How to detect or listen when notifications are received from any app?

I would like to know how it can be detected when a notification is received, I understand that it can be done using AccessibilityService, but I can not get it to work, this is the code that I have in my service:

public class MyAccesibilityService extends AccessibilityService {

 @Override
 public void onAccessibilityEvent(AccessibilityEvent accessibilityEvent) {
    Toast.makeText(this, "Evento de:" + evt.getPackageName(), Toast.LENGTH_SHORT).show();
  }

  @Override
  public void onInterrupt() {

  }
}

I have also declared the service in the manifest file as follows:

<service android:name=".MyAccesibilityService" android:enabled="true">
        <intent-filter>
            <action android:name="android.accessibilityservice.AccessibilityService" />
        </intent-filter>
        <meta-data android:name="android.accessibilityservice"
            android:resource="@xml/accesibility" />
    </service>

And this is the meta-data xml code

<accessibility-service
android:accessibilityEventTypes="typeNotificationStateChanged"
android:notificationTimeout="100"
android:accessibilityFeedbackType="feedbackAllMask"
xmlns:android="http://schemas.android.com/apk/res/android" />

I hope you can help me!