I'm building a GUI with several JPanels and with a BoxLayout with Y-axis. I also use borders with titles around the JPanels. I wonder if it's possible to control the space between the border of the JPanel and the window frame? I'm also wondering if it's possible to justify the content inside the JPanels to the left or right? Thanks!
You could add an EmptyBorder using CompoundBorder to wrap both, the current border and the emtpy one. The empty border would not be rendered but allow you to define the margin to the frame using insets.
The justification of the panel's content would depend on the layout manager used there. Do you have a BoxLayout inside the panel as well?
Edit:
A really good and easy to use layout manager is MigLayout. It allows defining custom insets, alignment etc. inline and using just a single layoutmanager.
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I'm attempting to create a GUI as pictured:
I'm having some trouble deciding which layout would be the best for this.
I've attempted to use a GridBagLayout, but can't figure out how to make items different sizes, and how to position them.
I've also considered using a BorderLayout and creating an eastpanel, westpanel and centerpanel these using the respective layout constraints to put them there, but this feels incorrect.
I've also read the how to use GridBagLayout Java tutorial, but still can't figure out how to achieve the goal.
You should not force yourself to use only a single panel with a single layout. Nest several panels inside each other with each panel possibly having different layouts.
You could have 1 root panel with a BorderLayout. For the top you have a panel with a FlowLayout (or maybe a gridbaglayout). And the center can be another panel with a GridBagLayout or perhaps a combination of more nested panels.
There is no one magic layout that can do everything. Composition is the key.
I have two JPanel instances in a JLayeredPane, on different z-orders. I want both of my child JPanels to always fill the space of the LayeredPane.
The idea is for me to toggle the display of a 2nd panel over top of the first to display a modal-like dialog. Yes, I could just use a JDialog, but I thought it would be fun to try and create some transparancy overtop of the covered JPanel for a nice effect.
I find that using a layout manager on the JLayeredPane, like BorderLayout, and trying to set both children to CENTER conflicts since both panels can't be in the Center.
Is there a trick that I'm not seeing?
The idea is for me to toggle the display of a 2nd panel over top of the first
The easiest way to do this is to use a Glass Pane.
Check out the Disabled Glass Pane for an example of this approach.
There are two ways to create some "Glass Panel like" overlay for JPanels with JLayeredPane:
Add a ComponentListener to the JLayeredPane and update the sizes of all child components whenever the size of the JLayeredPane changes
Create a simple FillLayout, which expands the size of its child Components to the size of the Layout Container (In our case the JLayeredPane). You need to keep a list of children Components. During layoutContainer you copy the dimensions of the Container to these child Components. I wrote this and its really simple, but unfortunately I can't post it, since it's corporate. But if anyone is interested just ask in the comments. The implementation basically consists of one-liners.
For both solutions you need to make sure, that the panels on top are transparent, by setting setOpaque to false. This ensures that underlying panels render their content.
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
I'm having trouble organizing the contents of a JPanel. I've tried different layout managers but haven't gotten anything to work.
The JPanel contains 3 other JPanels and should look like this:
Does anyone know how I can achieve this layout?
Thanks in advance.
What you want is similar to a BorderLayout, but using one natively will cause the second pane to fill the bottom space (rather than the 3rd pane.)
However, you could use two in tandem to get this effect - The first BorderLayout pane would contain the second BorderLayout pane (in its centre) and panel 3 (on its east.)
In the second BorderLayout pane, you could then just set pane 1 to be the centre, and pane 2 to be the south.
Simplest, but not best solution, is to use null Layout Manager with manually set components bounds. It is called Absolute Positioning
Other approach is to use horizontal SplitPane with nested Vertical SplitPane: left one will contain vertical splitPane with Panel1 and Panel2, and right will be just Panel3.
I've got an arbitrary number of JPanels being created based on user input (like 1-8 panels). Right now, I'm putting all the panels in a larger panel using FlowLayout, and then adding that panel to my main window which is using BoxLayout. I want the panels to fit the width of the main window but right now they are very small. Should I use a different layout or is there a way to do this?
You have to choose GridLayout or GridBagLayout.
Yes, you should use a different layout manager. Use BorderLayout (tutorial here), which streches all the contents to fit the container.
Also, BorderLayout doesn't allow more than one component in each area, thus you will need another sub-panel to hold your panels. Don't use FlowLayout for that sub-panel, as it will not have the streching behaviour your are looking for.