getActiveNotifications() using NotificationListenerService

AndroidManifest.xml

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

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

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

        <service
            android:name=".MyNotificationService"
            android:permission="android.permission.BIND_NOTIFICATION_LISTENER_SERVICE"
            android:enabled="true"
            android:exported="true">

            <intent-filter>
                <action android:name="android.service.notification.NotificationListenerService" />
            </intent-filter>
        </service>
    </application>

</manifest>

MainActivity.java

package testapp.android.gradle.inutilfutil.com.myapplication;

import android.app.NotificationManager;
import android.content.ComponentName;
import android.content.Intent;
import android.provider.Settings;
import android.service.notification.NotificationListenerService;
import android.service.notification.StatusBarNotification;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

public class MainActivity extends AppCompatActivity {
    public static final String TAG = "MainActivity";
    private static final String ACTION_NOTIFICATION_LISTENER_SETTINGS = "android.settings.ACTION_NOTIFICATION_LISTENER_SETTINGS";


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    @Override
    public void onStart() {
        showNotifications();
        super.onStart();
    }

    @Override
    public void onResume() {
        showNotifications();
        super.onResume();
    }

    public void showNotifications() {
        if (isNotificationServiceEnabled()) {
            Log.i(TAG, "Notification enabled -- trying to fetch it");
            getNotifications();
        } else {
            Log.i(TAG, "Notification disabled -- Opening settings");
            startActivity(new Intent(ACTION_NOTIFICATION_LISTENER_SETTINGS));
        }
    }

    public void getNotifications() {
        Log.i(TAG, "Waiting for MyNotificationService");
        MyNotificationService myNotificationService = MyNotificationService.get();
        Log.i(TAG, "Active Notifications: [");
        for (StatusBarNotification notification : myNotificationService.getActiveNotifications()) {
            Log.i(TAG, "    " + notification.getPackageName() + " / " + notification.getTag());
        }
        Log.i(TAG, "]");
    }

    private boolean isNotificationServiceEnabled(){
        String pkgName = getPackageName();
        final String allNames = Settings.Secure.getString(getContentResolver(), "enabled_notification_listeners");
        if (allNames != null && !allNames.isEmpty()) {
            for (String name : allNames.split(":")) {
                if (getPackageName().equals(ComponentName.unflattenFromString(name).getPackageName())) {
                    return true;
                }
            }
        }
        return false;
    }
}

MyNotificationService.java

package testapp.android.gradle.inutilfutil.com.myapplication;

import android.service.notification.NotificationListenerService;
import android.service.notification.StatusBarNotification;
import android.util.Log;

import java.util.concurrent.Semaphore;

public class MyNotificationService extends NotificationListenerService {
    private static final String TAG = "MyNotificationService";
    static MyNotificationService _this;
    static Semaphore sem = new Semaphore(0);

    public static MyNotificationService get() {
        sem.acquireUninterruptibly();
        MyNotificationService ret = _this;
        sem.release();
        return ret;
    }

    @Override
    public void onListenerConnected() {
        Log.i(TAG, "Connected");
        _this = this;
        sem.release();
    }

    @Override
    public void onListenerDisconnected() {
        Log.i(TAG, "Disconnected");
        sem.acquireUninterruptibly();
        _this = null;
    }

    @Override
    public void onNotificationPosted(StatusBarNotification sbn) {

    }

    @Override
    public void onNotificationRemoved(StatusBarNotification sbn) {
        super.onNotificationRemoved(sbn);
    }
}

It only works the first time we start the app and give the notification permission. But the second time, with permission already enabled, it simply dont connect to the service. How to fix this pleaseee?

Hi bro, could you find an answer for this?

I have absolutely no memory of writing this, or why 🤣

I took a look at it briefly -- Have you tried requestRebind()? -- https://developer.android.com/reference/android/service/notification/NotificationListenerService.html#requestRebind(android.content.ComponentName)

Alternatively, the implementation seems to be exactly the same as calling NotificationManager.getActiveNotifications() -- I imagine that enabling the NotificationService adds the missing permissions to the package.