Develop Reference

JAVA JTextField doesnt show up

So Im trying to make a little program to calculate the area of a specific shape.
The user should be able to make a input via a textfield (Like the height and stuff of the shapes). The he should press a button and the price should get printed.
But it doesnt show up.
Code:
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class Rechner extends JFrame implements ActionListener{
private static JButton button1;
private static JButton button2;
private static JButton button3;
private static JButton button4;
private static JTextField numberField;
private JPanel jpanel;
public Rechner(String titel){
super(titel);
jpanel = new JPanel();
numberField = new JTextField(1500);
add(numberField, BorderLayout.CENTER);
button1 = new JButton("Rechteck");
button1.setBounds(10, 10, 150, 30);
button1.addActionListener(this);
add(button1);
button2 = new JButton("Dreieck");
button2.setBounds(170, 10, 150, 30);
button2.addActionListener(this);
add(button2);
button3 = new JButton("Trapez");
button3.setBounds(330, 10, 150, 30);
button3.addActionListener(this);
add(button3);
button4 = new JButton("Parallelogramm");
button4.setBounds(490, 10, 150, 30);
button4.addActionListener(this);
add(button4);
setResizable(false);
}
public static void main(String[] args) {
Rechner frame = new Rechner("Menu");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(660, 400);
frame.setLayout(null);
frame.setVisible(true);
}
public void actionPerformed(ActionEvent e) {
if(e.getSource() == button1){
System.out.println("fff");
}
String numberStr = numberField.getText();
}
}

The default layout manager of a JFrame (well, of its content pane in fact) is BorderLayout.
Without specified constraints , the component is added to BorderLayout.CENTER, so
add(component);
is the same as
add(component, BorderLayout.CENTER);
and each component added this way will replace the last component added to the center.
Also note that setBounds will have no effect if there is a layout manager, and that you create a JPanel that you never use.
Finally, you may want to have a look at this guide : A Visual Guide to Layout Managers

This line is mainly the problem:
add(numberField, BorderLayout.CENTER);
Is causing the TextField to fill the entire space. Then, the next time you add a component to the JFrame with BorderLayout.CENTER, the JTextField gets replaced. To fix this:
super(titel);
jpanel = new JPanel();
add(jpanel, BorderLayout.NORTH); //adding the jpanel
button1 = new JButton("Rechteck");
jpanel.add(button1);
button1.setBounds(10, 10, 150, 30);
//adding the other buttons to the JPanel...
//...
//...
button4.addActionListener(this);
button3.addActionListener(this);
button2.addActionListener(this);
button1.addActionListener(this);
numberField = new JTextField(1500);
add(numberField);//this will cause it to fill the remaining space
setResizable(false);
Explanation:
The buttons should go into the JPanel you created, and the JPanel should go into the JFrame's NORTH. That way they don't cover the JFrame

