How to Send data as JSON over to MQTT broker in flutter - flutter

Question

return RaisedButton(
color: Colors.green,
disabledColor: Colors.grey,
textColor: Colors.white,
disabledTextColor:Colors.black38 ,
child: Text("Break"),
onPressed: state == MQTTAppConnectionState.connectedSubscribed
? () {
setState(() {
value = 0;
action = jsonData;
});
publishMessage(action);
}
: null, //
);
}
I have multiple buttons in my app that passes different message to mqtt client
I want to pass different json data to mqtt client for each button
sample json data for single button
{
"Motor":"BLDC motor",
"Acc": 70,
"F/R": "Forward",
"Break":"False",
"Key":"True"
}
help me to pass single json data to mqtt client when the button is pressed

Answer 1

Pass the values in the publish method and make this changes there it will work
return RaisedButton(
color: Colors.green,
disabledColor: Colors.grey,
textColor: Colors.white,
disabledTextColor:Colors.black38 ,
child: Text("Break"),
onPressed: state == MQTTAppConnectionState.connectedSubscribed
? () {
setState(() {
break1 = "True";
value = 0;
});
publish(break1);
}
: null,//
);
void publish(String break1) {
final MqttClientPayloadBuilder builder = MqttClientPayloadBuilder();
builder.addString(
json.encode(
{
"break": "$break1",
}
)
);
_client!.publishMessage(_topic, MqttQos.exactlyOnce, builder.payload!);}