Don't post the same topics multiple times, even less in the wrong section. Thanks. I deleted the duplicate thread. You can edit this one if you want to improve it.

I'm very sorry about that.

Although I made an effort to follow the old advice in order to get it right, somehow there is no sound after the first collision detection.

I apologize for have not checked the regulations of forum.

an here is what I have done for far.

import ddf.minim.*;
// ---------------------------------------------------------------------------- Initialisation
// Global (i.e. PApplet-wide) constants and variables
final color BACKGROUND = color (255, 255, 255) ; // the background colour(white)
PImage bg, binImage, document;

Bin bin ;
int numCircle = 3 ; // the number of circles
Circle[] circles = new Circle[numCircle] ; // declare and create the array

AudioSnippet song;
Minim minim ;
// -------------------------------------------------
void setup() {
  size(960, 600) ; // set the mianpanel size as 960 * 600)
  background(BACKGROUND) ;

  // set the images
  bg = loadImage("A.png") ;
  binImage = loadImage("B.jpg") ;
  document = loadImage("C.png") ;
  smooth() ;
  noStroke() ;

  bin = new Bin(width-251, height-143, 100) ; // set both the position and the radius
  for (int i = 0; i < circles.length; i++) {
    // set the position of the circles (in this case, random)
    float x = random(400, 600) ;
    float y = random(100, 300) ;
    circles[i] = new Circle(x, y, 30, document) ; // create each object
  }
 
  // set the sound
  minim = new Minim(this) ;
  song = minim.loadSnippet("A.wav");
}

// ------------------------------------------------------------------------------ Main methods
// Display the elements
void draw() {
  fill(BACKGROUND) ;
  image(bg, 0, 0) ; // set the position of the bgImage

  bin.paint() ; // draw the circle(bin)
  image(binImage, width-300, height-200) ; // set the postion of the binImage

  for (int i = 0; i < circles.length; i++) {
    circles[i].paint() ; // draw the objects consist in the Circle paint() function
    circles[i].collisionDetection() ; // implement the collisionDetection
    circles[i].soundPlay() ;
  }
}

// prepare for the sound finishes
void stop(){
  song.close();
  minim.stop();
  super.stop();
}
// -------------------------------------------------
void mousePressed() {
  for (int i = 0; i < numCircle; i++) {
    circles[i].dragPressed() ; // when the mouse is pressed, do the drawPressed() function
    circles[i].collisionDetection() ; // implement the collisionDetection
  }
}
void mouseReleased() {
  for (int i = 0; i < numCircle; i++) {
    circles[i].dragReleased() ; // when the mouse is pressed, do the drawPressed() function
    circles[i].collisionDetection() ; // implement the collisionDetection
  }
}
// --------------------------------------------------------------------------------------------------------------

class Bin {
  // ----------------------------------------------------------------- Constants and variables
  public float bx, by ; // the x and y-coordinate of the circle(object)
  private int radius ; // the radius of the circle
  // ---------------------------------------------------------------------------- Constructors
  Bin(float bxPos, float byPos, int radi) {
    this.bx = bxPos ;
    this.by = byPos ;
    this.radius = radi ;
  }
  // --------------------------------------------------------------------------- Public methods
  public void paint() {
    // draw a circle
    ellipse(bx, by, radius, radius) ;
  }
}
// ------------------------------------------------------------------------------------------- ------------------
class Circle {
  // ----------------------------------------------------------------- Constants and variables
  private float x, y ; // the x and y-coordinate of the circle(object)
  private float dx, dy ; // the difference between the circle's position and the mouse position
  private int radius ; // the radius of the circle
  private boolean startDrag ; // prepare for drag signal
  private boolean isStop ; // prepare to stop drawing circles
  private boolean isPlay ;

  private float scale = 0.5 ; // the size of an image (half of the original size)
  public PImage img ; // set the image variable
  // ---------------------------------------------------------------------------- Constructors
  Circle(float xPos, float yPos, int radi, PImage img) {
    this.x = xPos ;
    this.y = yPos ;
    this.radius = radi ;
    this.img = img ;
  }
  // --------------------------------------------------------------------------- Public methods
  public void paint() {
    // when the circles collieded with other, stop drawing
    if (isStop && isPlay) { // if only if both isStop and isPlay are ture
      song.play() ; // play the sound
      return ; // Exit the function, without drawing anything
    }

