Develop Reference

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

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?

Image/text not showing in JFrame

I want to create a Window with an image and a text so far i've got this:
public void ShowPng1() {
ImageIcon theImage = new ImageIcon("Icon_Entry_21.gif");
panel.setSize(270, 270);
JLabel label = new JLabel("Hello, World!");
JLabel imageLabel = new JLabel(theImage);
imageLabel.setOpaque(true);
panel.add(imageLabel);
panel.add(label);
panel.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
panel.setVisible(true);
}
My panel:
private JFrame panel = new JFrame();
For some reason it won't load nor image nor text, it just pops up as a white window. What can be the problem? I've also tried changing the format to .png, didn't work.
UPDATE
import java.awt.BorderLayout;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
public class Img {
private JFrame panel = new JFrame();
public Img(){
ShowPng1();
}
public void ShowPng1() {
ImageIcon theImage = new ImageIcon("Icon_Entry_21.gif");
panel.setSize(300, 300);
panel.setResizable(false);
JLabel label = new JLabel("Hello, World!");
JLabel imageLabel = new JLabel(theImage);
imageLabel.setOpaque(true);
panel.add(imageLabel);
panel.add(label, BorderLayout.PAGE_END);
panel.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
panel.setVisible(true);
}
public static void main(String[] args) {
new Img();
}
}
I've managed to get this working, which is ridiculous because I can't figure out how to make it work with my program. Reimeus gave me an idea on creating this script separately, the fix and that worked. I will have to look through my entire program to see if I'm missing anything. Creating it in a separate class should work as well.

it just pops up as a white window
Sounds like you're blocking the EDT on startup. You may need to use one of Swing's concurrency mechanisms to solve it. Post a Minimal, Complete, Tested and Readable example so we can determine this for sure.
In the meantime...
You're displacing the component containing the theImage component in the BorderLayout.CENTER location
panel.add(label);
You could organize your labels so that they can appear simultaneously (placing the components at 2 different BorderLayout locations will do)
panel.add(imageLabel);
panel.add(label, BorderLayout.PAGE_END);

You should make a JPanel and add it to the frame, and then add the labels to the panel
Something like
private JPanel panel = new JPanel;
and then add it to the frame in your method calling
frame.add(panel);

Java JLabel text in middle of vertical axis

I have a JLabel that contains variable text in a certain location in my GUI. The problem is that the text gets displayed at the bottom of the space where the JLabel is located. This does not convey to the end user the relevant information about the other contents of the GUI. Instead, I need the text of the JLabel to be printed in the middle of the vertical axis of the JLabel. A simplified version of my code is below. Can anyone show me how to alter it so that the text displays in the middle of the vertical axis instead of the bottom?
Main.java:
import java.awt.*;
import javax.swing.*;
public class Main {
public static void main(String[] args) {
JFrame frame = new JFrame("Main");
frame.getContentPane().setLayout(new FlowLayout());
frame.getContentPane().add(new VerticalLabel("Hello"));
Dimension prefSize = new Dimension(400, 300);
frame.setPreferredSize(prefSize);
frame.setMinimumSize(prefSize);
frame.pack();
frame.setVisible(true);
}
}
VerticalLabel.java:
import javax.swing.*;
import java.awt.*;
import javax.swing.border.EtchedBorder;
public class VerticalLabel extends JLabel {
public VerticalLabel(String labelText) {
Dimension myDim = new Dimension(15, 250);
this.setPreferredSize(myDim);
this.setHorizontalAlignment(LEFT);
this.setVerticalAlignment(CENTER);
this.setText(labelText);
this.setVerticalTextPosition(CENTER);
this.setUI(new VerticalLabelUI(false));
this.setBorder(new EtchedBorder());
}
}

Hardcoding a random preferred size is not a good idea.
You wrote a custom UI, so it is the responsibility of the UI to paint the text in the proper position.
Instead of creating a custom UI you can use the Text Icon approach to display vertical text. Create the label as follows:
JLabel label = new JLabel();
label.setHorizontalAlignment(JLabel.CENTER);
TextIcon labelIcon = new TextIcon(label, "Hello", TextIcon.Layout.VERTICAL);
label.setIcon( vIcon );
Add the label to the CENTER of a panel using a BorderLayout and the vetical text will be centered vertically and horizontally.

import javax.swing.*;
import java.awt.*;
import javax.swing.border.EtchedBorder;
public class VerticalLabel extends JLabel{
public VerticalLabel(String labelText){
this.setHorizontalAlignment(LEFT);
this.setVerticalAlignment(CENTER);
this.setText(labelText);
this.setVerticalTextPosition(CENTER);
//this.setUI( new VerticalLabelUI(false) );
this.setBorder( new EtchedBorder() );
}
public static void main(String[] args){
// should be done on the EDT.
JFrame frame = new JFrame("Main");
frame.getContentPane().setLayout( new GridBagLayout() );
frame.getContentPane().add(new VerticalLabel("Hello"));
Dimension prefSize = new Dimension(200,150);
frame.setPreferredSize(prefSize);
frame.setMinimumSize(prefSize);
frame.pack();
frame.setVisible(true);
}
}

How to place images on top of each other in java

I have a background image of a road, which I have displayed on a JFrame using an ImageIcon. I want to put a car on top of that background image at a certain (x,y) location.
I tried using another ImageIcon and the background does not appear when I run the program , however the car does.
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
public class Gui extends JFrame {
private ImageIcon northcar = new ImageIcon("src/north.gif");
private ImageIcon usIcon = new ImageIcon("src/trafficLight.jpg");
public Gui() {
add(new JLabel(usIcon)); // background image does not appear after the i added the northcar label
add(new JLabel(northcar)); // this picture can be seen
}
public static void main(String[] args) {
Gui frame = new Gui();
frame.setTitle("TestImageIcon");
frame.setLocationRelativeTo(null); // Center the frame
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setBounds(0, 0, 650, 650);
frame.setVisible(true);
}
}
I heard about using a canvas but have no clue. Any ideas ?
Many Thanks

How about using LayeredPane, this might help.

add(new JLabel(usIcon));
add(new JLabel(northcar));
Change the order to:
add(new JLabel(northcar));
add(new JLabel(usIcon));
Read up on Z-Order. Simply the last component added gets painted first.