I'm building up a panel that will go in a larger program; the following program still illustrates my question, but it looks a bit more complicated than it absolutely has to because there are places I will add things later.
package sandbox;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class SpacingPlay extends JFrame
{
private static final long serialVersionUID = 1L;
public static void main(String[] args)
{
SpacingPlay sp = new SpacingPlay();
sp.setVisible(true);
}
public SpacingPlay()
{
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new DragNDropPanel();
add(panel);
pack();
}
class DragNDropPanel extends JPanel
{
private static final long serialVersionUID = 1L;
public DragNDropPanel()
{
JPanel currentImagePanel = getCurrentImagePanel();
JPanel leftPanel = new JPanel();
leftPanel.setLayout(new BoxLayout(leftPanel, BoxLayout.PAGE_AXIS));
leftPanel.add(currentImagePanel);
// other things will go here; I cut them out to make this simpler.
setLayout(new BorderLayout());
// put things in a containing panel so that they aren't stretched being in the WEST part of a borderlayout.
JPanel leftContainingPanel = new JPanel();
leftContainingPanel.add(leftPanel);
add(leftContainingPanel, BorderLayout.WEST);
}
private Component createStandardSpace()
{
return Box.createRigidArea(new Dimension(0, 15));
}
private JPanel getCurrentImagePanel()
{
JPanel currentImagePanel = new JPanel();
currentImagePanel.setLayout(new BoxLayout(currentImagePanel, BoxLayout.PAGE_AXIS));
JLabel currentImageLabel = new JLabel("none");
currentImageLabel.setBorder(BorderFactory.createDashedBorder(Color.BLUE));
currentImageLabel.setAlignmentX(Component.CENTER_ALIGNMENT);
Dimension defaultLabelSize = new Dimension(150,150); // was expecting this to enlarge the label.
currentImageLabel.setPreferredSize(defaultLabelSize);
currentImageLabel.setSize(defaultLabelSize);
JButton clearButton = new JButton("Clear");
clearButton.setAlignmentX(Component.CENTER_ALIGNMENT);
clearButton.setBorder(BorderFactory.createLineBorder(Color.GREEN));
currentImagePanel.add(currentImageLabel);
currentImagePanel.add(createStandardSpace());
currentImagePanel.add(clearButton);
currentImagePanel.setBorder(BorderFactory.createLineBorder(Color.ORANGE));
return currentImagePanel;
}
}
}
I would like the currentImageLabel to be a standard size; I intend for it to get different images put into it during the program, and want it to get these without changing size. My idea was to set a size and preferred size and then scale the images I put there to that size.
However, the defaultLabelSize doesn't have the effect I thought it would. The label goes into a boxLayout panel; it is added, then a rigid space, then a button. I expected the label to be the default size, not shrunk to min allowed. I've put in colored borders to try to understand better what's happening; it appears that the preferred size is honored for the overall boxLayout panel, but not for the placement of the button below the label. EDIT: In other words, I want the button below the label to be placed below the label when the label is forced to be bigger. But the size I put on the label doesn't seem to work.
What do I need to do to fix the size of currentImageLabel?
Not 100% why the label is only sized to the text and not the (hard coded) preferred size. I have not been able to duplicate this behaviour using other combinations of panels and layout managers.
You are using pack so all components should be sized to their preferred sizes.
Dimension defaultLabelSize = new Dimension(150,150); // was expecting this to enlarge the label.
currentImageLabel.setPreferredSize(defaultLabelSize);
currentImageLabel.setSize(defaultLabelSize);
A few comments:
Setting the size will never work. The layout manager will always override the size/location based on the rules of the layout manager.
The layout manager can use (or ignore) the preferred, minimum and maximum sizes of a component. In the case of the BoxLayout is does attempt to use the preferred size but will respect the minimum and maximum sizes (depending on the available space in the parent panel).
What do I need to do to fix the size of currentImageLabel?
So, to achieve your desired goal of a fixed preferred size for the JLabel you can use:
Dimension defaultLabelSize = new Dimension(150,150); // was expecting this to enlarge the label.
currentImageLabel.setPreferredSize(defaultLabelSize);
currentImageLabel.setMinimumSize(defaultLabelSize);
currentImageLabel.setMaximumSize(defaultLabelSize);
//currentImageLabel.setSize(defaultLabelSize);
Edit:
was looking for why this doesn't seem to work
For further clarification, change your original code to:
currentImageLabel.setPreferredSize(defaultLabelSize);
System.out.println(currentImageLabel.getPreferredSize());
System.out.println(currentImageLabel.getMinimumSize());
System.out.println(currentImageLabel.getMaximumSize());
You will see the min/max sizes of the label are not affected.
