Android Studio - MQTT to JSON











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I am struggling to send/receive the MQTT messages as JSON.



This is my code:



public class MainActivity extends AppCompatActivity {
Gson gson = new Gson();

public static final String BROKER_URL = "tcp://iot.eclipse.org:1883";


String userid = "12345"; //
//We have to generate a unique Client id.
String clientId = userid + "-sub";

// Default sensor to listen for -
// Change to another if you are broadcasting a different sensor name
String sensorname = "brightness";
String sensorTemp = "temperature";

String topicname = userid + "/" + sensorname;
String topicname2 = userid + "/" + sensorTemp;
public final String TOPIC_BRIGHTNESS = userid + "/brightness";
public final String TOPIC_TEMPERATURE = userid + "/temperature";
public final String TOPIC_DOORLOCK = userid + "/doorlock";
private MqttClient mqttClient;
Button publishTemperatureBtn;
Switch publishDoorState;
SeekBar tempSeekBar;
TextView tempLabel;

SensorData oneSensor = new SensorData("unknown", "unknown");
String oneSensorJson = new String();

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
publishTemperatureBtn = (Button) findViewById(R.id.publishTemperatureBtnID);
tempSeekBar = (SeekBar) findViewById(R.id.temperatureSeekBar);
publishDoorState = (Switch) findViewById(R.id.doorSwitch);
tempLabel = (TextView) findViewById(R.id.temperatureLabel);

publishTemperatureBtn.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Code here executes on main thread after user presses button
System.out.println("PUBLISHING");
runOnUiThread(new Runnable() {
public void run() {
publishTemperature();
}
});
}
});

publishDoorState.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton compoundButton, boolean isChecked) {
if (isChecked == true) {
runOnUiThread(new Runnable() {
@Override
public void run() {
publishDoorStateMethod_ON();
}
});
} else if (isChecked == false) {
runOnUiThread(new Runnable() {
@Override
public void run() {
publishDoorStateMethod_OFF();
}
});
}
}
});


tempSeekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
@Override
public void onProgressChanged(SeekBar seekBar, int i, boolean b) {
tempLabel.setText(i + "°C");
}

@Override
public void onStartTrackingTouch(SeekBar seekBar) {

}

@Override
public void onStopTrackingTouch(SeekBar seekBar) {
runOnUiThread(new Runnable() {
@Override
public void run() {
publishTemperature();
}
});
}
});


// start new
// Create MQTT client and start subscribing to message queue
try {
// change from original. Messages in "null" are not stored
mqttClient = new MqttClient(BROKER_URL, clientId, null);
mqttClient.setCallback(new MqttCallbackExtended() {
@Override
public void connectionLost(Throwable cause) {
//This is called when the connection is lost. We could reconnect here.
}

@Override
public void messageArrived(final String topic, final MqttMessage message) throws Exception {
System.out.println("DEBUG: Message arrived. Topic: " + topic + " Message: " + message.toString());
// get message data

final String messageStr = message.toString();

runOnUiThread(new Runnable() {
public void run() {
System.out.println("Updating UI");
// Update UI elements

if ((topic).equals(topicname)) {
System.err.println("Sensor gone!");
TextView sensorValueTV = (TextView) findViewById(R.id.sensorValueTV);
sensorValueTV.setText(messageStr);
} else if ((topic).equals(topicname2)) {
System.err.println("Sensor gone!");
TextView sensorTempValue = (TextView) findViewById(R.id.sensorTempValue);
sensorTempValue.setText(messageStr);
}


}
});

}

@Override
public void deliveryComplete(IMqttDeliveryToken token) {
//no-op
}

@Override
public void connectComplete(boolean b, String s) {
//no-op
}
});
} catch (MqttException e) {
e.printStackTrace();
System.exit(1);
}

// temp use of ThreadPolicy until use AsyncTask
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);

startSubscribing();


}


public void startSubscribing() {
try {
mqttClient.connect();

//Subscribe to all subtopics of home
final String topic = topicname;
mqttClient.subscribe(topic);
final String topic2 = topicname2;
mqttClient.subscribe(topic2);

System.out.println("Subscriber is now listening to " + topic);

