File name changing with the content which will be changed two times.

FileRenaming.js

var window = Ti.UI.createWindow({
 layout:'vertical',
});
window.open();

var dir = Titanium.Filesystem.getFile(Titanium.Filesystem.applicationDataDirectory);

var f = Ti.Filesystem.getFile(Ti.Filesystem.applicationDataDirectory,'file_A.txt');
f.write('first value ');

var button = Titanium.UI.createButton({
 title : 'one',
 top : 10,
 width : 100,
 height : 50
});
button.addEventListener('click', function(e) {
 var success = f.rename('file_B.txt');
 if (success == true) {
  Ti.API.info('File has been renamed');
 } else {
  Ti.API.info('File has NOT been renamed');
 }

 Ti.API.info('f.name = ' + f.name);
 f.write('second value');
 Ti.API.info('File_A updated by : ' + f.read());

 var newf = Ti.Filesystem.getFile(Ti.Filesystem.applicationDataDirectory,
   'file_B.txt');
 Ti.API.info('File name is  ' + newf.name);
 Ti.API.info('File reading ::' + newf.read());


});

window.add(button);

var button1 = Titanium.UI.createButton({
 title : 'two',
 top : 10,
 width : 100,
 height : 50
});
button1.addEventListener('click', function(e) {
 var success = f.rename('file_B.txt');
 if (success == true) {
  Ti.API.info('File has been renamed');
 } else {
  Ti.API.info('File has NOT been renamed');
 }

 Ti.API.info('f.name = ' + f.name);
 f.write('second value');
 Ti.API.info('File_A updated by : ' + f.read());

 var newf = Ti.Filesystem.getFile(Ti.Filesystem.applicationDataDirectory,
   'file_B.txt');
 Ti.API.info('File name is  ' + newf.name);
 Ti.API.info('File reading ::' + newf.read());


});

window.add(button1);