Set Layout of panel within CardLayout

I am trying to create a UI for an imaginary vehicle that has both Automatic and Manual modes. When the user sets the vehicle into one of the modes, it should only display the controls relevant to that mode, and I've accomplished this using a CardLayout.
However, I'd also like to be able to specify the location of the various elements of the layout for each card manually - for a static layout I'd do something along the lines of mainPanel.setLayout(null), but this simply gives a blank window when used on a CardLayout (hence the two commented-out lines in the code below).
How would I achieve both of these things? My current code is below:
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class UI extends JFrame implements ActionListener{
public UI() {
initUI();
}
private JPanel cardPanel;
private CardLayout cardLayout = new CardLayout();
public final void initUI() {
cardPanel = new JPanel();
cardPanel.setLayout(cardLayout);
JPanel manualPanel = new JPanel();
getContentPane().add(manualPanel);
//manualPanel.setLayout(null);
cardPanel.add(manualPanel, "manual");
JPanel autoPanel = new JPanel();
//autoPanel.setLayout(null);
cardPanel.add(autoPanel, "auto");
JButton startButton = new JButton("START/STOP");
startButton.setBounds(50, 150, 200, 50);
startButton.addActionListener(new startListener());
manualPanel.add(startButton);
autoPanel.add(startButton);
JButton autoButton = new JButton("SWITCH TO AUTO");
autoButton.setBounds(50, 250, 200, 50);
autoButton.addActionListener(new autoListener());
manualPanel.add(autoButton);
JButton upButton = new JButton("^");
upButton.setBounds(125, 320, 50, 50);
upButton.addActionListener(new returnListener());
manualPanel.add(upButton);
JButton downButton = new JButton("\\/");
downButton.setBounds(125, 380, 50, 50);
downButton.addActionListener(new returnListener());
manualPanel.add(downButton);
JButton ccwButton = new JButton("<-");
ccwButton.setBounds(55, 350, 50, 50);
ccwButton.addActionListener(new returnListener());
manualPanel.add(ccwButton);
JButton cwButton = new JButton("->");
cwButton.setBounds(195, 350, 50, 50);
cwButton.addActionListener(new returnListener());
manualPanel.add(cwButton);
JButton ngzButton = new JButton("SOMETHING ELSE");
ngzButton.setBounds(50, 450, 200, 50);
ngzButton.addActionListener(new returnListener());
manualPanel.add(ngzButton);
JButton manualButton = new JButton("SWITCH TO MANUAL");
manualButton.setBounds(50, 250, 200, 50);
manualButton.addActionListener(new manualListener());
autoPanel.add(manualButton);
JButton returnButton = new JButton("SOMETHING ELSE");
returnButton.setBounds(50, 350, 200, 50);
returnButton.addActionListener(new returnListener());
autoPanel.add(returnButton);
setTitle("UI");
setSize(800, 600);
setLocationRelativeTo(null);
setDefaultCloseOperation(EXIT_ON_CLOSE);
add(cardPanel, BorderLayout.NORTH);
}
public static void main(String[] args) {
UI ui = new UI();
ui.setVisible(true);
}
public void actionPerformed(ActionEvent e){
}
private class returnListener implements ActionListener {
public void actionPerformed (ActionEvent event) {
}
}
private class autoListener implements ActionListener {
public void actionPerformed (ActionEvent event) {
cardLayout.show(cardPanel, "auto");
}
}
private class startListener implements ActionListener {
public void actionPerformed (ActionEvent event) {
}
}
private class manualListener implements ActionListener {
public void actionPerformed (ActionEvent event) {
cardLayout.show(cardPanel, "manual");
}
}
}

In your example, you create a startButton, but you then attempt to add the same instance to two different panels. Because a component can only occupy one container, you'll need to create two buttons, one for each panel.
As an aside, instead of using a null layout, give each panel BorderLayout, add the buttons to a JPanel having the default FlowLayout, and add the button panel to the SOUTH. You can then nest your illustrations in the CENTER using whatever layout is appropriate.
Addendum: As #Frakcool comments, using a layout will improve the cross-platform appearance of your buttons. Invoke pack() on the enclosing window, and override getPreferredSize() on the nested illustration panel to give it the needed size. In this related example, the CENTER panel is used for drawing only; having no components, its layout then becomes irrelevant.

JFrame: How to disable window resizing?

I am creating a JFrame and I call the method setSize(500, 500). Now the desired behaviour is that JFrame should not be resized by user in any condition. Either by maximizing or by dragging the borders. It should be 500x500. How can I do it? I have also attached the code in case you can guide me better.
package com.techpapa;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class MainWindow extends JFrame{
private JTextField
write;
private JRadioButton
rb1,
rb2,
rb3;
private ButtonGroup
bg;
private ActionListener al = new ActionListener(){
public void actionPerformed(ActionEvent e){
write.setText("JRadioButton : " + ((JRadioButton)e.getSource()).getText());
}
};
public MainWindow(){
//Frame Initialization
setSize(500, 500);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setLayout(null);
setTitle(".:JRadioButton:.");
setVisible(true);
//Components Initialization
write = new JTextField(20);
write.setEditable(false);
rb1 = new JRadioButton("Male", false);
rb1.addActionListener(al);
rb2 = new JRadioButton("Female", false);
rb2.addActionListener(al);
rb3 = new JRadioButton("I don't want to specify", true);
rb3.addActionListener(al);
bg = new ButtonGroup();
//Add radio buttons to buttongroup
bg.add(rb1); bg.add(rb2); bg.add(rb3);
//Add to window
add(write);
write.setBounds(140, 100, 150, 20);
write.setDragEnabled(true);
add(rb1);
rb1.setBounds(180, 200, 100, 30);
add(rb2);
rb2.setBounds(180, 225, 100, 30);
add(rb3);
rb3.setBounds(180, 250, 130, 30);
}
public static void main(String[] args) {
new MainWindow();
}
}

You can use a simple call in the constructor under "frame initialization":
setResizable(false);
After this call, the window will not be resizable.

