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);
Related
In Java, when using the BorderLayout, is it possible to have two panels in the CENTER, but both be visible on the form.
Here is my code:
guiFrame.add(guiFieldsPanel, BorderLayout.CENTER);
guiFrame.add(guiButtonsPanel, BorderLayout.CENTER);
guiFrame.setVisible(true);
In the above code, both panels are set to the center, yet I can only see the guiButtonsPanel as it is 'on top' of the guiFieldsPanel.
Can i group both panels together, and then set them to be displayed in the CENTER?
See the Nested Layout Example for ideas about how to combine layouts to create the required layout. E.G.
Perhaps use a single row GridLayout for the center.
guiFrame.add(guiFieldsPanel, BorderLayout.CENTER);
guiFrame.add(guiButtonsPanel, BorderLayout.CENTER);
But that suggests a 2 column GroupLayout as seen in this answer. E.G.
You will need to create an intermediate panel that will contain both guiFieldsPanel and guiButtonsPanel, and then add that to the border layout.
final JPanel centre = new JPanel(new FlowLayout(FlowLayout.LEFT, 0, 0));
centre.add(guiFieldsPanel);
centre.add(guiButtonsPanel);
guiFrame.add(centre, BorderLayout.CENTER);
guiFrame.setVisible(true);
You can adjust the layout of centre as appropriate for your needs with respect to the relative positioning of guiFieldsPanel and guiButtonsPanel.
I am trying to build my own "Battleship" game and have problems with swing.
I now read endless docs on oracle tutorials on LayoutManagers, but not any of them works as I understand them. They only add a few buttons, but never two individual panels.
JPanel Background = new JPanel();
Background.setLayout(new BoxLayout(Background, BoxLayout.X_AXIS));
panelPlayer = new JPanel();
panelPlayer.setBorder(BorderFactory.createLineBorder(Color.black));
panelPlayer.setSize(700, 600);
// PC Field
panelPc = new JPanel();
panelPc.setBorder(BorderFactory.createLineBorder(Color.black));
panelPc.setSize(700, 600);
//adding to frame
getContentPane().add(Background);
Background.add(panelPlayer);
Background.add(panelPc);
After that I have a loop thats adds 16x16 buttons in a JButton[] once for every panel.
How to get the two panels to show a table layout?
I used GridLayout before, the grid works, but it always takes up the whole space of the frame, not of the Container or Panel or else. The panels are overlapping then.
GridBagLayout just puts the buttons in a row and beyond the screen.
Don't fix the size of the panel while using any layout. It works only when you use null layout
You can achieve your goal with GridBagLayout. While adding buttons specify gridx, gridy correctly, it will add buttons like table
just keep nesting the layouts.
in your case make a big one with two sides -
then in each side place another panel with your grid.
You can solve this by nesting panels. Each panel has its own layout manager, so it is a matter of breaking up your UI into pieces and choosing the layout manager for each piece.
If you want two panels side-by-side, then the panel that contains them should have a FlowLayout manager with horizontal orientation. Create a panel with FlowLayout and add the panels to it.
If each of the the side-by-side panels needs the grid of buttons, then set the panel layout to GridLayout and put the buttons in the panel. This fits what I remember of Battleship; in a grid layout, all the grid elements remain the same size no matter how the window is resized.
That should get you started. If, as I expect, you will want another panel with some game controls on it, look into BorderLayout; it has a section on each edge of a rectangle and another in the middle. Put the panel containing the two grids in the center of a panel using BorderLayout, and then your game controls can go in a panel to the north, south, east, or west of that.
Good luck. Let us know if you have a specific problem (in another question).
I already have a panel made (its a row of buttons), and have it located at the bottom of a frame (SOUTH), but I would like to add two rows (panels/ subpanels) beneath it (a text input line and output line if it matters). Right now the only thing I know to do is declare and add more panels, which would be fine, but when I specify .SOUTH they go over top of the previous panel.
EDIT: The solution I used
As suggested by Ted Hopp, I added my original panel (now called subPanel1), as well as the two new panels which were going on top of the original (subPanel2 & subPanel3), to a fourth "container panel" (bottomCotainerPanel). Since I only had three subPanels, this allowed me to specify where in the containerPanel each subPanel would go (using NORTH, CENTER, SOUTH, might have to do something slightly different if you had more than 3...), and then specify where the contianerPanel would go in the frame (SOUTH).
subPanel1.setLayout(new GridLayout(1,6)); //Layout of subPanel1
subPanel1.add(clearButton);
subPanel1.add(customerNameLabel);
subPanel1.add(customerNameTextField);
subPanel1.add(showByNameButton);
subPanel1.add(openNewSavingsButton);
subPanel1.add(openNewCheckingButton);
subPanel2.add(sendChatTextField);
subPanel2.add(sendButton);
subPanel2.add(clearButton2);
subPanel3.add(receiveChatTextField);
subPanel3.add(nextButton);
subPanel3.add(previousButton);
bottomContainerPanel.setLayout(new GridLayout(3,1)); //Layout of Container Panel
bottomContainerPanel.add(subPanel1, BorderLayout.NORTH);
bottomContainerPanel.add(subPanel2, BorderLayout.CENTER);
bottomContainerPanel.add(subPanel3, BorderLayout.SOUTH);
tellerWindow.getContentPane().add(bottomContainerPanel, BorderLayout.SOUTH);
You need to add a single container panel as the SOUTH panel of the frame. The container itself should have the layout that you want for everything that goes at the bottom.
