Develop Reference

JPanel not showing inside JFrame in Java

I know this question has been asked a lot and I have done my research but still can not find anything. Below is proof of this before anyone gets upset:
I found this link:
https://coderanch.com/t/563764/java/Blank-Frame-Panel
and this:
Adding panels to frame, but not showing when app is run
and this:
Why shouldn't I call setVisible(true) before adding components?
and this:
JPanel not showing in JFrame?
But the first question says use repaint which I tried with no fix and the second and third to last questions talk about putting setVisible after components added which I have.
The last one talks about making the users JPanelArt a extension (done so) of JPanel instead of JFrame and not to make a frame in a frame constructor (also have not done)
When ever I run this I just get a blank frame, as if the panel was never added in.
I apologise if I have missed something in those links. Anyway below is my classes:
GUI.java (extends JFrame)
package javaapplication2;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class GUI extends JFrame{
public GUI(String name) {
super(name);
getContentPane().setLayout(null);
JPanel myPanel1 = new GUIPanel();
myPanel1.setLocation(20, 20);
getContentPane().add(myPanel1);
setDefaultCloseOperation(EXIT_ON_CLOSE);
pack();
setResizable(true);
}
public static void main(String[] args) {
JFrame frame = new GUI("Game");
frame.setVisible(true);
}
}
GUIPanel.java (extends JPanel)
package javaapplication2;
import java.awt.*;
import javax.swing.*;
public class GUIPanel extends JPanel {
JButton start;
JButton inspect1;
JButton inspect2;
JButton inspect3;
JButton suspect;
public GUIPanel() {
setLayout(new BorderLayout());
start = new JButton("Start Game");
inspect1 = new JButton("Inspect 1");
inspect2 = new JButton("Inspect 2");
inspect3 = new JButton("Inspect 3");
suspect = new JButton("Choose Suspect");
add(start, BorderLayout.WEST);
add(inspect1, BorderLayout.WEST);
add(inspect2, BorderLayout.WEST);
add(inspect3, BorderLayout.WEST);
add(suspect, BorderLayout.WEST);
}
}
I know it is very simple, but that is because I am following a tutorial from my lecturer to get the hang of things as I previously used a GUI builder which someone in this community pointed out to me is not good to start with (very correct!)

The issue lies in your GUI class when you call getContentPane().setLayout(null). Because of this method call, your JFrame is not displaying anything. If you remove it, your elements should show up.
I also noticed that you were setting each JButton to have a constraint of BorderLayout.WEST. This will most likely put your JButtons on top of each other and render only one of them.

How do I set the size of a JTextArea?

I'm fairly new to working with graphics in Java, and have been trying to make a simple console to display text based games in a window. I have a test class, where I'm working on the console, but when I add a JTextArea to my console window, it either takes up the entire window or doesn't display at all.
Here is my code:
import javax.swing.*;
import java.awt.*;
import java.util.*;
import java.awt.Event;
public class GUI {
public static void main(String[] args) {
JFrame frame = new JFrame("AoA");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
frame.setSize(1020,760);
frame.setBackground(Color.LIGHT_GRAY);
frame.setResizable(false);
JTextArea jta = new JTextArea(100,100);
jta.setEditable(false);
jta.setBackground(Color.WHITE);
frame.add(jta);
}
}
I know that some of my imports aren't used in this file, but they will used in the final game. I am also aware that the JTextArea is set to size 100,100, which I am unsure whether it is too large or small. I could really use some help on this, though.

Your problem is the installed by default BorderLayout in your frame. The easiest way to solve your problem is to set another layout manager.
public static void main(String[] args) {
SwingUtilities.invokeLater(GUI::startUp);
}
private static void startUp() {
JFrame frame = new JFrame("AoA");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(1020,760);
frame.setBackground(Color.LIGHT_GRAY);
frame.setResizable(false);
frame.setLayout(new FlowLayout()); // FlowLayout is required
JTextArea jta = new JTextArea(40,40);
jta.setEditable(false);
jta.setBackground(Color.WHITE);
// JScrollPane to get the scroll bars when required
frame.add(new JScrollPane(jta));
// setVisible should be last operation to get a correct painting
frame.setVisible(true);
}
Please take a look for layout managers in Swing

JFrame Image wont appear, require refresh? [duplicate]

I'm fairly new to JFrame and I want to know why my items are not showing up on the window. I know i dont have a ActionHandler but I just want my textfield's to show up on my window. Here's my code:
import java.awt.Font;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;
public class FirstGUI extends JFrame{
public void GUI(){
setTitle("Welcome");
setResizable(false);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
setSize(600,600);
JLabel title = new JLabel();
title.setText("Apple Inc. Member Login Port");
title.setFont(new Font("Arial", Font.PLAIN, 24));
JTextField login = new JTextField("Login",10);
JPasswordField pass = new JPasswordField("Password");
add(title);
add(login);
add(pass);
}
public static void main(String[] args){
FirstGUI a = new FirstGUI();
a.GUI();
}
}
but when i run it i get this:

but when i run it i get this:
You get an empty screen because you add the components to the frame after the frame is visible.
As has already been suggested you need to use an appropriate layout manager. FlowLayout is the easiest to start with.
invoke setVisible(true) AFTER adding the components to the frame.
So the code should be more like:
panel.add(...);
panel.add(...);
add(panel);
pack();
setVisible(true);

