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How did I get this? Get yourself a curl utility (if you on Win you can use this one) and run this command from the command prompt

% curl http://stream.twitter.com/spritzer.xml -uYOURUSERNAME:YOURPASSWORD

Note that YOURUSERNAME:YOURPASSWORD is just your regular Twitter user name/password – you don’t need to register dev account, nothing like that
You will now see long stream of XML snippets like one above. Change to spritzer.json and now you are streaming JSON

What to do with this? Hey – I have some ideas, you can get your own

Prerequisites

I’m using most excellent oauth-signpost library for this tutorial. You will need both core and commonshttp4 jars which you should simply drop into your project/assets folder and add to your Eclipse’s build path

Register App

Go and register your new wonderful app on Twitter. When filling the form don’t forget to choose “browser” as “Application Type”. If you fail to do that or if your current app doesn’t have that option selected then you won’t be able to redirect back to your Android app after Twitter authorization step. The form asks for “Callback URL”, you can enter any valid URL doesn’t matter which one since you will provide the “real” one programmatically.
Note “Consumer key” and “Consumer secret” values – you will need these in your app

Common code

Create consumer and provider where you see fit so you can reuse these later

    CommonsHttpOAuthConsumer consumer = new CommonsHttpOAuthConsumer(
            CONSUMER_KEY, CONSUMER_SECRET, SignatureMethod.HMAC_SHA1);

    OAuthProvider provider = new DefaultOAuthProvider(consumer,
            "http://twitter.com/oauth/request_token", "http://twitter.com/oauth/access_token",
            "http://twitter.com/oauth/authorize");
    HttpClient client = new DefaultHttpClient();

Authorization

Create some sort of trigger in your Android app such as checkbox “Enable Twitter”. When user triggers it the following should happen in your code

// Context ctx whichever way you passing it in
String authUrl = provider.retrieveRequestToken(CALLBACK_URL);
ctx.startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse(authUrl)));

Now – the CALLBACK_URL would be something like yourapp://twitt and basically it will be loaded by external browser if authentication/authorization is successful
So what will happen when this code is executed? The external browser will come up and display Twitter’s “Authorize Application Access” page. When user logs in and clicks “Allow” you should see message telling you that permission is granted and you will be redirected back.

Back from authorization

For your app to pick that app here are next steps
Add intent filter
Open AndroidManifest.xml and add the following lines to the activity that you want to handle further processing

Note “data” element – scheme and host should match your callback URL (remember yourapp://twitt?)
In Android when browser calls that callback URL then your app is brought forward and activity’s onResume() method is called. So in that method you should place the following code that basically gets you token and token_secret

// this must be places in activity#onResume()
Uri uri = this.getIntent().getData();
if (uri != null && uri.toString().startsWith(CALLBACK_URL)) {
    String verifier = uri.getQueryParameter(OAUTH_VERIFIER);
    // this will populate token and token_secret in consumer
    provider.retrieveAccessToken(verifier);
}

At this point you can call consumet#getToken() and consumer#getTokenSecret() to get and save token/secret for subsequent calls. According to Twitter – access token will not expire unless revoked by user

Posting update

Well, congrats – if you were able to execute all the steps above you now ready to post your first update. Here’s the code that will do it

        // create a request that requires authentication
        HttpPost post = new HttpPost("http://twitter.com/statuses/update.xml");
        final List nvps = new ArrayList();
        // 'status' here is the update value you collect from UI
        nvps.add(new BasicNameValuePair("status", status));
        post.setEntity(new UrlEncodedFormEntity(nvps, HTTP.UTF_8));
        // set this to avoid 417 error (Expectation Failed)
        post.getParams().setBooleanParameter(CoreProtocolPNames.USE_EXPECT_CONTINUE, false);
        // sign the request
        consumer.sign(post);
        // send the request
        final HttpResponse response = client.execute(post);
        // response status should be 200 OK
        int statusCode = response.getStatusLine().getStatusCode();
        final String reason = response.getStatusLine().getReasonPhrase();
        // release connection
        response.getEntity().consumeContent();
        if (statusCode != 200) {
            Log.e("TwitterConnector", reason);
            throw new OAuthNotAuthorizedException();
        }

Now – you can use different update URL to get JSON for example, but generally you can use code above to sign any of your Twitter requests.
Happy Twitting!!

P.S. If you decide to re-post this article please kindly provide link back to the original. And if you have Android phone checkout DroidIn - LinkedIn app.