.TYPE_PHONE;
    }
    windowManager = (WindowManager)this.getSystemService(WINDOW_SERVICE);

    mFloatingView = LayoutInflater.from(this).inflate(R.layout.layout_widget,null);


    WindowManager.LayoutParams layoutParams = new WindowManager
            .LayoutParams(WindowManager.LayoutParams.WRAP_CONTENT,
            WindowManager.LayoutParams.WRAP_CONTENT, LAYOUT_FLAG,
            WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE, PixelFormat.TRANSLUCENT);
    //initial position
    layoutParams.gravity = Gravity.TOP | Gravity.END;
    layoutParams.x = 0;
    layoutParams.y = 100;
    mFloatingView.setLayoutParams(layoutParams);
    mFloatingView.setVisibility(View.VISIBLE);
    **windowManager.addView(mFloatingView,layoutParams);**

}

@Override
public void onDestroy() {
    super.onDestroy();
}
@Nullable
@Override
public IBinder onBind(Intent intent) {
    return null;
}
private void createNotificationChannel() {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        NotificationChannel serviceChannel = new NotificationChannel(
                CHANNEL_ID,
                "Foreground Service Channel",
                NotificationManager.IMPORTANCE_DEFAULT
        );
        NotificationManager manager = getSystemService(NotificationManager.class);
        manager.createNotificationChannel(serviceChannel);
    }
}
}
}

Layout

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/container">

    <RelativeLayout
        android:id="@+id/layout_widget"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_margin="30dp">
        <TextView
            android:id="@+id/text_widget"
            android:layout_width="120dp"
            android:layout_height="120dp"
            android:textSize="22sp"
            android:text="10"
            android:textStyle="bold"
            android:gravity="center"
            android:textColor="@color/white"
            android:background="@drawable/back_circle"/>
    </RelativeLayout>
</RelativeLayout>

Manifest

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.foregroundservicetester">
    <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
    <uses-permission android:name="android.permission.FOREGROUND_SERVICE"/>

    <application
        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/Theme.ForegroundServiceTester">
        <activity
            android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <service
            android:name=".ForegroundService" android:enabled="true" android:exported="false" />
    </application>

</manifest>