This document describes how to create devices in the IoT Hub console and quickly try out device connection to IoT Hub over the MQTT protocol for message sending/receiving on the SDK demo.
Before connecting devices to the SDK, you need to create products and devices in the console and get the product ID, device name, device certificate (for certificate authentication), device private key (for certificate authentication), and device key (for key authentication), which are required for authentication of the devices when you connect them to the cloud. For more information, please see Device Connection Preparations.
After a product is created successfully in the console, it has three permissions by default:
${productId}/${deviceName}/control // Subscribe
${productId}/${deviceName}/data // Subscribe and publish
${productId}/${deviceName}/event // Publish
For more information on how to manipulate the topic permissions, please see Permission List.
Downloading the sample code of IoT Hub SDK for Android demo
Edit the configuration information in the app-config.json file.
{
"PRODUCT_ID": "",
"DEVICE_NAME": "",
"DEVICE_PSK": "",
"SUB_PRODUCT_ID": "",
"SUB_DEVICE_PSK": "",
"SUB_DEV_NAME": "",
"TEST_TOPIC": "",
"SHADOW_TEST_TOPIC": "",
"PRODUCT_KEY": ""
}
If key authentication is used during device creation in the console, you need to enter PRODUCT_ID (product ID), DEVICE_NAME (device name), and DEVICE_PSK (device key) in app-config.json;
If certificate authentication is used during device creation in the console, in addition to entering PRODUCT_ID (product ID) and DEVICE_NAME (device name) in app-config.json and setting DEVICE_PSK (device key) to null, you also need to configure mDevCert (device certificate content string) and mDevPriv (device private key content string) in the IoTMqttFragment.java file.
Alternatively, you can read the certificate through AssetManager. Specifically, create the assets directory in the hub-android-demo/src/main path of the demo, place the device certificate and private key in it, and configure mDevCertName (device certificate file name) and mDevKeyName (device private key file name) in the IoTMqttFragment.java file.
private String mDevCertName = "";
private String mDevKeyName = "";
private String mDevCert = ""; // Cert String
private String mDevPriv = ""; // Priv String
Select the hub-demo for Android application and click Run 'hub-demo on the Android Studio menu bar to install the demo.
Run the demo and click Connect to MQTT in the basic feature module for authenticated connection. Below is the sample code:
mMQTTSample = new MQTTSample(mParent, new SelfMqttActionCallBack(), mBrokerURL, mProductID, mDevName, mDevPSK, mDevCert, mDevPriv, mSubProductID, mSubDevName, mTestTopic, null, null, true, new SelfMqttLogCallBack()); // The `MQTTSample` class is used by the SDK to encapsulate API calls.
mMQTTSample.connect(); // Connect to MQTT
The above log represents the process in which the device is connected to the cloud over MQTT successfully.
I/TXMQTT1.2.3: Start connecting to ssl://AP9ZLEVFKT.iotcloud.tencentdevices.com:8883
I/TXMQTT: onConnectCompleted, status[OK], reconnect[false], userContext[MQTTRequest{requestType='connect', requestId=2}], msg[connected to ssl://AP9ZLEVFKT.iotcloud.tencentdevices.com:8883]
TXMqttActionCallBack is the callback for device action.
/**
* Callback for MQTT connection completion
*
* @param status Status.OK: connection succeeded; Status.ERROR: connection failed
* @param reconnect true: reconnection false: first connection
* @param userContext User context
* @param msg Connection information
*/
@Override
public void onConnectCompleted(Status status, boolean reconnect, Object userContext, String msg){}
/**
* Callback for MQTT disconnection
*
* @param cause Disconnection cause
*/
@Override
public void onConnectionLost(Throwable cause) {}
/**
* Callback for MQTT disconnection completion
*
* @param status Status.OK: disconnection succeeded; Status.ERROR: disconnection failed
* @param userContext User context
* @param msg Details
*/
@Override
public void onDisconnectCompleted(Status status, Object userContext, String msg) {}
/**
* Callback for message publishing completion
*
* @param status Status.OK: message publishing succeeded; Status.ERROR: message publishing failed
* @param token Message token, containing the message content structure
* @param userContext User context
* @param msg Details
*/
@Override
public void onPublishCompleted(Status status, IMqttToken token, Object userContext, String errMsg) {}
/**
* Callback for topic subscription completion
*
* @param status Status.OK: subscription succeeded; Status.ERROR: subscription failed
* @param token Message token, containing the message content structure
* @param userContext User context
* @param msg Details
*/
@Override
public void onSubscribeCompleted(Status status, IMqttToken asyncActionToken, Object userContext, String errMsg) {}
/**
* Callback for topic unsubscription completion
*
* @param status Status.OK: unsubscription succeeded; Status.ERROR: unsubscription failed
* @param token Message token, containing the message content structure
* @param userContext User context
* @param msg Details
*/
@Override
public void onUnSubscribeCompleted(Status status, IMqttToken asyncActionToken, Object userContext, String errMsg) {}
/**
* Push for the message received from the subscribed topic
*
* @param topic Topic name
* @param message Message content
*/
@Override
public void onMessageReceived(final String topic, final MqttMessage message) {}
getConnectStatus()API can be used to get the device connection status.
