I'm having an issue with switching between different JPanels in a JFrame. I am trying to add two different panels to a JFrame that the user can go back and forth between, with mainPanel being displayed when the program is run. mainPanel was showing correctly until I added buyPanel to the frame. Now I'm having issues displaying mainPanel again. When I currently run my program, it comes up as blank. The issue seems to be with the last three lines, however I can't figure out what is wrong.
I've included the relevant code below.
public class TestClass extends JFrame {
private JTextArea welcomeText;
private JComboBox commandsMenu;
private JPanel mainPanel;
private JPanel buyPanel;
private JTextArea buyType;
public TestClass() {
super("TestProgram");
setDefaultLookAndFeelDecorated(true);
setSize(550, 350);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Setup elements for main panel (includes commands menu)
mainPanel = new JPanel();
mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.Y_AXIS));
welcomeText = new JTextArea(10, 10);
welcomeText.setEditable(false);
welcomeText.setLineWrap(true);
welcomeText.setWrapStyleWord(true);
welcomeText.setText(menu());
commandsMenu = new JComboBox();
commandsMenu.setEditable(true);
commandsMenu.setPrototypeDisplayValue("Commands");
commandsMenu.setSize(50, 50);
commandsMenu.addItem("Buy");
commandsMenu.addItem("Quit");
mainPanel.add(commandsMenu);
mainPanel.add(welcomeText);
add(mainPanel);
// Setup elements for buy panel
buyPanel = new JPanel(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
buyType = new JTextArea();
buyType.setText("Type");
buyType.setEditable(false);
buyPanel.add(commandsMenu);
buyPanel.add(buyType);
add(buyPanel);
buyPanel.setVisible(false);
mainPanel.setVisible(true);
I am having issue where my JPanel is not setting up the size. I am not sure if is something to do with my JTab or JFrame. I am using GridBagLayout layout management. And for some reason are not able to set the size.
Here is a dummy code, following the same logic to my original source code:
FirstPanel.java
import javax.swing.*;
import java.awt.*;
public class FirstPanel extends JPanel {
private JLabel label1 = new JLabel("Label 1");
private JTextField textField1 = new JTextField();
private GridBagConstraints c = new GridBagConstraints();
public FirstPanel() {
//Size is not overriding
Dimension size = getPreferredSize();
size.width = 100;
setPreferredSize(size);
setBorder(BorderFactory.createTitleBorder("Border Title");
setLayout(new GridBagLayout());
addComponents();
}
private void addComponents() {
c.gridx = 0;
c.gridy = 0;
c.anchor = GridBagConstraints.NORTHWEST;
c.insets = new Insets(5, 0, 0, 0);
add(label1, c);
c.gridx = 1;
add(textField1, c);
c.weightx = 1;
c.weighty = 1;
add(new JLabel(""), c);
}
}
MainPanel.java
import javax.swing.*;
import java.awt.*;
public class MainPanel {
private JFrame frame = new JFrame("App");
private JPanel panel1 = new JPanel(new GridBagLayout());
private GridBagConstraints c = new GridBagConstraints();
private JTabbedPane tabPane = new JTabbedPane();
public MainPanel() {
addComponents();
frame.add(tabPane);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(500, 350);
frame.setVisible(true);
frame.setLocationRelativeTo(null);
frame.setResizable(false);
}
private void addComponents() {
tabPane.addTab("Tab 1", new FirstPanel());
}
}
Main.java
public class Main {
public static void main(String[] args) {
new MainPanel();
}
}
Or at least have two JPanels,
Exactly.
Frist you create a main panel using a BorderLayout that you add to the tabbed pane.
Then you have a second panel for your labels and text fields (using whatever layout manager you want). Then you add this panel to the BorderLayout.LINE_START.
Then you add your scrollpane containing the JTable to the BorderLayout.CENTER of the main panel.
Read the tutorial on Layout Manager. Nest panels with different layout managers as required.
want to have JTable taking 50% of the other side.
Picking a random number like 50% is not the way to design a GUI. What happens if the frame is made smaller/larger. What happens to the space? Design the layout with flexibility in mind, just like your browser window is designed. There are always fixed areas where the size is determined by the components added and there is a flexible area that grows/shrinks as desired.
I'm currently designing a GUI assignment planner. I have run across a few issues along the way. For one part of my program I have a panel to hold assignments that still need to be completed. What I would like to create is a panel that will add containers (holding the components to display an assignment) to a panel. However, the only way I can conceive of doing this is by lengthening the panel each time a container is added. Unfortunately, to the best of knowledge, this isn't possible since a panel is given a defined width and depth when it is created. Ideally, if possible, I'd like to increase the panel length every time a container is added. A scrollbar would scroll down the panel.
