I have a JTabbedPane with a Border Layout.
Here's the code I'm using to add the components:
add(columnNames, BorderLayout.NORTH);
add(scroll, BorderLayout.CENTER);
add(useCtrl, BorderLayout.SOUTH);
setVisible(true);
Question:
Notice the excess whitespace to the right inside the JScrollPane. I don't want that there. I would like for the JScrollPane not to change size at all when changing the size of the JFrame. I have tried setSize() and setPreferredSize(), but the size of the JScrollPane always changes. I've tried using GridLayout, but I get the same result.
Place the JScrollPane in a JPanel with another layout. (e.g. BoxLayout or GridBagLayout). And add the JPanel to the center.
The size of a graphics object is controlled by the layout manager. The BorderLayout will always expand the CENTER object to take up all available space. GridLayout expands all it's children proportionally. If you try a GridBagLayout and set the weightx to 0, that will prevent expansion horizontally.
There are a lot of layout managers available, browse the API for more choices and experiment until you find the resizing behavior you want. Each has a fairly good explanation of how it works in the javadoc.
Related
I have a JFrame that has a JPanel inside. I call "setPreferredSize(new Dimension(500, 600));" but I want the JPanel and its contents to resize when someone resizes the JFrame.
BorderLayout is the way to go. Components start at their preferred size, but are expanded as needed to fill the region they are in.
Set your layout on your frame with BorderLayout
Add your JPanel by
frame.add(yourPanel, BorderLayout.CENTER);
This will allow it to stretch vertically & horizontally
As for the Contents inside a JPanel, give it a layout that will accommodate stretching as well.
Use a layout manager instead of setting the bounds for each component.
It is going to vary from program to program how you want your components to move.
Take a look at this and try to see which layout will work best for you.
I have a JPanel inside of a JScrollPane which is nested inside some other containers. My JPanel uses a modified FlowLayout from SO user jxd in this question.
This may be information overkill but the full nesting of the panel in question is as follows:
JPanel (ModifiedFlowLayout) > JScrollPane > JPanel (GridBagLayout) > JTabbedPane > JPanel (GridBagLayout) > JSplitPane > JPanel (BorderLayout) > JFrame.
The problem is that when I call pack() on my JFrame the JScrollPane/JPanel expands horizontally to fill the entire remaining screen space (across multiple monitors). The space used is more than is needed to display all of the components in the JPanel. I tried using setMaximumSize() on my JPanel but it seems to be ignored in this scenario.
Ideally I would like the panel to have it's size dictated by space left after sizing the components that surround it. Can/how can this been done?
The preferred size of a FlowLayout will try to display all components on a single row. I don't know how the ModifiedFlowLayout works but you can check out Wrap Layout which does the same thing.
However, when using Wrap Layout you can use the setSize(...) method to make a suggestion as to what the initial width should be. Initial wrapping of components should then be based on that size.
I have a collection of JPanels for different elements: JPanel showPane, seasonsPane, episodesPane, airingsPane
all of which have setLayout set to null and are of fixed size 304x416. I added those JPanels to a JPanel called showViewPanel of size 1280x416 and set up a BoxLayout like so (below is the code in the JFrame):
showViewPanel.setLayout(new BoxLayout(showViewPanel, BoxLayout.X_AXIS));
showViewPanel.setSize(1280, 416);
showViewScroll = new JScrollPane(showViewPanel);
add(showViewScroll);
setSize(304, 416);
setVisible(true);
What I can't figure out is why it does not produce a scrollable view of all the components and instead resizes showViewPanel to match the size of the window. What am I doing wrong?
all of which have setLayout set to null and are of fixed size 304x416.
Don't use a null layout!!! Don't manually set the size of a panel!!! Your panels should be using a layout manager so the preferred size will be calculated automatically.
If you want all your panels to be the same size then maybe use a GridLayout for your main panel (instead of the BoxLayout) and then add your child panels to this panel.
Scrollbars will automatically appear when needed if you let the layout managers do their job.
Override the preferredSize of the subpanels to 304x416 instead. The scrollpane relies on the preferred size of the content (which depends on the preferred size of its contents).
The layout manager will set the size of the subpanels depending on their preferred sizes, so your custom ones get overridden. Generally, you should get rid of null layouts and learn to use the layout managers. Absolute placement leads to trouble all the time, and is not worth the hassle even when it does not.
I'm building a Swing application in Java using NetBeans and I have a problem with layout. My main frame contains a JScrollPane which contains a JPanel called contentPanel which in turn contains a JPanel called listPanel. The listPanel is empty when the program starts, but when the user interacts with the program an unpredictable number of smaller JPanels are added to it. I've used the NetBeans GUI-builder to snap the top edge of listPanel to the top of contentPanel, and the same with the bottom edges.
The problem I have is that when more components are added to listPanel the vertical scrollbar doesen't appear on my scrollpane. The verticalScrollBarPolicy of my scrollpane is set to AS_NEEDED and its viewportView is set to contentPanel. What I think I need to do is to make contentPanel grow when more items are added to listPanel.
The problem I have is that when more components are added to listPanel the vertical scrollbar doesen't appear on my scrollpane.
The scrollbar will appear when the preferred size of the component added to the scrollpane is greater than the size of the scrollpane. When you add components dynamically you need to tell the scrollpane something has changed. So you basic code should be:
panel.add( subPanel );
panel.revalidate();
Or, because you are adding a panel to the sub panel, you may need to revalidate the scrollpane (I don't remember):
panel.add( subPanel );
scrollPane.revalidate();
The key is the revalidate() which tell the layout manager to recalculate its size.
Use a different LayoutManager. One that will allow for vertical growth like BoxLayout. Also remember that you can use multiple layouts and nest them inside of each other for different effects.
I have a JTabbedPane and a JTextArea, I want the Textareas/Panes to resize to fit the window when the window is resized. How do I do this? I'm also fuzzy on if it's the right text component to use.
Really Muddled.
EDIT: I was setting explicit size as a dumb dumb. I've got it all worked out. What I did is set the viewport of a JScrollPane as the JTextArea and remove all explicit sizing.
Thanks chaps!
You can use whatever components you like. All JComponents can resize with a resizing parent container. You simply need to choose the correct LayoutManager.
Depending on how you want everything set up, I assume you will want to add your JTabbedPane to your JFrame like so:
JTabbedPane jtp;
JFrame frame;
// JFrame's default layour is border layout.
frame.add(jtp, BorderLayout.CENTER);
This will cause the JTabbed pane to take up all of the space of the JFrame.
You will also need to set your JTabbedPane's layout manager to BorderLayout, and also any tab you add to the JTabbedPane will need to have a BorderLayout.
To set the layout of your components, do:
JComponent anyComponent;
anyComponent.setLayout(new BorderLayout());
Have a look at the Java LayoutManager tutorials for more information.
I should mention that the reason I suggest BorderLayout is because any component added to the CENTER of a BorderLayout will automatically take up any space not taken up by any of the borders. And, since you aren't adding anything to any of the other borders (NORTH, SOUTH, EAST, WEST) the component in the center will take up the entire space.
Every JComponent is resized automatically when the container it resides in, is resized.
It's not a matter of the right component but more a matter of which LayoutManager to use.
When adding a Component to a container, you can set the minimum size, default size and maximum size.
On resizing the container, the component will scale automatically until reaching the desired maximum size.
If you need code snippets, tell me and I will fire up my IDE later.
cheers
EDIT: jjnguy beat me to it.. nvm then :p