Re: Applet code conversion...

On 4/30/2012 3:50 PM, linus wrote:


Here's what I did. There are 2 files. First, the main class, which has 3
important properties:

a) main() sets the global variable "applet" to be false.
b) there is an appletEntryPoint() method.
c) There is a managed content pane (vs) which I didn't include code for,
but basically is responsible for drawing everything. As you see from the
main.java setup code it's swing, so no big deal here. So I was obviously
able to use one gui codebase for both app and applet. In fact this used
to be just an application until I made the above changes to turn it into
an applet.
public class Screen extends JPanel implements KeyListener, Runnable,
Serializable {...} is what I used in my game.

Getting the applet on the web was another story. This is just the code
side. It was hell getting it up and running on the web but thats a
HTML/JNLP/whatever issue.

Basically the key to doing this is understanding how the two entry
points can be combined. The main() entry point in the main application
class (say main() in class Main in Main.java) and the Applet entry
point. Both entry points must set up a content pane, say, and this
content pane will contain the gui code. So create your gui, then call
the code which creates the content pane, this code is the same for both
classes. Say put it in it's own class MyContentPane() or something. Then
once the gui code is running in that content pane you are good to go and
it doesn't matter what entry point you used. The only thing I keep an
"applet" global for is for things like saving; the applet version can't
save a file to disk, so this item is greyed out on the menus (etc).

Main.java <--- contains the main *application* class (see below)
MainApplet.java <--- contains the main *applet* class (see below Main.java):

// Main.java
package netwhack;

import ...

public class Main {

     // Execute game
     public static void main(String args[]) {
         applet = false; // global variable

         // Frame setup code.
         try {
             SwingUtilities.invokeAndWait(new Runnable() {
                 public void run() {
                     //Make sure we have nice window decorations.
                     //JFrame.setDefaultLookAndFeelDecorated(true);

                     //Create and set up the window.
                     JFrame frame = new JFrame("Netwhack");
                    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

                     //Create and set up the content pane.
                     vs.setOpaque(true); //content panes must be opaque
                     frame.setContentPane(vs);

                     //Display the window.
                     frame.setLocation(100, 100);
                     frame.pack();
                     frame.setVisible(true);
                     frame.requestFocus();
                 }
             });
         } catch (Exception e) {
             System.out.println("Failed to initialize Screen:" + e);
             System.out.flush();
             System.exit(0);
         }

         rungame(engine);

     }

// note; vs and the gui is set up by the applet prior to calling this.
// We just pass the instance of the content pane to our game engine so
we know which content pane we're updating.
     public static void applet_entry_point(Screen vs) {
         applet = true;
         Engine engine = new Engine();
         engine.vs = vs;
         rungame(engine);
     }

     public static void rungame(Engine engine) {
         //snip
     }
}

=============================================
== Now for MainApplet.java ==================
=============================================

// MainApplet.java
//
// launch Main from an applet context.
//

package whatever;

import ...

public class MainApplet extends JApplet {

     static Screen vs = null;
     /**
      * Initialization method that will be called after the applet
      * is loaded
      * into the browser.
      */

     public void init() {
         //Execute a job on the event-dispatching thread
         //creating this applet's GUI.
         try {
             javax.swing.SwingUtilities.invokeAndWait(new Runnable() {

                 public void run() {
                     createGUI();
                 }
             });
         } catch (Exception e) {
             System.err.println("createGUI didn't successfully complete");
         }

         program_thread(); // run the program.
         setPreferredSize(vs.getPreferredSize());
         setSize(vs.getPreferredSize());
     }

     private void createGUI() {
         vs = new Screen(80, 25, Main.font_filename, 16);
         Container c = getContentPane();
         c.add(vs);
         setPreferredSize(vs.getPreferredSize());
         setSize(vs.getPreferredSize());
     }

     public int main(String args[]) {
         init();
         return 0;
     }

     // runs our procedure in it's own thread so we can exit.
     public void program_thread() {
         Runnable r = new Runnable() {

             public void run() {
                 Netwhack.applet_entry_point(vs);
             }
         };
         Thread t = new Thread(r);
         t.start();
     }

     public void start() {
         setPreferredSize(vs.getPreferredSize());
         setSize(vs.getPreferredSize());
     }

     public void stop() {
     }

     public void destroy() {
     }
}