} catch (MqttException e) {
e.printStackTrace();
System.exit(1);
}
}

public void publishTemperature() {
try {
final MqttTopic temperatureTopic = mqttClient.getTopic(TOPIC_TEMPERATURE);
final int temperatureNumber = 30;
EditText temperatureETValue = (EditText) findViewById(R.id.temperatureETValue);
final String temperature = tempLabel.getText().toString();


temperatureTopic.publish(new MqttMessage(temperature.getBytes()));

System.out.println("Now publishing " + temperatureTopic);

} catch (MqttException e) {
e.printStackTrace();
System.exit(1);
}
}

public void publishDoorStateMethod_ON() {
try {
final MqttTopic doorButtonTopic = mqttClient.getTopic(TOPIC_DOORLOCK);
String doorState;
Button doorStateButton = (Button) findViewById(R.id.doorSwitch);
doorState = "ON";
doorButtonTopic.publish(new MqttMessage(doorState.getBytes()));

System.out.println("Now publishing " + doorButtonTopic);
} catch (MqttException e) {
e.printStackTrace();
System.exit(1);
}
}

public void publishDoorStateMethod_OFF() {
try {
final MqttTopic doorButtonTopic = mqttClient.getTopic(TOPIC_DOORLOCK);
String doorState;
Button doorStateButton = (Button) findViewById(R.id.doorSwitch);
doorState = "OFF";
doorButtonTopic.publish(new MqttMessage(doorState.getBytes()));

System.out.println("Now publishing " + doorButtonTopic);


} catch (MqttException e) {
e.printStackTrace();
System.exit(1);
}
}
}


This is what I have been tasked to do:




  1. Amend the Android code to send/receive the MQTT messages as json strings representing sensor objects. You will need to include the same SensorData object that you used in the Eclipse labs, and include the Gson class in your Android project. Use sample code from the Eclipse client/server labs to remind you how to create json objects from the SensorData object, and how to extract the object data when a json object arrives.


I already have my SensorData object. The examples in Elicpse that I have are no help whatsoever. Could someone please point me in the right direction.










share|improve this question






















  • We won't do your homework for you. You need to be a lot more specific about what you need help with.
    – hardillb
    Nov 22 at 7:25















up vote
0
down vote

favorite












I am struggling to send/receive the MQTT messages as JSON.



This is my code:



public class MainActivity extends AppCompatActivity {
Gson gson = new Gson();

public static final String BROKER_URL = "tcp://iot.eclipse.org:1883";


String userid = "12345"; //
//We have to generate a unique Client id.
String clientId = userid + "-sub";

// Default sensor to listen for -
// Change to another if you are broadcasting a different sensor name
String sensorname = "brightness";
String sensorTemp = "temperature";

String topicname = userid + "/" + sensorname;
String topicname2 = userid + "/" + sensorTemp;
public final String TOPIC_BRIGHTNESS = userid + "/brightness";
public final String TOPIC_TEMPERATURE = userid + "/temperature";
public final String TOPIC_DOORLOCK = userid + "/doorlock";
private MqttClient mqttClient;
Button publishTemperatureBtn;
Switch publishDoorState;
SeekBar tempSeekBar;
TextView tempLabel;

SensorData oneSensor = new SensorData("unknown", "unknown");
String oneSensorJson = new String();

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
publishTemperatureBtn = (Button) findViewById(R.id.publishTemperatureBtnID);
tempSeekBar = (SeekBar) findViewById(R.id.temperatureSeekBar);
publishDoorState = (Switch) findViewById(R.id.doorSwitch);
tempLabel = (TextView) findViewById(R.id.temperatureLabel);

publishTemperatureBtn.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Code here executes on main thread after user presses button
System.out.println("PUBLISHING");
runOnUiThread(new Runnable() {
public void run() {
publishTemperature();
}
});
}
});

publishDoorState.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton compoundButton, boolean isChecked) {
if (isChecked == true) {
runOnUiThread(new Runnable() {
@Override
public void run() {
publishDoorStateMethod_ON();
}
});
} else if (isChecked == false) {
runOnUiThread(new Runnable() {
@Override
public void run() {
publishDoorStateMethod_OFF();
}
});
}
}
});


tempSeekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
@Override
public void onProgressChanged(SeekBar seekBar, int i, boolean b) {
tempLabel.setText(i + "°C");
}