    // when the mouse drag starts, starDrag turns "true" and implement the function
    if (startDrag) { // startDrag == true
      x = mouseX + dx; 
      y = mouseY + dy;
    }

    // draw a circle
    noFill() ;
    ellipse(x, y, radius, radius) ;

    // display an image over the circle
    image(document, x-img.width/4, y-img.height/4, img.width*scale, img.height*scale) ;
  }
  // ------------------------------------------------------- Getters and setters
  // ------------------------------------------------------- Setters
  // ------------------------------------------------------ Other public methods
  public void collisionDetection() {
    // if the centre of the cicle and the bin(circle) position is less than the radius,
    if (dist(x, y, bin.bx, bin.by) <= radius) {
      isStop = true ;
    }
  }

  public void soundPlay() {
    if (isStop) {
      isPlay = true ; // turn the sound "true"
    }
  }

  public void dragPressed() {
    // if the centre of the cicle and the mouse position is less than the radius of the circle,
    if (dist(x, y, mouseX, mouseY) <= radius) {
      startDrag = true ; // the drag turns "true"
      // calculate the distance between the circle's position and that of mouse
      dx = x - mouseX;
      dy = y - mouseY;
    }
  }

  public void dragReleased() {
    startDrag = false ; // the darg turns "false"
  }
  // -------------------------------------------------------------------------------------------
}
// -------------------------------------------------------------------------------------------

I can't help here as I rarely use Minim, but I hope somebody else can help.
Have you looked at the Processing examples to see how such samples are used?

Hi,
first there are two classes in minim to play samples. I don't remember which is which, but there's one that lets you play the same sample several times and one that forces you to reload the sample. Check the examples.

Also the ability to play several audio files at once depends a lot on your hardware and platform. On linux you don't have much control unless you use jack, which is painful with java.

> phi.
This is the sample code I've found before and refering to.

import ddf.minim.*;

Minim minim;
AudioSnippet song;
 
void setup()
{
  minim = new Minim(this);
  song = minim.loadSnippet("A.wav");
}

void draw()
{
}

void keyPressed()
{
  if ( key == 'p' )
  {
    song.rewind();
    song.play();
  }
}
 
void stop()
{
  song.close();
  minim.stop();
  super.stop();
}
------------------------------------------------------
> charlesgg
I dont know much about Lunix yet because I often use Windows at home.

Hi

Is there any way that the backgound image can be changed after the circle collision detection?

like, if there are "n" cirlces and when all the circles have collided and disappeared then, the background image changes.

Regards.

Load the alternative image in setup(), set into a global variable. Add a conditional around the image() call after background (start of draw()) to draw one image or the other, depending on a boolean (changed when your condition is met).

This is what Ive done but the error say "Cannot invoke noCircles() on the array type Forgetting.Circle[]."

before I did this, I had a fuction;
public void noCircles(){
// chageImage turns "true" when the numCircle gets zero.
    if(numCircle > 0){
      numCircle-- ;
    } else {
      imageChange = true ;
    }
  }
}

 and assign the imageChange into the function below the void draw but it did not work out neither.

