I have a board that sends jsons with telemetry to Azure IoT hub (using http). I want to read telemetry data with my android device. I looked some examples of reading messages from IoT hub for android, but I found only how to read them from "Cloud to device feedback" endpoint. So now my application looks like:
Json from the board ----> "Events" endpoint ---> Function application that resending json to "Cloud to device feedback" endpoint -----> "Cloud to device feedback" endpoint ----> Android device.
I'm a beginner in Azure, so I'm sure that exists smarter way to do that. (Json from the board ----> "Events" endpoint ---> Android device). I did it on my desktop, but looks like android doesn't work with some libraries from desktop project.
Does anybody know how can I do it? (maybe some guides or lessons)
Part of android code:
public void btnReceiveOnClick(View v) throws URISyntaxException, IOException
{
System.out.println("Receiving:");
Button button = (Button) v;
// Comment/uncomment from lines below to use HTTPS or MQTT protocol
//IotHubClientProtocol protocol = IotHubClientProtocol.HTTPS;
IotHubClientProtocol protocol = IotHubClientProtocol.MQTT;
DeviceClient client = new DeviceClient(connString, protocol);
if (protocol == IotHubClientProtocol.MQTT)
{
MessageCallbackMqtt callback = new MessageCallbackMqtt();
Counter counter = new Counter(0);
client.setMessageCallback(callback, counter);
} else
{
MessageCallback callback = new MessageCallback();
Counter counter = new Counter(0);
client.setMessageCallback(callback, counter);
}
try
{
client.open();
} catch (Exception e2)
{
System.out.println("Exception while opening IoTHub connection: " + e2.toString());
}
try
{
Thread.sleep(1000);
} catch (InterruptedException e)
{
e.printStackTrace();
}
client.closeNow();
try {
....
}catch (JSONException je){
....
}
}
// Our MQTT doesn't support abandon/reject, so we will only display the messaged received
// from IoTHub and return COMPLETE
static class MessageCallbackMqtt implements com.microsoft.azure.sdk.iot.device.MessageCallback
{
public IotHubMessageResult execute(Message msg, Object context)
{
responce = new String(msg.getBytes(), Message.DEFAULT_IOTHUB_MESSAGE_CHARSET);
Counter counter = (Counter) context;
System.out.println(
"[from MessageCallbackMqtt] Received message " + counter.toString()
+ " with content: " + responce);
counter.increment();
return IotHubMessageResult.COMPLETE;
}
}
static class EventCallback implements IotHubEventCallback
{
public void execute(IotHubStatusCode status, Object context)
{
Integer i = (Integer) context;
System.out.println("[from EventCallback] IoT Hub responded to message " + i.toString()
+ " with status " + status.name());
}
}
static class MessageCallback implements com.microsoft.azure.sdk.iot.device.MessageCallback
{
public IotHubMessageResult execute(Message msg, Object context)
{
Counter counter = (Counter) context;
System.out.println(
"Received message " + counter.toString()
+ " with content: " + new String(msg.getBytes(), Message.DEFAULT_IOTHUB_MESSAGE_CHARSET));
int switchVal = counter.get() % 3;
IotHubMessageResult res;
switch (switchVal)
{
case 0:
res = IotHubMessageResult.COMPLETE;
break;
case 1:
res = IotHubMessageResult.ABANDON;
break;
case 2:
res = IotHubMessageResult.REJECT;
break;
default:
// should never happen.
throw new IllegalStateException("Invalid message result specified.");
}
System.out.println("Responding to message " + counter.toString() + " with " + res.name());
counter.increment();
return res;
}
}