So is this possible? Am I approaching this the right way? I am very new to GUI so I am open to improvements and suggestions. If anyone would like me to post my code so far, I will. (Beware, it is in very rough shape at the moment)
Attached below is a rough draft of what I am trying to make:
TIA
This is the majority of my code so far. The problem is that once i add a certain amount of containers it starts to make them smaller. I just want to extend it every time a container is added. Most of the comments are for documentation or to remind to do something.
import javax.swing.*;
import java.awt.*;
//import java.util.ArrayList;
public class MyWindow
{
private final JFrame frame = new JFrame();
private final int WINDOW_WIDTH = 500, WINDOW_DEPTH = 500;
private JPanel panel;
private JPanel toDoList, completed;
//ArrayList<JFrame> frame = new ArrayList<>();
public MyWindow()
{
frame.setTitle("Assignment Planner");
this.contents();
}
private void contents()
{//use an arraylist to create containers ArrayList<JPanel> container = new ArrayList<>();
frame.setSize(WINDOW_WIDTH, WINDOW_DEPTH);
panel = new JPanel(new GridLayout(2, 1));
toDoList = new JPanel();
toDoList.setLayout(new /*GridLayout(0,1,5,5)*/BoxLayout(toDoList, BoxLayout.PAGE_AXIS));
toDoList.setPreferredSize(new Dimension(250, 250));
panel.add(toDoList);
completed = new JPanel();
//panelCompleted.setLayout(new GridLayout(0, 1)); //fix like one above
panel.add(completed);
JScrollPane scroll = new JScrollPane(toDoList);
panel.add(scroll); //scroll panes for both panels
JScrollPane scroll2 = new JScrollPane(completed);
panel.add(scroll2);
toDoList.add(assignment());
toDoList.add(Box.createRigidArea(new Dimension(0,1)));
toDoList.add(assignment());
toDoList.add(Box.createRigidArea(new Dimension(0,1)));
toDoList.add(assignment());
toDoList.add(Box.createRigidArea(new Dimension(0,1)));
beginningScrollPaneValue += 110;
toDoList.setPreferredSize(new Dimension(250, beginningScrollPaneValue));
toDoList.revalidate(); //scroll.revalidate();
toDoList.repaint(); //scroll.repaint();
frame.getContentPane().add(panel, BorderLayout.CENTER);//add the panel in the JFrame's content pane in the center
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
JPanel assignment()
{
JPanel container = new JPanel(new GridBagLayout());
container.setMaximumSize(new Dimension(500,100));
GridBagConstraints c = new GridBagConstraints();
c.weightx = 0.5;
JCheckBox cb = new JCheckBox();
c.fill = GridBagConstraints.NONE;
c.gridx = 1;
c.gridy = 0;
container.add(cb, c);
container.setBackground(Color.red);//does no fill area behind checkbox
return container;
}
}
So I want the button Select to be above button Back and I don't want them overlapping each other. But when I set them both the PAGE_END, they overlap. How do I get around this?
Here is the code for the problem:
public void methodName() {
JPanel controls = new JPanel(new BorderLayout(5,5));
final CardLayout cl = new CardLayout();
final JPanel panel = new JPanel(cl);
controls.add(panel);
this.getContentPane().setLayout(new FlowLayout(FlowLayout.LEADING));
list = new JList<Object>(objectName);
list.setVisibleRowCount(7);
select = new JButton("Select");
back = new JButton("Back");
select.addActionListener(this);
controls.add(new JScrollPane(list));
controls.add(select, BorderLayout.PAGE_END);
controls.add(back, BorderLayout.PAGE_END);
controls.setBorder(new EmptyBorder(25,25,0,0));
add(controls);
refreshFrame();
}
Here is what it looks like when they are both added in but are overlapping:
This is what I want it to look like:
Any ideas?
Thanks in advance!
Place the 2 JButtons on a new JPanel using GridLayout like this
JPanel basePanel = new JPanel(new GridLayout(0, 1, 0, 3));
basePanel.add(select);
basePanel.add(back);
controls.add(basePanel, BorderLayout.PAGE_END);
GridLayout can provide a vertical gap between buttons in its constructor as shown in your question
create a new jpanel with gridLayout(2,1) then add the two buttons to the jpanel then add the Jpanel to the Jframe
I have some questions on positioning components and some questions on text fields and text areas (Java Swing). Any help is greatly appreciated.
Right now I am trying to have two text fields beside each other with a different label above each describing what that text field does. To achieve this I have placed them in a GridLayout(2, 2).
Is this the best way? It is the only way I know to have a label directly over another component. Is there a better way? What about if there is just one label above one button. Is it sensible to position this through a GridLayout(2, 1)? I am visually impaired so I do not think positioning buttons just by their pixel position is an option unless there is a simple way to place components at a relative number of pixels to another component.
