I am using MigLayout and I would like to create an effect like using BoxLayout's "glue" to create an invisible space that will flexibly fill the area between two components. From the tutorial:
I understand that in MigLayout, gaps are used to create spaces between components. I can create a rigid space with "gap 10". The MiG Layout Cheatsheet says that I can append push to a bound size with a gap to "make that gap "greedy" and take any left over space" (e.g. "gap rel:push"), but that doesn't seem to work in the following code that I've tried:
JFrame frame = new JFrame("Test");
JPanel panel = new JPanel(new MigLayout());
JLabel label1 = new JLabel("Testing");
label1.setBorder(BorderFactory.createLineBorder(Color.black)); //Border to clearly show JLabel boundaries
panel.add(label1, "");
JLabel label2 = new JLabel("Testing Once Again");
label2.setBorder(BorderFactory.createLineBorder(Color.black)); //Border to clearly show JLabel boundaries
panel.add(label2, "gap rel:push");
frame.setContentPane(panel);
frame.pack();
frame.setMinimumSize(new Dimension(400, 100));
frame.setPreferredSize(new Dimension(400, 100));
frame.setVisible(true);
Which displays a window like this:
I would expect for the "gap rel:push" parameter to work like horizontal glue in the picture above and thus push the JLabel on the right all the way to the right edge of the window, but it doesn't.
How can I get the same effect as BoxLayout's glue using MigLayout? Am I misusing the "gap" parameter or is there some other way to accomplish it?
Also, I realize that I could use docking in the example given, but I'd like an answer without that because it won't work in a more complex layout I'm creating.
Save yourself some sanity points and enable debug borders on the MiGLayout: new MigLayout("debug").
It's possible that the gap is indeed pushing the components apart, but the layout isn't using all of the available space. This should be obvious if you turn on debug borders. Try making the layout use all available space: new MigLayout("debug, fill").
Instead of placing a gap between your label and the cell edge, you may want to place a gap between the two columns: new MigLayout("debug, fill", "[]rel:push[]"). The difference should become clear when using a multi-row layout. In this case, you may not need the fill constraint: new MigLayout("debug", "[]rel:push[]").
I don't have a compiler handy to run this against, but I hope I've given you something to work with.
Related
i made a custom JFrame for the desktop application and i added a JPanel on the very top of the app to serve as a subtitute of the title box. the problem is when i added a button it located right in the middle of the JPanel instead of the usual left top. AND it would not move even if i set it at a different location.
here is the code:
JFrame f = new JFrame("Hello");
f.setResizable(true);
JPanel pa = new JPanel();
JButton btn = new JButton("Exit");
btn.setBackground(Color.white);
btn.setText("Button");
btn.setSize(300, 80);
btn.setLocation(50, 0);
pa.setBackground(Color.red);
pa.setPreferredSize(new Dimension(width,60));
pa.add(btn);
f.setBackground(Color.white);
f.setUndecorated(true);
f.getContentPane().add(pa, BorderLayout.NORTH);
f.setSize(new Dimension(width,height));
f.setLocation(200, 200);
f.setVisible(true);
You use a BorderLayout in the frame. You can do the same thing in the panel.
pa.setLayout(new BorderLayout());
pa.add(btn, BorderLayout.WEST);
In general, setLocation tends to fight against the layout manager, so you usually don't want to use it unless you're going to position everything by hand.
that is one way to do it, but BorderLayout way is not very good way because i also want to add another button next to it.
Then what this might need is a FlowLayout using FlowLayout.LEADING as the alignment.
But as general tips:
Provide ASCII art or a simple drawing of the intended layout of the GUI (showing all components) at minimum size, and if resizable, with more width and height - to show how the extra space should be used.
For better help sooner, post a
Minimal, Complete, and Verifiable example or Short, Self Contained, Correct Example of your attempt.
I am extremely new to Java Swing, and I'm having quite a bit of issues getting a nice layout going. I have checked out google, and even other answers on this website, but no information I find seems to solve the issue. Here is the result of my efforts:
As you can see, the label, text field, and button are all out of alignment. It is my goal for all of them to have the same left-hand border, and for the button and text field to have the same right-hand border, with these left and right hand borders being each the same distance from the left and righthand sides of my window.
Here are the important parts of my code:
public void run()
{
JFrame frame = new JFrame("Arduino Server");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
InstancePanel = new ServerGUIPanel();
frame.getContentPane().add(InstancePanel);
frame.pack();
frame.setVisible(true);
}
And, in ServerGUIPanel.java:
public ServerGUIPanel()
{
setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
setPreferredSize(new Dimension(500, 500));
setBorder(new EmptyBorder(10, 10, 10, 10));
StatusLabel = new JLabel("STATUS: BOOTUP");
add(StatusLabel);
PortField = new JTextField();
PortField.setPreferredSize(new Dimension(5000, 20));
PortField.setMaximumSize(PortField.getPreferredSize());
PortField.setActionCommand("PortChanged");
add(PortField);
ConnectionButton = new JButton();
ConnectionButton.setPreferredSize(new Dimension(5000, 20));
ConnectionButton.setMaximumSize(ConnectionButton.getPreferredSize());
ConnectionButton.setActionCommand("ConnectionClicked");
add(ConnectionButton);
}
Does anyone have a simple solution to this? What am I doing wrong here?