I agree to MadProgrammer's suggestions (+1)
Well, lets take a look at your program though
You actually have created a JFrame with components in it. Its working fine as well, but your question of "why are my items not showing up in the JFrame" is not because you did something wrong but because missed out something i.e. revalidate()
Try:
public static void main(String[] args){
FirstGUI a = new FirstGUI();
a.GUI();
a.revalidate();
}
I'm not saying this will give you perfect UI.. what I'm trying to say is this will help you understand the Swing better. Learn about Swing Layout managers and then work on your UI to have better results
revalidate(): This component and all parents above it are marked as needing to be laid out. This means the Layout Manager will try to realign the components. Often used after removing components. It is possible that some really sharp swing people may miss this. I would think that you will only know this if you are actually using Swing.

The default layout manager for JFrame is BorderLayout.
This means that your components are essentially all been added ontop of each other.
Try changing the layout manager to something like FlowLayout (for example)...
Take a look at A Visual Guide to Layout Managers and Using Layout Managers for more details.
Also, avoid setSize where possible, use Window#pack instead
Update
I'd also like to introduce you to Initial Threads which should be used to launch your UI code...

The only one reason :
setVisible(True); method for the frame should be put on the end of the code.
if you give this line on the top of the code that is when you create a frame. This will cause that problem.

Don't add the components directly to your frame. Instead add to the content pane, which is where a JFrame stores all of the components that it draws. Usually this is a JPanel.
Here is an example:
public class GUI
{
private JPanel content;
public void GUI
{
/*Other code*/
content = new JPanel();
add(content); //make content the content pane
content.add(title);
content.add(login);
content.add(pass);
}
If that fails, call setVisible(true) and setEnabled(true) on all of your components.
On a side note you may want to make your GUI function a constructor.

import javax.swing.*;
import java.awt.*;
class Myframec extends JFrame
{
Myframec()
{
Container c = this.getContentPane();
c.setLayout(null);
this.setBounds(10,10,700,500);
this.setTitle("Welcome");
this.setDefaultCloseOperation(this.EXIT_ON_CLOSE);
JPanel panel = new JPanel();
panel.setBounds(0,0,700,500);
panel.setBackground(Color.gray);
panel.setLayout(null);
c.add(panel);
Font f = new Font("Arial",Font.BOLD,25);
Font f1 = new Font("Arial",Font.BOLD,20);
JLabel lable = new JLabel();
lable.setBounds(130,10,400,100);
lable.setText("Apple Inc. Member Login Port");
lable.setFont(f);
panel.add(lable);
JTextField login = new JTextField("Login",10);
login.setBounds(120,150,400,30);
login.setFont(f1);
panel.add(login);
JPasswordField pass =new JPasswordField("Password");
pass.setBounds(120,200,400,30);
pass.setFont(f1);
lable.setFont(f);
panel.add(pass);
c.setVisible(true);
this.setVisible(true);
}
public static void main(String[] argm)
{
Myframec frame = new Myframec();
frame.setVisible(true);
}
}

My JFrame window won't appear

My JFrame window won't appear, though, by the tutorial I've been watching, I've been doing everything spot on, yet nothing happens. It doesn't even give me an error, which makes it so much worse. This is the code:
import javax.swing.*;
import java.awt.*;
public class Window {
public class Window {
public void newWindow() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(frame.EXIT_ON_CLOSE);
JLabel label = new JLabel("I am a star! A beautiful shining star!", SwingConstants.CENTER);
frame.getContentPane().add(label);
frame.setVisible(true);
}
}
(This is a second class, the main one properly links to this one)

JFrame uses a layout manager named BorderLayout by default. To see components added to the frame, you should refer to its javadocs. However, the easiest choice here is to use FlowLayout. You also should use JFrame's pack() method, which, according to Oracle:
Causes this Window to be sized to fit the preferred size and layouts of its subcomponents. The resulting width and height of the window are automatically enlarged if either of dimensions is less than the minimum size as specified by the previous call to the setMinimumSize method.
Thus, this should work for you:
import javax.swing.*;
import java.awt.*;
public class Window {
public void newWindow() {
JFrame frame = new JFrame();
frame.getContentPane().setLayout(new FlowLayout()); // specify the layout manager
frame.setDefaultCloseOperation(frame.EXIT_ON_CLOSE);
JLabel label = new JLabel("I am a star! A beautiful shining star!", SwingConstants.CENTER);
frame.getContentPane().add(label);
frame.pack(); // handles sizing of the window
frame.setVisible(true);
}
}
Notice that I removed the duplicate public class Window declaration, which might have been the reason you didn't see a frame at all. If it's still not working for you, I think you aren't calling the newWindow() method. If you want the window to show by simply calling new Window();, then you should change public void newWindow() to public Window().

import javax.swing.*;
import java.awt.*;
public class Window {
public void newWindow() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JLabel label = new JLabel("I am a star! A beautiful shining star!", SwingConstants.CENTER);
frame.getContentPane().add(label);
frame.setVisible(true);
frame.pack();
}
}

From what I see, your not setting the size of the JFrame. Try,
frame.setSize(500, 500);

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?