Nodemcu WIFI temperature and slider

MIT App Inventor Help
1

Hello, i would like to make an application to use slider and measure temperature on Nodemcu. Im using DS18B20 termometer. I send you a code, maybe there is a false. Please make an app in MIT to show me how it should look like or fix the code. Slider is working well but temperature measurment not.

#define ENB   12          
#include <OneWire.h>
#include <DallasTemperature.h>
#include <ESP8266WiFi.h>
#include <WiFiClient.h> 
#include <ESP8266WebServer.h>

OneWire oneWire(D4); //Podłączenie do D4
DallasTemperature sensors(&oneWire); //Przekazania informacji do biblioteki
String command;             //String to store app command state.
String command_2;
int data = 0;         // 400 - 1023.
double tempC = 0;

const char* ssid = "wifi_temp_slider";
ESP8266WebServer server(80);

void setup() {
 sensors.begin(); //Inicjalizacja czujnikow
 pinMode(ENB, OUTPUT);  
  
  Serial.begin(115200);
  
// Connecting WiFi

  WiFi.mode(WIFI_AP);
  WiFi.softAP(ssid);

  IPAddress myIP = WiFi.softAPIP();
  Serial.print("AP IP address: ");
  Serial.println(myIP);
 
 // Starting WEB-server 
     server.on ( "/", HTTP_handleRoot );
     server.onNotFound ( HTTP_handleRoot );
     server.begin();    
}

void goAhead()
{ 

      analogWrite(ENB, data);    
  }


void loop() {
    server.handleClient();
    
      command = server.arg("State");
      //command_2 = server.arg("State2");
      if (command == "0"){ data = 20; goAhead();}
      else if (command == "1") { data = 0; goAhead();}
      else if (command == "2") { data = 100; goAhead();}
      else if (command == "3") { data = 150; goAhead();}
      else if (command == "4") { data = 250; goAhead();}
      else if (command == "5") { data = 370; goAhead();}
      else if (command == "6") { data = 400; goAhead();}
      else if (command == "7") { data = 480; goAhead();}
      else if (command == "8") { data = 550; goAhead();}
      else if (command == "9") { data = 700; goAhead();}
      temperatura();
}

void HTTP_handleRoot(void) {

if( server.hasArg("State") ){
       Serial.println(server.arg("State"));
  }  
   server.send ( 200, "text/html", "" );
  delay(1);
}
 

void temperatura 
{
  sensors.requestTemperatures(); //Pobranie temperatury czujnika
  //Serial.print("Aktualna temperatura: ");
   tempC = sensors.getTempCByIndex(0);
  Serial.println(tempC);
}