Develop Reference

How to call this method into my other file?

I want to be able to call the Introduction.Intro() method into my main file code, but it tells me I am unable to call a non-static method intro from a static context. Since I am still fairly new to coding I'm not entirely sure what the problem is. I've added my codes down below. I've tried countless online methods but sadly none have seemed to work.
import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class Start extends JFrame implements ActionListener
{
private JFrame Main;
private JPanel PanelA, PanelB, PanelC;
private JLabel Text, ImageL;
private JButton Button;
private ImageIcon Image;
public Start ()
{
//Button
Button = new JButton("Start");
Button.addActionListener(new ButtonListener());
//Text
Text = new JLabel("Welcome To The Game"); //ADD NAME OF THE GAME
//Image
Image = new ImageIcon(getClass().getResource("download.jfif")); //ADD THE IMAGE FOR WELCOME
ImageL = new JLabel(Image);
//Top Panel (PanelA) - Image
PanelA = new JPanel();
PanelA.setBorder(BorderFactory.createEmptyBorder(0,200,150,200));
PanelA.setLayout(new FlowLayout(FlowLayout.CENTER));
PanelA.add(ImageL);
//Middle Panel (PanelB) - Text
PanelB = new JPanel();
PanelB.setBorder(BorderFactory.createEmptyBorder(50,200,10,200));
PanelB.setLayout(new FlowLayout(FlowLayout.CENTER));
PanelB.add(Text);
//Bottom Panel (PanelC) - Buttons
PanelC = new JPanel();
PanelC.setBorder(BorderFactory.createEmptyBorder(0,200,20,200));
PanelC.setLayout(new FlowLayout(FlowLayout.CENTER));
PanelC.add(Button);
//Main Frame
Main = new JFrame ();
Main.add(PanelA, BorderLayout.NORTH);
Main.add(PanelB, BorderLayout.CENTER);
Main.add(PanelC, BorderLayout.SOUTH);
Main.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Main.setTitle("GAME TITLE"); //ADD THIS LATER
Main.pack();
Main.setVisible(true);
}
#Override
public void actionPerformed(ActionEvent ae)
{
}
public class ButtonListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
if(e.getSource() == Button)
{
Introduction.Intro1(); //THESE LINE RIGHT HERE
return null; //THESE LINE RIGHT HERE
}
}
}
public static void main(String[] args)
{
new Start();
}
}
import java.awt.BorderLayout;
import java.awt.FlowLayout;
import javax.swing.BorderFactory;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class Introduction
{
private JFrame Main;
private JPanel PanelD;
private JLabel Text, ImageL;
private JButton Button;
private ImageIcon Image;
public void Intro()
{
Image = new ImageIcon(getClass().getResource("guy.jfif"));
ImageL = new JLabel(Image);
PanelD = new JPanel();
PanelD.setBorder(BorderFactory.createEmptyBorder(0,100,10,100));
PanelD.setLayout(new FlowLayout(FlowLayout.CENTER));
PanelD.add(ImageL);
PanelD.setVisible(true);
Main.add(PanelD, BorderLayout.NORTH);
}
}
EDIT: So I made another method in the Introduction class where I added this line of code, it managed to fix the error, however, the panel isn't being saved and my JFrame is outputting blank.
public static JFrame Intro1()
{
Introduction M = new Introduction();
return M;
}

If you are looking to initialize the Introduction class in main method of Start class, You can add belo code in main method after Start()
Introduction M = new Introduction();
You main method becomes :
public static void main(String[] args)
{
new Start();
Introduction M = new Introduction();
m.Intro
}
Looking at this set of code, It looks like there is incompatible issue, as you have declare JFrame as return type, while you are returning instance of Introduction.
public static JFrame Intro1()
{
Introduction M = new Introduction();
return M;
}

Let the user place Buttons in Java

I want to code a little tool that simulates a deterministic, finite automaton (like JFLAP) for myself.
My JFrame is just blank. How can I let the user place buttons on left click? And how do I assign the right values to that button (like which function to call when pressed).
I know I can place a button with
JButton button = new JButton("Press me");
frame.add(button);
But I don't know how I could dynamically code that.
Any help is welcome. Also if you think it's stupid to solve my problem with buttons, I'd like to hear suggestions for improvement.