enum ConnectStatus {
kConnectIdle, // Initial status
kConnecting, // Connecting
kConnected, // Connected
kConnectFailed,// Connection failed
kDisconnected // Disconnected
}
Run the demo and click Disconnect from MQTT in the basic feature module to disconnect from MQTT. Below is the sample code:
mMQTTSample.disconnect(); // Close the MQTT connection
The following logcat log represents the process in which the device is disconnected from MQTT successfully.
I/TXMQTT: onDisconnectCompleted, status[OK], userContext[MQTTRequest{requestType='disconnect', requestId=3}], msg[disconnected to ssl://AP9ZLEVFKT.iotcloud.tencentdevices.com:8883]
Before running the demo, you need to configure the topic to be subscribed to as TEST_TOPIC (topic permission) in the app-config.json file. For more information on how to generate a topic, please see Creating device in console.
Run the demo and click Subscribe to Topic in the basic feature module to subscribe to a topic. Below is the sample code:
mMQTTSample.subscribeTopic();// Subscribe to the topic
The following logcat log represents the process in which the device subscribes to a topic successfully.
I/com.tencent.iot.hub.device.java.core.mqtt.TXMqttConnection: Starting subscribe topic: AP9ZLEVFKT/gateway1/data
D/TXMQTT: onSubscribeCompleted, status[OK], topics[[AP9ZLEVFKT/gateway1/data]], userContext[MQTTRequest{requestType='subscribeTopic', requestId=5}], errMsg[subscribe success]
A device can unsubscribe from a previously subscribed topic.
Run the demo and click Unsubscribe from Topic in the basic feature module to unsubscribe from a topic. Below is the sample code:
mMQTTSample.unSubscribeTopic();// Unsubscribe from the topic
The following logcat log represents the process in which the device unsubscribes from a topic successfully.
I/com.tencent.iot.hub.device.java.core.mqtt.TXMqttConnection: Starting unSubscribe topic: AP9ZLEVFKT/gateway1/data
D/TXMQTT: onUnSubscribeCompleted, status[OK], topics[[AP9ZLEVFKT/gateway1/data]], userContext[MQTTRequest{requestType='unSubscribeTopic', requestId=6}], errMsg[unsubscribe success]
Before running the demo, you need to configure the topic to be published to as TEST_TOPIC (topic permission) in the app-config.json file. For more information on how to generate a topic, please see Creating device in console.
Run the demo and click Publish to Topic in the basic feature module to publish to a topic. Below is the sample code:
Map<String, String> data = new HashMap<String, String>();// Data to be published
data.put("car_type", "suv");// Vehicle type
data.put("oil_consumption", "6.6");// Vehicle fuel consumption
data.put("maximum_speed", "205");// Maximum vehicle speed
data.put("temperature", String.valueOf(temperature.getAndIncrement()));// Temperature information
mMQTTSample.publishTopic("data", data);// Publish to the topic. The `publishTopic` method packages the `data` into `MqttMessage` for publishing.
The following logcat log represents the process in which the device publishes to a topic successfully.
I/com.tencent.iot.hub.device.java.core.mqtt.TXMqttConnection: Starting publish topic: AP9ZLEVFKT/gateway1/data Message: {"oil_consumption":"6.6","temperature":"0","maximum_speed":"205","car_type":"suv"}
D/TXMQTT: onPublishCompleted, status[OK], topics[[AP9ZLEVFKT/gateway1/data]], userContext[MQTTRequest{requestType='publishTopic', requestId=8}], errMsg[publish success]