Question

In this game, I am trying to have multiple lasers spawn at given coordinates, but for some reason, the app crashes every time the numLasers is greater than 1. I have tried everything, and I could really use some help.

Here is my code:

public class LaserSpawn {

    private int amountOfVisibleLasers;
    private Context context;
    private long timeLastCreatedLaser;
    private Laser[] holderLaser;

    public LaserSpawn(Context context, int numLasers){
        this.context = context;
        holderLaser = new Laser[numLasers];

        this.amountOfVisibleLasers = numLasers;
        for(int i = 0; i< numLasers; i++){
            holderLaser[0] = new Laser(context, -10, -10);
        }
    }

    public void updatePlayerLaser(boolean shootLaser, float x, float y) {
    // Check if a new Laser should be created

    if(shootLaser == true) {    
        if(timeLastCreatedLaser + 100 < System.currentTimeMillis()) {
            timeLastCreatedLaser = System.currentTimeMillis();
            boolean createdNewLaser = false;

            for(int i = 0; i < this.amountOfVisibleLasers; i++) {
                if(createdNewLaser == false) {
                    if(holderLaser[i].isDisposed()) {
                        this.generateNewLaser(i,x,y);
                        createdNewLaser = true;

                    }
                }
            }
        }
    }

    // Update all the other Lasers
    for(int i = 0; i < this.amountOfVisibleLasers; i++) {
        if(holderLaser[i].isDisposed() == false) {
            holderLaser[i].update();
        }

    }

}

private void generateNewLaser(int i, float x, float y) {
    holderLaser[i].setY(y);
    holderLaser[i].setX(x);
}

Thanks!

Answer 1

I’m pretty sure this is your problem:

holderLaser[0] = new Laser(context, -10, -10);

You only ever create a new Laser in the first position of your array. If you try access a second one you’ll get a null pointer exception.

It should be something like

holderLaser[i] = new Laser(context, -10, -10);