I've got a JDialog which contains a series of JPanels in a CardLayout. Some of these panels contain JTables which I would like to be resized in line with any resizing of the JDialog. I am not sure how to achieve this and any help would be greatly appreciated.
At present the tables simply remain their current size and do not scale. I'm sure its something simple but I'm having trouble locating the exact approach needed.
Many thanks in advance. I will provide any more information if required.
edit: The JDialog is used as a wizard, so only one of the panels is being displayed at any one time, hence the use of CardLayout. I would ideally like to keep this is layout manager, although if it is the source of the problems then obviously I would rethink!
You can keep the CardLayout, but you need to do the following:
1. set the layout of your JDialog to BorderLayout, and add a new JPanel (contentPanel) to the JDialog
2. now set this contentPanel layout to be CardLayout
3. add your other panels to the cardlayout as required.
4. Also make sure off the layouts you use on each of the panels you're adding to the CardLayout. By default JPanel uses FlowLayout, I think, and this is not ideal for a JTable. So you might need to play around with the layout of the panel containing the table as well; try out BoxLayout or BorderLayout for that as well.
Related
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.
Is there any way to tell a JPanel using CardLayout where to add a component?
Let' s say I have one of these panels in the center of a frame, and I want to display 3 components inside that panel. Would this be possible?
Sure, it's easy. Just put a JPanel as one of the cards, then position the components in the panel using whatever layout works best.
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.
I have a JFrame.
I also have a Box class which extends Component.
This box class has a paint method which makes a filled rectangle.
When I add multiple of these Box components to my JFrame, only the most recently added one is displayed when I call repaint on the JFrame.
I took a look at the layout managers, but I am not sure that's what I want. All I want is to be able to make an animation of whole bunch of rectangles wherever I want on the screen.
(I also tried creating a panel, adding the panel to the JFrame, and then adding all the Box components to the panel. This did not work either).
Thanks in advance!
You have 2 choices.
You can change the layout of your frame:
JFrame frame;
frame.setLayout(new FlowLayout());
Now, if you add more than one box, it will show up on the frame.
The other option is to do what you said you tried. (Adding a panel to the frame)
JPanel pane = new JPanel();
frame.add(pane);
(add the boxes to 'pane')
Also, you should be careful with the sizing of your Box. You will probably want a call to setPreferredSize() somewhere in the creation of the Box. This will tell Java what size to make the box when it is added to the layout.
You should also take a look at the Java Layout Manager Tutorials. There is lots of great info there.
And, one more thing. The reason only one box at a time was being displayed on the frame was because JFrame's layout manager is BorderLayout. And, when you call add on a component that has a BorderLayout, the component is automatically added to the center of the component. Subsequent calls to add will overwrite the center component, leaving only one component in the middle.
You do need to check out other layout managers. JFrame by default uses BorderLayout and without specifying the "place" a component is added, they get added to CENTER. Depending on what you want your UI to look like depends on the layout manager to use. I would suggest maybe using Netbeans GUI builder.
EDIT: Missed the part about what you want to add but the concept is still the same, if you just add these components to the default layout manager, they will get overwritten. Sounds like you may need to do your painting inside of just one of your Box components or create a JPanel and set the layout to null but then you would have to place them explicitly. Really depends on what you want to do with it exactly.
Do your layout on paper first, then read up on Swing layout managers.
Be aware that some Swing components only allow one component to be added to them. I've run across this when using Tabbed panes. Each tab can only accept one control (JPane?) so you have to create a separate panel with a layout to arrange the related controls and then as a unit add the pane to the tab. There are similar arrangements in the Swing library.
You could set the frame layout to null and then use setBounds() to position your boxes exactly where you want.
Thank you for all your answers.
Since I am using my own custom class, Box, I have the ability of setting the position of my the rectangle through the paint method.
I realized my Box class was extending the wrong thing. It should have been extending javax.swing.Jcomponent.
If I now use a panel with an OverlayLayout, add my components to that panel, they all show up properly.