How to manipulate an on-screen LED on the Android?

/*
   -- LED Strip Controller --
   
   This source code of graphical user interface 
   has been generated automatically by RemoteXY editor.
   To compile this code using RemoteXY library 2.3.3 or later version 
   download by link http://remotexy.com/en/library/
   To connect using RemoteXY mobile app by link http://remotexy.com/en/download/                   
     - for ANDROID 4.1.1 or later version;
     - for iOS 1.2.1 or later version;
    
   This source code is free software; you can REDistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.    
*/

#include <EEPROM.h>                   // used for saving settings

//////////////////////////////////////////////
//        RemoteXY include library          //
//////////////////////////////////////////////

// RemoteXY select connection mode and include library 
#define REMOTEXY_MODE__HARDSERIAL

#include <RemoteXY.h>

// RemoteXY connection settings 
#define REMOTEXY_SERIAL Serial
#define REMOTEXY_SERIAL_SPEED 115200


// RemoteXY configurate  
#pragma pack(push, 1)
uint8_t RemoteXY_CONF[] =
  { 255,4,0,3,0,46,0,8,26,0,
  1,2,64,50,21,8,24,31,83,97,
  118,101,0,4,128,1,19,98,10,134,
  134,4,128,1,32,98,10,204,204,4,
  128,1,6,98,10,1,1,65,15,17,
  49,21,10 };
  
// this structure defines all the variables of your control interface 
struct {

    // input variable
  uint8_t save_button; // =1 if button pressed, else =0 
  int8_t GRN; // =0..100 slider position 
  int8_t BLU; // =0..100 slider position 
  int8_t RED; // =0..100 slider position 

    // output variable
  uint8_t RGB_led_r; // =0..255 LED Red brightness 
  uint8_t RGB_led_g; // =0..255 LED Green brightness 
  uint8_t RGB_led_b; // =0..255 LED Blue brightness 

    // other variable
  uint8_t connect_flag;  // =1 if wire connected, else =0 

} RemoteXY;
#pragma pack(pop)

/////////////////////////////////////////////
//           END RemoteXY include          //
/////////////////////////////////////////////      
  
 
// EEPROM Addresses
#define SETTINGS_ID       "LED STRIP V5"
#define SETTINGS_ADDRESS  64

// Arduino Pins
// PWM Outputs
const byte pin_RED = 11;              // RED Channel (PWM)
const byte pin_GRN = 10;              // GRN Channel (PWM)
const byte pin_BLU =  9;              // BLU Channel (PWM)

// Define the settings udt
typedef struct udt_Settings {
  uint8_t RED;            // 0 to 255 
  uint8_t GRN;            // 0 to 255 
  uint8_t BLU;            // 0 to 255 
  char    id[19];         // this is last to catch structure changes
};

//Create the settings data of type udt_Settings
udt_Settings settings;

// other variables
uint8_t RED_PWM_Max = 100;
uint8_t GRN_PWM_Max = 100;
uint8_t BLU_PWM_Max = 100;


#ifdef REMOTEXY_MODE__SOFTSERIAL 
  SoftwareSerial mySerial = SoftwareSerial(REMOTEXY_SERIAL_RX,REMOTEXY_SERIAL_TX);
#endif

// **********************************************************************

void setup() {
  RemoteXY_Init (); 

  pinMode (pin_RED, OUTPUT);
  pinMode (pin_GRN, OUTPUT);
  pinMode (pin_BLU, OUTPUT);
  
  // connect to the serial port

#ifdef REMOTEXY_MODE__SOFTSERIAL 
  mySerial.begin(REMOTEXY_SERIAL_SPEED);
#endif

#ifndef REMOTEXY_MODE__SOFTSERIAL 
  Serial.begin(REMOTEXY_SERIAL_SPEED);
#endif

  // retrieve settings from EEPROM
  
  EEPROM.get(SETTINGS_ADDRESS, settings);

// initialise start-up settings if not present
if (strcmp(settings.id, SETTINGS_ID) != 0) {
  settings.RED = RED_PWM_Max/2;         // half brightness 
  settings.GRN = GRN_PWM_Max/2;         // half brightness 
  settings.BLU = BLU_PWM_Max/2;         // half brightness 
  strcpy(settings.id, SETTINGS_ID);

  EEPROM.put(SETTINGS_ADDRESS, settings);
  }

RemoteXY.RED = settings.RED;
RemoteXY.GRN = settings.GRN;
RemoteXY.BLU = settings.BLU;

} // end setup

// ***********************************************************************
// LOOP
// ***********************************************************************
void loop() { 
  RemoteXY_Handler ();

// PWM Control 
// OMG this is so simple it's untrue 
// Read the slider positions, and control the RGB ouputs
// such a shame the sliders are 0-100, but the RGB values are 0-255
// which is why we need to "map" them
 
  analogWrite(pin_RED, map(RemoteXY.RED, 0, 100, 0, RED_PWM_Max));
  analogWrite(pin_GRN, map(RemoteXY.GRN, 0, 100, 0, GRN_PWM_Max));
  analogWrite(pin_BLU, map(RemoteXY.BLU, 0, 100, 0, BLU_PWM_Max));

// Show the colour mix on the mobile device display

  RemoteXY.RGB_led_r = map(RemoteXY.RED, 0, 100, 0, 255); 
  RemoteXY.RGB_led_g = map(RemoteXY.GRN, 0, 100, 0, 255); 
  RemoteXY.RGB_led_b = map(RemoteXY.BLU, 0, 100, 0, 255); 

// respond to the Save button if pressed

  if (RemoteXY.save_button) {
    RemoteXY.save_button = 0;
    
// turn the LEDs off for visual indication of "saving"
    analogWrite(pin_RED,0);
    analogWrite(pin_GRN,0);
    analogWrite(pin_BLU,0);
    
    settings.RED = RemoteXY.RED; 
    settings.GRN = RemoteXY.GRN; 
    settings.BLU = RemoteXY.BLU; 

    EEPROM.put(SETTINGS_ADDRESS, settings);

    delay(750);
  } // if (RemoteXY.save_button)
  
} // void(loop)