I'm trying to achieve a design whereby one of my JPanel's heights is only set to the height of it's inner components. Currently it's laid out like so:
JPanel (BoxLayout)
JPanel (CardLayout)
JPanel (BoxLayout)
JPanel (BoxLayout)
JPanel (FlowLayout)
It currently displays as so, I want the top bit to expand the both on the x and y axis pushing the "Your Name" to above the status bar.
I need to use BoxLayouts it seems so that it flows from top to bottom.
Please help!
I want the top bit to expand the both on the x and y axis pushing the "Your Name" to above the status bar.
Then is sounds like you can use a BorderLayout as the top level panel, instead of the BoxLayout.
Since the default layout manager for the content pane of the frame is a BorderLayout you can just add the panels directly to the content pane of the frame:
frame.add(cardLayoutPanel, BorderLayout.CENTER);
frame.add(flowLayoutPanel, BorderLayout.PAGE_END);
When you add a panel to the "PAGE_END", its preferred height is respected.
When you add a panel to the "CENTER" it gets all the extra spaces available in the frame.
Read the Swing tutorial on Layout Managers for more information and working examples.
I need to use BoxLayouts it seems so that it flows from top to bottom.
You don't need to use a BoxLayout (as demonstrated above), but you can still use it if you want. BoxLayout respects the maximum size of a panel. So you could override the getPreferredSize() method of your panel using the flow layout to return the preferred height of the panel.
#Override
public Dimension getMaximumSize()
{
Dimension preferred = super.getPreferredSize();
Dimension maximum = super.getMaximumSize();
maximum.height = preferred.height;
return maximum;
}
Now the height of the flow panel will be respected and all the extra space will go to the other panel.
Related
I'm trying to use a BoxLayout to display 2 panels vertically and I searched how to center the components in those panels. At the moment, my components are placed on the top center of each panel, and I want to get them at the center X and Y.
I added the components I want in the 2 panels, then I added the panels in my BoxLayout. This way they're displayed vertically as I want them to be, but as I said I don't want them to be on top center.
I tried to use methods such as setAlignementY and setLocation but any of them actually moves the components. I also saw that a BoxLayout will try to set the components as wide as the widest component, but as I have only 2 panels which have the same size I don't really understand it.
This is basically how I've added my components (without trying to center) :
private void initPanels ()
{
this.titlePanel.add(this.title);
this.bookInputPanel.add(bookTitle);
this.bookInputPanel.add(bookInput);
this.authorInputPanel.add(by);
this.authorInputPanel.add(authorInput);
this.authorInputPanel.add(this.authorsTable);
this.buttonsPanel.add(confirm);
this.contentPanel.setLayout(new BoxLayout(this.contentPanel, BoxLayout.Y_AXIS));
this.contentPanel.add(bookInputPanel);
this.contentPanel.add(authorInputPanel);
this.add(this.titlePanel, BorderLayout.NORTH);
this.add(this.contentPanel, BorderLayout.CENTER);
this.add(this.buttonsPanel, BorderLayout.SOUTH);
}
I made a picture to show you exactly what I want but it seems that I need 10 rep to do it, sorry about that.
This way they're displayed vertically as I want them to be, but as I said I don't want them to be on top center.
One way is to add "glue" to the top/bottom of the panel. This "glue" will expand to fill the extra space available to the panel:
this.contentPane.add(Box.createVerticalGlue());
this.contentPanel.add(bookInputPanel);
this.contentPanel.add(authorInputPanel);
this.contentPane.add(Box.createVerticalGlue());
Read the section from the Swing tutorial on How to Use BoxLayout for more information about the feature of a BoxLayout.
Another option might be to use a "wrapper" panel that uses a different layout manager. For example the GridBagLayout with the default constraints will automatically center the component horizontally/vertically:
//this.add(this.contentPanel, BorderLayout.CENTER);
JPanel wrapper = new JPanel( new GridBagLayout() );
wrapper.add( contentPanel );
this.add(wrapper, BorderLayout.CENTER);
I have a set of JPanel's within a JFrame. One of the panels contains a JTextArea. At the moment I create this like so:
JTextArea = new JTextArea(5, 40);
And this gives me a text area which is 5 rows by (roughly) 40 columns.
