I just started GUI programming in Java and I am having trouble setting the background image to a JFrame using JLabel. I have read many answers to the same question on this website but the code is too complicated for a beginner.
My source code is as follows and the image I'm using is already in src folder (I get the output window but there is no image in it):
public class staffGUI extends JFrame {
private JLabel imageLabel = new JLabel(new ImageIcon("staff-directory.jpg"));
private JPanel bxPanel = new JPanel();
public staffGUI(){
super("Staff Management");
bxPanel.setLayout(new GridLayout(1,1));
bxPanel.add(imageLabel);
this.setLayout(new GridLayout(1,1));
this.add(bxPanel);
this.setVisible(true);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLocationRelativeTo(null);
this.setResizable(false);
this.pack();
}
ImageIcon(String) "Creates an ImageIcon from the specified file". The actual physical image is loaded in a background thread, so even though the call might return immediately, the actually loading could still be running in the background.
This means that ImageIcon does not throw any errors if the image can't be loaded, making sometimes annoying to work with. I prefer to use ImageIO.read where possible, as it will throw an IOException when it can't read a image for some reason.
The reason you image is not loading is because the image doesn't actually exist from the context of the JVM, which is looking in the current working directory of the image.
When you included resources within the context of the program, they can no longer be addressed as files and need to be loaded through the use of Class#getResource or Class#getResourceAsStream, depending on your needs.
For example
imageLabel = new JLabel(getClass().getResource("/staffdirectory/staff-directory.jpg"));
Where possible, you should supply the path to the image from the context of the source root
Can you give an example how I can use the "ImageIO.read" in my code?
import java.awt.GridLayout;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class staffGUI extends JFrame {
private JLabel imageLabel;
private JPanel bxPanel = new JPanel();
public staffGUI() {
super("Staff Management");
imageLabel = new JLabel();
try {
BufferedImage img = ImageIO.read(getClass().getResource("/staffdirectory/staff-directory.jpg"));
imageLabel.setIcon(new ImageIcon(img));
} catch (IOException ex) {
ex.printStackTrace();
}
bxPanel.setLayout(new GridLayout(1, 1));
bxPanel.add(imageLabel);
this.setLayout(new GridLayout(1, 1));
this.add(bxPanel);
this.setVisible(true);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLocationRelativeTo(null);
this.setResizable(false);
this.pack();
}
}
Try this example i am sure it will work. Make sure that you have a images folder inside your src folder and put the image in it.
private JLabel imageLabel = new JLabel(getClass().getResource("/staffdirectory/staff-directory.jpg"));
will not work and eclipse will give error as JLabel(URL) is not defined; secondly private modifier is not allowed here.
import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.Toolkit;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
class BackgroundImageJFrame extends JFrame {
private static final long serialVersionUID = 6337428393053702097L;
JButton b1;
JLabel l1;
public BackgroundImageJFrame() {
setTitle("Background Color for JFrame");
setSize(400, 400);
setLocationRelativeTo(null);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setVisible(true);
setLayout(new BorderLayout());
JLabel background = new JLabel(
new ImageIcon(Toolkit.getDefaultToolkit().getImage(
getClass().getResource("/images/free-wallpaper-4.jpg"))));
add(background);
background.setLayout(new FlowLayout());
l1 = new JLabel("Here is a button");
b1 = new JButton("I am a button");
background.add(l1);
background.add(b1);
setSize(400, 400);
}
public static void main(String args[]) {
new BackgroundImageJFrame();
}
}
Related
since some hours I am trying to create a JFrame whit following behavior:
I have a Title (with maybe an Image included) -This is centered at the top. -> Check
The rest of this JFrame should be filled with JPanel.
The first JPanel should be placed in the center on top. The second JPanel should be placed under the first and so on. When the first JPanel runs out of the screen, a second row needs to be created.
I dont care if they are reordered or not. Here is a drawing i prepared to show what I want:
Example - I need one of that behaviors
I have tried out so many combination of different Layouts.. But still can't find the right solution.
