Thread: How to get visible size of jpanel

a.jpg
So, i noticed a little misbehavior in java with all the sizes of jpanel. When i set bounds of jpanel, i.e., setbounds(0, 0, 100, 100), then the first point's (0,0) position is normal, but the second point is not point (100,100), because the size actually includes window decorations and/or shadows - a real mess, dont know what excatly is included, and the last visible point is something like (80,80) ... How can i get window decoration size, or how can i set visible size, not real size ?

I dont like layout managers and the way they work, so i dont use them, i do everything manually, it is much easier to place elements in the right place manualy, layout manager is like stupid AI in games Actually, this is not a big deal, i could just calculate myself java's miscalculations, but i just wondered if there is something in java, that determines size of window borders.

Originally Posted by startas

How can i get window decoration size, or how can i set visible size, not real size ?

Sounds like a bug introduced by the the code itself. Post the code in question where we can have a look

It will be just a program for myself, so no different pcs, especially devices, and screens. I'm just starting to build my programs gui, but initial code looks like this :

import java.awt.Dimension;
import javax.swing.ImageIcon;
import javax.swing.JLabel;
import javax.swing.JFrame;
import javax.swing.JPanel;
 
public class MyProgram{
    private JFrame frame;
    private JPanel panel;
    private JLabel label;
    private int frameWidth = 1300;
    private int frameHeight = 700;
    private ImageIcon backgroundImage;
 
    public MyProgram() {
        initUI();
    }
 
 
    public void initUI() {
        frame = new JFrame("my program");
        backgroundImage = new ImageIcon("images/background.jpg"); 
        panel = new JPanel();
        label = new JLabel(backgroundImage);
 
        panel.setLayout(null);
        frame.setLayout(null);
        frame.add(label);
 
        frame.setBounds(10, 10, frameWidth, frameHeight);
        panel.setBounds(0, 0, frameWidth, frameHeight);
 
        panel.setSize(new Dimension(frameWidth, frameHeight));
        frame.setSize(new Dimension(frameWidth, frameHeight));
        label.setSize(new Dimension(frameWidth, frameHeight));
        label.setBounds(0, 0, frameWidth, frameHeight);
        frame.setResizable(false);
 
 
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
 
    public static void main(String[] args) {
        new MyProgram();
    }
}

The panel is never added to the frame, fix that first...

Ok, my bad, update : it's not the point if it is jpanel or jlabel or jbutton or whatever, the point is, i can set frame's size i.e. to 1300x700, but i cant fit other elements into frame's work place 1:1, my element's (buttons, labels, other things...) starting point (0,0) gets good position, as you can see in picture above - it's point number 1, but i dont know how to get/set the last point in frame's work place (xxx,yyy) - point number 2 in picture above - without manual calculations / tweaks like frameWidth-15 or whatever i will get from experiments.

See post #5.
Learn to use layout managers, it is not hard, and very helpful when used correctly.

Do not force the size of the frame. Set the preferred size of the JPanel, add everything to the panel, add the panel to the frame, call frame.pack().
The frame will size itself around the panel and give itself room for the decorations, the top left corner of the displayable area will be 0,0

If i have a simple JTabbedPane tabbedPane, and i add a few tabs to it with tabbedPane.addTab("name", JPanel panel), is it possible to add the same one element, i.e. JButton, to all of those panels-tabs ? Because i simply tried to do to all panels panelX.add(button), but button is visible only on the last panel i added it to, not on all panels.

s it possible to add the same one element, i.e. JButton, to all of those panels-tabs ?

No it is not. A component can only be in one place at any given point in time. If added to a new/different container, it will remove itself from its previous container (as shown by your tests). I do not have the documentation handy at this point, but this rule is printed somewhere in there, and should be easy enough to discover with a search engine and enough keywords.

So the only variant to keep one element over every other element is to add that element directly to frame, i.e. JFrame frame.add(button, 0) ?

What do you mean by "over every other element"?
---What ever, the answer will still be 'No'
JFrame is a Container and will function like all other Containers in terms of how things are treated when added, (Other factors do come in to play like LayoutManager)

Well, visually. I have a few panels-tabs, tabs has their own elements, and i need a way to add somewhere element, which will be visible over all other elements, so far the only way i found is to add element directly to jframe to position 0, frame.add(element, 0).

I do not understand the effect you are trying to achieve, perhaps a screenshot of what you want, or some code to show what you are attempting to accomplish?

I'm making a simple game, and part of the game is elements, that randomly appears/disappears at random positions, i realised these elements via jbutton, and i'm looking for the best way to keep these elements always on top over the rest of graphics. The part of appearing of element is realised via a simple frame.add(button, 0), and part of removing button is realised via frame.remove(button).
There is nothing to not understand, open task manager and set "always on top", you will see what i'm trying to do.

You have an endearing personality, even in this medium.

"on top" and "over" could mean the y or z ordering depending on the context, and you were never specific.
Look at the glass pane and the layered pane