Develop Reference

Java swing: trouble understanding adding image to JLabel

I hope everyone is doing alright this fine day.
I'm learning swing and I was confused by how to reference an image. I understand that I should use a JLabel and then add that JLabel to the Frame using this.add();, but even looking at the oracle documentation here:
https://docs.oracle.com/javase/6/docs/api/javax/swing/ImageIcon.html
It is still unclear how to reference a file without giving the entire path like
C:\Users\someUser\eclipse-workspace\andSoOn.png
And I can't do that. I have to send my work to my teacher once I'm done, and the code won't reference the file like it does on my system. I tried several things, and I ended up making a new folder in the src in eclipse called ImageAssets and moving the files there, but nothing seems to work. Here is what it looks like
Here is an example of my attempt to display an image from within the package.
import java.awt.*;
import javax.swing.*;
public class Hangman extends JFrame
{
JButton playGameButton,
OptionsButton;
private ImageIcon hangman7;
private JLabel mainLabel;
public static void main(String[] args)
{
new Hangman();
}
public Hangman()
{
this.setSize(1000,800);
this.setLocationRelativeTo(null);
this.setVisible(true);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setTitle("Hangman");
this.setResizable(false);
playGameButton = new JButton("Start Game");
OptionsButton = new JButton("Options");
//hangman7 = new ImageIcon(getClass().getResource("Images\\ hangman7.png"));//just an attempt at something
mainLabel = new JLabel();
mainLabel.setIcon(new ImageIcon("hangman7.png"));
JPanel somePanel = new JPanel();
somePanel.setLayout(new BorderLayout());
somePanel.add(playGameButton, BorderLayout.WEST);
somePanel.add(OptionsButton, BorderLayout.EAST);
somePanel.add(mainLabel, BorderLayout.CENTER);
this.add(somePanel);
this.validate();
}
Thank you so much for taking the time to help me. I tried to be very detailed; if anything is unclear please ask.

In your case, you want let the class loader find the resource, like this:
mainLabel.setIcon(
new ImageIcon(getClass().getResource("/ImageAssets/hangman7.png")));

Undefined Type for JFrame

so i was getting a error in Eclipse for my java program to make a new JFrame and i couldnt quiet figure out my it wouldnt load the correct data to set it to be visable and to set the title, location, size, and what it should do when someone closes the JFrame so id like some help if i could please
import javax.swing.*;
import java.awt.*;
public class JFrame
{
public static void main(String[] args)
{
JFrame JF = new JFrame();
JF.setTitle("Test");
JF.setSize(400, 200);
JF.setLocation(200, 300);
JF.setDefaultCloseOperation(javax.swing.JFrame.EXIT_ON_CLOSE);
JF.setVisible(true);
}
}
Thanks for the help in advance

You named your own class JFrame, thus hiding the standard javax.swing.JFrame class.
Choose another name for your class.

How should I be adding a GridLayout of JButtons below a JLabel?

So, I'm working on a project for my Java class. The objective is to create a basic GUI program that displays Hello World as a string and provides four buttons for manipulating the string. Something like this: example
I haven't even gotten to the manipulation part of the program yet as I can't seem to get my window formatted correctly no matter what I try.
I am able to get my four buttons to display, but everything I have thrown at it to get the JLabel to display Hello World above the buttons is utterly failing me.
This seems so very simple, so I'm afraid there's something obvious I'm missing. I've scoured the web for a week and found lots of info on how to do this in theory, so from what I can understand, this must be a problem with my syntax.
To date I have not found an implementation that does anything along the lines of what I am needing to do. This is driving me crazy and I'm going to go past my due date either way. I just have to have an answer! Thank you so much to anyone who can point me in the right direction!
Here is my code in its current form. I felt like I was getting close with this, but it returns an exception to the console when running. Again, all help is greatly appreciated!
import java.awt.*;
import javax.swing.*;
public class HelloWorld
{
private JButton uppercaseButton;
private JButton lowercaseButton;
private JButton phraseButton;
private JButton resetButton;
private JPanel grid;
public JPanel ButtonGrid()
{
JPanel grid = new JPanel();
grid.setLayout(new GridLayout(2, 2));
uppercaseButton = new JButton("Uppercase");
lowercaseButton = new JButton("Lowercase");
phraseButton = new JButton("New Phrase");
resetButton = new JButton("Reset");
grid.add(uppercaseButton);
grid.add(lowercaseButton);
grid.add(phraseButton);
grid.add(resetButton);
return grid;
}
private static void createAndShowGUI()
{
JFrame frame = new JFrame("THIS IS MY TITLE");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JLabel lbl = new JLabel("HELLO WORLD");
lbl.setPreferredSize(new Dimension(175, 100));
frame.getContentPane().add(lbl, BorderLayout.PAGE_START);
ButtonGrid b = new ButtonGrid();
b.setVisible( true );
b.setSize( 300, 200 );
frame.getContentPane().add(b, BorderLayout.CENTER);
frame.pack();
frame.setVisible(true);
}
public static void main( String[] args ){
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}