From point 2 above you will see that the BoxLayout is respecting the maximum size.
Therefore, by also overriding the maximum size, you allow the label to be displayed at is preferred size.
However, when you calculate the preferred size of the "currentImagePanel" the ( hardcoded) preferred size of the label is used in the preferred size calculation of the panel, so that panel is displayed at the preferred size.
Another note. The "leftContainingPanel" is not needed. You can just add the "leftPanel" to the BorderLayout.WEST, since the BorderLayout will respect the width of the component you add.
Related
I have done tons of searching over the past two hours, and I've given up. The image below shows what I am trying to achieve (don't judge my drawing it's late and I made it in paint quickly):
Basically, I want a JScrollPane to have a JPanel with a 2-column GridLayout, and as I add elements I want the GridLayout to expand downward. I want the elements to use their Preferred Size and to NOT expand within the GridLayout.
Currently I have a JScrollPane and a JPanel with a GridLayout, and a JPanel containing the grid with a FlowLayout. As a test, I add 10 buttons to the grid. Here's my current code:
// Setup main panel
JPanel pnlUsers = new JPanel(new GridLayout(0, 2));
pnlUsers.setOpaque(true);
pnlUsers.setBackground(Color.GREEN);
// Setup GridLayout Container
JPanel pnl2 = new JPanel();
pnl2.setOpaque(false);
pnl2.add(pnlusers);
// Setup scrollpane
JScrollPane scrUsers = new JScrollPane(pnl2);
scrUsers.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED);
scrUsers.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
scrUsers.setOpaque(false);
scrUsers.getViewport().setOpaque(false);
scrUsers.setBorder(null);
// Add users
for (int i = 0; i < 10; i++) {
pnlUsers.add(new JButton("Button " + (i + 1));
}
This gives a very good result, with the buttons using their preferred size as seen in the image below:
Unfortunately, the buttons are still not filling the horizontal space. So, I attempted to make pnl2 a BoxLayout instead and add some vertical glue...
// Setup GridLayout Container
JPanel pnl2 = new JPanel();
pnl2.setLayout(new BoxLayout(pnl2, BoxLayout.Y_AXIS));
pnl2.setOpaque(false);
pnl2.add(pnlusers);
pnl2.add(Box.createVerticalGlue());
I also created my own temporary button class that sets the preferred size to use the minimum size:
public class TempButton extends JButton {
public PLTempButton(String msg) {
super(msg);
this.setPreferredSize(this.getMinimumSize());
}
}
Which resulted in the following:
This is much better, but there's still a problem. If there are not enough buttons to cause the JScrollPane to scroll, the buttons height are not consistent and will resize as you resize the window vertically. Why?
Obviously when I add 100 buttons, they use their preferred size:
Maybe I'm just not understanding the differences between minimum, preferred and maximum size? But I want the buttons to use the height they're set even if there aren't enough to cause the scroll-pane to, well, scroll. What can I do to fix this?
1) How do I even get a GridLayout within a ScrollPane?
Create a JPanel
Apply a GridLayout to the JPanel
Wrap the JPanel in a JScrollPane
For example
JPanel panel = new JPanel(new GridLayout(0, 2));
JScrollPane scrollPane = new JScrollPane(panel);
// Add the scroll pane to what ever parent container you're using
2) How do I get said GridLayout to expand horizontally, including the added components?
That doesn't make sense with regards to all previous part of the question, you said "and have it slowly expand downward the more things I add"
Having said that, the "basic" answer is, you configure the GridLayout and let it do it's job. The above example is configured for 2 columns and n number of roes
3) How would I add a "margin" to the components?
That's a broad answer, you could:
Make use of the horizontal and vertical gap properties of the GridLayout
Use a compound layout and adjust the insets of the an appropriate layout manager (like GridBagLayout)
Recommendations
I would recommend reading through Laying Out Components Within a Container to get a better understanding of the layout managers.
Remember, you not stuck to using one.
I would also recommend reading through How to Use Scroll Panes as you're asking basic questions about the API which are better covered through the tutorials
The following mre demonstrates creating a JPanel with GridLayout warped by JScrollPane and setting its horizontal and vertival gaps.
