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使用Android应用程序的基于本地代理(MQTT)的发布/订阅

本文介绍了使用Android应用程序的基于本地代理(MQTT)的发布/订阅的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

在我当前的项目中，我正在使用基于MQTT本地代理的实现和设置，并使用此链接.基于本地代理的MQTT实施效果很好.

In my current project, I am using MQTT local broker based implementation and setup using this link. The local broker based MQTT implementation is working perfectly.

最初，我是通过此本地代理使用Node.js发布者和订阅者来启用消息交换，并且它也可以在没有Internet连接的情况下工作(由于这些设备连接到同一网络，因此mqtt API用于基于本地代理的实现就像http://192.168.0.105).

At initially, I am using Node.js publisher and subscriber with this local broker to enable the exchange of messages and it works without internet connection also (as these devices are connected to the same network, mqtt API for local broker based implementation is like http://192.168.0.105).

现在，我想用Android应用程序替换Node.js订户.我的Android应用程序使用mqtt paho库进行通信并使用mqtt API mqtt://test.mosquitto.org:1883.如果我使用的是mqtt开放代理，即mosquitto，则Node.js发布者和Android应用程序订阅者都可以正常工作(这种情况是在谈论使用API​​ mqtt://test.mosquitto.org:1883的基于mosquitto的mqtt实现).

Now, I would like to replace Node.js subscriber with Android application. My android application using mqtt paho library for communication and using mqtt APImqtt://test.mosquitto.org:1883. If I am using mqtt open broker i.e. mosquitto than Node.js publisher and Android application subscriber both are working properly (this case is talking about mosquitto based mqtt implementation using the API mqtt://test.mosquitto.org:1883).

现在，我想在Android应用程序中使用基于本地代理的实现.因此，我必须使用http://192.168.0.105替换mqtt://test.mosquitto.org:1883 API，因为我想使用基于本地代理的mqtt实现.当我在Android代码中使用http://192.168.0.105 API并将其部署到移动设备时，它显示错误，不幸的是，Android应用程序已在Andoid应用程序中停止.

Now, I want to use local broker based implementation in Android application. So I have to replace mqtt://test.mosquitto.org:1883 API with http://192.168.0.105 as I want to use local broker based mqtt implementation. When I use http://192.168.0.105 API in the android code and deploy to mobile device, it displays error that Unfortunately, Android Application has stopped in andoid application.

如何在android应用程序中使用基于本地代理的实现?

另外共享Node.js发布者和订阅者的代码.Node.js发布者(基于本地代理的实现)

Additionally sharing the code of Node.js publisher and subscriber.Node.js publisher (local broker based implementation)

var mqtt = require('mqtt');
var client = mqtt.connect('http://192.168.0.105');
setInterval(function() {
var data = {
     "tempValue" : Math.random(),
     "unitOfMeasurement" : 'C'
     };
client.publish('tempMeasurement', JSON.stringify(data));
}, 5000);

Node.js订户(基于本地代理的实现)

Node.js subscriber (local broker based implementation)

var mqtt = require('mqtt');
var client = mqtt.connect('http://192.168.0.105');
client.subscribe('tempMeasurement'); 
client.on('message', function(topic, payload) {
       if (topic.toString() == "tempMeasurement") {  
       console.log("Mesage Received "+ payload.toString());
   }       
 });

MQTT订阅服务器的共享代码以提高清晰度:

Sharing code of MQTT Subscriber for better clarity:

package iotsuite.pubsubmiddleware;

import org.eclipse.paho.client.mqttv3.MqttClient;
import org.eclipse.paho.client.mqttv3.MqttException;
import org.eclipse.paho.client.mqttv3.internal.MemoryPersistence;

public class MQTTSubscriber {

// URI for open MQTT broker
// public static final String BROKER_URL = "tcp://test.mosquitto.org:1883";
public static final String BROKER_URL = "mqtt://192.168.0.105";

private MqttClient client;

public MQTTSubscriber(PubSubMiddleware pubsub) {
    try {
        client = new MqttClient(BROKER_URL, MqttClient.generateClientId(),
                new MemoryPersistence());

        client.setCallback(new PushCallback(pubsub));
        client.connect();

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

public void subscribe(String topicName) throws MqttException {

    client.subscribe(topicName);

    System.out.println("Subscribed. Topic: " + topicName);
}

}

并使用以下代码订阅tempMeasurement:

package framework;

 import iotsuite.common.Logger;
 import iotsuite.pubsubmiddleware.PubSubMiddleware;
 import iotsuite.pubsubmiddleware.Subscriber;
 import iotsuite.semanticmodel.Device;
 import android.util.Log;
 import com.google.gson.Gson;
 import com.google.gson.JsonObject;
 import com.google.gson.JsonParser;

 public abstract class SmartHomeApp implements Runnable, Subscriber {

protected final PubSubMiddleware myPubSubMiddleware;
protected final Device myDeviceInfo;
Gson gson = new Gson();

public SmartHomeApp(PubSubMiddleware pubSubM, Device deviceInfo) {

    this.myPubSubMiddleware = pubSubM;
    this.myDeviceInfo = deviceInfo;
    postInitialize();

}

protected void postInitialize() {
    subscribeDisplayTemp();