If you just want to split panel onto 2 equal parts at south and north use GridLayout. If you want something in the middle you can use BorderLayout.
If you want to give your user ability to change the sub-panels size use JSplitPane.
I had a similar problem trying to put several rows of buttons into a panel borrowed from the ListDemo example. Well, the first thing to do is to read about BorderLayout: How to Use BorderLayout, or at least see the image shown there:
You cannot have multiple bottom rows in a BorderLayout. But you can use a nested layout. What we need is a BoxLayout, see How to Use BoxLayout:
.
We just have to replace the buttons shown on the above image by rows of buttons.
public class MyStuff extends JPanel {
...
public MyStuff() {
super(new BorderLayout());
...
JPanel buttonArea = new JPanel();
buttonArea.setLayout(new BoxLayout(buttonArea, BoxLayout.PAGE_AXIS));
add(buttonArea, BorderLayout.PAGE_END);
...
//if you dislike the default center alignment:
//panelWithButtons1.setAlignmentX(Component.LEFT_ALIGNMENT);
buttonArea.add(...);// add the 1st panel with buttons
buttonArea.add(...);// add the 2nd panel with buttons
buttonArea.add(...);// add the 3rd panel with buttons
I want to add a Jpanel on a jscrollpane; also I want to have only vertical scrolling. I want to set layout of my jPanel "flowLaout" and add several components to my jPanel in my code by jpanel.add(component) method. The result is that all components are placed in just one row that excide width of jpanel and are not shown. I have used this tricks and both failed:
jScrollPane1.setHorizontalScrollBar(null);
jScrollPane1.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
Wrap Layout should work for you.
I am unsure of the particulars for your current project, but i would recommend MigLayout. It has never served me wrong.
I am currently writing a touchscreen interface with nested MigLayout panels up to 4 or five layers deep, and have not had a single problem.
Please use the below policy to turn on vertical scrolling and turn off horizontal scrolling(Works with Java SE 7):
Panel graphicPanel = new Panel();
JScrollPane scrollbar = new JScrollPane(graphicPanel);
scrollbar.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED);
scrollbar.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
scrollbar.setPreferredSize(new Dimension(1300, 600));
scrollbar.setVisible(true);
add(scrollbar, BorderLayout.CENTER);
BorderLayout does something strange. If I add two panels to a Container with the same constraint (BorderLayout.CENTER for instance), then the first one goes away, even if the second one is deleted or made invisible
It seems as though it would make sense for it to "stack" each element on top of the previous ones.
Is this correct and by design? If so, is there some documentation on it?
Has anyone else been frustrated by it? Have you a solution, such as a custom LayoutManager?
Sample code:
JFrame frame = new JFrame();
frame.setSize(500, 500);
JPanel panel1 = new JPanel();
panel1.setBackground(Color.blue);
frame.getContentPane().add(panel1);
JPanel panel2 = new JPanel();
panel2.setBackground(Color.red);
frame.getContentPane().add(panel2);
panel2.setVisible(false); // Seems like it should allow us to see panel1.
frame.setVisible(true);
This creates and displays a 500x500 blank box.
BorderLayout was simply not designed to do what you want. Separation of responsibility. If you want that behavior you should compose: combine the BorderLayout with a CardLayout. Though for the actual stack behavior, you'll have to code something yourself (or find someone who already has.)
Is this correct and by design?
Yes.
You need to understand the basics of how layout managers work. One of the jobs of the layout manager is to set the "location" and "size" of the components added to the panel. In the case of a BorderLayout it only tracks 5 components so only the last component added to the CENTER is known by the layout manager.
Layout management is not done when components are added to the panel. It is done when the frame is packed, or made visible (or the revalidate() method is invoked) . In this case the blue panel is not part of the components managed by the BorderLayout so its size remains (0, 0), which means there is nothing to paint.
Try changing your code to:
JPanel panel1 = new JPanel();
panel1.setSize(200, 200);
and you will see the blue panel painted at the specified size.
Now try commenting out:
//panel2.setVisible(false);
and you will see both panels. This is because as components are added to the panel they are assigned a ZOrder. Basically the last component added is painted first, which is why the blue panel is painted on top of the red panel. Check out the setComponentZOrder() method of the Container class for more information.
The CardLayout is probably the layout manager you should be using, but you can check out the Overlap Layout as well.