The Jpanel is added using a BorderLayout (the default layout manager of JFrame content pane) which allows it to expand:
import java.awt.BorderLayout;
import java.awt.GridLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
public class SwingMain {
private String text ="Growing ";
private JPanel grid;
private JFrame f;
SwingMain() {
creategui();
}
void creategui(){
f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setLocationRelativeTo(null);
JButton addComponentBtn = new JButton("Add Component");
addComponentBtn.addActionListener(e-> addComponent());
f.add(addComponentBtn, BorderLayout.PAGE_START);
grid = new JPanel(new GridLayout(0, 2, 10, 10)); //any number of rows, 2 columns, H and V gap
f.add(new JScrollPane(grid), BorderLayout.CENTER);
f.pack();
f.setVisible(true);
}
void addComponent() {
grid.add(new JLabel(text) );
text +="."; //make text longer so JLable grows
f.pack();
}
public static void main(String[] args) {
new SwingMain();
}
}
Ok so I wanted to make a box layout to test it out, and on the layout help page it specifies that you can give it an alignement, which is what I tried but it seems to not work at all.
package gameflow;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Toolkit;
import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class LoginScreen extends JFrame
{
private static final Dimension SCREENSIZE = Toolkit.getDefaultToolkit().getScreenSize();
private static final double DEFAULTHEIGHT = (SCREENSIZE.getHeight() * 80) / 100;
private static final double DEFAULTWIDTH = (SCREENSIZE.getWidth() * 80) / 100;
private static final long serialVersionUID = -7245840869407664992L;
private JTextField userfield = new JTextField(), passfield = new JTextField();
private JLabel userlabel = new JLabel("Username"), passlabel = new JLabel("Password");
private static final Dimension fieldSize = new Dimension();
public LoginScreen()
{
super("Wraith: the game");
setBounds((SCREENSIZE.width * 10) / 100, (SCREENSIZE.height * 10) / 100,(int)DEFAULTWIDTH,(int)DEFAULTHEIGHT);
fieldSize.setSize((double)this.getWidth()/2,(double)this.getHeight()/30);
userfield.setMaximumSize(fieldSize);
userfield.setForeground(new Color(1f,1f,1f));
passfield.setMaximumSize(fieldSize);
passfield.setForeground(new Color(1f,1f,1f));
userlabel.setMaximumSize(fieldSize);
passlabel.setMaximumSize(fieldSize);
JPanel panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.PAGE_AXIS));
panel.setBackground(new Color(0f,0f,0f));
panel.setAlignmentX(0.5f);
panel.add(userlabel);
panel.add(userfield);
panel.add(passlabel);
panel.add(passfield);
this.add(panel, BorderLayout.CENTER);
}
}
as you see, Panel has a boxlayout inside the JFrame whom has a BorderLayout, the components wont align to center. Why?
First of all when you create a text field you should use:
JTextField textField = new JTextField(10);
The number will allow the component to determine a preferred size to display about 10 character. However, the actual size of the component may be determined by the layout manager.
the components wont align to center. Why?
Because that is the rule of the BoxLayout. When the panel is added to the BorderLayout of the JFrame, the panel is resized to fill then entire area of the frame. So know the BoxLayout will resize the components to fill the space available based in its rules.
First, each component is displayed at its preferred height and extra space is just added to the bottom of the panel. So all components appear at the top of the frame.
If you want the components to be vertically centered in the panel then you need to add "glue" to the top and bottom of the panel. Then empty space will be added above/below the components so they appear centered. Reread the tutorial link for more information on how "glue" works.
Next the components are resize horizontally to fill the width of the panel. A component is only filled up to its maximum width. For many components (label, button...) the maximum width is the preferred width, but some components (text components) don't have a maximum width.
So to center the components horizontally you need to set the alignment of each component using:
theComponent.setAlignment(0.5f);
For the text field you can prevent the text field from growing by using:
textField.setMaximumSize( textField.getPreferredSize() );
So experiment with these properties to see the different effect.
Having said all that, the easiest way to center a panel (vertically and horizontally) on a frame is to use the GridBagLayout on the content pane of the frame. Then the code is just:
setLayout( new GridBagLayout() );
add(panel, new GridBagConstraints());
and now the panel is centered in the frame at its preferred size.
