Excellent answer from above turned into a simple utility method.
private Uri buildURI(String url, Map<String, String> params) {
// build url with parameters.
Uri.Builder builder = Uri.parse(url).buildUpon();
for (Map.Entry<String, String> entry : params.entrySet()) {
builder.appendQueryParameter(entry.getKey(), entry.getValue());
}
return builder.build();
}