Systematic Instrucations in Java?

Newbie & Debugging Questions
#1

How could I make a set of systematic instrucations? like so after one thing is done the next thing works?

like in this example;


derpX += .04;
derpY -= .5;
derpX += .3;
//these variables are x and y values for a moving image

Like I want these operations to work one at a time, not like the normally would (as they normally operate all at the same time) how could i do this?

#2

There’re lot ways to achieve sequence execution, ranging from putting while() after each statement, to create your own callback listener.

#3

could you show me an example? sorry for my noobish java skills

#4

They already do run one after another, not all at the same time?

#5 

float targetX = derpX + .4;
derpX += .4
while (derpX != targetX);
derpY -= .5;

The last statement will be executed after derpX meets the target.
I can’t provide callback examples, too much classes and interfaces needed. Try to google it.

#6

They do, but the first one will still be operating while the last one is. And thats the problem. I would want these to operate one at a time

#7

I dont see how I can use this for many sets of instruction… :frowning:

#8

Guys just saying this is how i finally got it to work. Thanks for any tips though.


			if (move01 == true) {
				homelessX += .04f;
				if (homelessX > 700) {
					move01 = false;
					move02 = true;
				}
			}
			if (move02 == true) {
				homelessY += .04f;
				if (homelessY > 900) {
					move02 = false;
					move03 = true;
				}
			}
			if (move03 == true) {
				homelessX += .04f;
				if (homelessX > 800) {
					move03 = false;
					move04 = true;
				}
			}
			if (move04 == true) {
				homelessY += .04f;
				if (homelessY > 1000) {
					move04 = false;
					move05 = true;
				}
			}
			if (move05 == true) {
				homelessX -= .04f;
				if (homelessX < 675) {
					move05 = false;
					move06 = true;
				}
			}
			if (move06 == true) {
				homelessY += .04f;
				if (homelessY > 1100) {
					move06 = false;
					move07 = true;
				}
			}
			if (move07 == true) {
				homelessX -= .04f;
				if (homelessX < 600) {
					move07 = false;
					move08 = true;
				}
			}
			if (move08 == true) {
				homelessY -= .04f;
				if (homelessY < 743) {
					move08 = false;
					move01 = true;
				}
			}
//homelessX and homelessY are the x and y cordinates of the image
#9

Great then.

#10

Hot damn dude, that’s too much!

Here’s a better (and scalable) example:


class Action {
    enum Conditions {
        LESS_THAN, GREATER_THAN;
        
        public boolean test(float v1, float v2) {
            switch(this) {
                case LESS_THAN: return v1 < v2;
                case GREATER_THAN: return v1 > v2;
            }
        }
    }
    
    private boolean doneX, doneY;
    private Condition cond;
    private float condValue;
    
    private float dx, dy;
    
    public Action(float dx, float dy) {
        this.dx = dx;
        this.dy = dy;
    }
    
    public void act(Player player) {
        player.x += dx;
        player.y += dy;
    }
    
    public Action doneWhenX(Condition cond, float condValue) {
        doneX = true; doneY = false;
        this.cond = cond;
        this.condValue = condValue;
        return this;
    }
    
    public Action doneWhenY(Condition cond, float condValue) {
        doneY = true; doneX = false;
        this.cond = cond;
        this.condValue = condValue;
        return this;
    }
    
    public boolean isDone(Player player) {
        if(cond == null)
            throw new IllegalArgumentException("No condition specified.");
        
        if(doneX)
            return cond.test(player.x, condValue);
        if(doneY)
            return cond.test(player.y, condValue);
    }
}

public class MyClass {
    public static void main(String[] args) {
        PriorityQueue<Action> actions = new PriorityQueue<>();
        actions.add(new Action(0.04f,0).doneWhenX(Action.Condition.GREATER_THAN, 700));
        //...
        
        Action curAction = null;

        // gameloop
        while(true) {
            //...
            
            if(curAction == null || curAction.isDone())
                curAction = actions.poll();
            
            if(curAction != null)
                curAction.act(player);
            
            //...
        }
    }
}