That leads me to my next question.
What is the best way to have the same UI as above but with another component (button) centered under it. Essentially the UI should compose of two Named text fields with a calculate button under. The way I did this is by putting the above components in a panel, and adding that plus the calculate button to a surrounding panel with a GridLayout(2, 1). The problem is that the button becomes as big as the panel above it (I'm assuming). How can I adjust this and still have the button perfectly aligned under the panel of text fields/labels? Similarly with labels above text areas. The label should be small but have a larger space for the text area under.
(text field):
Again referring to the UI above, if the user types many characters into the first text field, will the letters go over the text field on the right? If so how can I prevent this?
If I append text to a text area and it is already full, will it automatically allow the user to scroll? If not what is a simple way to make the text area scrollable?
Right now I am not setting a size of the text area. Does it just grow as I add text? Does it have a default size as in number of characters?
There are a number of layout managers that might be capable of providing you with what you need.
MigLayout
JGoodies FormLayout
GridBagLayout
For, GridBagLayout would be my choice (I'm biased, as I've been using this layout manager for the past 12 years ;))
public class TestLayout17 {
public static void main(String[] args) {
new TestLayout17();
}
public TestLayout17() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 0;
gbc.insets = new Insets(2, 2, 2, 2);
add(new JLabel("Label 1"), gbc);
gbc.gridx++;
add(new JLabel("Label 2"), gbc);
gbc.gridx = 0;
gbc.gridy++;
gbc.fill = GridBagConstraints.HORIZONTAL;
add(new JTextField(10), gbc);
gbc.gridx++;
add(new JTextField(10), gbc);
gbc.gridx = 0;
gbc.gridy++;
gbc.fill = GridBagConstraints.NONE;
gbc.gridwidth = 2;
add(new JButton("Click"), gbc);
}
}
}
I also agree with Eng.Fouad's suggestion of using compound containers to make your life easier in the long run
You might find Laying Out Components Within a Container a worth while read.
Right now I am trying to have two text fields beside each other with a
different label above each describing what that textfield does. To
achieve this I have placed them in a GridLayout(2, 2). Is this the
best way? It is the only way I know to have a label directly over
another component. Is there a better way? What about if there is just
one label above one button. Is it sensible to position this through a
GridLayout(2, 1)?
Myself, I always do it via nested panels with BorderLayout. For example:
JFrame frame = new JFrame("The Title");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panOuter = new JPanel(new BorderLayout());
JPanel panLeft = new JPanel(new BorderLayout());
panLeft.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JPanel panRight = new JPanel(new BorderLayout());
panRight.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
panOuter.add(panLeft, BorderLayout.WEST);
panOuter.add(panRight, BorderLayout.EAST);
JLabel lblLeft = new JLabel("Label 1", JLabel.CENTER);
JLabel lblRight = new JLabel("Label 2", JLabel.CENTER);
JTextField txtLeft = new JTextField(10);
JTextField txtLright = new JTextField(10);
panLeft.add(lblLeft, BorderLayout.NORTH);
panLeft.add(txtLeft, BorderLayout.CENTER);
panRight.add(lblRight, BorderLayout.NORTH);
panRight.add(txtLright, BorderLayout.CENTER);
frame.setContentPane(panOuter);
frame.pack();
frame.setVisible(true);
Note that, you can manipulate the gaps between the components with setting empty borders. Also, you may use BorderLayout.LINE_START and BorderLayout.LINE_END instead of using BorderLayout.WEST and BorderLayout.EAST, and this will add support for RTL languages (e.g Arabic).
That leads me to my next question. What is the best way to have the
same UI as above but with another component (button) centred under it.
Essentially the UI should compose of two Named text fields with a
calculate button under. The way I did this is by putting the above
components in a panel, and adding that plus the calculate button to a
surrounding panel with a GridLayout(2, 1). The problem is that the
button becomes as big as the panel above it (I'm assuming). How can I
adjust this and still have the button perfectly aligned under the
panel of textfields/labels?
I would do it via nested panels as I did earlier, but now the bottom panel has a FlowLayout layout manager to get a good size for the button:
JFrame frame = new JFrame("The Title");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panOuter = new JPanel(new BorderLayout());
JPanel panLeft = new JPanel(new BorderLayout());
panLeft.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JPanel panRight = new JPanel(new BorderLayout());
panRight.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JPanel panBottom = new JPanel(); // default is FlowLayout
panBottom.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
panOuter.add(panLeft, BorderLayout.WEST);
panOuter.add(panRight, BorderLayout.EAST);
panOuter.add(panBottom, BorderLayout.SOUTH);
JLabel lblLeft = new JLabel("Label 1", JLabel.CENTER);
JLabel lblRight = new JLabel("Label 2", JLabel.CENTER);
JTextField txtLeft = new JTextField(10);
JTextField txtLright = new JTextField(10);
JButton btnBottom = new JButton("Press it!");
panLeft.add(lblLeft, BorderLayout.NORTH);
panLeft.add(txtLeft, BorderLayout.CENTER);
panRight.add(lblRight, BorderLayout.NORTH);
panRight.add(txtLright, BorderLayout.CENTER);
panBottom.add(btnBottom);
frame.setContentPane(panOuter);
frame.pack();
frame.setVisible(true);
Similarly with labels above text areas. The label should be small but
have a larger space for the text area under.
