Image Viewer in Android

I'd like to create an eBook reader app for Android but in my case, all books are basically just scanned images compiled in PDF format.

But after a lot head banging and several开发者_高级运维 tests it turned out that PDF rendering on Android is awfully slow, especially on low-end devices.

So I'm wondering if theres a way to show these images directly instead of PDF but still show them as a "book", so technically an "image viewer" but the user doesn't notice. Is it possible?

I'd appreciate any help. Thanks!

PDF isn't made up of images, they're vectors, there's a way to convert that to image files.

There are a couple open-source java PDF to Image converters though like:

http://www.jpedal.org/

http://code.google.com/p/pdfonejava/

I'm sure there are more but you'll have to find them.

Then just cache those images and there are several open-source android image viewers like:

http://code.google.com/p/android-mysample-project/source/browse/trunk/ARCamera/src/net/android/sample/imageviewer/ImageViewer.java?spec=svn9&r=9

Is this what your aiming for or am I completely off?

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    PdfReader reader;
    File file = new File("/sdcard/vineeth/anni.prc");
    try {
        reader = new PdfReader(file.getAbsolutePath());
        for (int i = 0; i < reader.getXrefSize(); i++) {
            PdfObject pdfobj= reader.getPdfObject(i);
            if (pdfobj == null || !pdfobj.isStream()) {
                continue;
            }
            PdfStream stream = (PdfStream) pdfobj;
            PdfObject pdfsubtype = stream.get(PdfName.SUBTYPE);
            if (pdfsubtype != null && pdfsubtype.toString().equals(PdfName.IMAGE.toString())) {
                byte[] img = PdfReader.getStreamBytesRaw((PRStream) stream);
                FileOutputStream out = new FileOutputStream(new File(file.getParentFile(), 
                String.format("%1$05d", i) + ".jpg"));
                out.write(img);
                out.flush();
                out.close();
            }
        }
    } catch (Exception e) {
        // TODO: handle exception
    }
}