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What layout should I use for chat history

![two muppets][1]
I want to make a chat history in java swing.
I have a JScrollPane. I append dinamic multiple JPanels in him.
I use BoxLayout but I have a problem:
- When appending the first JPanel it are height 100% of JScrollPane.
- When appending the second JPanel, both are height 50% of total JScrollPane.
I want to make each JPanel have fixed height (40px).
What layout should I use or what should I do?

First off, I'd consider using a JList and not a grid of JPanels.
Your JList cell may easily display what looks like a JPanel view by simply using the right renderer.
And you'd lesson GUI override doing this.
If you must use JPanels, I'd put them in a GridLayout or BoxLayout container (JPanel)
Add this container to a BorderLayout using container (JPanel), to its BorderLayout.PAGE_START position
And then add this final container to the JScrollPane's viewport.

How to create a rectangle with multiple images inside?

What is the best way to display let's say rectangle (3x5) with icons 20x20 px.? I want to change the image file of every pic icon later (= it's not just static pictures). I tried to make JFrame full of JPanels, but i was able to display only one panel at a time. I don't want to use GridLayout, because I need just small rectangle inside a frame. Any ideas how to do it? Couldn't find any tutorial or solution. I'm completely new to GUI developement. Thanks

You do want to use a GridLayout. Your problem is that the JFrame you put the icons into uses a BorderLayout by default (and really, you shouldn't change the layout of a top level component).
What this means is that, if you add multiple panels to the frame, without using one of the NORTH, EAST, SOUTH, WEST constraints, only one of the panels will be visible and take up all the space. If you use a GridLayout for that one panel you get, the icons will be stretched, because the panel receives all the space due to the frame's BorderLayout. An alternate layout that doesn't stretch its contents is FlowLayout, but the layout to use depends heavily on your context.
To display the icons, a JLabel is handy. Use an ImageIcon for the label's icon. You can later use setIcon() on the label to choose a new icon.
overall, my approach would be this:
use a JFrame which has a BorderLayout
to the frame, add a JPanel to the frame. The default layout is a FlowLayout, which will prevent the stretching
to the panel, add a JPanel with an appropriate GridLayout
to that panel, add the JLabels, each having an appropriate ImageIcon

How to put two java swing JPanels next to each other and have a table in it?

I am trying to build my own "Battleship" game and have problems with swing.
I now read endless docs on oracle tutorials on LayoutManagers, but not any of them works as I understand them. They only add a few buttons, but never two individual panels.
JPanel Background = new JPanel();
Background.setLayout(new BoxLayout(Background, BoxLayout.X_AXIS));
panelPlayer = new JPanel();
panelPlayer.setBorder(BorderFactory.createLineBorder(Color.black));
panelPlayer.setSize(700, 600);
// PC Field
panelPc = new JPanel();
panelPc.setBorder(BorderFactory.createLineBorder(Color.black));
panelPc.setSize(700, 600);
//adding to frame
getContentPane().add(Background);
Background.add(panelPlayer);
Background.add(panelPc);
After that I have a loop thats adds 16x16 buttons in a JButton[] once for every panel.
How to get the two panels to show a table layout?
I used GridLayout before, the grid works, but it always takes up the whole space of the frame, not of the Container or Panel or else. The panels are overlapping then.
GridBagLayout just puts the buttons in a row and beyond the screen.

Don't fix the size of the panel while using any layout. It works only when you use null layout
You can achieve your goal with GridBagLayout. While adding buttons specify gridx, gridy correctly, it will add buttons like table

just keep nesting the layouts.
in your case make a big one with two sides -
then in each side place another panel with your grid.

You can solve this by nesting panels. Each panel has its own layout manager, so it is a matter of breaking up your UI into pieces and choosing the layout manager for each piece.
If you want two panels side-by-side, then the panel that contains them should have a FlowLayout manager with horizontal orientation. Create a panel with FlowLayout and add the panels to it.
If each of the the side-by-side panels needs the grid of buttons, then set the panel layout to GridLayout and put the buttons in the panel. This fits what I remember of Battleship; in a grid layout, all the grid elements remain the same size no matter how the window is resized.
That should get you started. If, as I expect, you will want another panel with some game controls on it, look into BorderLayout; it has a section on each edge of a rectangle and another in the middle. Put the panel containing the two grids in the center of a panel using BorderLayout, and then your game controls can go in a panel to the north, south, east, or west of that.
Good luck. Let us know if you have a specific problem (in another question).

