/**
 * Authorize a user in Instagram. Will show up the auth dialog and will
 * allow the user to enter his/her credentials.
 * <p>
 * <b> Pay attention</b> Use the listener afterwards to save the
 * authentication token.
 * 
 * @param listener
 *            - A dialog listener that can react to various authentication
 *            events. Cannot be null.
 * @param permissions
 *            - Use various permissions. Can be empty but not null.
 * @param activity
 *            - An activity that will be the parent of the dialog box.
 */
public void authorize(final DialogListener listener,
		final Activity activity, final String... permissions) {
	InstagramModule module = new InstagramModule();
	final InstagramAuthDialog dialog = new InstagramAuthDialog(activity,
			listener, mAppId, permissions);
	dialog.setCancelable(false);
	dialog.show();
}

public class InstagramModule implements
	DialogListener {
	@Override
	public void onComplete(final Bundle values) {
		String accessToken = values.getString("access_token");
	}

	@Override
	public void onError(final DialogError error) {
		// Log error
	}

	@Override
	public void onCancel() {
		// User canceled.
	}
}
...
authorize(new InstagramModule(), activity, "likes", "comments");

InstagramClient userClient = new DefaultInstagramClient(appId, mAccessToken);
final String endPoint = format("media/%s/comments",
					"1234");
final InstagramCollection<Comment> comments = client
					.fetchCollection(endPoint, Comment.class);

<dependency>
	<groupId>com.blinxbox.restinstagram</groupId>
	<artifactId>auth</artifactId>
	<version>1.2-SNAPSHOT</version>
	<scope>provided</scope>
</dependency>

<dependency>
	<groupId>com.blinxbox.restinstagram</groupId>
	<artifactId>auth</artifactId>
	<version>1.2-SNAPSHOT</version>
	<type>apklib</type>
</dependency>

<dependency>
	<groupId>com.blinxbox.restinstagram</groupId>
	<artifactId>restig</artifactId>
	<version>1.0-SNAPSHOT</version>
</dependency>