ButtonGrid b = new ButtonGrid();
ButtonGrid is not a class, it is a method of the HelloWorld class that returns an instance of a JPanel.
So you need to create an instance of the HelloWorld class so you can invoke the method:
HelloWord hw = new HelloWorld()
JPanel b = hw.ButtonGrid();
And since "buttonGrid" is a method is should NOT start with an upper case character so you need to rename the method and then use:
//ButtonGrid b = new ButtonGrid();
HelloWord hw = new HelloWorld()
JPanel b = hw.buttonGrid();

Thanks to both suggestions for pointing me in the right direction!
What ended up working was basically what redxef suggested first. Camickr then helped me further because I was thinking about my methods all wrong. By combining both of those JPanels into the first method and renaming it HelloWorld, I was able to clean up some other issues I was having as well.
I'm happy to report that as a result, the project was finished and turned in with about an hour to spare. Again, thanks so much!!

I created my GUI in a GUI class' constructor. How would I access its Frames, Panels etc. from another class?

First of all, this is a more specific question than it seems to be. To start off: I am currently doing a small application with a rather small GUI, so I decided to make a GUI class, and initialize my whole GUI in this constructor.
This would look like this:
public class GUI extends JFrame{
public GUI{
//Initialize GUI here, including its Frames, Panels, Buttons etc.
}
}
How can I now access the GUIs frame etc. from an external class? If I would create an object of the GUI class, I would simply duplicate my GUI window. I did not come across any other ideas than making the frame, panel and so on static.
I'm somewhat lost right now. Also I'm pretty sure that I am not thinking the right way into this case, but I need someone to point me to the right direction. If someone could help me out, I would be very thankful.

First of all, using static is the worst solution possible, even if your GUI class is a singleton (buf if it is, at least it will work fine).
Why don't you simply create getters and/or setters ? And finally, it is usually not normal that external classes need to access the components of another graphic class. You should wonder if your design is the most fitted for your needs.

Here's a simple GUI to change the background color of a JPanel with a JButton. Generally, this is how you construct a Swing GUI.
package com.ggl.testing;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class ChangeDemo implements Runnable {
private boolean isYellow;
private JFrame frame;
public static void main(String[] args) {
SwingUtilities.invokeLater(new ChangeDemo());
}
#Override
public void run() {
frame = new JFrame("Change Background Demo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel mainPanel = new JPanel();
mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.PAGE_AXIS));
JPanel namePanel = new JPanel();
JLabel nameLabel = new JLabel(
"Click the button to change the background color");
nameLabel.setAlignmentX(JLabel.CENTER_ALIGNMENT);
namePanel.add(nameLabel);
mainPanel.add(namePanel);
final JPanel buttonPanel = new JPanel();
buttonPanel.setLayout(new FlowLayout());
buttonPanel.setBackground(Color.YELLOW);
isYellow = true;
JButton changeButton = new JButton("Change Color");
changeButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
isYellow = !isYellow;
if (isYellow) buttonPanel.setBackground(Color.YELLOW);
else buttonPanel.setBackground(Color.RED);
}
});
buttonPanel.add(changeButton);
mainPanel.add(buttonPanel);
frame.add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
}
You don't access the Swing components of the GUI from other classes. You create other classes to hold the values of the GUI.
Generally, you use the model / view / controller pattern to construct a Swing GUI. That way, you can focus on one part of the GUI at a time.
Take a look at my article, Java Swing File Browser, to see how the MVC pattern works with a typical Swing GUI.

