double buffering fail...

Newbie & Debugging Questions
#1

Ok… I was attempting to make a 2D game, but for some odd reason double buffering isn’t working. I have used it in several other programs and set it up the same way here, but here it doesn’t work. In the other programs the code was shorter and only one or two Images were being loaded. This program loads all the images at launch, adds all componets, sets up double buffering, but right after this I tell it to change the canvas background color to blue, screen stays white. I tell it to run the game loop (which at this point only paints parts of the background) and it does nothing. I checked with a println() to see if the Images finished loading (they did), so i just don’t know why it wont work. the code is here: http://pastebin.com/h1T4beYW

If your unwilling to look through the whole code (understandable its long), pls just tell me any Ideas you have on what might cause double buffering to not work. pls feel free to correct me if I’m doing anything horridly ineffecient or unneccesary (because I’m sure I have), Ty for any help.

#2

lines 48 and 49.

base.getWidth() returns 0. Your scale is f****d up

#3

THANK YOU FOR FINDING THAT!!! ;D ;D ;D ;D It actually paints now, THANK U SOOO MUCH!

holy crap 0_0 it does, why does base.getWidth() return 0… I have another class called GPanel that uses that method (it extends panel) and while inside GPanel (this.getWidth()) the method returns correctly, but then when its used in another class (and base.getWidth() is called) it returns 0. Why the heck does it do that?

#4

It’s really a simple answer as to why it does that.

Due to the way that swing and the like works, most objects either are assigned a size by what’s inside of them or by the layout manager of the object that they’re added to (Typically more the latter than the former, but there are objects where the former is important). You’re adding the base object to a Container (JFrame in the form of DescendedRupture) that doesn’t have a layout manager, and since you do not manually adjust the size of the object, it has nowhere to get its size from (So it has dimensions of 0.) Check if your other panel is being added to a container that has a layout manager assigned to it.

To fix this issue, you can replace


DescendedRupture()
    {
        super("Descended Rupture");
        addWindowListener(this);
        setSize(806,624);
        setResizable(false);
        add(base);

with


DescendedRupture()
    {
        super("Descended Rupture");
        addWindowListener(this);
        setSize(806,624);
        setResizable(false);
        setLayoutManager(new BorderLayout());
        add(base, BorderLayout.CENTER);
#5

Descended Rupture actually extended regular frame (no swing at all) I was paranoid about the EDT so I didn’t use swing at all… Also I tried adding a (1,1) grid layout to the frame (DescendedRupture) then added the base panel, base.getWidth() still returned 0, I tried setting its layout to null (just in case, even though I think it is null by default) then adding the base panel, and using base.setBounds(), no matter what I set its width and height to in setBounds, base.getWidth() still returned 0. I don’t know what to make of it, but thankfully I could get around it because a canvas was on top of base, and its getWidth() and getHeight() methods worked.