I have two JPanel to place inside a JFrame, I want them both to occupy the full width of the frame but I don't know how. Also I'm not a big fan of the setBounds() method so I was wondering if there is a way to just make the component take the full width and just specify the desired height after.
Here is my code:
public class Test extends JFrame {
public Test() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(400, 400);
setLocationRelativeTo(null);
setLayout(new BorderLayout());
JPanel header = new JPanel();
header.setBounds(0,0,300,50);
header.setLayout(new BorderLayout());
header.setBackground(Color.gray);
JPanel body = new JPanel();
body.setBounds(0,50,300,300);
body.setLayout(new BorderLayout());
body.setBackground(Color.black);
add(header, BorderLayout.NORTH);
add(body, BorderLayout.CENTER);
//setLayout(null);
setVisible(true);
}
}
You need to remove the setLayout(null), this reverses the work of the earlier setLayout(new BorderLayout())
You then need to set the preferred size of both the header and body using setPreferredSize instead of using setBounds()
public Test() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(400, 400);
setLocationRelativeTo(null);
setLayout(new BorderLayout());
JPanel header = new JPanel();
header.setPreferredSize(new Dimension(400, 50));
header.setLayout(new BorderLayout());
header.setBackground(Color.gray);
JPanel body = new JPanel();
body.setPreferredSize(new Dimension(400, 300));
body.setLayout(new BorderLayout());
body.setBackground(Color.black);
add(header, BorderLayout.NORTH);
add(body, BorderLayout.CENTER);
setVisible(true);
}
The basic answer is, you need to take advantage of the layout management framework.
Layout managers work by taking into consideration the preferred/minimum/maximum size of a component - beware though, these are guides only and layout managers may ignore some or all of them based on their needs and the available space.
This is a simple example which overrides the getPreferredSize method of the header to return a "desirable" size:
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.setLayout(new BorderLayout());
JPanel header = new JPanel() {
#Override
public Dimension getPreferredSize() {
return new Dimension(300, 50);
}
};
header.setLayout(new BorderLayout());
header.setBackground(Color.gray);
// I would allow the content of the panel determine the actual size
// but I've overridden `getPreferredSize` for demonstration purposes
JPanel body = new JPanel() {
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
};
body.setLayout(new BorderLayout());
body.setBackground(Color.black);
frame.add(header, BorderLayout.NORTH);
frame.add(body, BorderLayout.CENTER);
// pack is preferred over setSize, as it will "pack" the window around
// the content, which will produce a more consistent result
frame.pack();
frame.setVisible(true);
The problem with doing this is, the component will no longer take into consideration the sizing requirements of its children, so you might end up with some strange side effects.
There are other solutions which might provide some other advantages and disadvantages and you'd need to consider them for your use case.
Why override getPreferredSize rather then calling setPreferredSize?
Mostly, control. You can prevent other parts of the code from modifying the state and you control "how" the calculation gets done. Sure, nothing stops other codes from extending the component and overriding the method as well, but that's more complicated and doesn't take into consideration scenarios where an instance of the component is provided, rather than created.
Why use pack over setSize?
pack will "pack" the window frame around the content, so the content will always match its preferred size, rather than shrinking the content so that the frame decorations can be accommodated. It will, overall, generate a more consistent result across multiple platforms
Related
In most of the GUI programs, when the user resizes it, the components of the program, such as text fields, buttons, etc. tend to increase or decrease their size depending on the decisions of the user. I'm trying to implement this idea into my GUI program. I'm a little bit lost about how I can do it. By the way, I created my program without the usage/help of the Eclipse Swing or Netbeans' GUI.