Here is my code, which is working fine besides the fact, that my panels are ordered from left to right instead of from top to down.. :(
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
#SuppressWarnings("serial")
public class myFrameClass extends JFrame {
myFrameClass() {
super();
setLayout(new BorderLayout());
GraphicsDevice[] gs = GraphicsEnvironment.getLocalGraphicsEnvironment().getScreenDevices();
GraphicsConfiguration[] gc = gs[0].getConfigurations();
setUndecorated(true);
setBackground(Color.WHITE);
setLocation(gc[0].getBounds().x, gc[0].getBounds().y);
setExtendedState(JFrame.MAXIMIZED_BOTH);
add(getHeader(), BorderLayout.NORTH);
add(getPanels());
setVisible(true);
}
private JPanel getPanels() {
JPanel p = new JPanel();
p.setLayout(new FlowLayout());
int cnt = 6;
for (int i = 0; i < cnt; i++) {
p.add(getPanel());
}
return p;
}
private JPanel getPanel() {
JPanel p = new JPanel();
p.setBackground(Color.RED);
p.setPreferredSize(new Dimension(200, 200));
return p;
}
private JPanel getHeader() {
JPanel p = new JPanel();
p.add(new JLabel("Titel"));
return p;
}
public static void main(String args[]) {
new myFrameClass();
}
}
I also found Oracle VerticalFlowLayout but was not able to access it. Might it help me? In case - how to use it?
Otherwise.. How to use JFrame to archive that behavior?
Thank you
I'm learning how to create application in Java.
I'm having trouble getting the JLabel to have a background color whilst the JPanel is white, behind it. Also, is there a way to resize the JPanel to half of what the JFrame is?
Any help would be very much appreciated. Thank you.
package PracticeOne;
import java.awt.BorderLayout;
public class PracticeOne {
public static void main(String[] args) {
Frame container = new Frame();
Panel box = new Panel();
Label txt = new Label();
box.add(txt);
container.add(box, BorderLayout.CENTER);
}
}
package PracticeOne;
import javax.swing.JFrame;
public class Frame extends JFrame {
/**
*
*/
private static final long serialVersionUID = 1L;
Frame(){
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setSize(500, 500);
this.setVisible(true);
this.setLocationRelativeTo(null);
this.setTitle("Testing this out");
}
}
package PracticeOne;
import java.awt.Color;
import java.awt.Dimension;
import javax.swing.JPanel;
public class Panel extends JPanel {
/**
*
*/
private static final long serialVersionUID = 1L;
public Dimension d = new Dimension(100,100);
Panel(){
this.setSize(d);
this.setAlignmentX(CENTER_ALIGNMENT);
this.setBackground(Color.WHITE);
}
}
package PracticeOne;
import java.awt.Color;
import javax.swing.JLabel;
public class Label extends JLabel {
/**
*
*/
private static final long serialVersionUID = 1L;
Label(){
this.setSize(50, 50);
this.setText("ya boy is working here");
this.setForeground(Color.BLACK);
this.setBackground(Color.ORANGE);
}
}
I'm having trouble getting the JLabel to have a background color whilst the JPanel is white
You need to call setOpaque(true); in your JLabel
Also, is there a way to resize the JPanel to half of what the JFrame is?
You could use a GridLayout, and place 2 JPanels in it, that way, you're going to have 2 JPanels using half the size of your JFrame each.
Also, rename your classes, Panel belongs to the name of a class in AWT, same for Frame and Label, this might confuse your (and whoever reads your code).
Never extend JFrame, instead build your GUI based on JPanels. See extends JFrame vs creating it inside of class and The use of multiple JFrames, Good / Bad practice? The general consensus says it's bad.
Also you should also check Should I avoid the use of setPreferred|Maximum|MinimumSize() in Swing? Again, yes, you should and instead override the getPreferredSize() method.