@Override
public void onStartTrackingTouch(SeekBar seekBar) {

}

@Override
public void onStopTrackingTouch(SeekBar seekBar) {
runOnUiThread(new Runnable() {
@Override
public void run() {
publishTemperature();
}
});
}
});


// start new
// Create MQTT client and start subscribing to message queue
try {
// change from original. Messages in "null" are not stored
mqttClient = new MqttClient(BROKER_URL, clientId, null);
mqttClient.setCallback(new MqttCallbackExtended() {
@Override
public void connectionLost(Throwable cause) {
//This is called when the connection is lost. We could reconnect here.
}

@Override
public void messageArrived(final String topic, final MqttMessage message) throws Exception {
System.out.println("DEBUG: Message arrived. Topic: " + topic + " Message: " + message.toString());
// get message data

final String messageStr = message.toString();

runOnUiThread(new Runnable() {
public void run() {
System.out.println("Updating UI");
// Update UI elements

if ((topic).equals(topicname)) {
System.err.println("Sensor gone!");
TextView sensorValueTV = (TextView) findViewById(R.id.sensorValueTV);
sensorValueTV.setText(messageStr);
} else if ((topic).equals(topicname2)) {
System.err.println("Sensor gone!");
TextView sensorTempValue = (TextView) findViewById(R.id.sensorTempValue);
sensorTempValue.setText(messageStr);
}


}
});

}

@Override
public void deliveryComplete(IMqttDeliveryToken token) {
//no-op
}

@Override
public void connectComplete(boolean b, String s) {
//no-op
}
});
} catch (MqttException e) {
e.printStackTrace();
System.exit(1);
}

// temp use of ThreadPolicy until use AsyncTask
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);

startSubscribing();


}


public void startSubscribing() {
try {
mqttClient.connect();

//Subscribe to all subtopics of home
final String topic = topicname;
mqttClient.subscribe(topic);
final String topic2 = topicname2;
mqttClient.subscribe(topic2);

System.out.println("Subscriber is now listening to " + topic);

} catch (MqttException e) {
e.printStackTrace();
System.exit(1);
}
}

public void publishTemperature() {
try {
final MqttTopic temperatureTopic = mqttClient.getTopic(TOPIC_TEMPERATURE);
final int temperatureNumber = 30;
EditText temperatureETValue = (EditText) findViewById(R.id.temperatureETValue);
final String temperature = tempLabel.getText().toString();


temperatureTopic.publish(new MqttMessage(temperature.getBytes()));

System.out.println("Now publishing " + temperatureTopic);

} catch (MqttException e) {
e.printStackTrace();
System.exit(1);
}
}

public void publishDoorStateMethod_ON() {
try {
final MqttTopic doorButtonTopic = mqttClient.getTopic(TOPIC_DOORLOCK);
String doorState;
Button doorStateButton = (Button) findViewById(R.id.doorSwitch);
doorState = "ON";
doorButtonTopic.publish(new MqttMessage(doorState.getBytes()));

System.out.println("Now publishing " + doorButtonTopic);
} catch (MqttException e) {
e.printStackTrace();
System.exit(1);
}
}

public void publishDoorStateMethod_OFF() {
try {
final MqttTopic doorButtonTopic = mqttClient.getTopic(TOPIC_DOORLOCK);
String doorState;
Button doorStateButton = (Button) findViewById(R.id.doorSwitch);
doorState = "OFF";
doorButtonTopic.publish(new MqttMessage(doorState.getBytes()));

System.out.println("Now publishing " + doorButtonTopic);


} catch (MqttException e) {
e.printStackTrace();
System.exit(1);
}
}
}


This is what I have been tasked to do:




  1. Amend the Android code to send/receive the MQTT messages as json strings representing sensor objects. You will need to include the same SensorData object that you used in the Eclipse labs, and include the Gson class in your Android project. Use sample code from the Eclipse client/server labs to remind you how to create json objects from the SensorData object, and how to extract the object data when a json object arrives.


I already have my SensorData object. The examples in Elicpse that I have are no help whatsoever. Could someone please point me in the right direction.










share|improve this question






















  • We won't do your homework for you. You need to be a lot more specific about what you need help with.
    – hardillb
    Nov 22 at 7:25













up vote
0
down vote

favorite









up vote
0
down vote

favorite











I am struggling to send/receive the MQTT messages as JSON.



