Question

I got a problem I couldn’t get to work after about 2 Hours of trying. I want to have a loop that do 2 Methods (Draw and update) but also listen to Mouse/Keyboard events. I have a loop that Draws and Updates, but does nothing outside of the loop ( Listening to events ) I tried alot of things but nothing worked. Help Please?

I tried using the Runnable Thread, using different orders, using wait() and notify(), I’ve tried alot of things. But basicly I want to know how to run a loop and still check for User Input

Also when I try to quit the program clicking the red “X”, it won’t quit but still work

Here’s the Code:

import java.applet.Applet;
import java.awt.*;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

public class main extends Applet implements MouseListener, Runnable {

    public main() {
        super();
        init();
    }
    Thread t;
    Screen screen = new Screen();
    String Text = "Hello";
    boolean Running = true;
    boolean Click = false;
    int R = 0x00;
    int G = 0x00;
    int B = 0x00;
    int xpoints[] = {25, 40, 40, 25, 25};
    int ypoints[] = {40, 40, 25, 25, 25};
    int npoints = 5;

    public void run() {
        while (Running) {
            GameLoop();
        }
    }

    public void init() {
        this.addMouseListener(this);
        this.setSize(400, 300); //manually set your Frame's size
        t = new Thread(this);
        t.start();
    }

    public void paint(Graphics g) {
        g.setColor(new Color(R, B, G));
        g.fillPolygon(xpoints, ypoints, npoints);
        Running = true;
        t.run();
    }

    public void mousePressed(MouseEvent e) { //On Mouse Click
        System.exit(0);
    }

    public void mouseReleased(MouseEvent e) {
    }

    public void mouseEntered(MouseEvent e) {
        System.exit(0);
    }

    public void mouseExited(MouseEvent e) {
    }

    public void mouseClicked(MouseEvent e) {
    }

    public boolean keyDown(Event e, int key) {
        return true;
    }

    public void GameLoop() {
        if (Running) {
            if (R != 0xff) {
                R++;
            } else {
                if (G != 0xff) {
                    G++;
                } else {
                    if (B != 0xff) {
                        B++;

                    } else {
                        System.exit(0);
                    }
                }
            }
            try {
                sleep(20);
            } catch (InterruptedException e) {

                e.printStackTrace();
            }
            paint(getGraphics());
        }
    }

    public void sleep(int time) throws InterruptedException {
        Thread.sleep(time, 0);
    }
}

Answer 1

This tutorial should provide some insight as to how your program should be structured. And this one is helpful for the mouse listener.

Issues you should address:
1) You’re doing something fishy with the paint method. Why are you calling t.run() in there? The thread t is already running and looping constantly calling the paint() method to redraw the screen. Remove this call and see what you get.

1) The destruction of your thread/applciation is poor. The first example above provides a better way for that to occur

2) You have your System.Exit(0) on mousePressed() with the comment //on mouse click but nothing in mouseClicked()… it works but its bad convention

3)Having your class named main is extremely poor convention that is both confusing and impractical. Rename your class to something like “Game” or similar.

4) Why declare Screen if you don’t use it?