Vertically this works as I'd like it to, the area fills the entire height of the parent container - probably because the parent is the only element positioned in that row.
Horizontally the parent width is determined by elements underneath and it is (usually) wider than the JTextArea is. So I end up with a text area with large margins on either side. What is worse, when I resize the frame smaller to the point where the text area is exactly the width of the parent container, it suddenly 'flicks' and changes into a text area that is 1 row high and is then the width of the parent.
Excuse the crude drawing below which hopefully illustrates the issue.
In short: How to I create a JTextArea that always fills the maximum space available to it? (and if possible with a minimum width after which a scrollbar appears if the user sizes the frame even smaller)
In the parent container of the JTextArea (denoted as Panel 1 in your drawing), call the function:
panel1.setLayout(new BorderLayout());
For reference, see this documentation page:
https://docs.oracle.com/javase/7/docs/api/java/awt/BorderLayout.html
As you only have a single child in panel1, the BorderLayout layout manager of panel1 will by default stretch the text area to use all available space in the parent container.
You may want to take away the constructor parameters specifying the size of your TextArea. The BorderLayout should take care of sizes for you :)
You can request that Swing respects a certain minimum size for the text area by calling:
textArea.setMinimumSize(new Dimension(minimum_width, minimum_height));
You have to use layout manager, for start see oficial Oracle docu about layout managers. For your situation, BorderLayout or GridBagLayout should work fine.
Start with:
panel1.setLayout(new BorderLayout());
or
panel1.setLayout(new GridBagLayout());
With GridBagLayout you can more preciselly do layouting (with BorderLayout you have five areas - no more, no less). With GridBagLayout you can do more complicated layouts.
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.
Hi I have been learning Java Swing for creating a chess game to practice my Java programming skills.
I've added a JPanel to the east of the JFrame with BorderLayout and I've used the setPrefferedSize(new Dimension(x,y)) method to set the width and height.
After that I have created 4 JPanel and added them with BoxLayout on the previously created panel.
I have tried to set the size of the 4 panels with the setSize(x,y) and setPreferredSize(new Dimension(x,y)) but it dosent work the 4 panels automaticly changed there size to fit the main JPanel and after adding a JLabel on one of them the size of it increased automaticly .
This is my code:
this.setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
JPanel a = new JPanel();
a.setPreferredSize(new Dimension(50, 50)); //this dosent work
a.add(min);
a.setBackground(Color.red);
this.add;
JPanel b = new JPanel();
b.setBackground(Color.blue);
this.add(b);
JPanel c = new JPanel();
this.add(c);
JPanel d = new JPanel();
d.setBackground(Color.black);
this.add(d);
How can I change the size of each of these panels?
BoxLayout is best for laying out components with varying sizes along a single axis. From the Javadocs:
"BoxLayout attempts to arrange components at their preferred widths (for horizontal layout) or heights (for vertical layout)."
The idea is that they may have different heights (for a horizontal layout) and it will take the maximum height. And, they definitely may have different widths. Also, BoxLayout works with some, er, "interesting" filler pieces like Box.createHorizontalGlue(). These are actually quite useful for flexible, resizeable layouts once you get the hang of it. But, all in all, BoxLayout is for flexible, resizable layout of items with differing sizes.
For simpler cases, especially if you want both preferred width and preferred height to be "respected", use GridLayout as everybody else has suggested.
Is there any way to make a JSlider to fit the width of a JPanel when it resizes? I'm now using. JFrame's pack() method and when I resize the panel in which the slider is contained, the slider doesn't change its size.
Thanks in advance!
Actual sizing behaviour is controlled by the LayoutManager used in the panel. The default is FlowLayout which keeps the children at their preferredSize. Change to a LayoutManager which sizes them bigger/smaller than their pref, for a single child f.i. the center of a BorderLayout:
JPanel panel = new JPanel(new BorderLayout());
panel.add(mySlider)
There are others, read the chapter about LayoutManagers in snoracle's online Swing tutorial