Hello ladies and gentlemen, im trying to get a ball to draggable to any cell in the grid. Ive got my grid and the balls set up. but i think my implementation is wrong since i cannot find any method to drag them

Here is what i have so far!


Ball[][] grid;  // 2D Array of objects

int cols = 15;  // Number of columns and rows in the grid
int rows = 15;
int increment;

void setup() {
  size(600, 600);
  grid = new Ball[cols][rows];

  for (int i = 0; i < cols; i ++ ) {
    for (int j = 0; j < rows; j ++ ) {
      grid[i][j] = new Ball(i*40, j*40, 40, 40, i + j);
      grid[i][j].display();
    }
  }
  for (int i = 0; i < cols; i ++ ) {
    for (int j = 14; j < rows; j ++ ) {
      grid[i][j].greyscale();
      //fill(greyscale);
      grid[i][j].drawc();
    }
  }
}
void draw() {
}

void mousePressed() {
  rect (mouseX, mouseY, 30, 30);
}

void keyPressed() {
}


And the Cell Code is :

class Ball {      // Cell object

  float x, y;   // x,y location
  float w, h;   // width and height

  Ball(float tempX, float tempY, float tempW, float tempH, float tempAngle) { // Cell Constructor
    x = tempX;
    y = tempY;
    w = tempW;
    h = tempH;
  }

  void greyscale() {         
    increment=230 ;
  }

  void drawc() {
    ellipse(x+20, y+20, w/2, h/2);
    increment=increment-20;
  }

  void display() {
    //stroke(0);
    rect(x, y, w, h);
  }
}