Android: delete all files from the sdcard that match a regex

app.js

var win = Ti.UI.createWindow({ 
	backgroundColor: '#fff',
	layout: 'vertical'
});

var createButton = Ti.UI.createButton({
	title: "create files",
	top: 20,
	height: 50,
	width: 250,
});
createButton.addEventListener('click', function(e){
	if (Titanium.Filesystem.isExternalStoragePresent()) {
		var sdcardDir = Ti.Filesystem.getFile(Ti.Filesystem.externalStorageDirectory).getParent();
		for (var i = 12 - 1; i >= 0; i--){
			var newFile = Titanium.Filesystem.getFile(sdcardDir.nativePath,'newfile'+i+'.txt').write('test');
			Ti.API.info('Created: '+ newFile);
		};
		alert('files created');
	}else{
		alert('no sdcard present');
	};
});

var deleteButton = Ti.UI.createButton({
	title: "delete files",
	top: 20,
	height: 50,
	width: 250,
});
deleteButton.addEventListener('click', function(e){
	if (Titanium.Filesystem.isExternalStoragePresent()) {
		var sdcardDir = Ti.Filesystem.getFile(Ti.Filesystem.externalStorageDirectory).getParent();
		var files = sdcardDir.getDirectoryListing();
		Ti.API.info('ALL FILES '+files);
		 
		var qty = files.length;
		i=0;
		while (i < qty)
		{
		  Ti.API.info('ROW '+files[i]);
		  if(files[i].match(/newfile*/)){
			  var thefile = Titanium.Filesystem.getFile(sdcardDir.nativePath,files[i]);
			  thefile.deleteFile();
			  Ti.API.info('Deleted '+files[i]);
		  }
		   i++; 
		}
		alert('files deleted');
	}else{
		alert('no sdcard present');
	};
});

win.add(createButton);
win.add(deleteButton);
win.open();