Acessando o sistema de arquivos local em dispositivos J2ME com a API FileConnection

Acessando o sistema de arquivos local em dispositivos J2ME com a API FileConnection

A API FileConnection especificada em Jsr-75 d� acesso aos sistemas de arquivo locais em dispositivos como PDAs. O exemplo abaixo tem um browser para se movimentar no sistema de arquivos, permitindo selecionar e ler imagens armazenadas no diret�rio local.

import java.util.*;
import java.io.*;
import javax.microedition.io.*;
import javax.microedition.io.file.*;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

public class FileMidlet extends MIDlet implements CommandListener 
{
 private String currDirName;

 private Command view = new Command("Visualizar", Command.ITEM, 1);
 private Command back = new Command("Voltar", Command.BACK, 2);
 private Command exit = new Command("Sair", Command.EXIT, 3);
 
 private final static String UP_DIRECTORY = "..";
 private final static String MEGA_ROOT = "/";
 private final static String SEP_STR = "/";
 private final static char SEP = '/';

 public FileMidlet() 
 {
currDirName = MEGA_ROOT;
 }

 public void startApp() 
 {
boolean isAPIAvailable = false;
if (System.getProperty(
"microedition.io.file.FileConnection.version") != null)
{
isAPIAvailable = true;
try 
{
showCurrDir();
} 
catch (SecurityException e) 
{} 
catch (Exception e) {}
}
else
{
StringBuffer splashText = new StringBuffer(
getAppProperty("MIDlet-Name")).append("\n").append(
getAppProperty("MIDlet-Vendor")).
append(isAPIAvailable?"":"\nFileConnection API not available");
Alert splashScreen = new Alert(null,splashText.toString(),
null,AlertType.INFO);
splashScreen.setTimeout(3000);
Display.getDisplay(this).setCurrent(splashScreen);
}

 }

 public void pauseApp() {}

 public void destroyApp(boolean cond) 
 {
notifyDestroyed();
 }

 public void commandAction(Command c, Displayable d) 
 {
if (c == view) 
{
List curr = (List)d;
final String currFile = curr.getString(curr.getSelectedIndex());
new Thread(new Runnable() 
{
public void run() 
{
if (currFile.endsWith(SEP_STR) || 
currFile.equals(UP_DIRECTORY)) 
{
traverseDirectory(currFile);
} else 
{
showFile(currFile);
}
}
}).start()
}
else if (c == back) 
{
showCurrDir();
} 
else if (c == exit) 
{
destroyApp(false);
}
 }

 void showCurrDir() 
 {
Enumeration e;
FileConnection currDir = null;
List browser;
try 
{
if (MEGA_ROOT.equals(currDirName)) 
{
e = FileSystemRegistry.listRoots();
browser = new List(currDirName, List.IMPLICIT);
} 
else 
{
currDir = (FileConnection)Connector.open(
"file://localhost/" + currDirName);
e = currDir.list();
browser = new List(currDirName, List.IMPLICIT);
browser.append(UP_DIRECTORY);
}
while (e.hasMoreElements()) 
{
String fileName = (String)e.nextElement();
if (fileName.charAt(fileName.length()-1) == SEP) 
{
browser.append(fileName);
} 
else 
{
browser.append(fileName);
}
}
browser.setSelectCommand(view);
browser.addCommand(exit);
browser.setCommandListener(this);
if (currDir != null) 
{
currDir.close();
}
Display.getDisplay(this).setCurrent(browser);
} 
catch (IOException ioe) 
{}
 }
 
 void traverseDirectory(String fileName) 
 {
if (currDirName.equals(MEGA_ROOT)) 
{
if (fileName.equals(UP_DIRECTORY)) 
{
return;
}
currDirName = fileName;
} 
else if (fileName.equals(UP_DIRECTORY)) 
{
int i = currDirName.lastIndexOf(SEP, currDirName.length()-2);
if (i != -1) 
{
currDirName = currDirName.substring(0, i+1);
} 
else 
{
currDirName = MEGA_ROOT;
}
} 
else 
{
currDirName = currDirName + fileName;
}
showCurrDir();
 }
 
 void showFile(String fileName) 
 {
try 
{
FileConnection fc = (FileConnection)
Connector.open("file://localhost/" + currDirName + fileName);
if (!fc.exists()) 
{
throw new IOException("Arquivo n�o existe");
}
InputStream fis = fc.openInputStream();
byte[] b = new byte[1024];
int length = fis.read(b, 0, 1024);
fis.close();
fc.close();

TextBox tb = new TextBox("Visualizar arquivo: " + fileName, null, 1024,
TextField.ANY | TextField.UNEDITABLE);
 
tb.addCommand(back);
tb.addCommand(exit);
tb.setCommandListener(this);

if (length > 0) 
{
tb.setString(new String(b, 0, length));
}
Display.getDisplay(this).setCurrent(tb);
}
catch (Exception e) {}
 }
}

Acessando o sistema de arquivos local em dispositivos J2ME com a API FileConnection

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