I've have a JFrame contains some JPanels using a gridBagLayout (3 rows, one column). That's my code:
Container main_container = getContentPane();
GridBagLayout layout = new GridBagLayout();
main_container.setLayout(layout);
GridBagConstraints c = new GridBagConstraints();
StatoMagazzini jpanel_stato_magazzini = new StatoMagazzini();
c.gridx = 1;
c.gridy = 2;
c.fill = GridBagConstraints.BOTH;
layout.setConstraints(jpanel_stato_magazzini, c);
AcquistoLotto jpanel_acquisto = new AcquistoLotto(i, jpanel_stato_magazzini);
c.gridx = 1;
c.gridy=1;
c.fill = GridBagConstraints.HORIZONTAL;
c.anchor = GridBagConstraints.FIRST_LINE_START;
layout.setConstraints(jpanel_acquisto, c);
ButtonPanel jpanel_button_panel = new ButtonPanel(i);
c.gridx=1;
c.gridy=3;
c.anchor = GridBagConstraints.CENTER;
layout.setConstraints(jpanel_button_panel, c);
main_container.add(jpanel_acquisto);
main_container.add(jpanel_stato_magazzini);
main_container.add(jpanel_button_panel);
pack();
and that's the result (a ugly result): https://docs.google.com/file/d/0Bxi2arJ2Dv9xbEo0Smd5QUN4UGc/edit?usp=sharing
i would eliminate that empty spaces on top and extend the second component (that is a scrollable JTable). How i should modify code?
When a GridBagLayout has more space than it needs, it distributes that extra space using the weightx and weighty properties of each cell. If no cells have a non-zero weight property, the extra space is not allocated to any cell, and instead all cells are centered, and sized to their preferred width/height.
If you do c.weighty = 1 for the constraints used by the component containing the JTable, that component will be allocated all extra vertical space. You may also want to do c.weightx = 1 so the table will fill all horizontal space.
you could set the layout of the container to BorderLayout (or something equivalent) and create an extra JPanel with the GridBagLayout and add it to the container
because of Borderlayout, the JPanel will take as much space as possible
Related
I want to make the text automatically as wide as the window. I tried using text.setSize(window.getWidth(),20) and text.setBounds(window.getWidth(),20), (where text is JTextfield), but the only way that seems to work is: static JTextField text = new JTextField(int numberOfColumns); I'm using GridBag layout.
EDIT: I have edited example according to GridBagLayout.
Use layout manager. It will automatically expands component according to window.
For example;
Jpanel panel = new JPanel(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
c.gridx = 0;
c.fill = GridBagConstraints.HORIZONTAL;
c.gridwidth = GridBagConstraints.REMAINDER;
panel.add(textfield,c);
OK I have a panel, and I want to place two panels on to it, left and right, such that the right panel should be double the width of the left side panel.
I want to add a menu to the left side panel, and the details of the selected item will appear in the right side panel.
Secondly, the size of the panels and their components should increase proportionately when the window is expanded (If any methods can be used for the purpose, please suggest!)
I did try to use the GridBagLayout but I think I have not yet been able to grasp it well. So please suggest the simplest layout manager which can serve my purpose.
EDIT:- PROBLEMS WITH WHAT I HAD TRIED WITH THE GRIDBAG
//Set Layout
setLayout(new GridBagLayout());
GridBagConstraints c= new GridBagConstraints();
//Set Layout constraints of components and add them to the MainPanel
c.gridx=0;
c.gridy=0;
c.weightx=0.5;
c.insets= new Insets(5,5,5,5);
c.fill=GridBagConstraints.BOTH;
add(iListPanel);
iListPanel.setBorder(BorderFactory.createTitledBorder("Check") );
GridBagConstraints c1= new GridBagConstraints();
c.gridx=1;
c.gridy=0;
c.weightx=1;
c.insets= new Insets(5,5,5,5);
c.fill=GridBagConstraints.BOTH;
add(iDetailsPanel);
iDetailsPanel.setBorder(BorderFactory.createTitledBorder("Check"));
Of the layout managers that come with Java, I think GridBagLayout is the simplest one that will do that. It's worth the time to learn it, because it's about the only layout manager that's halfway-competent. This should do it:
JPanel panel = new JPanel();
panel.setLayout(new GridBagLayout());
GridBagConstraints c;
JPanel left = new JPanel();
left.setBorder(BorderFactory.createTitledBorder("Left"));
c = new GridBagConstraints();
c.weightx = 1;
c.weighty = 1;
c.fill = c.BOTH;
panel.add(left, c);
JPanel right = new JPanel();
right.setBorder(BorderFactory.createTitledBorder("Right"));
c = new GridBagConstraints();
c.weightx = 2;
c.weighty = 1;
c.fill = c.BOTH;
panel.add(right, c);
However, from the description of your problem, it sounds like JSplitPane will serve you better for this. It's a ready-made component to do more-or-less what you're asking, and has a user-resizeable separator as well. An example:
JSplitPane pane = new JSplitPane();
pane.setResizeWeight(1/3f); // right will be twice size of left
JPanel left = new JPanel();
left.setBorder(BorderFactory.createTitledBorder("Left"));
pane.setLeftComponent(left);
JPanel right = new JPanel();
right.setBorder(BorderFactory.createTitledBorder("Right"));
pane.setRightComponent(right);
Edit: The problem with your original code is that it does not use the constraints.
add(iListPanel);
should be:
add(iListPanel, c);
and likewise for iDetailsPanel.
