userlist_screen.java

J2ME下开发的P2P搜索程序,功能较基础,较简单,可供学习和参考使用.

/**
 *   Importing the basic packages required by various classes during 
 *	 the execution of the program.	
 */ 
  import com.sun.kjava.*;
  import java.lang.*;
  import javax.microedition.io.*;
  import java.io.*;
  import java.util.*;
 /**
  *  The packages below are included because these packages are 
  *	 required by the XML classes.
  */ 
 import org.kxml.*;
 import org.kxml.io.*;
 import org.kxml.parser.*;
 
 //  Declaration of a class userlist_screen..

  public class userlist_screen extends Spotlet
  {

//  Declaring button variables. 

  	private Button refresh; 
  	private Button search;
  	private Button viewfiles;
  	private Button browse_user;
  	private Button exit;
 // Declaring ScrollTextBox and textField variables. 
  	private ScrollTextBox userlist;
      private TextField option;	

  	Vector ip_address;
//  Declaring StreamConnection variable used for Sockets.. 	
  	StreamConnection socket = null;
//  Declaring InputStreams and OutputStreams used by the socket 
//  connections.
  	InputStream socket_inputstream;
      OutputStream socket_outputstream;
  /**
   *   Declaraing variables for the xmlparser and parse event(Where 
   *   the call backs after the parsing will be stored.	
   */  
  	AbstractXmlParser xmlparser;
  	ParseEvent event;
   /**
   *   Declaraing variables for storing the parameters passed on to  
   *   the class.
  */  
  	Vector folder_vector;	
  	Vector users_connected;
  	String text_for_display;
 /**
  *   Declaraing variables to folder_data where the folder information  
  *   is stored similerly the variable file_data where the file 
  *   information is stored.
  */  
  	String folder_data;
  	String file_data;
  	int counter;
  	String address;
  	String user_data;
  	Vector record_of_users;

// Constructor of the class userlist_screen is called.. 
  	userlist_screen(String text, Vector ip_addresses,Vector users_connected, boolean viewfile_flag ,Vector record_of_users)
  	{
// The current graphics is obtained...	
  		Graphics graphics = Graphics.getGraphics();	
 /**
  *  Initializing the variable of the graphics class and clearing   
  *	 the drawing region by calling the appropriate functions of 
  *	 the Graphics class namely (resetDrawRegion() and clearScreen()).
  */  
 	    graphics.resetDrawRegion();
         graphics.clearScreen();	
 		
 /**
  *  Displaying a string (Title) at a specified position by using 
  *	 the member function of the Graphics class
  */ 
  		graphics.drawString("List of Users",50,5);
  		

  // The variables are initialized by the parameters earlier defined	

 		ip_address = ip_addresses;
 		user_data = text;
 		this.users_connected = users_connected;
 		this.record_of_users = record_of_users;
 
 //	To make the spotlet as the current spotlet..

  	    register(NO_EVENT_OPTIONS);	

 /**
  *  Initializing the button object "refresh", placing it on the screen 
  *	 at the appropriate position and then painting(drawing it).
  */ 

 		refresh = new Button("Refresh",10,20);
 		refresh.paint();

 /**
  *  Initializing the button object "search", placing it on the screen 
  *	 at the appropriate position and then painting(drawing it).
  */ 

  		search = new Button("Search",60,20);
  		search.paint();

 /**
  *  Initializing the button object "viewfiles", placing it on the screen 
  *	 at the appropriate position, the painting of the "viewfiles" button
  *  will be decided by checking the view_file flag if the flag is true 
  *	 then the button will be painted on the screen else not.
  */ 

  		viewfiles = new Button("View Files",110,20);
  		if (viewfile_flag)
  		{
  		 viewfiles.paint();
  		}

 /**
  *  Initializing the ScrollTextBox object userlist, placing it on 
  *	 the screen at the appropriate position and then painting(drawing it).
  */ 

  		userlist = new ScrollTextBox(text,10,40,130,100);
  		userlist.paint();

