Android Application Crashes When Element Added to A List

Question

I have a list an element defined as such:

public List<Bullet> Bullets;
Bullet newBullet = new Bullet(0, 0, 0, 0, 0, 0, 0, 0);

When an onscreen button is pressed I run:

 newBullet.setProperties((int)(CannonCenterX + CannonEndX), (int)(CannonCenterY + CannonEndY), (int)(25*scaleX), (int)(25*scaleY), CannonEndX, CannonEndY, screenWidth, screenHeight);
 Bullets.add(newBullet);

That should change the properties of the newBullet element, and add a copy of it to the Bullet List. However once I do that the application crashes.

The threading part here:

// try locking the canvas for exclusive pixel editing on the surface
        try {
            canvas = this.surfaceHolder.lockCanvas();
            synchronized (surfaceHolder) {
                // update game state
                this.gamePanel.update();

                // draws the canvas on the panel
                this.gamePanel.onDraw(canvas);
            }
        } finally {
            // in case of an exception the surface is not left in
            // an inconsistent state
            if (canvas != null) {
                surfaceHolder.unlockCanvasAndPost(canvas);
            }
        }   // end finally   

Generates an exception and the program closes. I have no idea why adding an already generated element to a list would crash the program. Any help is appreciated.

-Nathan

Answer 1

You need to create the list:

public List<Bullet> Bullets = new ArrayList<Bullet>();