You want to use a BorderLayout.
panel.add(panelLeft,"West");
panel.add(panelRight,"East");
North, South and Center is also available
I'm a bit confused, is it possible to have multiple GridBagConstraints?
I have two panels using GridBagLayout, both affected by the same constraints. This gives me an issue when it comes to putting smaller components next to larger ones as illustrated below. The size of the panel on the left, means the cell on that row is very large, centering the panel on the right and it's components. I've tried using separate constraints for each panel but I haven't seen any differences, I think I'm doing something wrong.
How can I achieve two panels positioned next to each other, however have the components of each influenced by separate constraints?
Here's what I currently have:
Created with:
// layout
GridBagConstraints c = new GridBagConstraints();
// components
JPanel supplier = new JPanel(new GridBagLayout());
// grab the suppliers
Suppliers.Supplier[] suppliers = new Suppliers.Supplier[Suppliers.supplier.size()];
for (int i = 0; i < Suppliers.supplier.size(); i++) {
suppliers[i] = Suppliers.supplier.get(i);
}
JPanel resultsPanel = new JPanel();
JScrollPane scrollpane = new JScrollPane(resultsPanel, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
scrollpane.setPreferredSize(new Dimension(120, 300));
// style properties
c.gridx = 0;
c.gridy = 0;
c.insets = new Insets(10, 10, 10, 10);
supplier.add(scrollpane, c);
int position = 0;
for (int i = 0; i < Suppliers.supplier.size(); i++) {
b_supplierSuppliers.add(new JButton(suppliers[i].getName()));
b_supplierSuppliers.get(i).setActionCommand(suppliers[i].getId());
b_supplierSuppliers.get(i).addActionListener(this);
// style properties
c.gridx = 0;
c.gridy = position;
c.insets = new Insets(10, 10, 10, 10);
c.gridwidth = 1;
resultsPanel.add(b_supplierSuppliers.get(i), c);
position++;
}
JPanel resultsPaneltwo = new JPanel(new GridBagLayout());
// style properties
c.gridx = 1;
c.gridy = 0;
supplier.add(resultsPaneltwo, c);
// code label
l_supplierCode = new JLabel("Supplier Code");
// style properties
c.gridx = 1;
c.gridy = 0;
c.insets = new Insets(0, 10, 10, 10);
c.gridwidth = 4;
c.fill = 4;
resultsPaneltwo.add(l_supplierCode, c);
However I'm after:
Any help is much appreciated.
First, to answer your initial question. Yes, you should use different GridBagConstraints objects for each component. It's worth noting however that it is not essential to create new ones for each component, and changes to the constraint after it has been assigned to another won't affect the earlier component's position. So, for the sake of readability and later debugging it is worth declaring multiple constraints but it's not essential.
Also, it looks as though you need to specify a weighty for your constraint on your right cell. By default cells are centered in any spare space. In order to specify where that extra space is placed (vertically for y, and horizontally for x), you need to give the constraint a weight value;
c.weighty = 1;
This should make it so all extra vertical space is allocated to that cell's constraint, and as such push the cell to the top. If you create a second constraint and do the following;
c2.weighty = 1;
The extra space would be spread evenly between those two cell's constraints.I hope this helps. Let me know how you get on.
The official Oracle GridBagLayout guide says the following on the weight attributes;
weightx, weighty
Specifying weights is an art that can have a
significant impact on the appearance of the components a GridBagLayout
controls. Weights are used to determine how to distribute space among
columns (weightx) and among rows (weighty); this is important for
specifying resizing behavior. Unless you specify at least one non-zero
value for weightx or weighty, all the components clump together in the
center of their container. This is because when the weight is 0.0 (the
default), the GridBagLayout puts any extra space between its grid of
cells and the edges of the container.
Generally weights are specified with 0.0 and 1.0 as the extremes: the
numbers in between are used as necessary. Larger numbers indicate that
the component's row or column should get more space. For each column,
the weight is related to the highest weightx specified for a component
within that column, with each multicolumn component's weight being
split somehow between the columns the component is in. Similarly, each
row's weight is related to the highest weighty specified for a
component within that row. Extra space tends to go toward the
rightmost column and bottom row.
I'm new to Java Swing and I have been struggling to start the GridBagLayout from top left corner so that c.gridx=0 c.gridy=0 will put my object on the top left corner.
I'd appreciate if you could help me by telling what I need to do after this point:
JPanel panel = new JPanel(new GridBagLayout());
frame.add(panel);
GridBagConstraints c = new GridBagConstraints();
I know that I have to use NORTHWEST or FIRST_LINE_START constants, but I don't know how. I tried to do it this way' but it did not realize the constants.
frame.getContentPane().add(panel, BorderLayout.NORTHWEST);
Thanks for your help.