This is my code:



public class MainActivity extends AppCompatActivity {
Gson gson = new Gson();

public static final String BROKER_URL = "tcp://iot.eclipse.org:1883";


String userid = "12345"; //
//We have to generate a unique Client id.
String clientId = userid + "-sub";

// Default sensor to listen for -
// Change to another if you are broadcasting a different sensor name
String sensorname = "brightness";
String sensorTemp = "temperature";

String topicname = userid + "/" + sensorname;
String topicname2 = userid + "/" + sensorTemp;
public final String TOPIC_BRIGHTNESS = userid + "/brightness";
public final String TOPIC_TEMPERATURE = userid + "/temperature";
public final String TOPIC_DOORLOCK = userid + "/doorlock";
private MqttClient mqttClient;
Button publishTemperatureBtn;
Switch publishDoorState;
SeekBar tempSeekBar;
TextView tempLabel;

SensorData oneSensor = new SensorData("unknown", "unknown");
String oneSensorJson = new String();

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
publishTemperatureBtn = (Button) findViewById(R.id.publishTemperatureBtnID);
tempSeekBar = (SeekBar) findViewById(R.id.temperatureSeekBar);
publishDoorState = (Switch) findViewById(R.id.doorSwitch);
tempLabel = (TextView) findViewById(R.id.temperatureLabel);

publishTemperatureBtn.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Code here executes on main thread after user presses button
System.out.println("PUBLISHING");
runOnUiThread(new Runnable() {
public void run() {
publishTemperature();
}
});
}
});

publishDoorState.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton compoundButton, boolean isChecked) {
if (isChecked == true) {
runOnUiThread(new Runnable() {
@Override
public void run() {
publishDoorStateMethod_ON();
}
});
} else if (isChecked == false) {
runOnUiThread(new Runnable() {
@Override
public void run() {
publishDoorStateMethod_OFF();
}
});
}
}
});


tempSeekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
@Override
public void onProgressChanged(SeekBar seekBar, int i, boolean b) {
tempLabel.setText(i + "°C");
}

@Override
public void onStartTrackingTouch(SeekBar seekBar) {

}

@Override
public void onStopTrackingTouch(SeekBar seekBar) {
runOnUiThread(new Runnable() {
@Override
public void run() {
publishTemperature();
}
});
}
});


// start new
// Create MQTT client and start subscribing to message queue
try {
// change from original. Messages in "null" are not stored
mqttClient = new MqttClient(BROKER_URL, clientId, null);
mqttClient.setCallback(new MqttCallbackExtended() {
@Override
public void connectionLost(Throwable cause) {
//This is called when the connection is lost. We could reconnect here.
}

@Override
public void messageArrived(final String topic, final MqttMessage message) throws Exception {
System.out.println("DEBUG: Message arrived. Topic: " + topic + " Message: " + message.toString());
// get message data

final String messageStr = message.toString();

runOnUiThread(new Runnable() {
public void run() {
System.out.println("Updating UI");
// Update UI elements

if ((topic).equals(topicname)) {
System.err.println("Sensor gone!");
TextView sensorValueTV = (TextView) findViewById(R.id.sensorValueTV);
sensorValueTV.setText(messageStr);
} else if ((topic).equals(topicname2)) {
System.err.println("Sensor gone!");
TextView sensorTempValue = (TextView) findViewById(R.id.sensorTempValue);
sensorTempValue.setText(messageStr);
}


}
});

}

@Override
public void deliveryComplete(IMqttDeliveryToken token) {
//no-op
}

@Override
public void connectComplete(boolean b, String s) {
//no-op
}
});
} catch (MqttException e) {
e.printStackTrace();
System.exit(1);
}

// temp use of ThreadPolicy until use AsyncTask
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);

startSubscribing();


}


public void startSubscribing() {
try {
mqttClient.connect();

//Subscribe to all subtopics of home
final String topic = topicname;
mqttClient.subscribe(topic);
final String topic2 = topicname2;
mqttClient.subscribe(topic2);

System.out.println("Subscriber is now listening to " + topic);

} catch (MqttException e) {
e.printStackTrace();
System.exit(1);
}
}

public void publishTemperature() {
try {
final MqttTopic temperatureTopic = mqttClient.getTopic(TOPIC_TEMPERATURE);
final int temperatureNumber = 30;
EditText temperatureETValue = (EditText) findViewById(R.id.temperatureETValue);
final String temperature = tempLabel.getText().toString();


temperatureTopic.publish(new MqttMessage(temperature.getBytes()));

