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 this link .基于本地代理的 MQTT 实现工作完美。
最初,我使用 Node.js 发布者和订阅者与这个本地代理来启用消息交换,它也可以在没有互联网连接的情况下工作(因为这些设备连接到同一个网络,mqtt API 用于基于本地代理的实现就像 http://192.168.0.105
)。
现在,我想用 Android 应用程序替换 Node.js 订阅者。我的 android 应用程序使用 mqtt paho 库进行通信并使用 mqtt APImqtt://test.mosquitto.org:1883
。如果我使用的是 mqtt 开放式代理,即 mosquitto,那么 Node.js 发布者和 Android 应用程序订阅者都可以正常工作(这种情况是使用 API mqtt://test.mosquitto.org:1883< 讨论基于 mosquitto 的 mqtt 实现
)。
现在,我想在 Android 应用程序中使用基于本地代理的实现。所以我必须用 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并部署到移动设备时,在andoid应用程序中显示Unfortunately, Android Application has stopped错误。
如何在 android 应用程序中使用基于本地代理的实现?
另外分享 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)
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 订阅者(基于本地代理的实现)
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());
}
});
共享 MQTT Subscriber 代码以便更清晰:
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,我想显示从 Node.js 代码接收到的 tempValue
到 Android 应用程序。来自 Android 的错误如下:
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
最佳答案
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。
您需要为 Android 使用 tcp://
URI(这可能也适用于 NodeJS,但 mqtt://
绝对适用于 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);
关于android - 使用 Android 应用程序的基于本地代理 (MQTT) 的发布/订阅,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/41431163/