Thank you very much!
--Georges Oates Larsen
Read the section from the Swing tutorial on How to Use BoxLayout for the basics of using a BoxLayout as well as a section on alignment issues.
Basically you need to make sure the alignmentX value of all components is set to be left aligned.
Also:
Don't use setPreferredSize() to set the size of a component. Each Swing component will determine its own preferred size.
Use Java naming conventions. Variable names should NOT start with an upper case character.
I would not recommend using setPreferredSize() AND setMaximumSize(). The latter will cause problems when stretching your main frame. [Your components will likely not want resize]
You should be using layout managers to handle all the alignments itself. I would stay away from using BoxLayout in this case, as different components want to size differently, and that will sway the alignment when added into your BoxLayout panel.
Moreover, you might want to give your main frame a layout as well.
Can you post how you used your GridBagLayout?
I have a panel derived from JPanel. I have a custom control derived from JLabel. I am attempting to center this custom JLabel on my panel.
The only way I know to do this that will work is to use the a null layout (setLayout(null)) and then calculate the custom JLabel's setLocation() point so that it's in the right spot.
The custom JLabel is physically moved from one panel to this panel in this app and I believe the location previously set in setLocation is affecting things. However when I set it to (0,0) the component goes up into the upper left corner.
BorderLayout doesn't work because when only 1 component is provided and placed into BorderLayout.CENTER, the central section expands to fill all of the space.
An example I cut and pasted from another site used BoxLayout and component.setAlignmentX(Component.CENTER_ALIGNMENT). This didn't work either.
Another answer mentioned overriding the panel's getInset() function (I think that's what it was called), but that proved to be a dead end.
So far I'm working with a panel with a GridBagLayout layout and I include a GridBagConstraints object when I insert the custom JLabel into my panel. This is inefficient, though. Is there a better way to center the JLabel in my JPanel?
Set GridBagLayout for JPanel, put JLabel without any GridBagConstraints to the JPanel, JLabel will be centered
example
import java.awt.*;
import javax.swing.*;
public class CenteredJLabel {
private JFrame frame = new JFrame("Test");
private JPanel panel = new JPanel();
private JLabel label = new JLabel("CenteredJLabel");
public CenteredJLabel() {
panel.setLayout(new GridBagLayout());
panel.add(label);
panel.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.add(panel);
frame.setSize(400, 300);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
CenteredJLabel centeredJLabel = new CenteredJLabel();
}
});
}
}
Supose your JLabel is called label, then use:
label.setHorizontalAlignment(JLabel.CENTER);
Forget all the LayoutManagers in the Java Standard Library and use MigLayout. In my experience it's much easier to work with an usually does exactly what you expect it to do.
Here's how to accomplish what you're after using MigLayout.
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import net.miginfocom.swing.MigLayout;
public class Test
{
public static void main( String[] args )
{
JFrame frame = new JFrame( );
JPanel panel = new JPanel( );
// use MigLayout
panel.setLayout( new MigLayout( ) );
// add the panel to the frame
frame.add( panel );
// create the label
JLabel label = new JLabel( "Text" );
// give the label MigLayout constraints
panel.add( label, "push, align center" );
// show the frame
frame.setSize( 400, 400 );
frame.setVisible( true );
}
}
Most of that is just boilerplate. The key is the layout constraint: "push, align center":
align center tells MigLayout to place the JLabel in the center of its grid cell.
push tells MigLayout to expand the grid cell to fill available space.
BoxLayout is the way to go. If you set up a X_AXIS BoxLayout, try adding horizontal glues before and after the component:
panel.add(Box.createHorizontalGlue());
panel.add(label);
panel.add(Box.createHorizontalGlue());
I don't like the answers here.
I've never seen a valid use of a GridBagLayout ever in my career. Not saying there isn't one, just saying I haven't seen [a valid] one, and there might be correlation there. Moreover, adding a single JLabel to the middle of a Container might make it center for demonstrational purposes, but you're going to have a lot harder of a time later on if you try to continue to work with that over some other layouts.
I do like the suggestion about the BoxLayout, because that is actually a great way to do it. That said, that answer is only part of the puzzle, hence why I'm dredging up a 7 year old question.