You don't need to make it static or to create a new JFrame object every time.
Have a look at this simple code :
class UseJFrame {
public static void main(String...args) {
Scanner sc = new Scanner(System.in);
JFrame frame = new GUI();
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
System.out.println("Press E to exit");
String ip;
while(true) {
System.out.println("Show GUI (Y/N/E)? : ");
ip = sc.nextLine();
if(ip.equalsIgnoreCase("y") {
frame.setVisible(true);
} else if(ip.equalsIgnoreCase("n") {
frame.setVisible(false);
} else { // E or any other input
frame.dispose();
}
}
}
}
Note : Don't make GUI visible through constructor or it will show window at the very starting of creation of JFrame object.
If you want to use the same JFrame object at other places too then pool architecture would be better approach.

Putting everything into a JFrame

I want to know how to put put console output into a JFrame. For example, putting this output into a JFrame:
import static java.lang.System.out;
public class frame{
public static void main(String [] args){
out.println("hello");
}
}
How is it possible?

You need to set up the JFrame first.
JFrame frame = new JFrame("title");
Then, set the properties of the JFrame:
frame.setSize(1280,720); //Sets the program's size
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //Tells the program to exit on close
frame.setResizable(true); //Tells the program if resizing is enabled
Then, create a panel to store the components:
JPanel p = new JPanel();
After that, you must add the panel to the JFrame like so:
frame.add(p);
Then, with that done, you can use the components supplied in the swing framework, and add them to the panel. A reference for these components can be found here: http://docs.oracle.com/javase/tutorial/uiswing/components/componentlist.html.
To create a component, use the following code:
JLabel label = new JLabel();
Then, use it's build in functions to change it:
label.setText("new text");
Then, once again, to add a component to a panel, use the panel's add() method:
panel.add(label);
Those are just the basics of making a GUI with java. A full tutorial can be viewed here:
http://docs.oracle.com/javase/tutorial/uiswing/
Good Luck!

I can help you with this, but let me please fix some syntax errors you have. When you put the import, an import can't be static (that I know of) and when you want to print out something using "System.out.print" or "System.out.println" you MUST include the "System" part of the line. If you want to add text to a a JFrame use the JLabel to import both just do this bit of code:
import javax.swing.*;
That should import all of your swing elements such as JLabel and JFrame and JPanel, and try this code it will make a window that will have a button and a label. The button doesn't do anything in this code:
import javax.swing.*;
public class main{
public static void main(String[] args)
{
/*
* Creates the frame, makes it visible, and makes
* appear in the center of the screen. While also making it have a close operation
*/
JFrame frame = new JFrame("Button");
frame.setVisible(true);
frame.setSize(300, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
//Creates the panel, and adds it to the frame
JPanel panel = new JPanel();
frame.add(panel);
//Creates the label and adds it to the panel, also sets the text
JLabel label = new JLabel();
label.setText("Welcome" + "\n" + "\n");
panel.add(label);
//Creates the button and adds it to the panel
JButton button1 = new JButton("Button 1");
panel.add(button1);
}
}

1.If you want to use JFrame you have to extend your class to a subclass of JFrame:
public class frame extends JFrame {}
2.a)If you want to put Text in your Frame use JLabel and add it to your frame:
JLabel hello = new JLabel("Hello");
add(hello);
2.b)If you want a console output just call System.out.println() in the constructor
Here is a small example class:
import javax.swing.JFrame;
import javax.swing.JLabel;
public class Frame extends JFrame {
public static void main(String args[]) {
new Frame();
}
Frame() {
System.out.println("Hello");
JLabel hello = new JLabel("Hello");
add(hello);
this.setSize(100, 100);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
}
}
have a look to the oracle lessons... or any java book!

If that is the case, I don't want to get into GUI just yet. (Learning from a book) Can I convert my current project to a jar file and have it automatically open a command prompt window upon double click?