Don't forget to place your program on the Event Dispatch Thread (EDT) by changing your main() method as follows:
public static void main(String[] args) {
//Java 8 with lambda expressions
SwingUtilities.invokeLater(() ->
//Your code here
);
//Java 7 and below (Or 8 without lambda expressions)
SwingUtilities.invokeLater(new Runnable() {
//Your code here
});
}
Now, with all the above recommendations, your code should now look like this:
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridLayout;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class HalfSizePanelWithLabelInDifferentColor {
private JFrame frame;
private Container contentPane;
private JPanel pane;
private JPanel pane2;
private JLabel label;
private static final Dimension dim = new Dimension(100, 100);
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> new HalfSizePanelWithLabelInDifferentColor().createAndShowGui());
}
public void createAndShowGui() {
frame = new JFrame(getClass().getSimpleName());
contentPane = frame.getContentPane();
pane = new JPanel() {
#Override
public Dimension getPreferredSize() {
return dim;
}
};
pane2 = new JPanel();
pane.setOpaque(false);
pane2.setOpaque(false);
pane.setBorder(BorderFactory.createLineBorder(Color.RED));
pane2.setBorder(BorderFactory.createLineBorder(Color.BLUE));
label = new JLabel("Hello World!");
label.setBackground(Color.GREEN);
label.setOpaque(true);
contentPane.setLayout(new GridLayout(2, 1));
pane.add(label);
contentPane.add(pane);
contentPane.add(pane2);
contentPane.setBackground(Color.WHITE);
frame.setContentPane(contentPane);
frame.pack();
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
And your output would be like this:
Note that I added some colored borders to show where a pane starts and ends and where the other one starts and ends
I am writing some Java code that allows the user to see a frame with JLabel, JTextField and JButton.
I want the JLabel to be called "Count" and I have a problem with FlowLayout.
I want the interface to look like this:
Instead, I have this:
This is my code:
package modul1_Interfate_Grafice;
import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class Exercitiu04 implements ActionListener {
private JFrame frame;
private JLabel labelCount;
private JTextField tfCount;
private JButton buttonCount;
private int count = 0;
public void go() {
frame = new JFrame("Java Counter");
labelCount = new JLabel("Counter");
labelCount.setLayout(new FlowLayout());
frame.getContentPane().add(BorderLayout.CENTER, labelCount);
tfCount = new JTextField(count + " ", 10);
tfCount.setEditable(false);
labelCount.add(tfCount);
buttonCount = new JButton("Count");
labelCount.add(buttonCount);
buttonCount.addActionListener(this);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(350, 150);
frame.setLocation(400, 200);
}
#Override
public void actionPerformed(ActionEvent event) {
count++;
tfCount.setText(count + "");
}
public static void main(String[] args) {
Exercitiu04 a = new Exercitiu04();
a.go();
}
}
Solve it.
Instead of labelCount.setLayout(new FlowLayout());` i should have had
frame.setLayout(new FlowLayout());
From description of JLabel class,
JLabel is:
A display area for a short text string or an image, or both.
But here: labelCount.add(tfCount) and here labelCount.add(buttonCount) you're trying to put a textfield and a button into a label. In this case, positions of button and textfield are controlled by FlowLayout but position of the text in the label is not.
Instead of this, you should put all of your elements in common JPanel, like this:
...
frame = new JFrame("Java Counter");
frame.setLayout(new BorderLayout());
JPanel wrapper = new JPanel(); // JPanel has FlowLayout by default
labelCount = new JLabel("Counter");
labelCount.setLayout(new FlowLayout());
wrapper.add(labelCount);
tfCount = new JTextField(count + " ", 10);
tfCount.setEditable(false);
wrapper.add(tfCount);
buttonCount = new JButton("Count");
buttonCount.addActionListener(this);
wrapper.add(buttonCount);
frame.add(BorderLayout.CENTER, wrapper);
...
And, like MasterBlaster said, you should put swing methods in EDT.
There are only two things you should know about FlowLayout:
a) It is a default layout manager of the JPanel component
b) It is good for nothing.
This trivial layout cannot be achieved with FlowLayout.
When doing layouts in Swing, you should familiarize yourself
with some powerful layout managers. I recommend MigLayout and
GroupLayout.
package com.zetcode;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import net.miginfocom.swing.MigLayout;
/*
Simple UI with a MigLayout manager.
Author Jan Bodnar
Website zetcode.com
*/
public class MigLayoutCounterEx extends JFrame {
public MigLayoutCounterEx() {
initUI();
}
private void initUI() {
JLabel lbl = new JLabel("Counter");
JTextField field = new JTextField(10);
JButton btn = new JButton("Count");
createLayout(lbl, field, btn);
setTitle("Java Counter");
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
private void createLayout(JComponent... arg) {
setLayout(new MigLayout());
add(arg[0]);
add(arg[1]);
add(arg[2]);
pack();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
MigLayoutCounterEx ex = new MigLayoutCounterEx();
ex.setVisible(true);
});
}
}
The example is trivial. You just put the three components into the
cells.