 /**
  *  Initializing the TextFiled object option, placing it on the screen 
  *	 at the appropriate position ,painting(drawing it) and making the 
  *	 caret blink by setting the TextField as the current field.
  */  

 		option = new TextField("User No.:",10,145,50,10);	
 		option.paint();
 		option.setUpperCase(true);
        option.setFocus();
 /**
  *  Initializing the button object browse_user, placing it on 
  *	 the screen at the appropriate position and then painting(drawing it).
  */ 
  		browse_user = new Button("Browse",70,145);
  		browse_user.paint();
 /**
  *  Initializing the button object exit, placing it on the screen 
  *	 at the appropriate position and then painting(drawing it).
  */ 
 		exit = new Button("Exit",120,145);
 		exit.paint();
 	
 	} // end of the constructor userlist_screen

// Event Handling function. (KeyDown)..

 	  public void keyDown(int x)
        {
// Handle the input if the TextField is in focus.	
           if(option.hasFocus())
             {
               option.handleKeyDown(x);
             }
        }   // End KeyDowm
 
 	 
// Event Handling function. (penDown)..

 	  public void penDown(int x, int y)    
 	   {
// If refresh Button is pressed..
 		  if(refresh.pressed(x,y))
            {
// Remove the focus from the TextField and kill the TextField 
// blinking caret.
 				option.loseFocus();
 				option.killCaret();
// To show a new class fist unregister all the controls of the 
// existing class
 				unregister();
// Create an object of the class peer_application and call the 
// function startReading() to send a request to the server
 				peer_application refresh_application = new peer_application();
 				refresh_application.startReading();
// Then call the parser function it will return a vector.
 				Vector ip_addresses =  refresh_application.parseData();
 String text_for_display = refresh_application.returnTextForDisplay();
 				
 Vector users_connected = refresh_application.returnUsersConnected();
 				
 // Call the class userlist_screen with the parameters obtained in the
 // previous lines.. 
 
 				new userlist_screen(text_for_display,ip_addresses,users_connected,false,null);
 
 		   }

 // If search(Server Search) Button is pressed 

 		  if(search.pressed(x,y))
            {
 				
 // Remove the focus from the TextField and kill the TextField 
 // blinking caret.
 				option.loseFocus();
  				option.killCaret();
  // To show a new class fist unregister all the controls of the 
  // existing class
  				unregister();
   // Call the class serversearch with the parameters.	
  				new serversearch(user_data,ip_address,users_connected);
  			 
  		   }
  // If viewfiles is pressed..
  		  
  		  if(viewfiles.pressed(x,y))
             {
  				
   // The option enetered by the user in the TextField is obtained.
  			   String user_number = option.getText();
  			   try
  			   {

	//Converting it to an integer value.

  				 int userID = Integer.parseInt(user_number); 
  					try
  					{
	// The variables are assigned ..
  						String textDisplay = "";
  						String folderText="";
  						String fileText="";
  						
	// From the vector ip_address the address is obtained of the 
	// user whose serial number is entered.
  				address = (String)ip_address.elementAt(userID-1);
  		
	// From another vector record_of_users an enumeration is 
	// initialized.
  						Enumeration enum = record_of_users.elements();
	// A while loop is used which matches the ip_address with the 
	// enumeration	
  						while (enum.hasMoreElements())
  						{
  							if (((String)enum.nextElement()).equals(address))
  							{
  								String temp = (String)enum.nextElement();
  								
// If a match is found then the flahg for file / folder is 
// checked and accordingly the Files/ folders are placed in 
// their respective position.
  								if (((String)enum.nextElement()).equals("1"))
  								{
  									fileText = fileText+temp+"\n";
  									
  								}
  								else
  								{
  									folderText = folderText+temp+"\n";
  								}
  							}	
  
  						}
  
// A string variable is used to display the text in the ScrollTextBox 
  textDisplay = "       Folders    \n"+folderText+"\n"+"       Files \n"+fileText;
  							
// Remove the focus from the TextField and kill the TextField 
// blinking caret.

  						option.loseFocus();
  						option.killCaret();
// To show a new class fist unregister all the controls of the 
// existing class.
  						unregister();
  
	// Call to the class show files...
  						new showfiles(textDisplay,null, null, "ROOT",true);	
  
  
  				     }