Adding actionbar to listactivity

Question

Hello so I created a list and I want to add action bar. I am quite new to android so I would like to know how to add action bar while using ListActivity. Any help will be appreciated. Thanks My code:

     public class MainActivity extends ListActivity {

     ArrayList<Item> items = new ArrayList<Item>();

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


        items.add(new SectionItem("2x2 Matrices"));
        items.add(new EntryItem("Adding 2 Matrices"));
        items.add(new EntryItem("Subtracting 2 Matrices"));
        items.add(new EntryItem("Multiplying 2 Matrices"));
        items.add(new EntryItem("Multiplying by a constant"));
        items.add(new EntryItem("Dividing 2 Matrices"));
        items.add(new EntryItem("Negative of a Matrix"));
        items.add(new EntryItem("Inverse of a Matrix"));
        items.add(new EntryItem("Determinant of a Matrix"));

        /*Section2*/
        items.add(new SectionItem("3x3 Matrices"));
        items.add(new EntryItem("Item 4"));
        items.add(new EntryItem("Item 5"));
        items.add(new EntryItem("Item 6"));
        items.add(new EntryItem("Item 7"));
        /*Section3*/
        items.add(new SectionItem("Category 3"));
        items.add(new EntryItem("Item 8"));
        items.add(new EntryItem("Item 9"));
        items.add(new EntryItem("Item 10"));
        items.add(new EntryItem("Item 11"));
        items.add(new EntryItem("Item 12"));

        EntryAdapter adapter = new EntryAdapter(this, items);

        setListAdapter(adapter);
    }

}

Answer 1

Here is a good way:

In your layout file: activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<ListView
    android:id="@+id/list"
    android:layout_height="wrap_content"
    android:layout_width="match_parent">
</ListView>

Now for your activity:

public class MainActivity extends ActionBarActivity
{
    private ListView listView;
    private ListAdapter myAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listView = (ListView) findViewById(R.id.list);
        myAdapter = new ListAdapter(getApplicationContext());
        listView.setAdapter(myAdapter);

Good Luck!