Develop Reference

How to add an Image to a JFrame

I'm trying to add an image to a JFrame and set its location, I don't know why it just does not add into it, maybe I don't understand how the JFrame class works since a normal text JLabel adds into the JFrame simply without any trouble and a JLabel containing an image simply does not add in.
I would appreciate if someone would explain the error in the code, and maybe even give me a short explanation of why my way does not work. Thanks!
import java.awt.*;
import javax.swing.*;
public class Walk {
public static void main(String[] args) {
JFrame f = new JFrame("Study");
f.setSize(3000,1000);
f.getContentPane().setBackground(Color.white);
f.getContentPane().add(new JLabel("test", JLabel.CENTER) );
JLabel l = new JLabel(new ImageIcon("C:\\Users\\leguy\\OneDrive\\Desktop\\Stuff\\stillsp"));
l.setBounds(100, 100, 100, 100);
l.setVisible(true);
f.add(l);
f.setVisible(true);
}
}

are you using a gui class or you are writing its code into a main class
what is in your code is that you are writing its code so easy way is to just drag and drop try this link for normal jframes gui eclipse gui
about the picture into jframe is easy one all what you have to do is
1. create a label by setting its size as you want on the jframe by dragging and dropping only
2. follow the pictures
then you browser for your picture you want
select the picture and its done
Hope it helps

Make sure the path to your image is valid. All I did was point to a valid image on my PC and the code practically worked. There were a few things added and organized below.
import java.awt.Color;
import javax.swing.*;
public class Walk {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() { // Safety first...
#Override
public void run() {
String path = "C:\\Path\\To\\Image.png"; // Make sure it's correct
JFrame frame = new JFrame("Study");
JLabel label = new JLabel(new ImageIcon(path));
frame.setSize(3000, 1000);
frame.getContentPane().setBackground(Color.white);
frame.getContentPane().add(new JLabel("test", JLabel.CENTER));
label.setBounds(100, 100, 100, 100);
label.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(label);
frame.pack(); // Pack the frame's components.
frame.setVisible(true);
}
});
}
}
To make sure both labels show up, provide a layout and add them accordingly.
import java.awt.*;
import javax.swing.*;
public class Walk {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
String path = "C:\\Path\\To\\Image.png"; // Make sure it's correct
JFrame frame = new JFrame("Study");
Container container = frame.getContentPane();
JLabel imageLbl = new JLabel(new ImageIcon(path));
JLabel textLbl = new JLabel("test");
frame.setLayout(new BorderLayout());
frame.setSize(3000, 1000);
imageLbl.setBounds(100, 100, 100, 100);
imageLbl.setVisible(true);
container.setBackground(Color.WHITE);
container.add(textLbl, BorderLayout.NORTH);
container.add(imageLbl, BorderLayout.CENTER);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
});
}
}

JScrollPane doesn't work with JTextArea

I'm trying to add the ScrollPane to my TextArea, but it doesn't appear.
Here's the code:
import javax.swing.*;
public class PracownikGui extends JFrame {
private JPanel Panelek;
private JTextArea Tekscik;
private JScrollPane Skrol;
public PracownikGui() {
setMinimumSize(new Dimension(600, 600));
setLocationRelativeTo(null);
setContentPane(Panelek);
setResizable(false);
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
Tekscik();
public void Tekscik() {
Tekscik = new JTextArea(2, 10);
Skrol = new JScrollPane( Tekscik );
Tekscik.setSize(300, 300);
Tekscik.setLocation(20, 70);
Tekscik.setEditable(true);
Tekscik.setLineWrap(true);
add(Tekscik);
}}
Any help, please.

You're shooting yourself in the foot by setting a JTextArea's size or preferredSize since this prevents it from expanding into the JScrollPane:
Tekscik.setSize(300, 300);
set its rows and columns only.
Also you need to add the JScrollPane to the GUI, not the JTextArea.
Also, while null layouts and setBounds() or setSize(...) and setLocation(...) might seem to Swing newbies like the easiest and best way to create complex GUI's, the more Swing GUI'S you create the more serious difficulties you will run into when using them. They won't resize your components when the GUI resizes, they are a royal witch to enhance or maintain, they fail completely when placed in scrollpanes, they look gawd-awful when viewed on all platforms or screen resolutions that are different from the original one.
e.g.,
import javax.swing.*;
public class PracownikPanel extends JPanel {
private JTextArea tekscik = new JTextArea(5, 25);
public PracownikPanel() {
tekscik.setLineWrap(true);
tekscik.setWrapStyleWord(true);
JScrollPane skrol = new JScrollPane(tekscik);
skrol.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
add(skrol);
}
private static void createAndShowGui() {
PracownikPanel mainPanel = new PracownikPanel();
JFrame frame = new JFrame("PracownikPanel");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}