import javax.swing.*;
import java.awt.*;
import java.io.IOException;
public class CodeReviewerFrame extends JFrame {
EditorAreaPanel display = new EditorAreaPanel();
// FileOptionsPanel fileOptionsPanel = new FileOptionsPanel( display );
JPanel p = new JPanel();
JPanel panel = new JPanel();
public CodeReviewerFrame(String title) throws IOException {
super(title);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setPreferredSize(new Dimension(1500, 1000));
setLayout(new BorderLayout());
ImageIcon img = new ImageIcon("icon.png");
setIconImage(img.getImage());
p.setLayout(new BorderLayout());
p.add(new HomeOptionsPanel(display), BorderLayout.LINE_START);
p.add(new NewCommentPanel(display), BorderLayout.CENTER);
p.add(new CommentOptionsPanel(display), BorderLayout.LINE_END);
add(p, BorderLayout.PAGE_START);
panel.setLayout(new BorderLayout());
panel.add(new FileExplorerPanel(), BorderLayout.LINE_START);
panel.add(new FileOptionsPanel(display), BorderLayout.CENTER);
panel.add(new CommentShowPanel(display), BorderLayout.LINE_END);
add(panel, BorderLayout.CENTER);
pack();
setResizable(true);
setVisible(true);
/**
* Everything Under This is experimental
*/
GridBagConstraints constraints = new GridBagConstraints();
constraints.gridx = 0;
constraints.gridy = 0;
//add ( fileOptionsPanel, constraints );
}
}
There are components on each Panel that have been added, such as buttons in HomeOptionsPanel, huge JTextArea in the center of FileOptionsPanel plus four buttons up on the JTextArea, etc. Should I use new Layout type, or commands known as "repaint/revalidate," or implement changeListener? And should I only implement the code to the JFrame, or do it for each of the JPanels?
The behaviour of your UI upon window resizing depends (also) on the Layout Manager you are using.
Some Layout Managers (like BorderLayout) resize the components when the windows is resized, while others (like FlowLayout) don't.
It is not clear what LM you are using inside your panels, but most likely your issue stands in there.
I have a typical IDE style window with a top JMenuBar and JToolBar,
a large center console and a bottom status bar.
Here are the main parts of the code:
mainPanel = new JPanel();
mainPanel.setLayout(new BorderLayout());
JPanel topPanel = new JPanel();
. (JMenuBar and JToolBar)
.
mainPanel.add(topPanel, BorderLayout.NORTH);
cardPanel = new JPanel();
cardPanel.setLayout(cardLayout);
.
.
Dimension minDimension = new Dimension(680, 400);
Dimension maxDimension = new Dimension(750, 800);
JPanel centerPanel = new JPanel();
centerPanel.setMinimumSize(minDimension);
centerPanel.setPreferredSize(minDimension);
centerPanel.setMaximumSize(maxDimension);
centerPanel.setLayout(new BoxLayout(centerPanel, BoxLayout.Y_AXIS));
centerPanel.add(cardPanel);
mainPanel.add(centerPanel, BorderLayout.CENTER);
mainPanel.add(statusBar, BorderLayout.SOUTH);
I want to be able to control the sizing of the whole window,
with a minimum and maximum size.
I thought I could have the 'centerPanel' JPanel as a BoxLayout,
so I could have some control over it, but as it is, I can't
control the sizing of the window at all.
I tried to make the 'mainPanel' use a BoxLayout, instead of a BorderLayout, but there
where too many issues.
Is the main BorderLayout causing it to "ignore" the sizing?
I know that the parts, other than the center, have some sizing
control, that's why I tried to use a BoxLayout in the center.
Is it possible to keep the BorderLayout, and get it to work,
with some other modifications, or would I need to switch to some other Layout Manager?
Thanks!
I have this simple example where I want to display a large panel in a small frame.
Java documentation tell the scrollpane will automatically fit its contents in its viewport and add scrollbars.
However I have no such luck. No scrollpane nor its content appear.
Here is what I have tried.
public class MyWindow extends JFrame {
JPanel panel;
JScrollPane scroll;
public MyWindow(){
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
panel = new JPanel();
panel.setSize(1000,1000);
scroll = new JScrollPane(panel);
add(scroll,BorderLayout.CENTER);
setSize(300, 300);
setVisible(true);
}
}
As stated in similar questions,
I made the panel bigger than frame.
I added border layout to frame.
Still no luck.
The JScrollPane is free to disregard the initial size of the panel. You need to set the preferred size
panel = new JPanel() {
#Override
public Dimension getPreferredSize() {
return new Dimension(1000, 1000);
};
};
I've created a simple user interface in Swing but the setSize command does not appear to be working. Can anyone tell me what the problem is?
import java.awt.Container;
import javax.swing.*;
public class UserInterface1 {
private JTextField outputArea = new JTextField();
private JTextField errorReportArea = new JTextField();
private JPanel inputPanel = new JPanel();
public UserInterface1() {
JFrame frame = new JFrame("Fuel Station");
frame.setSize(500, 500);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
outputArea.setEditable(false);
errorReportArea.setEditable(false);
Container contentPane = frame.getContentPane();
contentPane.setLayout(new BoxLayout(contentPane, BoxLayout.Y_AXIS));
contentPane.add(outputArea);
contentPane.add(errorReportArea);
contentPane.add(inputPanel);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
UserInterface1 test = new UserInterface1();
}
}
Swing Frame setSize
The right answer to this is don't do that!
