Creating an Android NativeScript plugin

Question

I'm trying to create a plugin that allows a NativeScript application to connect to an MQTT server. When I try to run the application I get the following error in my application:

java.lang.RuntimeException: Unable to start activity ComponentInfo{org.nativescript.testMQTT/com.tns.NativeScriptActivity}: com.tns.NativeScriptException: Calling js method onCreate failed

TypeError: Cannot read property 'paho' of undefined File: ", line: 1, column: 265

StackTrace: Frame: function:'NativeScriptMQTTClient', file:'/data/data/org.nativescript.testMQTT/files/app/tns_modules/nativescript-mqtt/mqtt.js', line: 8, column: 44 Frame: function:'', file:'/data/data/org.nativescript.testMQTT/files/app/main-page.js', line: 4, column: 14 Frame: function:'require', file:'', line: 1, column: 266 Frame: function:'global.loadModule', file:'/data/data/org.nativescript.testMQTT/files/app/tns_modules/globals/globals.js', line: 19, column: 16 Frame: function:'resolvePageFromEntry', file:'/data/data/org.nativescript.testMQTT/files/app/tns_modules/ui/frame/frame-common.js', line: 72, column: 40 Frame: function:'Frame.navigate', file:'/data/data/org.nativescript.testMQTT/files/app/tns_modules/ui/fr

I'm using the following code with the Paho Java library in my mqtt.android.ts file:

export class NativeScriptMQTTClient { 
    private _topic: String; 
    private _content: String; 
    private _qos: number; 
    private _broker: String; 
    private _clientId: String; 
    private _persistance: org.eclipse.paho.client.mqttv3.persist.MemoryPersistance; 
    private _client: org.eclipse.paho.client.mqttv3.MqttClient; 
    private _connectOptions: org.eclipse.paho.client.mqttv3.MqttConnectOptions; 

    constructor(topic: String, qos: number, broker: string, clientId: String) { 
        this._topic = topic; 
        this._qos = qos; 
        this._broker = broker; 
        this._clientId = clientId; 
        this._persistance = new org.eclipse.paho.client.mqttv3.persist.MemoryPersistance(); 
    } 

    connect() { 
        this._client = new org.eclipse.paho.client.mqttv3.MqttClient(this._broker, this._clientId, this._persistance); 
        this._connectOptions = new org.eclipse.paho.client.mqttv3.MqttConnectOptions(); 
        this._connectOptions.setCleanSession(true); 
        console.log("Connecting to the broker: " + this._broker); 
        this._client.connect(this._connectOptions); 
        console.log("Connected to the broker: " + this._broker); 
        console.log("Publishing message: Hello from NativeScript (Morné)"); 
        this._client.publish(this._topic, "Hello from NativeScript (Morné)"); 
        console.log("Published message: Hello from NativeScript (Morné)"); 
        console.log("Disconnecting from the broker: " + this._broker); 
        this._client.disconnect(); 
        console.log("Disconnected from the broker: " + this._broker); 
    } 
}

And I have the following code in my main-page.ts file:

import {NativeScriptMQTTClient} from "nativescript-mqtt"; 

let client: NativeScriptMQTTClient = new NativeScriptMQTTClient("MQTT Examples", 2, "tcp://iot.eclipse.org:1883", "NativeScriptClient"); 
client.connect();

Any help would be greatly appreciated.

Have you included the library jar file (org.eclipse.paho.client.mqttv3-1.0.2.jar) in platforms/Android/libs in your plugin — Nick Iliev, Apr 21 '16 at 11:52

Nick Iliev · Accepted Answer · 2016-04-21T20:39:49.627

Based on MQTT api reference I have noticed the following

its MemoryPersistence and in your code is MemoryPersistance

this._persistance = new org.eclipse.paho.client.mqttv3.persist.MemoryPersistence();

Make sure you have included your .jar file in platforms/Android/libs (link to MQTT jar file v1.0.2)

Your package.json should look something like this (make sure you have mqtt.android.js file in the plugin transpiled if you code in TypeScript)

{
  "name": "nativescript-mqtt",
  "version": "0.0.3",
  "main": "mqtt.js",
  "nativescript": {
    "platforms": {
      "tns-android": {
        "version": "1.7.1"
      },
      "tns-ios": {
        "version": "1.7.0"
      }
    }
  }
}

also you should reffer to your plugin like

var mqttModule = require("nativescript-mqtt");

let client = new mqttModule.NativeScriptMQTTClient("MQTT Examples", 2, "tcp://test.mosquitto.org:1883", "NativeScriptClient");

At this point I am receiveing

JS: Connecting to the broker: tcp://test.mosquitto.org:1883

From that point on you should export your connect method with the proper d.ts file and logic. Hope that info will help you with you project!

Thanks that fixed it. Now to try figure out how to implement to iOS part of it. — MorneZaayman, Apr 22 '16 at 07:09

Creating an Android NativeScript plugin

1 Answers1