Read the section from the Swing tutorial on How to Use GridBagLayout. The secton on "weightx,weighty" states:
Unless you specify at least one non-zero value for weightx or weighty, all the components clump together in the center of their container.
You need to use your GridBagConstraints' anchor property. This should do it for you:
frame.setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.anchor = GridBagConstraints.NORTHWEST;
frame.add(panel, gbc);
I'm not guaranteeing that you won't have to set other properties of the constraints object to get the layout you desire. In particular, you may need to set weightx and weighty to be 1 so that the panel takes up all of the available space given to it.
For those, who use IDE (e.g. NetBeans), I finally found nice trick: if you want to add components to top and use their preferred sizes: add another empty panel with weighty = 1.0. Copied from auto-generated code (NetBeans):
gridBagConstraints = new java.awt.GridBagConstraints();
gridBagConstraints.gridx = 0;
gridBagConstraints.gridy = 2;
gridBagConstraints.weighty = 1.0;
jPanelOptions.add(jPanelFiller, gridBagConstraints);
a quick and simple way:
add a blank JLabel to end of page:
// your code goes here
gbc.weightx = 1;
gbc.weighty = 1;
bg.add(new JLabel(" "), gbc); // blank JLabel
There's a workaround. You can put the GridBagLayout panel in a BorderLayout panel with BorderLayout.NORTH. Then Component in GridBagLayout panel will start from top position.
static void test4(){
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(480, 360);
JPanel borderLayoutPanel=new JPanel(new BorderLayout());
JPanel gridBagLayoutPanel = new JPanel(new GridBagLayout());
borderLayoutPanel.add(gridBagLayoutPanel, BorderLayout.NORTH);
frame.add(borderLayoutPanel);
JButton testButton=new JButton("test button");
GridBagConstraints c = new GridBagConstraints();
c.gridx=0;
c.gridy=0;
gridBagLayoutPanel.add(testButton, c);
frame.setVisible(true);
}
if you want the grid to go all the way to the top, simply set all your weighty = 0 until the last item, set it to any number greater than 0, it will effectively push the rest of the buttons to the top.
Don't forget to also increment your button's gridy value.
Otherwise it will be centered.
(the same can be done using gridx and weightx value if you arent using the c.fill = GridBagConstraints.HORIZONTAL property.)
I am using a GridBagLayout to (currently) display two rows. I am aware this layout is overkill for this task, but am trying to learn how to use it. The problem is that I have added the two panels to the two separate rows and there is a huge gap around the content (see image and code below):
alt text http://www.imagechicken.com/uploads/1264533379009864500.png
Image background;
public Table(){
super();
ImageIcon ii = new ImageIcon(this.getClass().getResource("pokerTableV2.png"));
background = ii.getImage();
setSize(Constants.FRAME_WIDTH, Constants.TABLE_HEIGHT);
setLayout(new GridBagLayout());
GridBagConstraints constraints = new GridBagConstraints();
constraints.gridx = 0;
constraints.gridy = 0;
constraints.fill = GridBagConstraints.HORIZONTAL;
JButton button = new JButton("hello world");
JPanel panel1 = new JPanel();
panel1.setPreferredSize(new Dimension(800,100));
panel1.add(button, BorderLayout.CENTER);
panel1.setBackground(Color.yellow);
add(panel1, constraints);
constraints.gridx = 0;
constraints.gridy = 1;
JPanel middlePanel = new JPanel();
middlePanel.setPreferredSize(new Dimension(800,350));
middlePanel.add(button, BorderLayout.CENTER);
middlePanel.setBackground(Color.blue);
add(middlePanel, constraints);
}
Use
constraints.fill = GridBagConstraints.BOTH;
constraints.weightx = 1d;
constraints.weighty = 1d;
JavaDoc for weightx/weighty says:
Specifies how to distribute extra horizontal/vertical space.
JavaDoc for fill:
This field is used when the component's display area is larger
than the component's requested size. It determines whether to
resize the component, and if so, how.
Unfortunately, with GridBagLayout, if the contents do not fill the entire container that it is in, it will automatically center all its contents within its container. That is why you are getting a really large gap.
There are essentially two ways to fix this:
The hard way: Fiddle with the GridBagConstraints. I had limited success with this when trying to avoid the centre-ing behaviour.
The easy way: Put the GridBagLayout inside of a FlowLayout, and then set the alignment of the FlowLayout to top-left, or whatever you wish.
I have asked, and answered, this question myself sometime last week.
So in your case you are adding your panel1 and middlePanel directly to the JFrame (?), with a GridBagLayout
JFrame (GridBagLayout)
- panel1
- middlePanel
I would suggest this alternative structure instead, to get rid of all the extra space (and centre alignment as well, if you like).
JFrame (FlowLayout)
- JPanel (GridBagLayout)
- panel1
- middlePanel
HTH