Use setResizable on your JFrame
yourFrame.setResizable(false);
But extending JFrame is generally a bad idea.

Simply write one line in the constructor:
setResizable(false);
This will make it impossible to resize the frame.

This Code May be Help you : [ Both maximizing and preventing resizing on a JFrame ]
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
frame.setVisible(true);
frame.setResizable(false);

Just in case somebody didn't understand the 6th time around:
setResizable(false);

it's easy to use:
frame.setResizable(false);

You can use this.setResizable(false); or frameObject.setResizable(false);

If you are defining class like this
className extend JFrame{}
Use this code
this.setResizable(false);
or
setResizable(false);

Java Open a new window by clicking a button

Been sitting here at my computer for about 13 hours and I think my eyes are bleeding.
I found a little gui editor I love called GuiGenie.
It works perfect for creating the window with the buttons and all that good stuff.
The problem is i want to click a button in my first menu and have it open my other menu i made.
I just starting programming 4 weeks ago so I'm a complete noob.
I have a feeling its messing up because of the main methods but I have no idea and 13 hours of sitting here trying millions of things is making me go crazy : )
here is what i got so far
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class MyPanel extends JPanel {
private JTextField How;
private JLabel jcomp2;
private JLabel jcomp3;
private JButton jcomp4;
public MyPanel() {
//construct components
How = new JTextField (1);
jcomp2 = new JLabel ("How long were you parked?");
jcomp3 = new JLabel ("Minutes");
jcomp4 = new JButton ("openNewWindow");
//adjust size and set layout
setPreferredSize (new Dimension (315, 85));
setLayout (null);
//add components
add (How);
add (jcomp2);
add (jcomp3);
add (jcomp4);
//set component bounds (only needed by Absolute Positioning)
How.setBounds (245, 50, 60, 25);
jcomp2.setBounds (35, 30, 185, 50);
jcomp3.setBounds (250, 30, 60, 20);
jcomp4.setBounds (0, 0, 315, 25);
jcomp4.addActionListener( new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
}
});
}
public static void main (String[] args) {
JFrame frame = new JFrame ("MyPanel");
frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add (new MyPanel());
frame.pack();
frame.setVisible (true);
}
}
When the button is pressed, I want it to open this new window
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class MyPanel2 extends JPanel {
private JButton jcomp1;
private JButton jcomp2;
private JButton jcomp3;
private JTextField jcomp4;
public MyPanel2() {
//construct components
jcomp1 = new JButton ("test1");
jcomp2 = new JButton ("test2");
jcomp3 = new JButton ("test3");
jcomp4 = new JTextField (5);
//adjust size and set layout
setPreferredSize (new Dimension (395, 156));
setLayout (null);
//add components
add (jcomp1);
add (jcomp2);
add (jcomp3);
add (jcomp4);
//set component bounds (only needed by Absolute Positioning)
jcomp1.setBounds (20, 45, 100, 25);
jcomp2.setBounds (135, 60, 100, 25);
jcomp3.setBounds (260, 35, 100, 25);
jcomp4.setBounds (105, 115, 100, 25);
}
public static void main (String[] args) {
JFrame frame = new JFrame ("MyPanel");
frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add (new MyPanel2());
frame.pack();
frame.setVisible (true);
}
}
If anyone could help I would appreciate it greatly!!
I have a lot of respect for you pros out there because if you are a pro at this, you are probably smarter than 99.9% of the world.
This stuff hurts my brain.