JPanel grid = new JPanel();
GridLayout layout = new GridLayout (6,7,0,0);
grid.setLayout (layout);
slot = new ImageIcon ("");
for (int x = 0; x < 42; ++x)
{
slotbtn = new JButton(slot);
slotbtn.setContentAreaFilled (false);
//slotbtn.setBorderPainted (false);
slotbtn.setBorder (BorderFactory.createEmptyBorder (0,0,0,0));
slotbtn.setFocusPainted (false);
grid.add(slotbtn);
}
This is the output I get:
I am creating a 6x7 grid. The output I need is for there to be no space in between the rows and columns, everything should be compressed together. I tried pack and it didn't work. What am I doing wrong?
-- I tried FlowLayout but I had to resize the frame and I have other buttons on the frame so I don't think I'd prefer resizing it to make the buttons fit in their proper places.
-- I placed this JPanel inside another jpanel(which uses borderlayout and contains two other panels) and I placed it at the center, the two other panels North and South.
this issue because you divide the grid (the whole size of grid) to 7*6 so if you re-size the window you will see this gaps changed so if you wan't to remove this gab
calculate the size of the window (ex: width = 7* width of your image , hight = 6*hight of your mage)
or re-size your image
JButton employs a margin property to provide additional padding to the content area of the button, you could try using...
slotbtn.setMargin(new Insets(0, 0, 0, 0));
I would also try using something like slotbtn.setBorder(new LineBorder(Color.RED)); to determine if the spacing is from the button, icon or layout
GridLayout will also provide each cell with equal amount of space, based on the available space to the container, this means that the cell may increase beyond the size of the icon.
While a little more work, GridBagLayout would (if configured properly) honour the preferred size of each component.
Have a look at How to use GridBagLayout for more ideas.
I get no margins using your code, with any image I use. Check your image. And maybe post a runnable example replicating the problem. Maybe there's something going on you're not showing us. I'd start by checking the image for margins. Check it against this. If it still has margins, than its your image. Also, Don't set the size to anything! You may be stretching the panel unnecessarily, which will cause the gaps. Also if there an of your other panels are larger than the grip panel, it will also cause it to stretch. But take all your set(Xxx)sizes out and see what happens. Just pack()
import java.awt.GridLayout;
import javax.swing.*;
public class TestButtonGrid {
public TestButtonGrid() {
ImageIcon icon = new ImageIcon(getClass().getResource("/resources/stackoverflow3.png"));
JPanel panel = new JPanel(new GridLayout(6, 7));
for (int i = 0; i < 42; i++) {
JButton slotbtn = new JButton(icon);
slotbtn.setContentAreaFilled(false);
//slotbtn.setBorderPainted (false);
slotbtn.setBorder(BorderFactory.createEmptyBorder(0, 0, 0, 0));
slotbtn.setFocusPainted(false);
panel.add(slotbtn);
}
JFrame frame = new JFrame();
frame.add(panel);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
new TestButtonGrid();
}
}
I'm making what is basically a toolbar that contains a search field and some buttons. I'd like for the search field to grow in size (just the width) when the parent container gets wider, like when the user adjusts the split pane. Currently, the text field and the buttons will remain the same size and whitespace is added on either side as the container is widened. I can achieve this growing effect by using a BorderLayout in the container and putting the buttons on LINE_END and the text field in the CENTER. The problem I have with this is that the text field now becomes taller than a standard text field and it looks ugly. This behavior makes sense as the BorderLayout manager will give all the extra space (this includes vertical and hortizontal space) to the CENTER text field. I've tried to restrict this vertical growth by placing a maximum size on the text field, but BorderLayout will not honor it.
Here's what I've got:
final JTextField searchField = new JTextField("Enter your search terms");
searchField.setMaximumSize(new Dimension(Integer.MAX_VALUE, 25));
final JPanel controls = new JPanel(new BorderLayout());
controls.add(searchField, BorderLayout.CENTER);
controls.add(new JPanel(){{
add(new JButton("Search")); add(new JButton("I'm Feeling Lucky"));
}}, BorderLayout.LINE_END);
It would seem that this behavior is a commonly desired one and it should be easy to implement, but I've had no luck after looking through all the Oracle/Sun tutorials and Google search results.
Anybody have any solutions to this? I need to stick with standard Java Swing components - no third party libraries please.
Thank you!