The following code will add a JButton to a "blank" JFrame every time the mouse is clicked inside the JFrame. The JButton will be placed where the mouse click occurred. The JButton text will be a number. Each JButton will display a different number.
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.WindowConstants;
public class AdButton extends MouseAdapter implements Runnable {
private int counter;
private JFrame frame;
private JPanel contentPane;
public void mouseClicked(MouseEvent event) {
int x = event.getX();
int y = event.getY();
JButton button = new JButton(String.valueOf(++counter));
Dimension dim = button.getPreferredSize();
button.setBounds(x, y, dim.width, dim.height);
contentPane.add(button);
contentPane.revalidate();
contentPane.repaint();
}
#Override
public void run() {
showGui();
}
private void showGui() {
frame = new JFrame();
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
contentPane = (JPanel) frame.getContentPane();
contentPane.setLayout(null);
contentPane.addMouseListener(this);
frame.setSize(400, 450);
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new AdButton());
}
}

JAVA JButton in a different class refuses to activate when pressed

I'm failing to understand why my yankee and whiskey JButtons aren't working. Right now I only want them to close the program when romeo is greater than 1 and sierra is greater than 1.
import java.awt.*;
import java.lang.*;
import javax.swing.*;
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.InputEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.*;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.JPanel;
import java.util.Scanner;
public class AlphaMenu extends JFrame /*implements actionPerformed*/
{
private GraphicsDevice gamma;
public JButton charlie, zulu, yankee, xray;
public JFrame beta;
public JPanel delta, echo, foxtrot, golf, hotel;
public JTextArea whiskey, victor;
public BorderLayout uniform;
public ImageIcon bg;
public JLabel tango;
public int sierra, romeo;
public Integer quebec, papa;
public ActionEvent oscar;
public ActionEvent november;
public AlphaMenu()
{
//Initialization of Objects
charlie = new JButton("EXIT");
zulu = new JButton("Enter Time");
yankee = new JButton("Enter Amount of Money");
xray = new JButton("Calculate");
sierra = 0;
romeo = 0;
quebec = new Integer(0);
papa = new Integer(0);
whiskey = new JTextArea(2, 15);
victor = new JTextArea(2, 15);
bg = new ImageIcon("background.gif");
beta = new JFrame();
delta = new JPanel();
echo = new JPanel();
foxtrot = new JPanel();
golf = new JPanel();
hotel = new JPanel();
uniform = new BorderLayout();
ImageIcon bg = new ImageIcon("background.gif");
tango = new JLabel("");
tango.setIcon(bg);
//Modification of panels
beta.add(delta, uniform.PAGE_END);
beta.add(golf, uniform.PAGE_START);
beta.add(echo, uniform.LINE_START);
beta.add(foxtrot, uniform.LINE_END);
beta.add(hotel, uniform.CENTER);
golf.add(tango);
//Modification of JButton charlie & adding of JButtons
charlie.setPreferredSize(new Dimension(100, 50));
delta.add(charlie);
charlie.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
System.exit(0);
}
});
echo.add(whiskey);
echo.add(yankee);
foxtrot.add(victor);
foxtrot.add(zulu);
//Modification of JFrame beta
beta.setUndecorated(true);
beta.setExtendedState(JFrame.MAXIMIZED_BOTH);
beta.setResizable(false);
beta.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
beta.setVisible(true);
}
public void buttonSetup() throws NumberFormatException
{
//Modification of JButton yankee & JTextArea whiskey & int sierra
romeo = quebec.parseInt(whiskey.getText());
yankee.setPreferredSize(new Dimension(300, 50));
yankee.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent oscar)
{
System.exit(0);
}
});
//Modification of JButton zulu & JTextArea victor & int romeo
sierra = papa.parseInt(victor.getText());
zulu.setPreferredSize(new Dimension(300, 50));
zulu.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent november)
{
System.exit(0);
}
});
}
public void actionPerformed(ActionEvent e)
{
}
public static void main(String[] args)
{
new AlphaMenu();
}
}

So, you have two JTextArea (JTextField would probably be better) and a button. you want some buttons to execute exit when the text of both textareas is an integer greater than 1.
seems that your buttonSetup() function isn't called anywhere.
Anyway, I'd create an ActionListener that reads the texts, converts to integer, tests your condition and executes exit(). This ActionListener should be added to all the buttons you want to perform the action
final ActionListener al = new ActionListener() {
public void actionPerformed(ActionEvent event) {
try {
final int intRomeo = Integer.parseInt(romeo.getText());
final int intSierra = Integer.parseInt(sierra .getText());
if (intRomeo > 1 && intSierra > 1) {
// whatever you want to do
System.exit(0);
}
} catch (/*NumberFormat*/ Exception e) {
// ...not integers
}
};
}
whiskey.addActionListener(al);
yankee.addActionListener(al);
I have to add: the variable names you are using are really bad. Consider choosing something more significative.

