public static void startActivityAddress(final Context context, final Geopoint coords, final String address) {
        final Intent addressIntent = new Intent(context, CacheListActivity.class);
        Intents.putListType(addressIntent, CacheListType.ADDRESS);
        addressIntent.putExtra(Intents.EXTRA_COORDS, coords);
        addressIntent.putExtra(Intents.EXTRA_ADDRESS, address);
        context.startActivity(addressIntent);
    }
Check if a given username is valid (non blank), and show a toast if it isn't.

@param context  an activity
@param username the username to check
@return <tt>true</tt> if the username is not blank, <tt>false</tt> otherwise
main/src/main/java/cgeo/geocaching/CacheListActivity.java