app.js

/* updating functionality */
// 1. install all databases
	var eventsDB = Ti.Database.install('dbEvents.sql','events');
    	eventsDB.close();
	var imagesDB = Ti.Database.install('dbImages.sql','events_images');
    	imagesDB.close();
	var venuesDB = Ti.Database.install('dbVenues.sql','venues');
    	venuesDB.close();
	var videosDB = Ti.Database.install('dbVideos.sql','events_videos');
    	videosDB.close();
// 2. move lastUpdated.txt file to app directory
	var savedFile = Titanium.Filesystem.getFile(Titanium.Filesystem.applicationDataDirectory+Titanium.Filesystem.separator,'lastUpdated.txt');
		if(savedFile.exists()){
		} else {
			var lastUpdatedFile = Titanium.Filesystem.getFile(Titanium.Filesystem.resourcesDirectory, 'lastUpdated.txt');
			savedFile.write(lastUpdatedFile);
		}
// 3. if online, download newUpdates.txt from server
	if (Titanium.Network.online) {		
		var xhr = Titanium.Network.createHTTPClient();
			xhr.setTimeout(10000); // 10 secs
			xhr.open('GET','URL/newUpdates.txt');
			xhr.onload = function() {
				newUpdatesFile = Ti.Filesystem.getFile(Ti.Filesystem.applicationDataDirectory,'newUpdates.txt');
 
				if(newUpdatesFile.exists()){
					newUpdatesFile.deleteFile(true);
					newUpdatesFile.write(this.responseData);
				} else {
					newUpdatesFile.write(this.responseData);
				}
				if(this.readyState == 4 && this.status == "200" )
                {   
					tabGroup.open();
					Titanium.App.Properties.setString('update', 'YES');
                }
				xhr.onerror = function()
				{
					tabGroup.open();
					Titanium.App.Properties.setString('update', 'NO');
				};
			};
			xhr.send();
	} else {
		tabGroup.open();
		Titanium.App.Properties.setString('update', 'NO');
	}