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.
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.
I have a JFrame with layout BorderLayout, I add JPanels using BorderLayout.CENTER
I have a JPanel(added using CENTER), that uses GridLayout to place 4 buttons.
These buttons are MASSIVE, taking up the whole screen. Or, I do it my way as follows:
I have a JFrame with layout null, I set JPanel bounds and add them.
I have a JPanel:
It sets it's own bounds so it takes up center 1/2 of screen, and is only 1/8 of the screen
tall.
It adds buttons using grid layout, and results in a nice line of buttons.
Obviously the second option looks better, but as I wish to conform to the norm, and always use layouts... How to I mix customization and layouts?(Or just solve my problem at all)
When you add a componeent to BorderLayout.CENTER, it will expand to fill the remaining space of the container not used by the other portions of the BorderLayout. Also, you can only add one component at a time to BorderLayout.CENTER. Subsequent adds will replace the previous component.
As for solving your exact problem, I suggest you start by taking a look at A Visual Guide to Layout Managers. This will give you a primer on what layouts are available in the Swing API. Oracle also has more in-depth tutorials for each layout. By nesting layouts, you can give your UI any look that you wish while leveraging their power, especially auto-calculations when a window is resized or otherwise changed.
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.
How would I go about making the length of the tabs automatically resize based on how much room is left in that row of tabs.
Picture:
As you can see the tab's width is based off the text in the tab.
If you need me to explain what I want better then just ask me because I don't know if I made it clear enough.
You can use a custom component and set it's preferred size. For example, in ButtonTabComponent of TabComponentsDemo:
label.setPreferredSize(new Dimension(...));
You have to choose an appropriate dimension based on other aspects of your layout, so it won't be automatic.
I want to define a size for the actual tabbed pan.
The size of the JTabbedPane is a function of the dimensions and LayoutManager of the Container to which it has been added. In the example cited, the default layout of the frame's content pane is BorderLayout, and add(pane) adds it to the center by default.
To accomplish your goal, I see two approaches:
Divide the current width of the enclosing Container among the existing tabs and repaint the tabbed pane, as shown in this example.
Develop your own implementation of TabbedPaneUI and interpret SCROLL_TAB_LAYOUT accordingly.