A tiny wrapper around Eclipse Paho MQTT Java library, to have a lightweight background Android service, which handles all the following operations in a background thread:
implementation 'net.igenius:mqttservice:1.6.4'Before using the library, you have to initialize it. The ideal place to do that is in your Application subclass:
public class Initializer extends Application {
@Override
public void onCreate() {
super.onCreate();
MQTTService.NAMESPACE = "com.yourcompany.yourapp"; //or BuildConfig.APPLICATION_ID;
MQTTService.KEEP_ALIVE_INTERVAL = 60; //in seconds
MQTTService.CONNECT_TIMEOUT = 30; //in seconds
}
}All the commands supported by the service are implemented in the MQTTServiceCommand class. Some of them are:
// connect to the broker
MQTTServiceCommand.connect(final Context context, final String brokerUrl,
final String clientId, final String username,
final String password)
// disconnect from the broker
MQTTServiceCommand.disconnect(final Context context)
// subscribe to one or more topics
MQTTServiceCommand.subscribe(final Context context, final int qos,
final boolean autoResubscribeOnReconnect,
final String... topics)
// connect to a broker and subscribe to one or more topics with a QoS
MQTTServiceCommand.connectAndSubscribe(final Context context,
final String brokerUrl,
final String clientId,
final String username,
final String password,
final int qos,
final boolean autoResubscribeOnReconnect,
final String... topics)
// publish a payload to a topic, with a specific QoS
MQTTServiceCommand.publish(final Context context, final String topic,
final byte[] payload, final int qos)
// publish a payload to a topic, with QoS 0
MQTTServiceCommand.publish(final Context context, final String topic,
final byte[] payload)Explore the class for complete JavaDocs and all the available options.
To receive events globally in the app, even if it's in background, create a new class in your project:
import android.content.Context;
import net.igenius.mqttservice.MQTTServiceReceiver;
public class MQTTReceiver extends MQTTServiceReceiver {
@Override
public void onPublishSuccessful(Context context, String requestId,
String topic) {
// called when a message has been successfully published
}
@Override
public void onSubscriptionSuccessful(Context context, String requestId,
String topic) {
// called when a subscription is successful
}
@Override
public void onSubscriptionError(Context context, String requestId,
String topic, Exception exception) {
// called when a subscription is not successful.
// This usually happens when the broker does not give permissions
// for the requested topic
}
@Override
public void onMessageArrived(Context context, String topic,
byte[] payload) {
// called when a new message arrives on any topic
}
@Override
public void onConnectionSuccessful(Context context, String requestId) {
// called when the connection is successful
}
@Override
public void onException(Context context, String requestId,
Exception exception) {
// called when an error happens
}
@Override
public void onConnectionStatus(Context context, boolean connected) {
// called when connection status is requested or changes
}
}and then register it into the manifest (before </application> tag):
<receiver
android:name=".MQTTReceiver"
android:enabled="true"
android:exported="false">
<intent-filter>
<action android:name="com.yourcompany.yourapp.mqtt.broadcast" />
</intent-filter>
</receiver>Bear in mind that com.yourcompany.yourapp MUST be the same you defined in MQTTService.NAMESPACE setting.
public class YourActivity extends AppCompatActivity {
private MQTTServiceReceiver receiver = new MQTTServiceReceiver() {
@Override
public void onSubscriptionSuccessful(Context context,
String requestId, String topic) {
// called when a message has been successfully published
}
@Override
public void onSubscriptionError(Context context, String requestId,
String topic, Exception exception) {
// called when a subscription is not successful.
// This usually happens when the broker does not give permissions
// for the requested topic
}
@Override
public void onPublishSuccessful(Context context, String requestId, String topic) {
// called when a subscription is successful
}
@Override
public void onMessageArrived(Context context, String topic,
byte[] payload) {
// called when a new message arrives on any topic
}
@Override
public void onConnectionSuccessful(Context context, String requestId) {
// called when the connection is successful
}
@Override
public void onException(Context context, String requestId,
Exception exception) {
// called when an error happens
}
@Override
public void onConnectionStatus(Context context, boolean connected) {
// called when connection status is requested or changes
}
};
@Override
protected void onResume() {
super.onResume();
receiver.register(this);
}
@Override
protected void onPause() {
super.onPause();
receiver.unregister(this);
}
}By default the library logging is disabled. You can enable debug log by invoking:
MQTTServiceLogger.setLogLevel(LogLevel.DEBUG);wherever you want in your code. You can adjust the level of detail from DEBUG to OFF.
The library logger uses android.util.Log by default, so you will get the output in LogCat. If you want to redirect logs to different output or use a different logger, you can provide your own delegate implementation like this:
MQTTServiceLogger.setLoggerDelegate(new MQTTServiceLogger.LoggerDelegate() {
@Override
public void error(String tag, String message) {
//your own implementation here
}
@Override
public void error(String tag, String message, Throwable exception) {
//your own implementation here
}
@Override
public void debug(String tag, String message) {
//your own implementation here
}
@Override
public void info(String tag, String message) {
//your own implementation here
}
});You can find a fully working demo app which uses this library in the example-app directory. Just checkout the project and give it a try.