I would suggest you to use GridBagLayout , it is complicated but it is the most powerful layout.. When you learn it, you would not have any layout issue.
Here is the sample use of gridbaglayout for this question...
import java.awt.BorderLayout;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
public class GridBagLayoutExample extends JFrame {
GridBagLayoutExample() {
initUI();
}
private void initUI() {
final JTextField searchField = new JTextField("Enter your search terms");
final JPanel controls = new JPanel(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
c.weightx=1.0;
c.fill=GridBagConstraints.HORIZONTAL;
controls.add(searchField,c);
controls.add(new JPanel(){
{
add(new JButton("Search")); add(new JButton("I'm Feeling Lucky")); }});
setLayout(new BorderLayout());
add(controls, BorderLayout.NORTH);
pack();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new GridBagLayoutExample().setVisible(true);
}
});
}
}
it's a two part problem:
a) all xxSize (xx = min/max/pref) are mere hints to the LayoutManager. Each and every LayoutManager has its own behaviour if/how/when it respects those hints and if/how/when it violates one or more if the overall space is more or less than would fit the sum of pref for all components in the container. No way but learn which does what (documentation is ... ehem ... suboptimal)
b) JTextField is a bit crazy in allowing its height to grow indefinitely if space allows. Implying that even LayoutManagers which respect max (like f.i. BoxLayout) have no chance to do so, max is Integer.MAX_VALUE (or Short.MAX? forgot). To make it behave, subclass and override maxSize to return the pref height:
#Override
Dimension getMaximumSize() {
Dimension max = super.getMaximumSize();
max.height = getPreferredSize().height;
return max;
}
You should be able to use a horizontal BoxLayout.
searchField.setMaximumSize(new Dimension(Integer.MAX_VALUE, 25));
You should not guess at the height of the text field.
Dimension d = searchField.getPreferredSize();
d.width = Integer.MAX_VALUE;
searchField.setMaximumSize(d);
I know you said you don't want to use 3rd party libraries, but as a side note you might want to look at Text Field Prompt. It allows you to display a message that will disapear when you start typing in the text field.
Using BoxLayout.
JTextField search_field = new JTextField("Enter search term");
JPanel panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.LINE_AXIS));
panel.add(search_field);
This will dynamically change the size of textfield when resizing the frame.
I have 3 panels. One is the main panel which holds 2 smaller panels.
For the main panel, I used
setPreferredSize(new Dimension(350, 190));
For the smaller left panel, I used
setPreferredSize(new Dimension(100, 190));
For the smaller right panel, I used
setPreferredSize(new Dimension(250, 190));
but the smaller panels remain the same size. How can I fix this?
This is the code I have in my main Panel.
import model.*;
import java.awt.*;
import javax.swing.*;
public class Panel extends JPanel
{
public Panel(Prison prison)
{
setup();
build(prison);
}
private void setup()
{
setBorder(BorderFactory.createLineBorder(Color.blue));
setLayout(new BorderLayout(1, 1));
setPreferredSize(new Dimension(350, 190));
}
private void build(Prison prison)
{
JTabbedPane tab = new JTabbedPane();
tab.addTab("Input", null, new InputPanel(), "Input");
tab.addTab("Display", null, new DisplayPanel(), "Display");
add(tab);
}
}
Don't do this.
The whole point of layout managers is to allow dynamic resizing, which is necessary not just for user-resizable windows but also changing texts (internationalization) and different default font sizes and fonts.
If you just use the layout managers correctly, they will take care of panel sizes. To avoid having your components stretched out all over the screen when the user increases the window size, have an outermost panel with a left-aligned FlowLayout and the rest of the UI as its single child - that will give the UI its preferred size and any surplus is filled with the background color.
It looks like you're using a GridLayout, or perhaps a FlowLayout, neither being what you want. You probably want to use a BoxLayout, which respects its components preferred sizes.
final JPanel p = new JPanel();
p.setLayout(new BoxLayout(p, BoxLayout.X_AXIS));
p.add(leftPanel);
p.add(mainPanel);
p.add(rightPanel);
also- that is the preferred size. if you don't want to allow resizing, you can also set the maximum sizes as well.
if you're able, you may want to check out the MIG layout, but BoxLayout is also easy to use and in the java toolkit already.
It's this one.
buttonPanel = new JPanel();
buttonPanel.setSize(new Dimension(30, 100));
Don't let the layout manager adjust your sizes.