Even when we know the size of the content of a frame must be (e.g.) 500x500 px, we should not be guessing the size of the frame, which will vary by platform.
pack() knows how big to make the frame. We don't, so we should use it.
The size of the text fields can be specified using a font size and the number of columns.
The right size for inputPanel can be determined from the content within it.
Replace:
frame.setSize(500, 500);
by
frame.setPreferredSize(new java.awt.Dimension(500, 500));
It's because pack() resizes the frame to fit the dimensions of its contents or the preferred size, so you can remove the pack() call, or add a preferred size with setPreferredSize() method
I'm still trying to learn how layout managers work. I made a Frame with two JPanels.
The first one contains a textArea with a boxLayout.
The second one contains a flow layout with a button.
I set the preferredSize of each panel accordingly, packed them, but got unexpected results.
import java.awt.*;
import javax.swing.*;
public class LayoutMgrTest
{
public static void main(String[] args)
{
TableBasic frame = new TableBasic();
frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
frame.setVisible(true);
frame.getContentPane().setLayout(new GridLayout(2,1));
JPanel controlPane = new JPanel();
JPanel buttonPane = new JPanel();
controlPane.setLayout(new BoxLayout(controlPane, BoxLayout.PAGE_AXIS));
controlPane.setPreferredSize(new Dimension(200, 200));
controlPane.add(new JScrollPane(new JTextArea()));
buttonPane.setLayout(new FlowLayout(FlowLayout.LEFT));
buttonPane.setPreferredSize(new Dimension(100,20));
buttonPane.add(new JButton("Button1"));
buttonPane.add(new JButton("Button2"));
frame.getContentPane().add(controlPane, BorderLayout.NORTH);
frame.getContentPane().add(buttonPane, BorderLayout.SOUTH);
frame.setSize(new Dimension(500,500));
frame.pack();
}
}
Whatever I do, if I use a grid Layout, it seems to always allocate half of the available space to each control. I have been told that:
The height of each row is dependent on the height of each component
added in each row.
The buttonpane's height is 20. It's allocating much more than that to it:
What's wrong with this code?
I would like to leave the two JPanels intact please. It's easy to simply add the textbox and the buttons directly to the frame, but I need to do it with JPanels (because I will be adding borders and other things).
That's the result of using GridLayout as layout manager. Change it to BorderLayout:
frame.getContentPane().setLayout(new BorderLayout());
For example, this code (I changed a little as possible from the original):
import java.awt.*;
import javax.swing.*;
public class LayoutMgrTest
{
public static void main(String[] args)
{
JFrame frame = new JFrame();
frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
//frame.setVisible(true);
//frame.getContentPane().setLayout(new BorderLayout());
JPanel controlPane = new JPanel();
JPanel buttonPane = new JPanel();
controlPane.setLayout(new BoxLayout(controlPane, BoxLayout.PAGE_AXIS));
controlPane.setPreferredSize(new Dimension(200, 200));
controlPane.add(new JScrollPane(new JTextArea()));
buttonPane.setLayout(new FlowLayout(FlowLayout.LEFT));
buttonPane.setPreferredSize(new Dimension(100,40));
buttonPane.add(new JButton("Button1"));
buttonPane.add(new JButton("Button2"));
frame.add(controlPane, BorderLayout.NORTH);
frame.add(buttonPane, BorderLayout.SOUTH);
//frame.setSize(new Dimension(500,500));
frame.pack();
frame.setVisible(true);
}
}
Generates this frame:
I set the preferredSize of each panel accordingly,
That is another problem. You should NOT set the preferred size. That is the job of the layout manager. Just add your components to the panels and let the layout manager do its job.
Most compnents have a default preferred size. For some you need to give it a little tip.
For example when using a text area you would give a "suggested" preferred size by using:
JTextArea textArea = new JTextArea(rows, columns);
If you use LayoutManager, you should not set a size on a component except the frame.
the size for the components is calculated from the different layout managers.
you find more infos at http://download.oracle.com/javase/tutorial/uiswing/layout/howLayoutWorks.html
in your code, you can add the panel with the textarea to BorderLayout.CENTER. this should solve your problem. the component in BorderLayout.CENTER takes the whole space, except the space needed for the components in NORTH, EAST, SOUTH and WEST.