Question

I have button that launches a ListActivity, but every time I click on it, the app crashes with the following LogCat error:

01-10 13:12:51.327: E/AndroidRuntime(2970): FATAL EXCEPTION: main
01-10 13:12:51.327: E/AndroidRuntime(2970): java.lang.RuntimeException: Unable to start     activity ComponentInfo{com.app/com.app.Settings}: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'

This is the xml code:

<?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:background="@color/background"
android:orientation="vertical"
android:padding="15dip" >

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

</LinearLayout>

And this is the Java code:

import java.util.ArrayList;

import android.app.ListActivity;
import android.os.Bundle;
import android.widget.ArrayAdapter;

public class Settings extends ListActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.settings);
        ArrayList<String> listItems=new ArrayList<String>();
        listItems.add("foo");
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
                android.R.layout.simple_list_item_1,
                listItems);
            setListAdapter(adapter);
    }

}

I have already tried changing the list id to list but if I do this I get the following error:

If I do this I get the following error: `Error: No resource found that matches the given name (at 'id' with value '@id/list').`

Answer 1

ListActivity does not require that you assign a layout to it via the setContentView() method, if you only want to show a ListView ListActivity contains by default a ListView.

In case you need to include more Views than a ListView in your ListActivity you can still assign a layout to your Activity. In this case your layout must contain a ListView with the android:id attribute set to @android:id/list.

So change your list id to:

android:id="@android:id/list"