I would suggest you to use TitledBorder:
JFrame frame = new JFrame("The Title");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panOuter = new JPanel(new BorderLayout());
JPanel panLeft = new JPanel(new BorderLayout());
panLeft.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JPanel panRight = new JPanel(new BorderLayout());
panRight.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JPanel panBottom = new JPanel(); // default is FlowLayout
panBottom.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JPanel panInput = new JPanel(new BorderLayout());
panInput.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JPanel panConsole = new JPanel(new BorderLayout());
Border outsideBorder = BorderFactory.createEmptyBorder(5, 5, 5, 5);
Border insideBorder = BorderFactory.createTitledBorder("The Console");
Border theBorder = BorderFactory.createCompoundBorder(outsideBorder, insideBorder);
panConsole.setBorder(theBorder);
panInput.add(panLeft, BorderLayout.WEST);
panInput.add(panRight, BorderLayout.EAST);
panInput.add(panBottom, BorderLayout.SOUTH);
panOuter.add(panInput, BorderLayout.NORTH);
panOuter.add(panConsole, BorderLayout.CENTER);
JLabel lblLeft = new JLabel("Label 1", JLabel.CENTER);
JLabel lblRight = new JLabel("Label 2", JLabel.CENTER);
JTextField txtLeft = new JTextField(10);
JTextField txtLright = new JTextField(10);
JButton btnBottom = new JButton("Press it!");
JTextArea txtConsole = new JTextArea(5, 10);
panLeft.add(lblLeft, BorderLayout.NORTH);
panLeft.add(txtLeft, BorderLayout.CENTER);
panRight.add(lblRight, BorderLayout.NORTH);
panRight.add(txtLright, BorderLayout.CENTER);
panBottom.add(btnBottom);
panConsole.add(txtConsole, BorderLayout.CENTER);
frame.setContentPane(panOuter);
frame.pack();
frame.setVisible(true);
third (text field): Again referring to the UI above, if the user types
many characters into the first text field, will the letters go over
the text field on the right? If so how can I prevent this?
Try the above code, and see how it acts :)
Fourth: If I append text to a text area and it is already full, will
it automatically allow the user to scroll? If not what is a simple way
to make the text area scrollable?
You need to use something called JScrollPane:
JFrame frame = new JFrame("The Title");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panOuter = new JPanel(new BorderLayout());
JPanel panLeft = new JPanel(new BorderLayout());
panLeft.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JPanel panRight = new JPanel(new BorderLayout());
panRight.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JPanel panBottom = new JPanel(); // default is FlowLayout
panBottom.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JPanel panInput = new JPanel(new BorderLayout());
panInput.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JPanel panConsole = new JPanel(new BorderLayout());
Border outsideBorder = BorderFactory.createEmptyBorder(5, 5, 5, 5);
Border insideBorder = BorderFactory.createTitledBorder("The Console");
Border theBorder = BorderFactory.createCompoundBorder(outsideBorder, insideBorder);
panConsole.setBorder(theBorder);
panInput.add(panLeft, BorderLayout.WEST);
panInput.add(panRight, BorderLayout.EAST);
panInput.add(panBottom, BorderLayout.SOUTH);
panOuter.add(panInput, BorderLayout.NORTH);
panOuter.add(panConsole, BorderLayout.CENTER);
JLabel lblLeft = new JLabel("Label 1", JLabel.CENTER);
JLabel lblRight = new JLabel("Label 2", JLabel.CENTER);
JTextField txtLeft = new JTextField(10);
JTextField txtLright = new JTextField(10);
JButton btnBottom = new JButton("Press it!");
JTextArea txtConsole = new JTextArea(5, 10);
JScrollPane srcPane = new JScrollPane(txtConsole,
JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,
JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
panLeft.add(lblLeft, BorderLayout.NORTH);
panLeft.add(txtLeft, BorderLayout.CENTER);
panRight.add(lblRight, BorderLayout.NORTH);
panRight.add(txtLright, BorderLayout.CENTER);
panBottom.add(btnBottom);
panConsole.add(srcPane, BorderLayout.CENTER);
frame.setContentPane(panOuter);
frame.pack();
frame.setVisible(true);
I hope I answered all of your questions :)