Here is something you can do, for this situation, where you have multiple Forms or Windows what you can do is to use a JPanel which can have this CardLayout set as it's LayoutManager and then you can add the two JPanels to it and access them with the methods provided by the same.
Don't use setBounds() when using Absolute Positioning this is really not the right way of putting components to the parent container. Instead use setLocation(...) and setSize(...) methods. Consider not to use Absolute Positioning as much as possible for you. Certain lines in favour of the before said line taken from Java Docs are as follows :
Although it is possible to do without a layout manager, you should use a
layout manager if at all possible. A layout manager makes it easier to
adjust to look-and-feel-dependent component appearances, to different
font sizes, to a container's changing size, and to different locales.
Layout managers also can be reused easily by other containers, as well as
other programs.
Since the output of your program is really not a soothing experience in any sense. Atleast LayoutManager, can make that work a lot more easier for you, since you need not have to specify position and size for each and every component. Try walking through the Layout Mangers Tutorials, and get accustomed to them as soon as possible. They are the real life savers :-)
Here is a modified code taken from your SOURCE CODE
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class CardLayoutExample
{
private JPanel contentPane;
private MyPanel panel1;
private MyPanel2 panel2;
private void displayGUI()
{
JFrame frame = new JFrame("Card Layout Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel contentPane = new JPanel();
contentPane.setBorder(
BorderFactory.createEmptyBorder(5, 5, 5, 5));
contentPane.setLayout(new CardLayout());
panel1 = new MyPanel(contentPane);
panel2 = new MyPanel2();
contentPane.add(panel1, "Panel 1");
contentPane.add(panel2, "Panel 2");
frame.setContentPane(contentPane);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String... args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new CardLayoutExample().displayGUI();
}
});
}
}
class MyPanel extends JPanel {
private JTextField How;
private JLabel jcomp2;
private JLabel jcomp3;
private JButton jcomp4;
private JPanel contentPane;
public MyPanel(JPanel panel) {
contentPane = panel;
//construct components
How = new JTextField (1);
jcomp2 = new JLabel ("How long were you parked?");
jcomp3 = new JLabel ("Minutes");
jcomp4 = new JButton ("openNewWindow");
//adjust size and set layout
setPreferredSize (new Dimension (315, 85));
setLayout (null);
//set component bounds (only needed by Absolute Positioning)
How.setBounds (245, 50, 60, 25);
jcomp2.setBounds (35, 30, 185, 50);
jcomp3.setBounds (250, 30, 60, 20);
jcomp4.setLocation(0, 0);
jcomp4.setSize(315, 25);
jcomp4.addActionListener( new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
CardLayout cardLayout = (CardLayout) contentPane.getLayout();
cardLayout.next(contentPane);
}
});
//add components
add (How);
add (jcomp2);
add (jcomp3);
add (jcomp4);
}
}
class MyPanel2 extends JPanel {
private JButton jcomp1;
private JButton jcomp2;
private JButton jcomp3;
private JTextField jcomp4;
public MyPanel2() {
//construct components
jcomp1 = new JButton ("test1");
jcomp2 = new JButton ("test2");
jcomp3 = new JButton ("test3");
jcomp4 = new JTextField (5);
//adjust size and set layout
setPreferredSize (new Dimension (395, 156));
setLayout (null);
//set component bounds (only needed by Absolute Positioning)
jcomp1.setBounds (20, 45, 100, 25);
jcomp2.setBounds (135, 60, 100, 25);
jcomp3.setBounds (260, 35, 100, 25);
jcomp4.setBounds (105, 115, 100, 25);
//add components
add (jcomp1);
add (jcomp2);
add (jcomp3);
add (jcomp4);
}
}

Here is the code for myPanel class, use this one:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class MyPanel extends JPanel {
private JTextField How;
private JLabel jcomp2;
private JLabel jcomp3;
private JButton jcomp4;
public MyPanel() {
//construct components
How = new JTextField (1);
jcomp2 = new JLabel ("How long were you parked?");
jcomp3 = new JLabel ("Minutes");
jcomp4 = new JButton ("openNewWindow");
jcomp4.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
JFrame frame = new JFrame ("MyPanel");
frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add (new MyPanel2());
frame.pack();
frame.setVisible (true);
}
});
//adjust size and set layout
setPreferredSize (new Dimension (315, 85));
setLayout (null);
//add components
add (How);
add (jcomp2);
add (jcomp3);
add (jcomp4);
//set component bounds (only needed by Absolute Positioning)
How.setBounds (245, 50, 60, 25);
jcomp2.setBounds (35, 30, 185, 50);
jcomp3.setBounds (250, 30, 60, 20);
jcomp4.setBounds (0, 0, 315, 25);
jcomp4.addActionListener( new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
}
});
}
public static void main (String[] args) {
JFrame frame = new JFrame ("MyPanel");
frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add (new MyPanel());
frame.pack();
frame.setVisible (true);
}
}

How to absolutely position a JPanel over another JPanel with setLayout(null) and a background image?

