I am trying to use a GridBagLayout to have a JFrame that contains a JPanel that has a grid layout and a JPanel with just a large button. I want the rows to all be the same size, and the JPanel with the JButton to be the same size as one row. However, the button panel, which is currently empty, is about 1/3 of the JFrame. I'm not quite sure what's happening, but it is pretty important to me that I maintain this structure because the rest of my code uses this. Any help is appreciated, and thank you in advance.
This is my code:
import java.awt.*;
import javax.swing.*;
import javax.swing.border.*;
public class Minesweeper extends JPanel {
private final int SIZE = 7;
public void startGame(){
JFrame holder = new JFrame();
JPanel window = new JPanel();
JPanel pan = new JPanel();
holder.setLayout(new GridBagLayout());
GridBagConstraints con = new GridBagConstraints();
con.weightx = 1;
con.weighty = 1;
con.gridx = 0;
con.gridy = 0;
con.fill = GridBagConstraints.BOTH;
con.gridheight = SIZE;
con.gridwidth = SIZE;
holder.getContentPane().setBackground(Color.darkGray);
holder.setSize(450, 450);
holder.setResizable(false);
holder.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.setBackground(Color.darkGray);
window.setLayout(new GridLayout(SIZE, SIZE));
for (int c=0; c<(SIZE*SIZE); c++){
int row = (c/SIZE);
int col = (c%SIZE);
JPanel p = new JPanel();
p.setBackground(Color.gray);
Border b = BorderFactory.createEtchedBorder(EtchedBorder.RAISED);
p.setBorder(b);
window.add(p);
}
holder.add(window, con);
con.gridx = 0;
con.gridy = SIZE+1;
con.gridheight = 0;
con.gridwidth = SIZE;
holder.add(pan, con);
holder.setVisible(true);
}
public static void main(String[] args){
Minesweeper start = new Minesweeper();
start.startGame();
}
}
This is what is being shown:
con.gridy = SIZE+1;
You can't specify a gridy value of 8. There are only two components added to the grid. The grid doesn't know that one of your panels happens to contain 7 rows of components. So the value should be 1.
This won't solve the problem but should clear up a misunderstanding of how GridBagLayout works.
holder.setSize(450, 450);
You are manually setting a size to the frame. Each component is originally sized at its preferred size. When there is extra space in the frame the space is distributed equally between the two components.
You should NOT be setting the size. Each component should determine its own size and then you should use pack(). So you need to use custom components that override the getPreferredSize() method to return the appropriate size for each component so pack() can do its job.
Also, the pack() is done just before the setVisible().
Related
I am trying to set the layout of a JFrame to be a grid bag layout. I want to to essentially look like 4 grids of equal size, but with the bottom 2 merged into one panel. I am adding JPanels to each. However, I get 3 small grids at the middle of the JFrame, not properly sized. It looks like this instead.
My code is as follows:
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Hangman extends JPanel{
private String word;
private JPanel hA, gL, letters;
public void setupLayout(JFrame window){
window.setLayout(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
hA = new JPanel();
hA.setBackground(Color.blue);
c.fill = GridBagConstraints.BOTH;
c.gridx = 0;
c.gridy = 0;
window.add(hA, c);
gL = new JPanel();
gL.setBackground(Color.green);
c.fill = GridBagConstraints.BOTH;
c.gridx = 1;
c.gridy = 0;
window.add(gL, c);
letters = new JPanel();
letters.setBackground(Color.black);
c.fill = GridBagConstraints.BOTH;
c.weightx = 1.0;
c.gridx = 0;
c.gridy = 1;
c.gridwidth = 2;
window.add(letters, c);
}
public void startWindow(){
JFrame window = new JFrame();
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
int screenHeight = (int) screenSize.getHeight();
int windowHeight = (int) ((screenHeight / 4) * 3);
window.setSize(windowHeight, windowHeight);
window.setLocationRelativeTo(null);
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setupLayout(window);
window.setVisible(true);
}
public void startGame(){
Prep prepare = new Prep();
word = prepare.findWord(true);
startWindow();
}
public static void main(String[] args){
Hangman start = new Hangman();
start.startGame();
}
}
It's not very important what Prep does. It just takes a random word from a text file. I couldn't see how it would affect the layout. To recap, I need to make it so each of the 4 grid spaces span one fourth of the window, and then make the bottom 2 cells merged with a JPanel added to each of them. Any help is appreciated. Thank you in advance.