My 'Answer'
Really there is no short answer to your question. There is an exact answer to your question based on what you asked, but StackOverflow is about a community learning from each other, and I suspect you're trying to learn how to use layouts in general (or you were 7 years ago) and telling you to type a combination of keys to do exactly your demo case is not going to teach you the answer.
I'm going to try not to explain any layouts that you can't web-search the answer for on your own (with a link to the Oracle tutorial at the end, because I think it explains the different layouts fairly well).
BoxLayout
BoxLayout is one way to do it, and there is already a code snippet to demo it above so I won't provide one. I'll expand on it to say that, just as mentioned, that only answers your question exactly, but doesn't really teach you anything. Glue, as the BoxLayout refers to it, basically gives you an equal amount of remaining real-estate between all the 'glue' currently in the Container. So, if you were to do something like
panel.add(Box.createHorizontalGlue());
panel.add(label);
panel.add(Box.createHorizontalGlue());
panel.add(otherLabel);
You would find that your JLabel is no longer centered, because the 'glue' is only the remaining real-estate left, after two JLabels were added to the Container which will be equally divided between the two 'slots' (two calls to Container#add(Component) with a glue parameter) in theContainer`.
BorderLayout
BorderLayout is another way to go about this. BorderLayout is broken down into 5 regions. BorderLayout#CENTER, as you might guess, is the center region. The important note about this layout and how it centers things is how it obeys sizes of the Component that is in the center. That I won't detail though; the Oracle tutorial at the end covers it well enough if you're interested, I think.
Worth Noting
I suppose you could use a GridLayout, but it's a more simple way to do it over a GridBagLayout, which I already said even that I think is not a good approach. So I won't detail this one either.
The Point of it All
Now all that said, I think all LayoutManagers are worth a look. Just like anything else with relation to programming - use the tool that fits the job. Don't just assume because you used X layout before, that you should always use X layout and no other layout is viable. Figure out what you want your display to look like, and how you think it should behave with respect to resizing components, and then pick what you think would work best.
Another dual meaning of picking the right tool, is that you don't have to just fit all of your components into one single Container and make one layout do everything. There is nothing stopping you (and I strongly encourage you to) use multiple Containers and group them all together. Control each Container with a layout that is appropriate for that section of the display, and a different layout for a different Container.
Important!!
The reason why this is very important is because each layout has rules and things that they obey, and other things that they respect, and then others that are effectively ignored (i.e. preferred, maximum, and minimum sizes, for instance). If you use different layouts [correctly], you will find your display accepts dynamically being resized while still obeying the shape that you wanted it to hold. This is a very important key difference between doing it the right way, and just settling with GridBagLayout.
JPanel outer = new JPanel(new BorderLayout());
JPanel centerPanel = new JPanel();
centerPanel.setLayout(new BoxLayout(centerPanel, BoxLayout.PAGE_AXIS));
JPanel southPanel = new JPanel(new CardLayout());
outer.add(centerPanel, BorderLayout.CENTER);
outer.add(southPanel, BorderLayout.SOUTH);
Figure out what is appropriate to your scenario, and go with that. There is no one-size-fits-all unless you want something overly cumbersome and made redundant by other layouts (i.e. GridBagLayout).
Oracle's Tutorial
If you've made it this far, then I think you're looking for as much information as you can get. In which case, I strongly encourage you to read Oracle's tutorial on layout managers because it lays out general details of them all very well: https://docs.oracle.com/javase/tutorial/uiswing/layout/visual.html
Use this.
labelName.setHorizontalAlignment(SwingConstants.CENTER);
or
labelName.setHorizontalAlignment(JPanel.CENTER);
Both of them must work.
Do like this instead of libraries and layouts :
JLabel jlabel = new JLabel("Label Text", SwingConstants.CENTER);
Make sure to import javax.swing.SwingConstants INTERFACE , BUT DO NOT IMPLEMENT IT. It contains only constants and no methods.
Put the JLabel in a JPanel or else it will come at the center of the JFrame or JWindow (your top level container).
I have got a window that looks like window1 and I would like it to look like window2:
This is my code:
String q = "Have you used GUI before?";
JLabel textLabel2 = new JLabel(
"<html><div style=\"text-align: center;\">" + q + "</html>", SwingConstants.CENTER);
add(textLabel2, BorderLayout.NORTH);
JPanel radioPanel = new JPanel();
add(radioPanel, BorderLayout.CENTER);
JPanel btnPanel = new JPanel();
add(btnPanel, BorderLayout.SOUTH);
For the radio-buttons, I tried to use GridLayout, but it broke the position of "Yes" and "No". And for the "back" and "next" buttons, horizontal alignment did not work (btnPanel.setAlignmentX(RIGHT_ALIGNMENT);), apparently. Any solutions will be highly appreciated, I'm stuck with this bit way too long. Thanks
--EDIT--
That is working perfectly fine:
btnPanel.setLayout(new BoxLayout(btnPanel, BoxLayout.LINE_AXIS));
btnPanel.setBorder(BorderFactory.createEmptyBorder(0, 10, 10, 10));
btnPanel.add(Box.createHorizontalGlue());
so the buttons problem is solved.
