[JAVA][Beginning Java 8 Games Development]

Chapter 12 ■ Setting Boundaries for Your Action Figure in 2D: Using the Node Class LocalToParent Attribute
Further Modularization of the .update() Method: .setXYLocation()
You might think that the KeyEvent handling Boolean variables need to be processed inside of the .update() method,
but since they are simply evaluated and then increment the Bagel object’s iX and iY properties, this can be placed into
its own .setXYLocation() method as well, leaving us with only top-level method calls inside of our .update() method.
This will make further sprite manipulation and game play development much more organized, and will also help us to
see what code is being performed at what stages in the .update() cycle. What we are going to do, which is also shown
in Figure 12-14, is to create a .setXYLocation() method, which we will call first in our .update() method, and then place
the four conditional if() statements inside of this new private void setXYLocation(){...} method structure. The
new three method structure for our Bagel.java class .update() “chain of command” will utilize the following Java code:
public void update() {
setXYLocation();
moveInvinciBagel(iX, iY);
}
private void setXYLocation() {
if(invinciBagel.isRight()) { iX += vX }
if(invinciBagel.isLeft()) { iX -= vX }
if(invinciBagel.isDown()) { iY += vY }
if(invinciBagel.isUp()) { iY -= vY }
}
private void moveInvinciBagel(double x, double y) {
spriteFrame.setTranslateX(x);
spriteFrame.setTranslateY(y);
}
Figure 12-14. Create a .setXYLocation() method, install four if() statements inside it, and call it from .update() method
Next, we need to put some code in place that prevents our InvinciBagel character from going off of the screen, in
case our game player does not reverse his direction in time. Later when we implement scoring, we could add in code
that subtracts points for going “out of bounds,” but for now we are simply going to stop the movement, as if there was
an invisible barrier in place at the edges of the game play area (the Stage and Scene size boundaries).
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