Controlling and creating multiple sprites array Java Libgdx

Question

I am trying to create a game which has sprites and every second another is spawned, i tried using this as a base: https://github.com/libgdx/libgdx/wiki/A-simple-game However when the new one spawns in it destroys the old one and they start to spawn faster and faster. Here is the relevent code:

ownCreate method:

Array<Rectangle> chickens;
chickens = new Array<Rectangle>();
spawnChicken();

New Spawn Chicken method:

private void spawnChicken() {


        int choice;
        choice = MathUtils.random(0, 3);
        switch (choice){

        case 0:
            chicken.x = MathUtils.random(0,1920-85);
            chicken.y = 0;          
            break;
        case 1:
            chicken.x = MathUtils.random(0,1920-85);
            chicken.y = 1080-85;    
            break;
        case 2:
            chicken.x = 0;
            chicken.y = MathUtils.random(0,1080-66);
            break;
        case 3:
            chicken.x = 1920-85;
            chicken.y = MathUtils.random(0,1080-66);
            break;
        }


    chicken.height = 66;
    chicken.width = 85;
    chickens.add(chicken);
    runningChickens ++;
    lastSpawnTime = TimeUtils.nanoTime();

Render method:

if(TimeUtils.nanoTime() - lastSpawnTime > 1000000000)
    spawnChicken();

Iterator<Rectangle> iter = chickens.iterator();

while(iter.hasNext()){      
    Rectangle chicken = iter.next();
    //movement

Very similar to the wiki:

private Array<Rectangle> raindrops;
   private long lastDropTime; private void spawnRaindrop() {
      Rectangle raindrop = new Rectangle();
      raindrop.x = MathUtils.random(0, 800-64);
      raindrop.y = 480;
      raindrop.width = 64;
      raindrop.height = 64;
      raindrops.add(raindrop);
      lastDropTime = TimeUtils.nanoTime();
   }
 raindrops = new Array<Rectangle>();
   spawnRaindrop();
   if(TimeUtils.nanoTime() - lastDropTime > 1000000000) spawnRaindrop();
 Iterator<Rectangle> iter = raindrops.iterator();
   while(iter.hasNext()) {
      Rectangle raindrop = iter.next();
      raindrop.y -= 200 * Gdx.graphics.getDeltaTime();
      if(raindrop.y + 64 < 0) iter.remove();
   }

Not enough code is shown to understand this. On your fourth line, you add a chicken. What chicken is this? A member variable? What does spawnChicken() do, assign a new Rectangle instance to a member variable called chicken? And where in your code are your first four lines, in the create() method while the rest is in render()? — Tenfour04
I don't know if code is still missing, but I would expect spawnChicken() to start with the line Rectangle chicken = new Rectangle();. If chicken is a member variable, as it appears it must be if you didn't leave out any code, then your spawnChicken() method is simply moving the same chicken around each time you call it. — Tenfour04

Tanmay Patil Tanmay Patil · Accepted Answer · 2014-07-16T05:28:22

Put

Rectangle chicken = new Rectangle();

at the start of spawnChicken() method.

Reasons

If you keep chicken a member, it will be replaced every time spawnChicken() method is called.
Also, the same object is added to the array every time you try to spawn a chicken.

Controlling and creating multiple sprites array Java Libgdx

1 Answers