I made quite a few changes to your code. Your code wouldn't run.
Here's the GUI I created.
As you can see, there's a vertical scroll bar. The default action for the scroll bar is that it doesn't appear until you've filled the JTextArea with text.
Here are the important changes I made to your code.
Class names start with a capital letter. Method names and variable names start with a lower case letter.
A Swing application must start with a call to the SwingUtilities invokeLater method. This ensures that the Swing components are created and used on the Event Dispatch thread (EDT). Since the invokeLater method requires a Runnable, I had the PracownikGui class implement Runnable.
You use Swing components. You don't extend Swing components, or any other Java class, unless you want to override one of the methods in that class.
I removed all of the sizing and positioning statements, except for the statement that defines the rows and columns of the JTextArea. Hovercraft Full Of Eels explained this, but you use Swing layouts to get the arrangement of Swing components you want. The default layout for a JPanel is the FlowLayout. The default layout for a JFrame is the BorderLayout.
I added the JScrollPane to the JPanel. I added the JPanel to the JFrame.
Here's the code.
package com.ggl.testing;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
public class PracownikGui implements Runnable {
public static void main(String[] args) {
SwingUtilities.invokeLater(new PracownikGui());
}
private JFrame frame;
private JPanel panelek;
private JTextArea tekscik;
private JScrollPane skrol;
#Override
public void run() {
frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
panelek = new JPanel();
tekscik(panelek);
frame.setContentPane(panelek);
frame.setResizable(false);
frame.pack();
frame.setVisible(true);
}
public void tekscik(JPanel panelek) {
tekscik = new JTextArea(2, 20);
tekscik.setEditable(true);
tekscik.setLineWrap(true);
skrol = new JScrollPane(tekscik);
panelek.add(skrol);
}
}

How can I append a JTextArea from a method that doesn't contain the JTextArea?

I'm making some test code to practice OOP, and I want to append a JTextArea from the "writeToArea" to the "initialize" method where the JTextArea is defined and initialized. I already tried to directly call the "output" variable, but this returns an "output cannot be resolved" error. I want so that whenever I call the "writeToArea" method in the main class, I'll be able to add lines to the "output" JTextArea in the "initialize" method.
Here's the main class:
public class Pangea {
public static void main(String[] args) {
UI.initialize();
UI.writeToArea();
}
}
Here's the initialize class:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Font;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
public class UI {
static void initialize() {
System.out.println("Initializing GUI.");
JFrame frame = new JFrame();
Font myFont = new Font("Courier", Font.BOLD, 14);
JTextField input = new JTextField("");
JTextArea output = new JTextArea("Initiated Succesfully.");
output.setWrapStyleWord(true);
output.setLineWrap(true);
input.setFont(myFont);
output.setFont(myFont);
input.setForeground(Color.WHITE);
output.setForeground(Color.WHITE);
input.setBackground(Color.BLACK);
input.setCaretColor(Color.WHITE);
output.setBackground(Color.BLACK);
output.setEditable(false);
JScrollPane jp = new JScrollPane(output);
frame.setTitle("PANGEA RPG [0.01 ALPHA][WIP]");
frame.setResizable(false);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(input, BorderLayout.SOUTH);
frame.add(jp, BorderLayout.CENTER);
frame.pack();
frame.setSize(800, 500);
frame.setVisible(true);
System.out.println("GUI Initialized.");
}
static void writeToArea() {
System.out.println("\"writeToArea\" running.");
output.append("Hello!");
System.out.println("\"writeToArea\" finished.");
}
}
I've tried to do something similar to this: Updating jtextarea from another class but it didn't work. If anyone has any suggestions I'd be very thankful.

