安卓開發之mqtt協議

首先物聯網協議mqtt協議是基於tcp/ip協議的，使用了官方的mqttclient框架

/*
*初始化mqttclient
*/
private void init() {
        try {
            //MQTT的鏈接設置
            options = new MqttConnectOptions();
            //host爲主機名，test爲clientid即鏈接MQTT的客戶端ID，通常以客戶端惟一標識符表示，MemoryPersistence設置clientid的保存形式，默認爲之內存保存
            client = new MqttClient(new Ip().host, username,
                    new MemoryPersistence());
            //設置是否清空session,這裏若是設置爲false表示服務器會保留客戶端的鏈接記錄，這裏設置爲true表示每次鏈接到服務器都以新的身份鏈接
            options.setCleanSession(false);
//options.setWill(myTopic,null,2,false);

            //設置鏈接的用戶名
            options.setUserName(login_token);
            //設置鏈接的密碼
            options.setPassword(passWord.toCharArray());
            // 設置超時時間 單位爲秒
            options.setConnectionTimeout(10);
            // 設置會話心跳時間 單位爲秒 服務器會每隔1.5*20秒的時間向客戶端發送個消息判斷客戶端是否在線，但這個方法並無重連的機制
            options.setKeepAliveInterval(60);
            //設置回調
            client.setCallback(new MqttCallback() {
                @Override
                public void connectionLost(Throwable cause) {
                    //鏈接丟失後，通常在這裏面進行重連
                    System.out.println("connectionLost----------");

                }

                @Override
                public void deliveryComplete(IMqttDeliveryToken token) {
                    //publish後會執行到這裏
                    System.out.println("deliveryComplete---------"
                            + token.isComplete());
                }
                @Override
                public void messageArrived(String topicName, MqttMessage message)
                        throws Exception {
                    byte[] message1 = message.getPayload();
                    //  subscribe後獲得的消息會執行到這裏面
                    System.out.println("messageArrived----------" + message1[0] + Arrays.toString(message1));
                    System.out.println(message1[0] == 5);
                    String id = new String(subBytes(message1, 1, 16), "UTF-8");

                    System.out.print("mqtt收到的id" + id);
                    DeviceList device = getBookById(id);
                    System.out.print("device" + device.getName());
                    String name = device.getName();
                    String gName = device.getgName();
                    String type = device.getType();
                    System.out.print("名字爲" + name + gName);
                    /**
                    * 使用handler發送matt接收的消息，格式爲二進制數據
                    * */

                    Message msg = new Message();
                    msg.what = 1;
                    if (message1[0] == 1) {
//                        msg.obj = name + "設備心跳";
//                        handler.sendMessage(msg);
                        return;
                    }
                    if (message1[0] == 2) {
                        msg.obj = gName + "" + name + "報警";
                        msg.arg1 = Integer.parseInt(type);
                        handler.sendMessage(msg);
                        return;
                    }
                    if (message1[0] == 3) {
                        msg.obj = gName + "" + name + "上線";
                        handler.sendMessage(msg);
                        return;
                    }
                    if (message1[0] == 4) {
                        msg.obj = gName + "" + name + "離線";
                        handler.sendMessage(msg);
                        return;
                    }
                    if (message1[0] == 5) {
                        if (message1[17] == 0) {
                            msg.obj = gName + "" + name + "關門";
                        } else {
                            msg.obj = gName + "" + name + "開門";
                        }


                        handler.sendMessage(msg);
                        return;
                    }
                    if (message1[0] == 20 && message1[17] > 0 && message1[17] < 20) {

                        msg.obj = name + "電池電量:  " + message1[17] + "%";
                        handler.sendMessage(msg);
                        System.out.println("電池:" + name + "電池電量:  " + message1[17] + "%");
                        return;
                    }
                    if (message1[17] > 0) {
                        SharedPreferences sp = getActivity().getSharedPreferences(id, getActivity().MODE_PRIVATE);
                        // 得到sp的編輯器
                        SharedPreferences.Editor ed = sp.edit();
                        // 以鍵值對的顯示將用戶名和密碼保存到sp中
                        ed.putString("battery", String.valueOf(message1[17]));
                        // 提交用戶名和密碼
                        ed.commit();
                    }
                }
            });
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public byte[] subBytes(byte[] src, int begin, int count) {
        byte[] bs = new byte[count];
        System.arraycopy(src, begin, bs, 0, count);
        return bs;
    }