EDIT:
I needed to set the weight of all of them to be 1. It is solved.
GridBagLayout displays each component at its preferred size. Since you didn't add any components to the panels you just see a small panel.
If you want the panels to fill the space available then you need to play with the constraints.
Read the section from the Swing tutorial on How to Use GridBagLayout for more information and working examples. You will want to look at the "fill" and "weightx/weighty" constraints.
and then make the bottom 2 cells merged
you will also need to look at the "gridwidth/gridheight" constraints.
The question is, how do I align JScrollPane in resizeble JPane so that it aligns to the top-left corner instead of a center?
That feels like obvious task, yet I spent hours trying out all the different layouts and properties.
The frustration can be expressed, as there are only two options I could produce:
Use the layout which respects children's maximum preferred size, FlowLayout as example. Side effect - ScrollPane starts behaving as if it was plain Panel:
Use stretchable layout, for instance BorderLayout and place the element into BorderLayout.CENTER (BorderLayout.PAGE_START leads to 1.). I lose control on the location of Panel, and it in the center:
When window is small, scroll works as expected though:
Is it possible to have both of the two worlds: have JScrollPane not stretch beyound maximum preferred size, yet not lose the Scroll?
In case someone needs the source code:
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTabbedPane;
public class MainPanelTest extends JFrame {
public static void main(String[] args) {
new MainPanelTest().setVisible(true);
}
public MainPanelTest() {
super();
this.setLayout(new BorderLayout());
setupGUI();
}
private void setupGUI() {
JTabbedPane tabbedPane = new JTabbedPane();
tabbedPane.setTabLayoutPolicy(JTabbedPane.SCROLL_TAB_LAYOUT);
this.add(tabbedPane, BorderLayout.CENTER);
JComponent filesPanel = setupFilesPanel();
tabbedPane.addTab("Files", filesPanel);
JPanel secondPanel = new JPanel();
tabbedPane.addTab("Placeholder", secondPanel);
}
private JComponent setupFilesPanel() {
JPanel filesPanel = new JPanel();
filesPanel.setLayout(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
c.anchor = GridBagConstraints.NORTHWEST;
for(int i=0; i<15; i++) {
c.gridy = i;
filesPanel.add(new JLabel("Test row " + i), c);
}
JScrollPane scrollFilesPane = new JScrollPane(filesPanel);
scrollFilesPane.setMaximumSize(scrollFilesPane.getPreferredSize());
return scrollFilesPane;
}
}
The GridBagLayout divides the space into logical cells in which the components live. The anchor is only relevant if the logical cell is bigger than its component. This may happen if components within the same row/column demand a bigger size or if there is extra space and the associated weightx or weighty value is not zero. Since your desired behavior is about the extra space, you have to set the weight values accordingly. The weightx will be non-zero for the sole column but the weighty will be non-zero for the last row only to take up the entire space below it:
GridBagLayout gridBagLayout = new GridBagLayout();
JPanel filesPanel = new JPanel(gridBagLayout);
GridBagConstraints c = new GridBagConstraints();
c.gridx = GridBagConstraints.REMAINDER;
c.anchor = GridBagConstraints.NORTHWEST;
c.weightx = 1; // for the column
for(int i=0; i<15; i++)
filesPanel.add(new JLabel("Test row " + i), c);
// now change the last row:
c.weighty = 1;
gridBagLayout.setConstraints(
filesPanel.getComponent(filesPanel.getComponentCount()-1), c);
Alternatively you can leave the cells unmodified but manipulate the entire layout by adding an empty extra row and column consuming the additional space which will effectively move the original rows and columns to the upper left corner:
// add all visible components which should not grow
GridBagLayout gridBagLayout = new GridBagLayout();
JPanel filesPanel = new JPanel(gridBagLayout);
GridBagConstraints c = new GridBagConstraints();
c.gridx = GridBagConstraints.REMAINDER;
for(int i=0; i<15; i++)
filesPanel.add(new JLabel("Test row " + i), c);
// add an extra row consuming vertical extra space
int nRows=filesPanel.getComponentCount();
gridBagLayout.rowHeights=new int[nRows+1];
gridBagLayout.rowWeights=new double[nRows+1];
gridBagLayout.rowWeights[nRows]=1;
// add an extra column consuming extra horizontal space
gridBagLayout.columnWidths=new int[] { 0, 0 };
gridBagLayout.columnWeights=new double[] { 0, 1 };
See if this is what you are trying to achieve:
private JComponent setupFilesPanel() {
JPanel filesPanel = new JPanel();
filesPanel.setLayout(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
c.anchor = GridBagConstraints.NORTHWEST;
for(int i=0; i<15; i++) {
c.gridy = i;
filesPanel.add(new JLabel("Test row " + i), c);
}
// ---- Add this
JPanel newPanel = new JPanel(new GridBagLayout());
c.weightx = 1;
c.weighty = 1;
newPanel.setBackground(Color.yellow);
newPanel.add(filesPanel, c);
// ----
// ---- change the panel you pass to JScrollPanel constructor:
JScrollPane scrollFilesPane = new JScrollPane(newPanel); // <--------- newPanel
scrollFilesPane.setMaximumSize(scrollFilesPane.getPreferredSize());
return scrollFilesPane;
}
The changes are commented.