The main error in your code is the lack of OOP design. Making all static is poor design.
Also swing is event based, so you should append text to the textArea when an event happens. See the example i write for you.
public class UI {
private JPanel panel;
private JTextArea output;
public UI(){
initialize();
}
private void initialize() {
panel = new JPanel();
Font myFont = new Font("Courier", Font.BOLD, 14);
final JTextField input = new JTextField(""); // must be declared final cause you use it in anonymous class, you can make it instance variable if you want to as textArea
//add an actionListener then when you press enter this will write to textArea
input.addActionListener(new ActionListener(){
#Override
public void actionPerformed(ActionEvent evt){
writeToArea(input.getText());
}
});
output = new JTextArea("Initiated Succesfully",50,100);// let the component determinate its preferred size.
output.setWrapStyleWord(true);
output.setLineWrap(true);
input.setFont(myFont);
output.setFont(myFont);
input.setForeground(Color.WHITE);
output.setForeground(Color.WHITE);
input.setBackground(Color.BLACK);
input.setCaretColor(Color.WHITE);
output.setBackground(Color.BLACK);
output.setEditable(false);
JScrollPane jp = new JScrollPane(output);
panel.setLayout(new BorderLayout());
panel.add(input, BorderLayout.SOUTH);
panel.add(jp, BorderLayout.CENTER);
}
private void writeToArea(String something) {
System.out.println("\"writeToArea\" running.");
output.append(something);
System.out.println("\"writeToArea\" finished.");
}
public JPanel getPanel(){
return panel;
}
}
And in your client code
public class Pangea {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable(){
#Override
public void run(){
createAndShowGUI();
}
});
}
/**
* Create the GUI and show it. For thread safety,
* this method should be invoked from the
* event dispatch thread.
*/
private static void createAndShowGUI() {
//Create and set up the window.
System.out.println("Initializing GUI.");
JFrame frame = new JFrame();
frame.setTitle("PANGEA RPG [0.01 ALPHA][WIP]");
frame.setResizable(false);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Add contents to the window.
frame.add(new UI().getPanel());
frame.pack();//sizes the frame
frame.setVisible(true);
System.out.println("GUI Initialized.");
}
}
Here you have a tutorial with better examples than this How to Use Text Areas
I remove your setSize and use pack()
The pack method sizes the frame so that all its contents are at or
above their preferred sizes. An alternative to pack is
to establish a frame size explicitly by calling setSize or setBounds
(which also sets the frame location). In general, using pack is
preferable to calling setSize, since pack leaves the frame layout
manager in charge of the frame size, and layout managers are good at
adjusting to platform dependencies and other factors that affect
component size.

Read the section from the Swing tutorial on How to Use Text Areas. It will show you how to better structure your code so that you don't use static methods and variables everywhere.
Once you have a panel that has a reference to the text area you can add methods that allow you to update the text area on the panel.

JFrame Button Logic error

I've been spending some time relearning java and a peculiar logic error hit me here.
import javax.swing.*;
import java.awt.*;
class Frame
{
public static void main (String args[])
{
JFrame frame = new JFrame("Tester Frame");
frame.setSize(400, 500);
JButton btn1 = new JButton("FOO");
btn1.setSize(150, 50);
btn1.setLocation(45, 0);
JButton btn2 = new JButton("BAR");
btn2.setSize(150, 50);
btn2.setLocation(205, 0);
Container content = frame.getContentPane();
content.setBackground(Color.blue);
content.add(btn1);
content.add(btn2);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}//end main
}
I've created 2 JButton objects, and they should be the same size, with different location and text. This of course is not the case, the "FOO" button is exactly where and how I want it to be, but the "BAR" button is the size of the entire frame.
Help!

