PersistentMQTTTest

A sample app demonstrating a quick workaround to using PahoMQTT in Android Oreo+ using foreground notification

Background

• The PahoMQTT Class is controlled by the singleton ConnectionHolder, which manages the mqttCallback.
• Due to a restriction on the background services in Android Oreo onwards, the MQTT service is wrapped in the
  NotificationService which is a foreground service with a persistent notification.
• The notification can be modified, and the sample start button listener can be used to determine how to start the service.