Filter ListView when enter text in EditText

This is how to filter a ListView based on user input.

1.activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
    <EditText
        android:id="@+id/search_box"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:hint="Search"
        android:inputType="text"
        android:maxLines="1"/>
    <ListView android:id="@android:id/list"
        android:layout_width="fill_parent"
        android:layout_height="0dip"
        android:layout_weight="1"/>
</LinearLayout>

2.MainActivity.java

public class MainActivity extends ListActivity {
    private EditText filterText = null;
    ArrayAdapter<String> adapter = null;
    String[] list = new String[]{"a", "b", "c", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"};
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        filterText = (EditText) findViewById(R.id.search_box);
        filterText.addTextChangedListener(filterTextWatcher);
        adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1,
                list);
        setListAdapter(adapter);
    }

    private TextWatcher filterTextWatcher = new TextWatcher() {
        public void afterTextChanged(Editable s) {}

        public void beforeTextChanged(CharSequence s, int start, int count, int after) {}

        public void onTextChanged(CharSequence s, int start, int before, int count) {
            adapter.getFilter().filter(s.toString());
        }
    };

    protected void onDestroy() {
        super.onDestroy();
        filterText.removeTextChangedListener(filterTextWatcher);
    }
}