Screenshot:
You shouldn't use setSize when dealing with FlowLayout. Instead use pack(). It makes the window just about big enough to fit all your components in. That should tidy things up for you
I want to write a simple Swing application with a button and a text field at the bottom. I'm using a JTextField but it is not clickable. I searched on the web and SO, but I could not find a solution. In question How to Set Focus on JTextField?, I found the following :
addWindowListener( new WindowAdapter() {
public void windowOpened( WindowEvent e ){
entry.requestFocus();
}
});
but this does not help. In this other question (How do you set a focus on Textfield in Swing?) I found Component.requestFocus() but this does not work either. I also tried
entry.setFocusable(true);
entry.setEditable(true);
entry.setEnabled(true);
without effects. My code:
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.FlowLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
public class StackSample extends JFrame {
public StackSample() {
initUI();
pack();
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
private void initUI() {
JPanel panel = new JPanel(new BorderLayout());
add(panel, BorderLayout.CENTER);
JPanel bottomPanel = new JPanel(new FlowLayout());
panel.add(bottomPanel, BorderLayout.SOUTH);
JButton buttonDraw = new JButton("Draw");
bottomPanel.add(buttonDraw);
JTextField entry = new JTextField();
bottomPanel.add(entry);
setPreferredSize(new Dimension(250, 150));
setLocationRelativeTo(null);
}
private static final long serialVersionUID = 8359448221778584189L;
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
MyApp app = new MyApp();
app.setVisible(true);
}
});
}
}
Your JTextField is clickable. The only problem is that it's too small.
This is because you're using FlowLayout, which will make components as small as possible.
One solution is to simply switch to a layout that allows components to fill as much space as possible, such as BoxLayout:
JPanel bottomPanel = new JPanel();
bottomPanel.setLayout(new BoxLayout(bottomPanel,BoxLayout.X_AXIS));
You haven't specified a size for your JTextField, so it defaults to zero characters wide. Try using the constructor that specifies the number of columns.
Also, what is MyApp? I can't see any evidence that your StackSample is ever created or used.
I'm trying to display a different JFrame after the user does something in the same window they are using, similar to a login feature. Haven't been able to figure out how to do that.
The workaround I have now is to just hide the current JFrame and then open a new one, which simulates a similar effect. But ideally I want it to just display the next JFrame in the same existing window.
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;
public class Login extends JFrame {
private static int x = 0;
static JTextField txtInput = new JTextField(10);
static JButton btnSwitch = new JButton("Log on");
public Login(){
setLayout(new FlowLayout());
//add button and register
add(new JLabel("Enter password:"));
add(txtInput);
add(btnSwitch);
}
public static void main(String[] args) {
final JFrame frame = new Login();
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(200, 150);
frame.setVisible(true);
btnSwitch.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if(txtInput.getText().equals("123")){
//frame = new GUIHelloWorld(); this doesn't work because "The final local variable frame cannot be assigned, since it is defined in an enclosing type"
//so I went with the below workaround
GUIHelloWorld frame = new GUIHelloWorld();
frame.setLocationRelativeTo(null); // Center the frame
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300, 100);
frame.setVisible(true);
}
}
});
}
}
Once the user get pass the first part of the GUI, I want to show em something else like this:
import java.awt.GridLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
public class GUIHelloWorld extends JFrame {
public GUIHelloWorld(){
setLayout(new GridLayout(0,1));
add(new JLabel("Hello World"));
add(new JLabel("Welcome to the 2nd part of the GUI"));
}
public static void main(String[] args) {
JFrame frame = new GUIHelloWorld();
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300, 100);
frame.setVisible(true);
}
}
Can someone give me an idea of how to display a new JFrame into the existing window that the user is using?
Don't extend from JFrame, especially in the case, frame's can't be added to other frames. Instead, based you individual UI views on something like JPanel
Create a single instance of a JFrame, set it's layout manager to use a CardLayout.
Add each of your view's to the frame, naming each view appropriately
Use CardLayout to switch between the view as needed
You could also consider using a JDialog for the login window, but the basic advice remains; create windows, extend components...