Help | MP3 module can't read data in ()

[konor12]

Arduino can play with the code below(changing to next or previous audio).
But it seems it can't read the data inside ().
ex. When I change the number in the volume(), nothing happened.

#include <DFRobotDFPlayerMini.h>
#include <SoftwareSerial.h>
#include "Arduino.h"

SoftwareSerial mySoftwareSerial(11, 10); // RX, TX
DFRobotDFPlayerMini myDFPlayer;
//void printDetail(uint8_t type, int value);

void setup()
{
  //----------------------------------------mp3
  mySoftwareSerial.begin(9600);
  Serial.begin(115200);

  Serial.println();
  Serial.println(F("DFRobot DFPlayer Mini Demo"));
  Serial.println(F("sensing.. (take 3~5 seconds)"));

  if (!myDFPlayer.begin(mySoftwareSerial)) {  //Use softwareSerial to communicate with mp3.
    Serial.println(F("Error!"));
    while (true) {
      delay(0); // Code to compatible with ESP8266 watch dog.
    }
  }
  Serial.println(F("DFPlayer Mini working."));

  myDFPlayer.volume(10);  //Set volume value. From 0 to 30

  //----------------------------------------gesture
  while (!Serial);

  if (!APDS.begin()) {
    Serial.println("Error!");
    Serial.println("Detecting gestures ...");
  }

}

void loop()
{
  if (APDS.gestureAvailable()) {
    int gesture = APDS.readGesture();

 if (gesture == GESTURE_LEFT) {
      Serial.println("LEFT ");
      myDFPlayer.next();
      delay(5000);

    }
    if (gesture == GESTURE_RIGHT) {
      Serial.println("RIGHT ");
      myDFPlayer.previous();
      delay(5000);
    }
  }
}

Also, I want to assign which audio to be played.
It can't read and work. I think it's the same problem: can't read the data in the ().

 if (gesture == GESTURE_LEFT) {
      Serial.println("LEFT ");
      myDFPlayer.play(1);
      delay(5000);

    }
    if (gesture == GESTURE_RIGHT) {
      Serial.println("RIGHT ");
      myDFPlayer.play(2);
      delay(5000);
    }

I'm not pretty sure if that's the real problem...hope to solve this soon.

Thanks for everyone's help...

My reference for code