Using Dropbox API to upload a file with Android

How can I upload a File (graphic, audio and video file) with Android using the Dropbox API to Dropbox? I followed the tutorial on the Dropbox SDK Android page and could get the sample to work. But now instead of a String I want to upload an actual File object and am struggling.

The sample code works without any problems and looks like this:

    String fileContents = "Hello World!";
ByteArrayInputStream inputStream = new ByteArrayInputStream(fileContents.getBytes());
try {
    Entry newEntry = mDBApi.putFile("/testing_123456.txt", inputStream, fileContents.length(), null, null);
} catch (DropboxUnlinkedException e) {
    Log.e("DbExampleLog", "User has unlinked.");
} catch (DropboxException e) {
    Log.e("DbExampleLog", "Something went wrong while uploading.");
}   

But when I try to change it and upload an actual file with this code:

    File tmpFile = new File(fullPath, "IMG_2012-03-12_10-22-09_thumb.jpg");

// convert File to byte[]
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(bos);
oos.writeObject(tmpFile);
bos.close();
oos.close();
byte[] bytes = bos.toByteArray();

ByteArrayInputStream inputStream = new ByteArrayInputStream(bytes);
try {
    Entry newEntry = mDBApi.putFile("/IMG_2012-03-12_10-22-09_thumb.jpg", inputStream, tmpFile.length(), null, null);
} catch (DropboxUnlinkedException e) {
    Log.e("DbExampleLog", "User has unlinked.");
} catch (DropboxException e) {
    Log.e("DbExampleLog", "Something went wrong while uploading.");
}

I have no success getting a DropboxException error. I think something where I try to convert the File object to the byte-stream must be wrong but this is just an assumption.

Other than the String example there is nothing else documented on the Dropbox page for Android.

Thanks for any help.

I found the solution - if anyone is interested here is the working code:

private DropboxAPI<AndroidAuthSession> mDBApi;//global variable

File tmpFile = new File(fullPath, "IMG_2012-03-12_10-22-09_thumb.jpg");

FileInputStream fis = new FileInputStream(tmpFile);

            try {
                DropboxAPI.Entry newEntry = mDBApi.putFileOverwrite("IMG_2012-03-12_10-22-09_thumb.jpg", fis, tmpFile.length(), null);
            } catch (DropboxUnlinkedException e) {
                Log.e("DbExampleLog", "User has unlinked.");
            } catch (DropboxException e) {
                Log.e("DbExampleLog", "Something went wrong while uploading.");
            }