Checking who has the first Y in a list.

Newbie & Debugging Questions
#1

Hi there,

I was coding today some constructions, but the problem I saw was that the constructions were overlapping each other. So I thaught let’s make a simple forloop that look for the first y and then draws it.

    public void renderEntities(Screen screen) {
        for (Entity e : getEntities()) {
            for (int yDraw = 0; yDraw < this.height; yDraw++){
            	int yPlace = e.getY();
            	if(yPlace == yDraw){
                	e.render(screen);
            	}
        	}
        }
    }

The idea was simple, but afterwards I checked what I did and I thaught: What am I doing? So I looked at my code again and started to think at what was first the code:

public void renderEntities(Screen screen) {
        for (Entity e : getEntities()) {
                e.render(screen);
        }
}

This code is evrytime taking the first entity in the list (then the second etc.), so why was I looking for the first entity’s y? then ++ it, this will make entities that are later in the list and have a higher y invisible. But I don’t know how to search wich Y is first and then using that entity first, does anyone know how this works good and can explain me how it works? Because I need to learn how to programm and I want to solve the problem!

Already thanks!
-RoseSlayer

#2

It looks like you want to sort your collection of entities. You can do it like this.


       Comparator<Entity> entityYComparator = new Comparator<Entity>() {

            @Override
            public int compare(Entity o1, Entity o2) {
                return o1.getY() - o2.getY();
            }
        };
        Collections.sort(entities, entityYComparator );
#3

@Danny02, I am glad you helped me with this!
I searched a small tutorial for it what it is actually doing really so I can use it in more ways!

Thanks again!
-RoseSlayer