collidesWith method AndEngine not working

Question

I am having lots of problems with the collidesWith() method on AndEngine. I can see that on the screen, the player and coin sprites I have created are obviously colliding, yet the code below is not executing.

scene.registerUpdateHandler(new IUpdateHandler() {

        @Override
        public void reset() {
            // TODO Auto-generated method stub

        }

        @Override
        public void onUpdate(float pSecondsElapsed) {
            // TODO Auto-generated method stub
            checkCollision();
            scoreText.setText(String.valueOf(score));
        }
    });
    return scene;
}


public void checkCollision() {   
    if(player1.collidesWith(coin)) {
        player1.setColor(Color.RED);
        coin.detachSelf();
        score+=200;
    }
}

public void loadSprites() {   //This loads the sprites
    coin = new Coin(210, 220, this.coinTR,
            this.getVertexBufferObjectManager());
    player1 = new Player(INITX, INITY, this.player,
            this.getVertexBufferObjectManager()) {
        @Override
        protected void onManagedUpdate(float pSecondsElapsed) {
            // TODO Auto-generated method stub
            super.onManagedUpdate(pSecondsElapsed);
            // this.runRight();
            if (this.jump) {
                this.jump();
                this.checkPositionForJump();
            }
        }

    };

}

public void jump() {   //This jump method is part of the player class, it just follows a parabolic path to jump
    this.mX+=SPEED;
    this.mY = (float) (((this.mX - (this.startX + this.VERTX)) * (this.mX - (this.startX + this.VERTX)))
            / (this.STRETCH) + this.startY + this.VERTY);
}

As you can see it just follows a parabolic path from wherever it is currently positioned.

In the checkCollision() method, the if statement never evaluates to true. I have tried every single method I know and cannot get it to work properly. The only time it pseudo works is when I set the sprites to be in the exact same initial position, but other than that it never works. Any help would be greatly appreciated!

Answer 1

Modifying a sprite's location by setting its' mX and/or mY members can lead to the problems you're experiencing. It's always a good idea to use the setters for this.

Change the jump method (and any other place) so it uses setX and setY methods instead of mX and mY, and it should solve your problem.