Titanium Page Flip

var win = Ti.UI.currentWindow;
Titanium.PageFlip = Ti.PageFlip = require('ti.pageflip');

var pdf = 'http://assets.appcelerator.com.s3.amazonaws.com/docs/Appcelerator-IDC-Q1-2011-Mobile-Developer-Report.pdf';
var fileName = pdf.split('/').pop();
var pdfFile = Ti.Filesystem.getFile(Ti.Filesystem.applicationDataDirectory, fileName);

function downloadPDF() {
    var progressBar = Ti.UI.createProgressBar({ max: 1, min: 0, value: 0, visible: true });
    win.add(progressBar);
    var xhr = Ti.Network.createHTTPClient({
        ondatastream: function(e) {
            progressBar.value = e.progress;
        },
        onreadystatechange: function() {
            if (xhr.readyState == 4) {
                pdfFile.write(this.responseData);
                win.remove(progressBar);
                showPDF();
            }
        }
    });
    xhr.open('GET', pdf);
    xhr.send();
}

function showPDF() {
    /**
     * "createView" will return a pageflip view. It can be sized and positioned like any other Titanium view. Here we
     * call it with a pdf and a transition; it will handle paging the PDF for us.
     */
    var scrollView = Ti.UI.createScrollView({
        zoomScale:1.0,
        minZoomScale:1.0,
        maxZoomScale:4.0
    });

    var pageflip = Ti.PageFlip.createView({
        transition: Ti.PageFlip.TRANSITION_FLIP, /* All Options: TRANSITION_FLIP [default], TRANSITION_SLIDE, TRANSITION_FADE */
        pdf: pdfFile.nativePath,
        tapToAdvanceWidth: '15%'
    });
    scrollView.add(pageflip);
    win.add(scrollView);

    scrollView.addEventListener('doubletap', function(){
        scrollView.zoomScale = 1.0;
    })

    function updateWindowTitle(evt) {
        win.title = 'PDF, 1 < ' + (evt.currentPage+1) + ' > ' + evt.pageCount;
    }
    updateWindowTitle(pageflip);

    pageflip.addEventListener('change', function(evt) {
        scrollView.zoomScale = 1.0;
        updateWindowTitle(evt);
    });
}

if (pdfFile.exists()) {
    showPDF();
}
else {
    downloadPDF();
}