This question already has answers here:
Resizing issue with canvas within jscrollpane within jsplitpane
(3 answers)
Closed 8 years ago.
The program i want to make is
Divide an applet/frame(awt) into two parts using panel. The first panel contains four buttons naming ellipse, rectangle, circle and triangle. Taking one button and asking coordinates and make a figure on the other panel.
Please someone explain me the concept or working because im not good at layouts and know methods to use to convey from one panel to other..
Thank you very much
I would recommend starting out with a layout manager.. if you want 2 JPanels next to each other, you can use the GridLayout layout manager. It takes 2 arguments, and one of it's overloaded constructors takes 4 arguments.
setLayout(new GridLayout(rows, columns)); //one commonly used constructor
setLayout(new GridLayout(rows, columns, horizontalSpacePixels, verticleSpace));
GridLayout, when used will reshape to fit the largest component, and make each part of the grid an equal size-- however this isn't the case when you use a GridLayout inside of a GridLayout (the inner GridLayout might be too big to fit within the confines that the outer GridLayout puts on it.). If I simply do
JFrame jf = new JFrame("Laying the grid out");
jf.setLayout(new GridLayout(5, 5));
JPanel[] jp = new JPanel[25];
JLabel[] jl = new JLabel[25];
for(int i = 0; i < 25; i++) {
jp[i] = new JPanel();
jp[i].setBackground(Color.YELLOW);
jl[i] = new JLabel("This is label no. " + (i+1));
jp[i].add(jl[i]);
}
//now to add all 25 components in the 5x5 grid; you simply add them, and it
//automatically positions the jpanels in the order that you place them.. left to right.
for(int i = 0; i < 25; i++)
jf.add(jp[i]);
Here is an example program that involves a simple GridLayout, and an actionListener that responds to button events by changing one of the JPanel's color.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Gui {
private JPanel p2;
private JLabel side2;
private JFrame jf;
public static void main(String[] args){
new Gui();
}
public Gui(){
jf = new JFrame("Holds 2 panels side by side.");
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jf.setLayout(new GridLayout(1, 2));
JPanel p1 = new JPanel();
p2 = new JPanel();
p1.setBackground(Color.BLACK);
p2.setBackground(Color.BLACK);
p1.setLayout(new BoxLayout(p1, BoxLayout.X_AXIS));
JLabel[] space = new JLabel[20];
for(int i = 0; i < 20; i++)
space[i] = new JLabel(" ");
JButton jb1 = new JButton("Button 1");
JButton jb2 = new JButton("Button 2");
jb1.addActionListener(new BListen());
jb2.addActionListener(new BListen());
p1.add(space[0]);
p1.add(jb1);
p1.add(space[1]);
p1.add(jb2);
p1.add(space[2]);
jf.add(p1);
side2 = new JLabel("Change the color here with the buttons there.");
side2.setForeground(Color.GREEN);
p2.add(side2);
jf.add(p2);
jf.setSize(600, 200);
jf.setVisible(true);
}
private class BListen implements ActionListener {
public void actionPerformed(ActionEvent e) {
String buttonClicked = e.getActionCommand();
if(buttonClicked.equals("Button 1")) {
JOptionPane.showMessageDialog(null, "You pressed Button 1.");
p2.setBackground(Color.BLUE);
side2.setForeground(Color.MAGENTA);
jf.setVisible(true);
}
else if(buttonClicked.equals("Button 2")) {
JOptionPane.showMessageDialog(null, "You pressed Button 2.");
p2.setBackground(Color.ORANGE);
side2.setForeground(Color.DARK_GRAY);
jf.setVisible(true);
}
}
}
}
I have a GridBagLayout with two components: JRadioButton and JLabel. Text in a label differs by length. This GridbagLayout is added to JPanel. So when I have a lot of components they are not aligned well at the end. Here is what I mean:
-----radio btn-label-----
---radio btn-label --
-------radio btn-lbl-----
But I need the following:
-radio btn-label -
-radio btn-label -
-radio btn-lbl -