For starters, readability...it would probably help the "sloppiness" if you used more appropriate names for your variables, indented different sections of code, and used comments to help describe sections in layman's terms. Maybe "btnExit" and "btnCalculate" would help make things a little easier to navigate.
Moving forward, you also don't have two different classes here, you have one class with several methods. Which is fine but wanted to inform you of that. I think maybe you need to add the buttons to their panels after your action listeners and formatting for each button. I'm just getting into some swing stuff myself and I've noticed moving the .add() functions around in the code has helped when I run into issues like this. Try the following bellow. I indented and used new naming conventions for the comments, but the code uses your convention.
//add the pnlEcho to frmBeta
beta.add(echo, uniform.LINE_START);
//format btnYankee
yankee.setPreferredSize(new Dimension(300, 50));
//btnYankee action listener
yankee.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) { //default action event
System.exit(0); //you could use this
beta.dispose(); //or you could dispose the frame and
//do more work after it is gone
}
});
//add btnYankee to pnlEcho
echo.add(yankee);

I'm failing to understand why my yankee and whiskey JButtons aren't
working
The variable wiskey is not JButton type but JTextArea type.

get keystrokes in java without focusing?

i wanted to make a java program for getting keystrokes without focusing and without keyevent class object for my project ..
is there any way to do so..??
i tried this but it is not fulfilling my requirements!!
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.KeyStroke;
import javax.swing.text.Keymap;
public class key1 {
private static void showUI() {
JFrame jFrame = new JFrame("");
jFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container container = jFrame.getContentPane();
JTextField txt = new JTextField();
container.add(txt, BorderLayout.NORTH);
ActionListener actListener = new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
System.out.println(event.getActionCommand() + " selected");
}
};
JPanel jPane = new JPanel();
JButton defaultButton = new JButton("Hit Enter");
defaultButton.addActionListener(actListener);
jPane.add(defaultButton);
JButton otherButton = new JButton("Onother Button");
otherButton.addActionListener(actListener);
jPane.add(otherButton);
container.add(jPane, BorderLayout.SOUTH);
Keymap map = txt.getKeymap();
KeyStroke stroke = KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, 0, false);
map.removeKeyStrokeBinding(stroke);
jFrame.getRootPane().setDefaultButton(defaultButton);
jFrame.setSize(350, 250);
jFrame.setVisible(true);
}
public static void main(String args[]) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
showUI();
}
});
}
}

I don't believe this is possible at the Swing level..the entire KeyEvent API revolves around some Component having focus :(
In fact, I'm pretty sure the JVM only generates events based on what the OS gives to it..and you can only get those events if something is in focus.
However, I've found a library that might do what you want. I have never used it though..just looked up out of curiosity:
http://code.google.com/p/jnativehook/

AWT button not clickable in VLCJ

I have created a simple VLCJ project that consists of a simple embedded player and a button to exit.
The code is as follows:
package test;
import java.awt.BorderLayout;
import java.awt.Button;
import java.awt.Color;
import java.awt.Frame;
import java.awt.Panel;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import uk.co.caprica.vlcj.binding.LibVlc;
import uk.co.caprica.vlcj.component.EmbeddedMediaPlayerComponent;
import uk.co.caprica.vlcj.runtime.RuntimeUtil;
import com.sun.jna.Native;
import com.sun.jna.NativeLibrary;
public class Demo {
private final JFrame frame;
private final EmbeddedMediaPlayerComponent mediaPlayerComponent;
private JPanel videoPane;
private JPanel buttonPane;
private Button exitButton;
private ActionListener a;
private static String vlc_location = "C:\\Program Files\\VideoLAN\\VLC";
public static void main(String[] args) {
NativeLibrary.addSearchPath(RuntimeUtil.getLibVlcLibraryName(), vlc_location);
Native.loadLibrary(RuntimeUtil.getLibVlcLibraryName(), LibVlc.class);
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new Demo().run();
}
});
}
public Demo() {
mediaPlayerComponent = new EmbeddedMediaPlayerComponent();
a = new MyActionListener();
exitButton = new Button("Exit");
exitButton.setActionCommand("Exit app");
exitButton.addActionListener(a);
buttonPane = new JPanel();
buttonPane.setLayout(new BorderLayout());
buttonPane.setBackground(Color.black);
buttonPane.add(exitButton, BorderLayout.CENTER);
videoPane = new JPanel();
videoPane.setLayout(new BorderLayout());
videoPane.setBackground(Color.black);
videoPane.add(mediaPlayerComponent, BorderLayout.CENTER);
videoPane.add(buttonPane, BorderLayout.PAGE_END);
frame = new JFrame("vlcj demo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocation(100, 100);
frame.setSize(1200, 800);
frame.setContentPane(videoPane);
frame.setVisible(true);
}
public void run() {
mediaPlayerComponent.getMediaPlayer().playMedia(video_file);
}
class MyActionListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent arg0) {
String s = arg0.getActionCommand();
if (s.equals("Exit")) {
System.exit(0);
}
}
}
}
The problem is that the button does show up but it cannot be clicked. When i removed the videoPane, it was back to clickable! Any ideas if I'm missing something?
I am using the version 2.1.0 for vlcj.
Thanks!

Thanks MadProgrammer for your advise. I went on to think about it and tried commenting away the line of code in run(). The JButton came back!
However, when i un-commented the code in run(), the JButton disappeared. I was thinking maybe the Swing runnable was causing issue with the creation of the JButton.
Hence, what i did was to comment away the whole Swing runnable and just use:
final Demo demo = new Demo();
demo.run();
The demo can now play video and display the Exit button, thanks!