if i work with turnTowards(); the image is turned away (90 degrees) but i can change the rotation. but still my question is how to let him move towards the other object.?

Have you tried calling the move(1); method. You can adjust it by changing "1" to whatever you want. Also, it would be more helpful if you posting what code you have so far.

When using 'move(1)', there are only four directions that the actor can move (the four cardinal directions). When using 'move(2)', you only add the four diagonals. When moving in such small steps, it is better to keep track of the actors x and y location with 'double' values and use 'setLocation(int, int)' for the movement. If your actor is facing away from the object with using turnTowards, then your differences in coordinates need to be negated (you should subtract the coordinate of the actor from the coordinate of the object).

Thanks for your replies. I think its better to use setLocation() too . But how do i get him to move into the other actors direction ? And how can i make an actor move faster without adjusting the speed or move over two (or more) cells ?

You can use one of the methods of the Actor class that return an Actor or a list of Actor objects to acquire a reference to the object you want your actor to face and use 'turnTowards' to turn the actor toward that object's location. As far as making your actor move faster, the ways you listed are the only ways.

ok thank you. so thats my act method: why the actor turns around my ship if i start the scenario? With this method, the ship is faced, that works so far, but now my actor shall move towards the ship, how can i make him doing this?

I do not know what you want. It should be moving toward a Ship object at this point. Please explain more precisely what you want and supply what code you have tried.

ok heres my act Method of the Actor which shall move to the object: (its the only method with the constructor) no the actor should face the others direction and move towards this (he doesnt change the direction if the other object moves, but this is right)

This is because the actor is not placed into the world until after it is constructed. In fact, 'new DartLaser()' creates the object (this is when the constructor is run), then 'addObject' places the object into a world (this is when the value returned from 'getWorld()' changes from 'null' to the world object the actor is placed into and the 'addedToWorld' method is executed; hence your nullPointerException). What you need to do is move the code that is in the constructor to an overriden 'addedToWorld' method that is automatically executed when the object is placed into a world.