This is how my grid looks like for now:
public class MyPanel extends JPanel {
private JLabel info;
private JRadioButton select;
public MyPanel() {
this.achiev = achiev;
achievementInfo = new JLabel();
selectAchiev = new JRadioButton();
setLayout(new GridBagLayout());
GridBagConstraints constraints = new GridBagConstraints();
constraints.gridx = 0;
constraints.gridy = 0;
constraints.anchor = GridBagConstraints.LINE_START;
add(selectAchiev, constraints);
StringBuilder builder = new StringBuilder();
builder.append("<html><b>").append("some text").append("</b><p>");
builder.append("<i>").append("some more text").append("</i>");
info.setText(builder.toString());
constraints.gridx = 1;
constraints.gridy = 0;
constraints.fill = GridBagConstraints.HORIZONTAL;
add(info, constraints);
}
//--------------
JPanel panel = new JPanel(new BoxLayout(), BoxLayout.YAXIS);
for(int i = 0; i < 10; ++i) {
panel.add(new MyPanel());
}
You're adding 10 panels which all have their own gridbag layout, checkbox and label. So each panel has its own grid, and the width of the cells are computed independantly, based on the components they contain.
If you want a well-aligned single grid, you should have a single panel using GridBagLayout, and add your 10 labels and 10 checkboxes to this unique panel.
Moreover, you should give a weightx > 0 to the label's constraint if you really want it to fill horizontally.
I think you miss the weightx, weighty constraints as it is said in this GrigBadLayout document:
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.
If you want to make your components look like that, i refer using BoxLayout
private void init() {
Box outerBox = new Box(BoxLayout.Y_AXIS);
outerBox.add(createLineWithRadioButtonAndLabel());//line 1
outerBox.add(createLineWithRadioButtonAndLabel());//line 2
outerBox.add(createLineWithRadioButtonAndLabel());//line 3
add(outerBox);
}
private Box createLineWithRadioButtonAndLabel() {
Box line = new Box(BoxLayout.X_AXIS);
JRadioButton radio = new JRadioButton("radio button");
JLabel label = new JLabel("some text");
line.add(radio);
line.add(Box.createRigidArea(new Dimension(20, 1)));// add some horizontal space. Here is 20
line.add(label);
line.add(Box.createHorizontalGlue());
return line;
}
I've been trying to make a JLabel that is sized relatively to the size of the window yet for some reason this JLabel is not appearing on the screen.
This is the code used in my MainGUI class which holds the basic interface:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class MainGUI extends JFrame{
JPanel core;
GridBagConstraints c;
JLabel[] sts;
public MainGUI(){
core = new JPanel(new GridBagLayout());
getContentPane().add(core, BorderLayout.CENTER);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setSize(500, 500);
sts = new JLabel[10];
int width = (int)(66/100) * getWidth(), height = (int)(75/100) * getHeight(); //problem: due to these sizes the JLabel is not appearing
for(int i = 0; i < sts.length; i++){
sts[i] = new JLabel("test");
sts[i].setOpaque(true);
sts[i].setBackground(Color.BLACK);
sts[i].setForeground(Color.BLACK);
sts[i].setPreferredSize(new Dimension(width,height)); //size being set
}
c = new GridBagConstraints();
c.gridx = 0;
c.gridy = 0;
core.add(sts[1], c);
}
}
Any help in finding a solution for this would be greatly appreciated, thanks in advance.
Few issues-
Foreground and background colors are same for label
You need to set some text on the label
Check if preferred size is calculated correctly, as the label is displayed if that line is commented out. The height and width calculated is zero.
This will always return zero as the result of division is int-
int width = (int)(66/100) * getWidth();
Make it-
int width = (int)(((float)66/100) * getWidth());
Try RelativeLayout library. A tutorial is here at Wiki.