1) You are attempting to use Absolute LayoutManager via setSize and setLocation etc, but without calling setLayout(null) on the component you are adding the JButtons to. However this is not a best practice in Swing.
When adding to JFrame contentpane default layout is BorderLayout which adds components to is default position of BorderLayout.CENTER.
Have a read on A Visual Guide to Layout Managers
2) Also when using a correct LayoutManager you would omit JFrame#setSize(..) call and replace it with JFrame#pack() before setting the JFrame visible.
3) Also have a read on Concurrency in Swing specifically on The Event Dispatch Thread
which dictates all swing components be created on EDT via SwingUtillities.invokeXXX(..) block:
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
//create and manipulate swing components here
}
});
4) Also rather use JFrame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); as this will allow any other threads timers etc to carry on execution even after JFrame has been disposed.

add:
frame.getContentPane().setLayout(null);
To your code after the line:
frame.setSize(400, 500);

Components added to a container are tracked in a list. The order of the list will define the components' front-to-back stacking order within the container. If no index is specified when adding a component to a container, it will be added to the end of the list (and hence to the bottom of the stacking order).In your code the buttons are stacked over the other.That is why you get this Error(as you think it is).
This will solve your problem:-
import javax.swing.*;
import java.awt.*;
class OP3
{
public static void main (String args[])
{
JFrame frame = new JFrame("Tester Frame");
frame.setSize(400, 500);
JButton btn1 = new JButton("FOO");
btn1.setSize(150, 50);
btn1.setLocation(45, 0);
JButton btn2 = new JButton("BAR");
btn2.setSize(150, 50);
btn2.setLocation(205, 0);
JPanel p = new JPanel(new FlowLayout());
p.add(btn1);
p.add(btn2);
frame.add(p);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}//end main
}

Just add a panel to the frame and add the buttons to the panel.
import javax.swing.*;
import java.awt.*;
class source
{
public static void main (String args[])
{
JFrame frame = new JFrame("Tester Frame");
frame.setSize(400, 500);
JPanel panel=new JPanel();//panel added here
panel.setSize(frame.size());
panel.setLocation(0, 0);
JButton btn1 = new JButton("FOO");
btn1.setSize(150, 50);
btn1.setLocation(45, 0);
JButton btn2 = new JButton("BAR");
btn2.setSize(150, 50);
btn2.setLocation(205, 0);
panel.add(btn1);
panel.add(btn2);
Container content = frame.getContentPane();
content.setBackground(Color.blue);
content.add(panel);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}//endmain

How set location of an image in a JFrame

I'm trying to set the the location of an image in a JFrame. I thought label.setLocation(100, 100); would set the location of the image to 100, 100 (top left corner), but it doesn't seem to do anything no matter were I put it. I even tried panal.setLocation(100, 100). Both do nothing, I get no errors and the image does appears but at 0, 0. What am I doning wrong? Here's my code:
import javax.swing.*;
public class DisplayImage {
public DisplayImage() {
JFrame frame = new JFrame("Display Image");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = (JPanel)frame.getContentPane();
JLabel label = new JLabel();
label.setIcon(new ImageIcon("src/img/school.png"));
label.setLocation(100, 100);
panel.add(label);
frame.setLocationRelativeTo(null);
frame.pack();
frame.setVisible(true);
}
public static void main (String args[]) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new DisplayImage();
}
});
}
}

By default a JFrame uses a BorderLayout. When you add your label to the frame the label is added to the CENTER of the BorderLayout. The layout manager will override the location.
One simple solution is to add an EmptyBorder to the label with the top/left insets being 100. Then instead of add the label to the center you would add the label to the NORTH. The code would be something like:
label.setBorder( new EmptyBorder(...) );
panel.add(label, BorderLayout.SOUTH);
As a general rule you should not be trying to specify exact location of a component. Let the layout managers to their jobs.

The JFrame, by default, uses a BorderLayout as it's layout manager. This will override any settings you supply to the setLocation method.
You have a number of options...
Use something like JLayeredPane, which does not, but default, have layout manager of it's own set by default. See How to use layered panes for more details
Create a custom component capable of renderering the image where you want it. Check out Performing Custom Painting for more details
Create your own layout manager that performs the operations you want...

This works for me:
import java.awt.Dimension;
import javax.swing.*;
public class DisplayImage {
public DisplayImage() {
JFrame frame = new JFrame("Display Image");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = (JPanel)frame.getContentPane();
panel.setLayout(null);
JLabel label = new JLabel();
label.setIcon(new ImageIcon("rails.png"));
panel.add(label);
Dimension size = label.getPreferredSize();
label.setBounds(100, 100, size.width, size.height);
frame.setSize(300, 200);
frame.setVisible(true);
}
public static void main (String args[]) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new DisplayImage();
}
});
}
}
But you should read this:
http://docs.oracle.com/javase/tutorial/uiswing/layout/none.html