Question

我刚刚开始使用Android Studio并且关注了YouTube视频，但我一直无法连接到MQTT服务器。 Gradle构建中有16个错误。我不知道问题出在哪里。如何连接到MQTT服务器？

Error:warning: Ignoring InnerClasses attribute for an anonymous inner class
Error:(org.eclipse.paho.client.mqttv3.persist.MqttDefaultFilePersistence$2) that doesn't come with an
Error:associated EnclosingMethod attribute. This class was probably produced by a
Error:compiler that did not target the modern .class file format. The recommended
Error:solution is to recompile the class from source, using an up-to-date compiler
Error:and without specifying any "-target" type options. The consequence of ignoring
Error:this warning is that reflective operations on this class will incorrectly
Error:indicate that it is *not* an inner class.
Error:warning: Ignoring InnerClasses attribute for an anonymous inner class
Error:(org.eclipse.paho.client.mqttv3.persist.MqttDefaultFilePersistence$1) that doesn't come with an
Error:associated EnclosingMethod attribute. This class was probably produced by a
Error:compiler that did not target the modern .class file format. The recommended
Error:solution is to recompile the class from source, using an up-to-date compiler
Error:and without specifying any "-target" type options. The consequence of ignoring
Error:this warning is that reflective operations on this class will incorrectly
Error:indicate that it is *not* an inner class.
Error:Execution failed for task ':app:transformClassesWithDexForDebug'.
> com.android.build.api.transform.TransformException: com.android.ide.common.process.ProcessException: java.util.concurrent.ExecutionException: com.android.dex.DexException: Multiple dex files define Landroid/support/v4/accessibilityservice/AccessibilityServiceInfoCompat$AccessibilityServiceInfoVersionImpl;
Information:BUILD FAILED
Information:Total time: 5.816 secs
Information:17 errors
Information:0 warnings
Information:See complete output in console

这是我的代码

package com.example.leejunwen.newmqtt;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.Toast;

import org.eclipse.paho.android.service.MqttAndroidClient;
import org.eclipse.paho.client.mqttv3.IMqttActionListener;
import org.eclipse.paho.client.mqttv3.IMqttToken;
import org.eclipse.paho.client.mqttv3.MqttClient;
import org.eclipse.paho.client.mqttv3.MqttException;



public class MainActivity extends AppCompatActivity {

    static String MQTTHOST = "test.mosquitto.org:1883";

    MqttAndroidClient client;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        String clientId = MqttClient.generateClientId();
        client =new MqttAndroidClient(this.getApplicationContext(), MQTTHOST, clientId);

        try {
            IMqttToken token = client.connect();
            token.setActionCallback(new IMqttActionListener() {
                @Override
                public void onSuccess(IMqttToken asyncActionToken) {
                    // We are connected
                    Toast.makeText(MainActivity.this,"connected",Toast.LENGTH_LONG).show();
                }

                @Override
                public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
                    // Something went wrong e.g. connection timeout or firewall problems
                    Toast.makeText(MainActivity.this,"connection fail",Toast.LENGTH_LONG).show();

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

这是我的build.gradle

apply plugin: 'com.android.application'

android {
    compileSdkVersion 24
    buildToolsVersion "25.0.2"
    defaultConfig {
        applicationId "com.example.leejunwen.newmqtt"
        minSdkVersion 15
        targetSdkVersion 24
        versionCode 1
        versionName "1.0"
        }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

repositories {
    maven {
        url "https://repo.eclipse.org/content/repositories/paho-snapshots/"
    }
}


dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:24.2.1'
    compile 'org.eclipse.paho:org.eclipse.paho.client.mqttv3:1.0.2'
    compile 'org.eclipse.paho:org.eclipse.paho.android.service:1.0.2'
}

这是我的AndroidManifest

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.leejunwen.newmqtt">

    <uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.READ_PHONE_STATE" />
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <service android:name="org.eclipse.paho.android.service.MqttService" >
        </service>
    </application>

</manifest>

无法使用Android Studio连接到MQTT服务器

0 个答案: