java - Android search with Fragments

Question

Does somebody know of a tutorial or an example of how to implement the standard Android search interface with Fragments? In other words, is it possible to put a standard search with a SearchManager in a Fragment?

Answer 1

In short, you can't. There are a couple of reasons why creating a search interface within a Fragment is not possible.

1. When creating a searchable interface, you must specify a default "searchable activity" in your Android manifest. As I'm sure you know, a Fragment cannot exist without a parent Activity and thus, this separation is not possible.

2. If you already figured out #1 already, I assume you asked this question in hopes that there is some magical "hack" out there that can get the job done. However, the documentation states that,

   When the user executes a search in the search dialog or widget, the system starts your searchable activity and delivers it the search query in an Intent with the ACTION_SEARCH action. Your searchable activity retrieves the query from the intent's QUERY extra, then searches your data and presents the results.

   The underlying, internal system that is responsible for providing search results expects an Activity, not a Fragment; thus, implementing a search interface that is completely independent of an Activity is not possible, as it would require changes to the underlying system itself. Check out the source code for the SearchableInfo class if you don't believe me :).

That being said, it doesn't seem like it would be too difficult to achieve something similar to what you are describing. For instance, you might consider implementing your searchable-Activity so that it will accept the android.intent.action.SEARCH intent and (instead of immediately displaying the results in a ListView, for example) will pass the search query to your Fragments. For instance, consider the following searchable Activity:

public class SearchableActivity extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        if (Intent.ACTION_SEARCH.equals(getIntent().getAction())) {
          String query = intent.getStringExtra(SearchManager.QUERY);
          doMySearch(query);
        }
    }

    /**
     * Performs a search and passes the results to the container
     * Activity that holds your Fragments.
     */
    public void doMySearch(String query) {
        // TODO: implement this
    }
}

When a search-request is made, the system will launch your searchable activity, perform the query, and will pass the results to some container Activity (based on your implementation of doMySearch). The container Activity will then pass these results to the contained searchable Fragment, in which the results will be displayed. The implementation requires a bit more work than what you were probably hoping for, but I'm sure there are ways that you can make it more modular, and it seems like this might be the best that you can do.

p.s. If you use this approach, you might have to pay special attention to which Activitys are added/removed to the backstack. See this post for some more information on how this might be done.

p.p.s. You might also forget about the standard search interface completely and just implement a simple search within a Fragment as described in Raghav's post below.