System.out.println("Now publishing " + temperatureTopic);

} catch (MqttException e) {
e.printStackTrace();
System.exit(1);
}
}

public void publishDoorStateMethod_ON() {
try {
final MqttTopic doorButtonTopic = mqttClient.getTopic(TOPIC_DOORLOCK);
String doorState;
Button doorStateButton = (Button) findViewById(R.id.doorSwitch);
doorState = "ON";
doorButtonTopic.publish(new MqttMessage(doorState.getBytes()));

System.out.println("Now publishing " + doorButtonTopic);
} catch (MqttException e) {
e.printStackTrace();
System.exit(1);
}
}

public void publishDoorStateMethod_OFF() {
try {
final MqttTopic doorButtonTopic = mqttClient.getTopic(TOPIC_DOORLOCK);
String doorState;
Button doorStateButton = (Button) findViewById(R.id.doorSwitch);
doorState = "OFF";
doorButtonTopic.publish(new MqttMessage(doorState.getBytes()));

System.out.println("Now publishing " + doorButtonTopic);


} catch (MqttException e) {
e.printStackTrace();
System.exit(1);
}
}
}


This is what I have been tasked to do:




  1. Amend the Android code to send/receive the MQTT messages as json strings representing sensor objects. You will need to include the same SensorData object that you used in the Eclipse labs, and include the Gson class in your Android project. Use sample code from the Eclipse client/server labs to remind you how to create json objects from the SensorData object, and how to extract the object data when a json object arrives.


I already have my SensorData object. The examples in Elicpse that I have are no help whatsoever. Could someone please point me in the right direction.










share|improve this question













I am struggling to send/receive the MQTT messages as JSON.



This is my code:



public class MainActivity extends AppCompatActivity {
Gson gson = new Gson();

public static final String BROKER_URL = "tcp://iot.eclipse.org:1883";


String userid = "12345"; //
//We have to generate a unique Client id.
String clientId = userid + "-sub";

// Default sensor to listen for -
// Change to another if you are broadcasting a different sensor name
String sensorname = "brightness";
String sensorTemp = "temperature";

String topicname = userid + "/" + sensorname;
String topicname2 = userid + "/" + sensorTemp;
public final String TOPIC_BRIGHTNESS = userid + "/brightness";
public final String TOPIC_TEMPERATURE = userid + "/temperature";
public final String TOPIC_DOORLOCK = userid + "/doorlock";
private MqttClient mqttClient;
Button publishTemperatureBtn;
Switch publishDoorState;
SeekBar tempSeekBar;
TextView tempLabel;

SensorData oneSensor = new SensorData("unknown", "unknown");
String oneSensorJson = new String();

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
publishTemperatureBtn = (Button) findViewById(R.id.publishTemperatureBtnID);
tempSeekBar = (SeekBar) findViewById(R.id.temperatureSeekBar);
publishDoorState = (Switch) findViewById(R.id.doorSwitch);
tempLabel = (TextView) findViewById(R.id.temperatureLabel);

publishTemperatureBtn.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Code here executes on main thread after user presses button
System.out.println("PUBLISHING");
runOnUiThread(new Runnable() {
public void run() {
publishTemperature();
}
});
}
});

publishDoorState.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton compoundButton, boolean isChecked) {
if (isChecked == true) {
runOnUiThread(new Runnable() {
@Override
public void run() {
publishDoorStateMethod_ON();
}
});
} else if (isChecked == false) {
runOnUiThread(new Runnable() {
@Override
public void run() {
publishDoorStateMethod_OFF();
}
});
}
}
});


tempSeekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
@Override
public void onProgressChanged(SeekBar seekBar, int i, boolean b) {
tempLabel.setText(i + "°C");
}

@Override
public void onStartTrackingTouch(SeekBar seekBar) {

}

@Override
public void onStopTrackingTouch(SeekBar seekBar) {
runOnUiThread(new Runnable() {
@Override
public void run() {
publishTemperature();
}
});
}
});