Java Swing layout issue

I added child panel to parent panel by using method 'parent.addTab(child)' and added one JLabel in the child panel but setBounds method is not working in child panel. This JLabel is getting showed at one fix location. setBounds is working fine in parent panel. What to do?

You need to define an appropriate layout manager for your child panel. For example, if you chose to use BorderLayout you could arrange for the label to be shown in the center of the panel as follows:
JTabbedPane parent = new JTabbedPane();
JPanel child = new JPanel(new BorderLayout());
// Create label with centrally aligned text (default is left).
JLabel label = new JLabel("Hello, World", JLabel.CENTER_ALIGNMENT);
// Add label to center of the child panel.
child.add(label, BorderLayout.CENTER);
// Add child panel as a tab within parent JTabbedPane.
// The child panel will expand to fit the size of the tab.
parent.addTab("My Tab", child);
For more a flexible layout consider using GridBagLayout.

setBounds only work for containers that have their layout set to null. (Or for moving frames around on the desktop.)
JPanel's default layout manager is FlowLayout which lays out components in order horizontally, and dropping to a new row when the current is full (like text in a page).
Using a null layout and setBounds isn't a recommended way to lay out GUIs - it's very fragile - too much depends on the size of the container / frame and the size, resolution and font settings of the desktop can easily break the layout.
Read through the Using Layout Managers section of the Swing tutorial to figure out what layout managers can help you accomplish what you want.

JLabel on top of another JLabel

Is it possible to add a JLabel on top of another JLabel? Thanks.

The short answer is yes, as a JLabel is a Container, so it can accept a Component (a JLabel is a subclass of Component) to add into the JLabel by using the add method:
JLabel outsideLabel = new JLabel("Hello");
JLabel insideLabel = new JLabel("World");
outsideLabel.add(insideLabel);
In the above code, the insideLabel is added to the outsideLabel.
However, visually, a label with the text "Hello" shows up, so one cannot really see the label that is contained within the label.
So, the question comes down what one really wants to accomplish by adding a label on top of another label.
Edit:
From the comments:
well, what i wanted to do was first,
read a certain fraction from a file,
then display that fraction in a
jlabel. what i thought of was to
divide the fraction into 3 parts, then
use a label for each of the three.
then second, i want to be able to drag
the fraction, so i thought i could use
another jlabel, and place the 3'mini
jlabels' over the big jlabel. i don't
know if this will work though..:|
It sounds like one should look into how to use layout managers in Java.
A good place to start would be Using Layout Managers and A Visual Guide to Layout Managers, both from The Java Tutorials.
It sounds like a GridLayout could be one option to accomplish the task.
JPanel p = new JPanel(new GridLayout(0, 1));
p.add(new JLabel("One"));
p.add(new JLabel("Two"));
p.add(new JLabel("Three"));
In the above example, the JPanel is made to use a GridLayout as the layout manager, and is told to make a row of JLabels.

The answer to your original question is yes for the reasons given that any Component can be added to a Container.
The reason you don't see the second label is because by default a JLabel uses a null layout manager and the size of the second label is (0, 0) so there is nothing to paint. So all you need to do is set the bounds of the second label and away you go.
You can't use a layout manager if you want to drag components around because as soon as you resize the frame etc, the layout manager will be invoked and the components will be repositioned based on the layout manager of the component.

it's a matter of layout.
you can do that using null layout (with hard coded locations) or with a custom layout.

you can use a JLayeredPane and set it's border to No Border.

you can add put them above each others by using the horizontal or vertical gap (hgap,vgap) the attributes of the layout
JPanel p = new JPanel(new GridLayout(2, 1,-40,0));
//the 40 is the hgap , make it the same with the label height .