/paho.mqtt.android.example/src/main/java/paho/mqtt/java/example/PahoExampleActivity.java

/*******************************************************************************
 * Copyright (c) 1999, 2016 IBM Corp.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * and Eclipse Distribution License v1.0 which accompany this distribution.
 *
 * The Eclipse Public License is available at
 *    http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 *   http://www.eclipse.org/org/documents/edl-v10.php.
 *
 */
package paho.mqtt.java.example;

import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import org.eclipse.paho.android.service.MqttAndroidClient;
import org.eclipse.paho.client.mqttv3.DisconnectedBufferOptions;
import org.eclipse.paho.client.mqttv3.IMqttActionListener;
import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
import org.eclipse.paho.client.mqttv3.IMqttMessageListener;
import org.eclipse.paho.client.mqttv3.IMqttToken;
import org.eclipse.paho.client.mqttv3.MqttCallbackExtended;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.eclipse.paho.client.mqttv3.MqttException;
import org.eclipse.paho.client.mqttv3.MqttMessage;

import java.util.ArrayList;

public class PahoExampleActivity extends AppCompatActivity{
    private RecyclerView mRecyclerView;
    private HistoryAdapter mAdapter;
    private RecyclerView.LayoutManager mLayoutManager;

    MqttAndroidClient mqttAndroidClient;

    final String serverUri = "tcp://iot.eclipse.org:1883";

    final String clientId = "ExampleAndroidClient";
    final String subscriptionTopic = "exampleAndroidTopic";
    final String publishTopic = "exampleAndroidPublishTopic";
    final String publishMessage = "Hello World!";


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_scrolling);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                publishMessage();
            }
        });




        mRecyclerView = (RecyclerView) findViewById(R.id.history_recycler_view);
        mLayoutManager = new LinearLayoutManager(this);
        mRecyclerView.setLayoutManager(mLayoutManager);

        mAdapter = new HistoryAdapter(new ArrayList<String>());
        mRecyclerView.setAdapter(mAdapter);


        mqttAndroidClient = new MqttAndroidClient(getApplicationContext(), serverUri, clientId);
        mqttAndroidClient.setCallback(new MqttCallbackExtended() {
            @Override
            public void connectComplete(boolean reconnect, String serverURI) {

                if (reconnect) {
                    addToHistory("Reconnected to : " + serverURI);
                    // Because Clean Session is true, we need to re-subscribe
                    subscribeToTopic();
                } else {
                    addToHistory("Connected to: " + serverURI);
                }
            }

            @Override
            public void connectionLost(Throwable cause) {
                addToHistory("The Connection was lost.");
            }

            @Override
            public void messageArrived(String topic, MqttMessage message) throws Exception {
                addToHistory("Incoming message: " + new String(message.getPayload()));
            }

            @Override
            public void deliveryComplete(IMqttDeliveryToken token) {

            }
        });

        MqttConnectOptions mqttConnectOptions = new MqttConnectOptions();
        mqttConnectOptions.setAutomaticReconnect(true);
        mqttConnectOptions.setCleanSession(false);







        try {
            //addToHistory("Connecting to " + serverUri);
            mqttAndroidClient.connect(mqttConnectOptions, null, new IMqttActionListener() {
                @Override
                public void onSuccess(IMqttToken asyncActionToken) {
                    DisconnectedBufferOptions disconnectedBufferOptions = new DisconnectedBufferOptions();
                    disconnectedBufferOptions.setBufferEnabled(true);
                    disconnectedBufferOptions.setBufferSize(100);
                    disconnectedBufferOptions.setPersistBuffer(false);
                    disconnectedBufferOptions.setDeleteOldestMessages(false);
                    mqttAndroidClient.setBufferOpts(disconnectedBufferOptions);
                    subscribeToTopic();
                }

                @Override
                public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
                    addToHistory("Failed to connect to: " + serverUri);
                }
            });


        } catch (MqttException ex){
            ex.printStackTrace();
        }

    }

    private void addToHistory(String mainText){
        System.out.println("LOG: " + mainText);
        mAdapter.add(mainText);
        Snackbar.make(findViewById(android.R.id.content), mainText, Snackbar.LENGTH_LONG)
                .setAction("Action", null).show();

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.

        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement

        return super.onOptionsItemSelected(item);
    }

    public void subscribeToTopic(){
        try {
            mqttAndroidClient.subscribe(subscriptionTopic, 0, null, new IMqttActionListener() {
                @Override
                public void onSuccess(IMqttToken asyncActionToken) {
                    addToHistory("Subscribed!");
                }

                @Override
                public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
                    addToHistory("Failed to subscribe");
                }
            });

            // THIS DOES NOT WORK!
            mqttAndroidClient.subscribe(subscriptionTopic, 0, new IMqttMessageListener() {
                @Override
                public void messageArrived(String topic, MqttMessage message) throws Exception {
                    // message Arrived!
                    System.out.println("Message: " + topic + " : " + new String(message.getPayload()));
                }
            });

        } catch (MqttException ex){
            System.err.println("Exception whilst subscribing");
            ex.printStackTrace();
        }
    }

    public void publishMessage(){

        try {
            MqttMessage message = new MqttMessage();
            message.setPayload(publishMessage.getBytes());
            mqttAndroidClient.publish(publishTopic, message);
            addToHistory("Message Published");
            if(!mqttAndroidClient.isConnected()){
                addToHistory(mqttAndroidClient.getBufferedMessageCount() + " messages in buffer.");
            }
        } catch (MqttException e) {
            System.err.println("Error Publishing: " + e.getMessage());
            e.printStackTrace();
        }
    }

}