// start new
// Create MQTT client and start subscribing to message queue
try {
// change from original. Messages in "null" are not stored
mqttClient = new MqttClient(BROKER_URL, clientId, null);
mqttClient.setCallback(new MqttCallbackExtended() {
@Override
public void connectionLost(Throwable cause) {
//This is called when the connection is lost. We could reconnect here.
}

@Override
public void messageArrived(final String topic, final MqttMessage message) throws Exception {
System.out.println("DEBUG: Message arrived. Topic: " + topic + " Message: " + message.toString());
// get message data

final String messageStr = message.toString();

runOnUiThread(new Runnable() {
public void run() {
System.out.println("Updating UI");
// Update UI elements

if ((topic).equals(topicname)) {
System.err.println("Sensor gone!");
TextView sensorValueTV = (TextView) findViewById(R.id.sensorValueTV);
sensorValueTV.setText(messageStr);
} else if ((topic).equals(topicname2)) {
System.err.println("Sensor gone!");
TextView sensorTempValue = (TextView) findViewById(R.id.sensorTempValue);
sensorTempValue.setText(messageStr);
}


}
});

}

@Override
public void deliveryComplete(IMqttDeliveryToken token) {
//no-op
}

@Override
public void connectComplete(boolean b, String s) {
//no-op
}
});
} catch (MqttException e) {
e.printStackTrace();
System.exit(1);
}

// temp use of ThreadPolicy until use AsyncTask
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);

startSubscribing();


}


public void startSubscribing() {
try {
mqttClient.connect();

//Subscribe to all subtopics of home
final String topic = topicname;
mqttClient.subscribe(topic);
final String topic2 = topicname2;
mqttClient.subscribe(topic2);

System.out.println("Subscriber is now listening to " + topic);

} catch (MqttException e) {
e.printStackTrace();
System.exit(1);
}
}

public void publishTemperature() {
try {
final MqttTopic temperatureTopic = mqttClient.getTopic(TOPIC_TEMPERATURE);
final int temperatureNumber = 30;
EditText temperatureETValue = (EditText) findViewById(R.id.temperatureETValue);
final String temperature = tempLabel.getText().toString();


temperatureTopic.publish(new MqttMessage(temperature.getBytes()));

System.out.println("Now publishing " + temperatureTopic);

} catch (MqttException e) {
e.printStackTrace();
System.exit(1);
}
}

public void publishDoorStateMethod_ON() {
try {
final MqttTopic doorButtonTopic = mqttClient.getTopic(TOPIC_DOORLOCK);
String doorState;
Button doorStateButton = (Button) findViewById(R.id.doorSwitch);
doorState = "ON";
doorButtonTopic.publish(new MqttMessage(doorState.getBytes()));

System.out.println("Now publishing " + doorButtonTopic);
} catch (MqttException e) {
e.printStackTrace();
System.exit(1);
}
}

public void publishDoorStateMethod_OFF() {
try {
final MqttTopic doorButtonTopic = mqttClient.getTopic(TOPIC_DOORLOCK);
String doorState;
Button doorStateButton = (Button) findViewById(R.id.doorSwitch);
doorState = "OFF";
doorButtonTopic.publish(new MqttMessage(doorState.getBytes()));

System.out.println("Now publishing " + doorButtonTopic);


} catch (MqttException e) {
e.printStackTrace();
System.exit(1);
}
}
}


This is what I have been tasked to do:




  1. Amend the Android code to send/receive the MQTT messages as json strings representing sensor objects. You will need to include the same SensorData object that you used in the Eclipse labs, and include the Gson class in your Android project. Use sample code from the Eclipse client/server labs to remind you how to create json objects from the SensorData object, and how to extract the object data when a json object arrives.


I already have my SensorData object. The examples in Elicpse that I have are no help whatsoever. Could someone please point me in the right direction.







android json mqtt






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asked Nov 21 at 23:55









TheApprentice

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  • We won't do your homework for you. You need to be a lot more specific about what you need help with.
    – hardillb
    Nov 22 at 7:25


















  • We won't do your homework for you. You need to be a lot more specific about what you need help with.
    – hardillb
    Nov 22 at 7:25
















We won't do your homework for you. You need to be a lot more specific about what you need help with.
– hardillb
Nov 22 at 7:25




We won't do your homework for you. You need to be a lot more specific about what you need help with.
– hardillb
Nov 22 at 7:25

















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