}

@Override
public void notifyReceived(String eventName, Object arg) {
    try {

        if (eventName.equals("tempMeasurement")) {
            Logger.log(myDeviceInfo.getName(), "TempMonitoringApp",
                    "Notification Received tempMeasurement ");
            JsonObject jsonObject = new JsonParser().parse(arg.toString())
                    .getAsJsonObject();
            double tempValue = jsonObject.get("tempValue").getAsDouble();
            // double yahootempValue =
            // jsonObject.get("yahootempValue").getAsDouble();
            TempStruct tempStruct = new TempStruct(tempValue, "C");
            System.out.println("tempValue is " + tempValue
                    + " in framework");
            Log.i("tempValue", "tempValue is received in framework");
            onNewDisplayTempNotify(tempStruct);
        }

    } catch (Exception e) {
        e.printStackTrace();
    }
}

@Override
public void run() {
}

public abstract void onNewDisplayTempNotify(TempStruct arg);

public void subscribeDisplayTemp() {

    this.myPubSubMiddleware.subscribe(this, "tempMeasurement");
}

}

使用上面的代码，我想将从Node.js代码收到的tempValue显示给Android应用程序.来自Android的错误如下:

Using the above code, I would like to display the tempValue received from Node.js code to Android application. Error from Android is as follow:

01-04 23:03:26.786: E/AndroidRuntime(21793): FATAL EXCEPTION: main
01-04 23:03:26.786: E/AndroidRuntime(21793): Process: com.example.android,      PID: 21793
01-04 23:03:26.786: E/AndroidRuntime(21793): java.lang.RuntimeException:    Unable to start activity         ComponentInfo{com.example.android/com.example.android.MainActivity}:       java.lang.IllegalArgumentException
01-04 23:03:26.786: E/AndroidRuntime(21793):    at    android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2426)
01-04 23:03:26.786: E/AndroidRuntime(21793):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2490)
01-04 23:03:26.786: E/AndroidRuntime(21793):    at android.app.ActivityThread.-wrap11(ActivityThread.java)
01-04 23:03:26.786: E/AndroidRuntime(21793):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1354)
01-04 23:03:26.786: E/AndroidRuntime(21793):    at android.os.Handler.dispatchMessage(Handler.java:102)
01-04 23:03:26.786: E/AndroidRuntime(21793):    at android.os.Looper.loop(Looper.java:148)
01-04 23:03:26.786: E/AndroidRuntime(21793):    at android.app.ActivityThread.main(ActivityThread.java:5443)
01-04 23:03:26.786: E/AndroidRuntime(21793):    at java.lang.reflect.Method.invoke(Native Method)
01-04 23:03:26.786: E/AndroidRuntime(21793):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:728)
01-04 23:03:26.786: E/AndroidRuntime(21793):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
01-04 23:03:26.786: E/AndroidRuntime(21793): Caused by: java.lang.IllegalArgumentException
01-04 23:03:26.786: E/AndroidRuntime(21793):    at  org.eclipse.paho.client.mqttv3.MqttClient.validateURI(MqttClient.java:204)
01-04 23:03:26.786: E/AndroidRuntime(21793):    at org.eclipse.paho.client.mqttv3.MqttClient.<init>(MqttClient.java:175)
01-04 23:03:26.786: E/AndroidRuntime(21793):    at iotsuite.pubsubmiddleware.MQTTPublisher.<init>(MQTTPublisher.java:21)
01-04 23:03:26.786: E/AndroidRuntime(21793):    at iotsuite.pubsubmiddleware.PubSubMiddleware.<init>(PubSubMiddleware.java:58)
01-04 23:03:26.786: E/AndroidRuntime(21793):    at      iotsuite.pubsubmiddleware.IoTSuiteFactory.getInstance(IoTSuiteFactory.java:16)
01-04 23:03:26.786: E/AndroidRuntime(21793):    at  sim.deviceD9.Startup.setUpNode(Startup.java:25)
01-04 23:03:26.786: E/AndroidRuntime(21793):    at sim.deviceD9.Startup.startDevice(Startup.java:63)
01-04 23:03:26.786: E/AndroidRuntime(21793):    at com.example.android.MainActivity.onCreate(MainActivity.java:21)
01-04 23:03:26.786: E/AndroidRuntime(21793):    at android.app.Activity.performCreate(Activity.java:6259)
01-04 23:03:26.786: E/AndroidRuntime(21793):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1130)
01-04 23:03:26.786: E/AndroidRuntime(21793):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2379)
01-04 23:03:26.786: E/AndroidRuntime(21793):    ... 9 more

推荐答案

问题是您的URI使用的是http://方案. http://用于连接到HTTP服务器而不是MQTT代理.

The problem is your URI is using the http:// scheme. http:// is for connecting to HTTP servers not MQTT brokers.

您需要在Android上使用tcp:// URI(这可能也适用于NodeJS，但是mqtt://肯定适用于NodeJS

You need to use the tcp:// URI for Android (this might work for NodeJS as well, but mqtt:// definately works for NodeJS

mqtt://192.168.0.105 

var mqtt = require('mqtt');
var client = mqtt.connect('mqtt://192.168.0.105');
setInterval(function() {
var data = {
     "tempValue" : Math.random(),
     "unitOfMeasurement" : 'C'
     };
client.publish('tempMeasurement', JSON.stringify(data));
}, 5000);

这篇关于使用Android应用程序的基于本地代理(MQTT)的发布/订阅的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！

10-12 05:21
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