Can playAdvertisement method can be called at any time like a playFolderTrack method, not just when there is music playing?

[skyerGalaxy]

Here's a piece of code I've written, and I'll mark the areas with red boxes where I have doubts

Here is two choose for me------playAdvertisement or playFolderTrack,but both them are not prefect

• when I use playAdvertisement ,if from The program starts,there play music all the time,there no doubt ,it's good.But when the program starts without music or muisc is end when program call playAdvertisement method ,playAdvertisement will lose effect.
• when I use playFolderTrack-----code in red box have effect whether there is music playing or not,but if this part code execute when I playing a music,music will pause,next music and previous music will chaos(The music for these two parts is not in the same folder)

so Can playAdvertisement methon can be called at any time like a playFolderTrack method, not just when there is music playing?

The full code is below

[skyerGalaxy]

#include <AFMotor.h>
#include <DFMiniMp3.h>
#include <SoftwareSerial.h>

AF_DCMotor motor1(1);
AF_DCMotor motor2(2);
AF_DCMotor motor3(3);
AF_DCMotor motor4(4);

int var;
int speed = 125;
int trigPin = 2;
int echoPin = 9;
long duration,distance;
bool isWelcomePlayed = false;




//MP3 Setting
class Mp3Notify
{
public:
  static void PrintlnSourceAction(DfMp3_PlaySources source, const char* action)
  {
    if (source & DfMp3_PlaySources_Sd) 
    {
        Serial.print("SD Card, ");
    }
    if (source & DfMp3_PlaySources_Usb) 
    {
        Serial.print("USB Disk, ");
    }
    if (source & DfMp3_PlaySources_Flash) 
    {
        Serial.print("Flash, ");
    }
    Serial.println(action);
  }
  static void OnError(uint16_t errorCode)
  {
    // see DfMp3_Error for code meaning
    Serial.println();
    Serial.print("Com Error ");
    Serial.println(errorCode);
  }
  static void OnPlayFinished(DfMp3_PlaySources source, uint16_t track)
  {
    Serial.print("Play finished for #");
    Serial.println(track);  
  }
  static void OnPlaySourceOnline(DfMp3_PlaySources source)
  {
    PrintlnSourceAction(source, "online");
  }
  static void OnPlaySourceInserted(DfMp3_PlaySources source)
  {
    PrintlnSourceAction(source, "inserted");
  }
  static void OnPlaySourceRemoved(DfMp3_PlaySources source)
  {
    PrintlnSourceAction(source, "removed");
  }
};


SoftwareSerial secondarySerial(A0, A1); // RX, TX
DFMiniMp3<SoftwareSerial, Mp3Notify> mp3(secondarySerial);

void setup() {
  Serial.begin(9600);           // set up Serial library at 9600 bps
  Serial.println('Bluetooth Car,start!');
  mp3.begin();
  mp3.setVolume(30);
  if (!isWelcomePlayed) {
    mp3.playFolderTrack(2, 1);  // play welcome message
    delay(500);
    isWelcomePlayed = true; // Set a flag to indicate that the Welcome message has already been played
  }
}



void loop() {
  if(isWelcomePlayed){
    ///////echo distance
    //init state---Low level
    digitalWrite(trigPin, LOW);
    delayMicroseconds(5);
    //trige high level----Pulse is emitted
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    //recover low level
    digitalWrite(trigPin, LOW);

    //Read high pulse time
    duration = pulseIn(echoPin, HIGH);

    //calclate distance
    distance = (duration/2)*0.034;     // Divide by 29.1 or multiply by 0.0343

    if(distance<30){
      mp3.playFolderTrack(2,2);
      delay(4000);
    }

    if(Serial.available()>0){
        //read command
        var = Serial.read();
        //Make different actions according to the command
        switch (var){
          case 'A':
            forward();
            break;
          case 'B':
            back();
            break;
          case 'C':
            left();
            break;
          case 'D':
            right();
            break;
          case 'E':
            topleft();
            break;
          case 'F':
            topright();
            break;
          case 'G':
            bottomleft();
            break;
          case 'H':
            bottomright();
            break;
          case 'I':
            horn();
            break;
          case 'J':
            accelerate();
            break;
          case 'K':
            cancelAccelerate();
            break;
          case 'L':
            previousMusic();
            break;
          case 'M':
            nextMusic();
            break;
        }
    }
  }
}




void horn(){
    mp3.playAdvertisement(2);
}

void accelerate(){
  speed = 255;
}

void cancelAccelerate(){
  speed = 255;
}

void previousMusic(){
  mp3.prevTrack();
}

void nextMusic(){
  mp3.nextTrack();
}




//forward
void forward()
{
  Serial.println("Forward");
  motor1.setSpeed(speed); //Define maximum velocity
  motor1.run(FORWARD); //rotate   the motor clockwise
  motor2.setSpeed(speed); //Define maximum velocity
  motor2.run(FORWARD); //rotate the motor clockwise
  motor3.setSpeed(speed);//Define   maximum velocity
  motor3.run(FORWARD); //rotate the motor clockwise
  motor4.setSpeed(speed);//Define   maximum velocity
  motor4.run(FORWARD); //rotate the motor clockwise
}

