Read Display File : Form « J2ME « Java

1. Java
2. J2ME
3. Form

Read Display File

/*--------------------------------------------------
* ReadDisplayFile.java
*
* Example from the book:     Core J2ME Technology
* Copyright John W. Muchow   http://www.CoreJ2ME.com
* You may use/modify for any non-commercial purpose
*-------------------------------------------------*/
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import java.io.*;

public class ReadDisplayFile extends MIDlet implements CommandListener
{
  private Display display;    // Reference to Display object
  private Form fmMain;       // Main form
  private Command cmHelp;    // Command to show a help file
  private Command cmExit;    // Command to exit the MIDlet
  private Alert alHelp;      // Alert to display help file text

  public ReadDisplayFile()
  {
    display = Display.getDisplay(this);
    
    cmHelp = new Command("Help", Command.SCREEN, 1);
    cmExit = new Command("Exit", Command.EXIT, 1);    
    
    fmMain = new Form("Read File");
    fmMain.addCommand(cmExit);
    fmMain.addCommand(cmHelp);
    fmMain.setCommandListener(this);
  }

  public void startApp()
  {
    display.setCurrent(fmMain);
  }

  public void pauseApp()
  { }

  public void destroyApp(boolean unconditional)
  { }

  public void commandAction(Command c, Displayable s)
  {
    if (c == cmHelp)
    {
      String str;
      // Access the resource and read its contents
      if ((str = readHelpText()) != null)
      {
        // Create an Alert to display the help text        
        alHelp = new Alert("Help", str, null, null);
        alHelp.setTimeout(Alert.FOREVER);
        display.setCurrent(alHelp, fmMain);
      }
    }
    else if (c == cmExit)
    {
      destroyApp(false);
      notifyDestroyed();
    } 
  }
  
  private String readHelpText()
  {
    InputStream is = getClass().getResourceAsStream("help.txt");
    try 
    {
      StringBuffer sb = new StringBuffer();
      int chr, i = 0;
      // Read until the end of the stream      
      while ((chr = is.read()) != -1)
          sb.append((char) chr);

      return sb.toString();
    }
    catch (Exception e)
    {         
      System.out.println("Unable to create stream");
    }
    return null;
  }
}



           
       

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