I'm working with JFrames in Java, specifically with absolutely positioned elements that need to overlap. I understand that to overlay components, one should make a JPanel (with setOpacity(false);), and position it with either setBounds(x,y,x2,y2); or setPosition(x,y) & setSize(x,y). Unfortunately the panels act like CSS's inline-divs; they take up only the needed amount of room on their line, and do not stack.
This is the code I have so far, but it doesn't seem to act like I'd imagine it would:
class Login extends JFrame {
private JPanel backgroundpanel;
private JPanel panel;
private JPanel panel2;
private JTextField usernameBox;
private JPasswordField passwordBox;
private JButton button;
private int height = 319;
private int width = 452;
private ImageIcon ii = new ImageIcon("special-window-BG.png");
private JLabel image;
public Login() {
setLayout(null);
setTitle("Login");
setSize(width,height);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLayout(null);
buildPanel();
add(backgroundpanel);
setVisible(true);
}
private void buildPanel() {
usernameBox = new JTextField(20);
passwordBox = new JPasswordField(20);
button = new JButton("Login");
image = new JLabel(ii);
backgroundpanel = new JPanel();
panel = new JPanel();
panel2 = new JPanel();
backgroundpanel.add(panel);
backgroundpanel.add(panel2);
backgroundpanel.add(image);
panel.setBackground(Color.red);
panel.setBounds(0, 0, 10, 10);
panel.setOpaque(false);
panel2.setBackground(Color.blue);
panel2.setBounds(0, 0, 10, 10);
panel2.setOpaque(false);
panel.add(passwordBox);
panel2.add(button);
backgroundpanel.setOpaque(false);
backgroundpanel.isOptimizedDrawingEnabled();
backgroundpanel.setBounds(0, 0, width, height);
...cot'd, however unnecessary.
So basically, I'd like to know how to absolutely position JPanels (or JComponents, if that's simpler) over a JPanel with a background-image.
Thanks for taking a look at this question, I've spent far too much time on this method; the commented-out code extends nearly 500 lines passed what I posted, so I have nowhere else to turn to. The image below shows a crude illustration of what I'm trying to accomplish, I'm not sure if I'actually come close to getting it yet, because sometimes the JComponents seem to disappear as if they're behind the background image, however I'd like to find the simple solution that's most likely right in front of my eyes!
http://i.stack.imgur.com/revz8.jpg

I'd like to find the simple solution that's most likely right in front of my eyes!
Something like this?
import java.awt.*;
import java.awt.image.BufferedImage;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
public class LoginPanel extends JPanel {
private static final long serialVersionUID = 1L;
BufferedImage image;
LoginPanel(BufferedImage image) {
super(new GridBagLayout());
this.image = image;
JPanel controls = new JPanel(new BorderLayout(15,35));
controls.setOpaque(false);
controls.setBorder(new EmptyBorder(110,0,0,0));
JPanel fields = new JPanel(new GridLayout(0,1,30,30));
fields.setOpaque(false);
controls.add(fields, BorderLayout.CENTER);
fields.add(new JTextField(20));
fields.add(new JPasswordField(20));
JPanel button = new JPanel(new GridBagLayout());
button.setOpaque(false);
controls.add(button, BorderLayout.PAGE_END);
button.add(new JButton("Log In"));
Dimension prefSize = new Dimension(image.getWidth(),image.getHeight());
setPreferredSize(prefSize);
add(controls);
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(image, 0, 0, getWidth(), getHeight(), this);
}
public static void main(String[] args) throws Exception {
URL url = new URL("http://i.stack.imgur.com/revz8.jpg");
final BufferedImage image = ImageIO.read(url);
SwingUtilities.invokeLater(new Runnable() {
public void run() {
LoginPanel p = new LoginPanel(image);
JOptionPane.showMessageDialog(null, p);
}
});
}
}

You're setting setLayout(null) on your JFrame but not on the "backgroundpanel" (which layout is default set to FlowLayout).
You shouldn't set layout of your Login frame - because it is default set to BorderLayout - and it's ok (you want the "backgroundpanel" to grow to match the parent).
Instead setLayout(null) on your JPanel - "backgroundpanel" - to which you add your arbitrary positioned panels.