//back
void back()
{
  Serial.println("Bacward");
  mp3.playAdvertisement(1);
  motor1.setSpeed(speed);   //Define maximum velocity
  motor1.run(BACKWARD); //rotate the motor anti-clockwise
  motor2.setSpeed(speed); //Define maximum velocity
  motor2.run(BACKWARD);   //rotate the motor anti-clockwise
  motor3.setSpeed(speed); //Define maximum   velocity
  motor3.run(BACKWARD); //rotate the motor anti-clockwise
  motor4.setSpeed(speed);   //Define maximum velocity
  motor4.run(BACKWARD); //rotate the motor anti-clockwise
}
  
  //turn left
void left()
{
Serial.println("Left");
  mp3.playAdvertisement(3);
  motor1.setSpeed(speed);   //Define maximum velocity
  motor1.run(BACKWARD); //rotate the motor anti-clockwise
  motor2.setSpeed(speed); //Define maximum velocity
  motor2.run(BACKWARD);   //rotate the motor anti-clockwise
  motor3.setSpeed(speed); //Define maximum   velocity
  motor3.run(FORWARD);  //rotate the motor clockwise
  motor4.setSpeed(speed);   //Define maximum velocity
  motor4.run(FORWARD);  //rotate the motor clockwise
}
  
  //turn right
void right()
{
  Serial.println("Right");
motor1.setSpeed(speed);   //Define maximum velocity
  motor1.run(FORWARD); //rotate the motor clockwise
  motor2.setSpeed(speed); //Define maximum velocity
  motor2.run(FORWARD); //rotate   the motor clockwise
  motor3.setSpeed(speed); //Define maximum velocity
  motor3.run(BACKWARD); //rotate the motor anti-clockwise
  motor4.setSpeed(speed);   //Define maximum velocity
  motor4.run(BACKWARD); //rotate the motor anti-clockwise
}
  
  //turn to topleft
void topleft(){
  Serial.println("Top Left");
motor1.setSpeed(speed);   //Define maximum velocity
  motor1.run(FORWARD); //rotate the motor clockwise
  motor2.setSpeed(speed); //Define maximum velocity
  motor2.run(FORWARD); //rotate   the motor clockwise
  motor3.setSpeed(speed/3.1);//Define maximum velocity
  motor3.run(FORWARD); //rotate the motor clockwise
  motor4.setSpeed(speed/3.1);//Define   maximum velocity
  motor4.run(FORWARD); //rotate the motor clockwise
}
  

  //turn to topleft
void topright()
{
  Serial.println("Top Right");
motor1.setSpeed(speed/3.1);   //Define maximum velocity
  motor1.run(FORWARD); //rotate the motor clockwise
  motor2.setSpeed(speed/3.1); //Define maximum velocity
  motor2.run(FORWARD);   //rotate the motor clockwise
  motor3.setSpeed(speed);//Define maximum velocity
  motor3.run(FORWARD); //rotate the motor clockwise
  motor4.setSpeed(speed);//Define   maximum velocity
  motor4.run(FORWARD); //rotate the motor clockwise
}
  

  //turn to bottomleft
void bottomleft()
{
  Serial.println("Botom Left");
motor1.setSpeed(speed);   //Define maximum velocity
  motor1.run(BACKWARD); //rotate the motor anti-clockwise
  motor2.setSpeed(speed); //Define maximum velocity
  motor2.run(BACKWARD);   //rotate the motor anti-clockwise
  motor3.setSpeed(speed/3.1); //Define maximum   velocity
  motor3.run(BACKWARD); //rotate the motor anti-clockwise
  motor4.setSpeed(speed/3.1);   //Define maximum velocity
  motor4.run(BACKWARD); //rotate the motor anti-clockwise
}
  
  //turn to bottomright
void bottomright()
{
  Serial.println("Bottom Right");
motor1.setSpeed(speed/3.1);   //Define maximum velocity
  motor1.run(BACKWARD); //rotate the motor anti-clockwise
  motor2.setSpeed(speed/3.1); //Define maximum velocity
  motor2.run(BACKWARD);   //rotate the motor anti-clockwise
  motor3.setSpeed(speed); //Define maximum   velocity
  motor3.run(BACKWARD); //rotate the motor anti-clockwise
  motor4.setSpeed(speed);   //Define maximum velocity
  motor4.run(BACKWARD); //rotate the motor anti-clockwise
}
  
//stop the bluetooth car
void Stop()
{
  motor1.setSpeed(0);   //Define minimum velocity
  motor1.run(RELEASE); //stop the motor when release   the button
  motor2.setSpeed(0); //Define minimum velocity
  motor2.run(RELEASE);   //rotate the motor clockwise
  motor3.setSpeed(0); //Define minimum velocity
  motor3.run(RELEASE); //stop the motor when release the button
  motor4.setSpeed(0);   //Define minimum velocity
  motor4.run(RELEASE); //stop the motor when release   the button
}