This is the current codes;

// ---------------------------------------------------------------------------- Initialisation
// Global (i.e. PApplet-wide) constants and variables
final color BACKGROUND = color (0, 0, 0) ; // the background colour(BLACK)
PImage fg, bg ;

Bin bin ;
int numCircle = 3 ; // the number of circles
Circle[] circles = new Circle[numCircle] ; // declare and create the array
// -------------------------------------------------
void setup() {
  size(960, 600) ; // set the mianpanel size as 960 * 600)
  background(BACKGROUND) ; // set the background colour
  smooth() ;
  noStroke() ;
 
  // set the images
  bg = loadImage("bgSad.png") ;
  fg = loadImage("bgHaapy.png") ;

  bin = new Bin(100, 300, 100) ;
  for (int i = 0; i < circles.length; i++) {
    // set the position of the circles (in this case, random)
    float x = random(100, 700) ;
    float y = random(300, 600) ;
    circles[i] = new Circle(x, y, 50) ; // create each object
  }
}

// ------------------------------------------------------------------------------ Main methods
// Display the elements
void draw() {
  background(BACKGROUND) ;
 
  if(circles.noCircles()){
    image(fg, 0, 0) ; // set the position of the fgImage
  }
  else {
    image(bg, 0, 0) ; // set the position of the bgImage
  }

  bin.paint() ; // draw the circle(bin)
  for (int i = 0; i < circles.length; i++) {
    circles[i].paint() ; // draw the objects consist in the Circle paint() function
    circles[i].collisionDetection() ;
    circles[i].noCircles() ;
  }
}
// -------------------------------------------------
void mousePressed() {
  for (int i = 0; i < numCircle; i++) {
    circles[i].dragPressed() ; // when the mouse is pressed, do the drawPressed() function
    circles[i].collisionDetection() ;
  }
}
void mouseReleased() {
  for (int i = 0; i < numCircle; i++) {
    circles[i].dragReleased() ; // when the mouse is pressed, do the drawPressed() function
    circles[i].collisionDetection() ;
  }
}
// ---------------------------------------------------------------------------------------------------------------------------------------------------------------

class Circle {
  // ----------------------------------------------------------------- Constants and variables
  private float x, y ; // the x and y-coordinate of the circle(object)
  private float dx, dy ; // the difference between the circle's position and the mouse position
  private int radius ; // the radius of the circle
  private boolean startDrag ; // prepare for drag signal
  private boolean isStop ; // prepare to stop drawing circles
  // ---------------------------------------------------------------------------- Constructors
  Circle(float xPos, float yPos, int radi) {
    this.x = xPos ;
    this.y = yPos ;
    this.radius = radi ;
  }
  // --------------------------------------------------------------------------- Public methods
  public void paint() {
    // when the circles collieded with other, stop drawing
    if (isStop) { // if isStop is true
      return ; // Exit the function, without drawing anything
    }

    // when the mouse drag starts, starDrag turns "true" and implement the function
    if (startDrag) { // startDrag == true
      x = mouseX + dx; 
      y = mouseY + dy;
    }

    // Draw the circles
    fill(255) ;
    ellipse(x, y, radius, radius) ;
  }
  // ------------------------------------------------------- Getters and setters
  // ------------------------------------------------------- Setters
  // ------------------------------------------------------ Other public methods
  public void collisionDetection() {
    // if the centre of the cicle and the bin(circle) position is less than the radius,
    if (dist(x, y, bin.bx, bin. by) <= radius) {
      isStop = true ;
    }
  }
 
 
  public boolean noCircles(){
    // chageImage turns "true" when the numCircle gets zero.
    if(numCircle > 0){
      numCircle-- ;
    } else {
      return true ;
    }
  }
 
 
  public void dragPressed() {
    // if the centre of the cicle and the mouse position is less than the radius of the circle,
    if (dist(x, y, mouseX, mouseY) <= radius) {
      startDrag = true ; // the drag turns "true"
      // calculate the distance between the circle's position and that of mouse
      dx = x - mouseX;
      dy = y - mouseY;
    }
  }

  public void dragReleased() {
    startDrag = false ; // the darg turns "false"
  }
  // -------------------------------------------------------------------------------------------
}
// ----------------------------------------------------------------------------------------------------------------------------------------

You did the same error as before: circles is an array, and arrays are objects in Java. They doesn't have the functions you define on the elements of the array.
Beside, this check on the number of circles doesn't belong to Circle, which is an element. No need to disperse this information. Either you manage them at the global level, or you create a class handling the collection of circles. A wrapper around the array of circles.