ListView中的布局文件在哪里？

Question

I am new to android and i am confused about something. I have created a simple ListView, here is my code:

public class MainActivity extends ListActivity {

    ArrayList<String> listItems;

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

        listItems = new ArrayList<String>();
        for(int i=0;i<20;i++){
            listItems.add("List Item #"+i);
        }

        ArrayAdapter<String> adapter = new ArrayAdapter<String>(MainActivity.this, android.R.layout.simple_list_item_1, listItems);
        setListAdapter(adapter);
    }
}

This correctly displays the list items on the screen, but here is my question: I have no xml files, no layouts in my project and i do not use setContentView function here. So why is this code working? How can it be displayed even though there is no xml files or layouts?

Thanks

Answer 1

You are using android.R.layout.simple_list_item_1 as the layout, which provides a TextView for you to work with. This is a layout provided by Android for simple lists of text.

If you want to make a more complex layout, you will/can define your own layout.

Answer 2

Android ships with default containers for list items.

As the name suggests, android.R.layout.simple_list_item_1 belongs to the android.R package and not to your app's resources.