کار با فایل ها

[seraj.90]

عزیری هست منبعی کامل برای کار با فایل ها رو معرفی کنه.


کسانی که مخالف آزادی دیگرانند ، خود لیاقت آزادی را ندارند.
«آبراهام -لینکلن»

[hesamy2004]

منظورت از منبعی کامل چیه؟ :متفکر:

کلاً با فایلها دوتا کار میکنن یا میخوننشون یا مینوسن توشون. برای هرکدومشون هم یه سمپل ببینی حله :چشمک:

برای خوندن فایل (منبع (http://www.roseindia.net/j2me/read-file.shtml)) :


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

public class ReadFile extends MIDlet implements CommandListener{
private Display display;
private Form form;
private Command read, exit;
private Alert alert;

public ReadFile(){
display = Display.getDisplay(this);
read = new Command("Read", Command.SCREEN, 1);
exit = new Command("Exit", Command.EXIT, 1);
form = new Form("Read File");
form.addCommand(exit);
form.addCommand(read);
form.setCommandListener(this);
}

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

public void pauseApp(){}

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

public void commandAction(Command c, Displayable s){
String label = c.getLabel();
if (label.equals("Read")){
String string = file();
if (string != null){
alert = new Alert("Reading", string, null, null);
alert.setTimeout(Alert.FOREVER);
display.setCurrent(alert, form);
}
} else if (label.equals("Exit")){
destroyApp(false);
}
}

private String file(){
InputStream is = getClass().getResourceAsStream("help.txt");
StringBuffer sb = new StringBuffer();
try{
int chars, i = 0;
while ((chars = is.read()) != -1){
sb.append((char) chars);
}
return sb.toString();
}catch (Exception e){}
return null;
}
}


برای نوشتن تو فایل (منبع (http://www.java-tips.org/java-me-tips/midp/how-to-write-to-a-file.html)):


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

public class FileConnection extends MIDlet implements CommandListener {
private Command exit, start;
private Display display;
private Form form;
public FileConnection ()
{
display = Display.getDisplay(this);
exit = new Command("Exit", Command.EXIT, 1);
start = new Command("Start", Command.EXIT, 1);
form = new Form("Write To File");
form.addCommand(exit);
form.addCommand(start);
form.setCommandListener(this);
}
public void startApp() throws MIDletStateChangeException
{
display.setCurrent(form);
}
public void pauseApp()
{
}
public void destroyApp(boolean unconditional)
{
}
public void commandAction(Command command, Displayable displayable)
{
if (command == exit)
{
destroyApp(false);
notifyDestroyed();
}
else if (command == start)
{
try
{
OutputConnection connection = (OutputConnection)
Connector.open("file://c:/myfile.txt;append=true", Connector.WRITE );
OutputStream out = connection.openOutputStream();
PrintStream output = new PrintStream( out );
output.println( "This is a test." );
out.close();
connection.close();
Alert alert = new Alert("Completed", "Data Written", null, null);
alert.setTimeout(Alert.FOREVER);
alert.setType(AlertType.ERROR);
display.setCurrent(alert);
}
catch( ConnectionNotFoundException error )
{
Alert alert = new Alert(
"Error", "Cannot access file.", null, null);
alert.setTimeout(Alert.FOREVER);
alert.setType(AlertType.ERROR);
display.setCurrent(alert);
}
catch( IOException error )
{
Alert alert = new Alert("Error", error.toString(), null, null);
alert.setTimeout(Alert.FOREVER);
alert.setType(AlertType.ERROR);
display.setCurrent(alert);
}
}
}
}