[android] Implementing SearchView in action bar

SearchDialog or SearchWidget ?

When it comes to implement a search functionality there are two suggested approach by official Android Developer Documentation.
You can either use a SearchDialog or a SearchWidget.
I am going to explain the implementation of Search functionality using SearchWidget.

How to do it with Search widget ?

I will explain search functionality in a RecyclerView using SearchWidget. It's pretty straightforward.

Just follow these 5 Simple steps

1) Add searchView item in the menu

You can add SearchView can be added as actionView in menu using

app:useActionClass = "android.support.v7.widget.SearchView" .

<menu xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:app="http://schemas.android.com/apk/res-auto"
   xmlns:tools="http://schemas.android.com/tools"
   tools:context="rohksin.com.searchviewdemo.MainActivity">
   <item
       android:id="@+id/searchBar"
       app:showAsAction="always"
       app:actionViewClass="android.support.v7.widget.SearchView"
   />
</menu>

2) Set up SerchView Hint text, listener etc

You should initialize SearchView in the onCreateOptionsMenu(Menu menu) method.

  @Override
  public boolean onCreateOptionsMenu(Menu menu) {
     // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);

        MenuItem searchItem = menu.findItem(R.id.searchBar);

        SearchView searchView = (SearchView) searchItem.getActionView();
        searchView.setQueryHint("Search People");
        searchView.setOnQueryTextListener(this);
        searchView.setIconified(false);

        return true;
   }

3) Implement SearchView.OnQueryTextListener in your Activity

OnQueryTextListener has two abstract methods

1. onQueryTextSubmit(String query)
2. onQueryTextChange(String newText

So your Activity skeleton would look like this

YourActivity extends AppCompatActivity implements SearchView.OnQueryTextListener{

     public boolean onQueryTextSubmit(String query)

     public boolean onQueryTextChange(String newText) 

}

4) Implement SearchView.OnQueryTextListener

You can provide the implementation for the abstract methods like this

public boolean onQueryTextSubmit(String query) {

    // This method can be used when a query is submitted eg. creating search history using SQLite DB

    Toast.makeText(this, "Query Inserted", Toast.LENGTH_SHORT).show();
    return true;
}

@Override
public boolean onQueryTextChange(String newText) {

    adapter.filter(newText);
    return true;
}

5) Write a filter method in your RecyclerView Adapter.

Most important part. You can write your own logic to perform search.
Here is mine. This snippet shows the list of Name which contains the text typed in the SearchView

public void filter(String queryText)
{
    list.clear();

    if(queryText.isEmpty())
    {
       list.addAll(copyList);
    }
    else
    {

       for(String name: copyList)
       {
           if(name.toLowerCase().contains(queryText.toLowerCase()))
           {
              list.add(name);
           }
       }

    }

   notifyDataSetChanged();
}

Relevant link:

Full working code on SearchView with an SQLite database in this Music App