    //根據id拿到屬性爲id的Book對象。
    public static DeviceList getBookById(String id) {
        DeviceList book = new DeviceList();
        book.setId(id);//設置傳入的id值
        //books.indexOf()根據id比較對象是否相等
        return deviceList1.get(deviceList1.indexOf(book));
        //返回關聯id的Book對象。
    }
    
    private void connect() {
        new Thread(new Runnable() {

            @Override
            public void run() {
                try {
                    client.connect(options);
                    Message msg = new Message();
                    msg.what = 2;
                    handler.sendMessage(msg);
                } catch (Exception e) {
                    e.printStackTrace();
                    Message msg = new Message();
                    msg.what = 3;
                    handler.sendMessage(msg);
                }
            }
        }).start();
    }

    protected boolean onKeyDown(int keyCode, KeyEvent event) {
        if (client != null && keyCode == KeyEvent.KEYCODE_BACK) {
            try {
                client.disconnect();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return super.getActivity().onKeyDown(keyCode, event);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        try {
            scheduler.shutdown();
            client.disconnect();
        } catch (MqttException e) {
            e.printStackTrace();
        }
    }

    private void startReconnect() {
        scheduler = Executors.newSingleThreadScheduledExecutor();
        scheduler.scheduleAtFixedRate(new Runnable() {

            @Override
            public void run() {
                if (!client.isConnected()) {
                    connect();
                }
            }
        }, 0 * 1000, 10 * 1000, TimeUnit.MILLISECONDS);
    }
其次使用handlermessage接收消息，並已notifacation的形式展現在通知欄頁面

 handler = new Handler() {            @Override            public void handleMessage(Message msg) {                super.handleMessage(msg);                if (msg.what == 1) {                    NotificationManager manager = (NotificationManager) getActivity().getSystemService(Context.NOTIFICATION_SERVICE);                    Notification myNotify = new Notification();                    myNotify.icon = R.drawable.logo;                    myNotify.tickerText = "新消息";                    myNotify.when = System.currentTimeMillis();                    //使用默認的聲音                    myNotify.defaults |= Notification.DEFAULT_SOUND;//使用默認的震動                    myNotify.defaults |= Notification.DEFAULT_VIBRATE;//使用默認的聲音、振動、閃光                    myNotify.defaults = Notification.DEFAULT_ALL;                    //  myNotify.flags=Notification.FLAG_AUTO_CANCEL;                    //  myNotify.flags = Notification.FLAG_NO_CLEAR;// 不可以自動清除                    RemoteViews rv = new RemoteViews(getActivity().getPackageName(),                            R.layout.activity_notification1);                    rv.setTextViewText(R.id.tv_desc, (String) msg.obj);                    myNotify.contentView = rv;                    Intent intent = new Intent(getActivity(), MainActivity.class);                    //    intent.addCategory(Intent.CATEGORY_LAUNCHER);                    //    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS);                    android.app.PendingIntent contentIntent = android.app.PendingIntent.getActivity(getActivity(), 0,                            intent, 0);                    myNotify.contentIntent = contentIntent;                    manager.notify(i1++, myNotify);                    PowerManager pm = (PowerManager) getActivity().getSystemService(Context.POWER_SERVICE);                    PowerManager.WakeLock wakeLock = pm.newWakeLock(PowerManager.ACQUIRE_CAUSES_WAKEUP |                            PowerManager.SCREEN_DIM_WAKE_LOCK, "target");                    boolean screen = pm.isScreenOn();                    if (!screen) {//若是滅屏                        wakeLock.acquire();                        wakeLock.release();                    }                    refresh();                } else if (msg.what == 2) {                    System.out.println("鏈接成功");                    System.out.print("鏈接成功大小" + listDatas2.size());                    try {                        client.subscribe(myTopic, 1);                        client.subscribe(myTopic1, 1);                    } catch (MqttException e) {                        e.printStackTrace();                    }                } else if (msg.what == 3) {                    //Toast.makeText(MainActivity.this, "鏈接失敗，系統正在重連", Toast.LENGTH_SHORT).show();                    System.out.println("鏈接失敗，系統正在重連");                }            }        };