如何使精灵对角移动？

Question

I have a sprite that needs to follow the command of an arrow sprite that rotates, right now I can only make my sprite move up,down and left,right. How about diagonally? I have no Idea how to do that, the sprite also needs to move always towards outside the screen.

EDIT: So this is what I did:

Vector2 position=new Vector2();

public void update(){

//getAngle() is the return value from another class     
position.set(MathUtils.cosDeg(cannonObj.getAngle()),MathUtils.sinDeg(cannonObj.getAngle()));
    sprite.setPosition(position.x,position.y);
    }

What happens is that when I rotate the arrow the main sprite is just moving like the arrow(moving in a circular motion).

//I also tried this
position.scl(2,2);
 or
position.translate(2,2);

Answer 1

sprite.x += sin(angle) * amount;
sprite.y += cos(angle) * amount;

I forget whether you have to enter your angle in radians or degrees. In Java you can use the Math class to do the calculations though.