However, still can't get the radio-buttons fixed.
--EDIT 2--
Fixed the background for the radio-buttons using setOpaque(false);
What do you mean by it "broke" the position of "yes" and "no" as a GridLayout should work just fine. I'd give it 1 column and 2 (or 0 for variable number of) rows via new GridLayout(0, 1). Be sure that its opaque property is set as false by doing radioPanel.setOpaque(false);. This way it will show the background color of the container that it sits in. You may need to make the JRadioButtons non-opaque as well, I'm not sure.
Your btnPanel could use a BoxLayout and use Box.createGlue() to push the buttons over to the right side.
Most importantly -- if you haven't yet done so, please read the tutorials on use of the Swing layout managers which you can find here.
A couple of things you can do about this. You need to change your LayoutManager. This is not a great task for BorderLayout. You could do nested BoxLayouts. A vertical box that has the vertical fixed height strut, label, vertical fixed height strut, yes radio, vertical fixed strut, no radio, Vertical glue, and the final button panel. Then use your edit in the button panel to horizontally align them. That's one option, but the nesting of the panels is annoying.
Another option go get TableLayout and learn how to use it. TableLayout is one of the best LayoutManagers. It's easy to use, solidly tested, and it makes Swing fun again. You'll never use GridBagLayout ever ever ever again.
http://java.sun.com/products/jfc/tsc/articles/tablelayout/
The final option is use the new GroupLayout. I'm not terribly familiar with it, but it looks pretty easy. And, it doesn't take as much code or nesting unnecessary panels like Box does.
I'm writing a small Java GUI program, and I'm having some issues with Java not laying things out properly. I haven't done much Java GUI code lately, so I'm having trouble seeing where the problem lies.
final JFreeChart chart = createChart(dataset);
final ChartPanel chartPanel = new ChartPanel(chart, false);
chartPanel.setPreferredSize(new Dimension(500, 270));
JPanel buttonPanel = new JPanel();
buttonPanel.setPreferredSize(new Dimension(500,50));
JButton toggleButton = new JButton("Toggle");
final JTextField minRange = new JTextField("10");
final JTextField maxRange = new JTextField("1000");
JButton setLimits = new JButton("Set Limits");
buttonPanel.add(toggleButton, BorderLayout.NORTH);
buttonPanel.add(minRange, BorderLayout.SOUTH);
buttonPanel.add(maxRange, BorderLayout.SOUTH);
buttonPanel.add(setLimits);
JSplitPane jsp = new JSplitPane(JSplitPane.VERTICAL_SPLIT, chartPanel, buttonPanel);
jsp.setDividerLocation(0.8);
setContentPane(jsp);
What's happening here is that all of the layout options are completely being ignored. The GUI components are showing up properly, and the divider specifically is ignoring the preferred size of JFreeChart, and squeezing it to about 5% of space at the top of the frame.
In addition to problems with the splitpane not respecting your desired sizes, you are using BorderLayout constants but you haven't specified the layout for the panel (the default is FlowLayout).
This:
JPanel buttonPanel = new JPanel();
Should be:
JPanel buttonPanel = new JPanel(new BorderLayout());
I believe that using a float proportion on JSplitPane only works once the split pane is "realized", otherwise you're getting a proportion of zero because it doesn't know how big its going to be.
also:
buttonPanel.add(minRange, BorderLayout.SOUTH);
buttonPanel.add(maxRange, BorderLayout.SOUTH);
BorderLayout only allows one component to be in each area, so min range will never appear, as maxRange is now "the" south component. if you want both you'll need to put those 2 components in another panel, then add that panel to the south.
Try setting the minimum size too.
See: Java GUI Problems
JSplitPane pays attention to the minimum size, not the preferred size. Try simply changing setPreferredSize to setMinumumSize.
Dan Dyer is correct, you didn't set the Layout.
You could also set it by buttonPanel.setLayout(new BorderLayout())
And John Gardner is correct that you set a component to BorderLayout.SOUTH twice.
Also check out MigLayout if you don't already know about it. Its the least "surprising" layout manager I've ever used. It just works. It takes some learning, but very straight forward once you get over the syntax.
And I would avoid SplitPane if you can...its very finicky
Never call setPreferredSize() - it should be a calculation.
For example, your ButtonPanel is being set to a fixed preferred size.
What if you add I18N support and the user is using a language with very long localizations? What if the user resizes the frame?
Check out my article on layout managers for details on how you should really use them. It's from 1999 but still applies:
http://java.sun.com/developer/onlineTraining/GUI/AWTLayoutMgr/
Enjoy!