ListView in xml layout Does not detected by R.id.XXX

Question

ListView is not detected in Custom.Class when bridging from custom.xml file ..i have done some silly mistake please correct me..

public class Custom extends Activity {

    /* (non-Javadoc)
     * @see android.app.Activity#onCreate(android.os.Bundle)
     */
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.custom);
        ListView lv=(ListView)findViewById(R.id.list); // list is not detected..showing error
    }
}

XML custom

<?xml version="1.0" encoding="utf-8"?>
<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/android:list"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
    </ListView>

</LinearLayout>

Answer 1

Replace

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

with

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

Whenever you want to give id to a View you have to use android:id="@+id/your_id

Answer 2

android:id="@+id/list" use the notation @+ to add new id

Answer 3

Change the following -- android:id="@+id/list"

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

Now following will detect the list- ListView lv=(ListView)findViewById(R.id.list);

If you want to refer Android resources , which are already defined in Android system, with @android:id/.. while to access resources that you have defined/created in your project, you use @id/.

Check this SO -- Difference between "@id/" and "@+id/" in Android

So for your case, you can also define list view by android:id="@android:id/list"
Also you can check this so Android: id list view

Answer 4

Using @id/android:list is for referencing the default list in a ListActivity.

You could change your Activity to a ListActivity and reference the ListView in your activity code with the getListView() method. For example:

public class Custom extends ListActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.custom);
        ListView lv = getListView();
    }
}

Alternatively as others have suggested you could use:

android:id="@+id/list"

Instead of:

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