wubala

Android ListActivity

2016/07/13

ListActivity is to simplify the handling of ListView. It extends Activity and provides simplified handling of lists.

Difference with Activity

  1. Override onListItemClick() method to add item click listener. With Activity, we need to create a separate listener with OnClickListener.
  2. No need to use findViewById() to find listview in layout resource.
  3. Could show a special view to replace list view automatically when there is no data in list.
  4. setListAdapter() to set adapter instead of calling ListView.setAdaper().

Please inform me if any expert know more about it.

Example

Points to pay attention:

  1. ListView must set id @android:id/list. So ListActivity could find it automatically.
  2. The view to show when there is no data in the list must set id android:id/empty.
<?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="@android:id/list"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:background="#00FF00"
        android:layout_weight="1"
        android:drawSelectorOnTop="false"/>

    <TextView android:id="@android:id/empty"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="#FF0000"
        android:text="No data"/>

</LinearLayout>

Then extend ListActivity and override onListItemClick() to add item listener

public class MainActivity extends ListActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        String[] data = {"a", "b", "c"};

        // Set data null to test no data textview
        // String[] data = {};

        ArrayAdapter<String> adapter = 
        	new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, data);

        // Add adapter	
        setListAdapter(adapter);
    }

    @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {
        super.onListItemClick(l, v, position, id);

        Toast.makeText(this, "Position:" + position + " id:" + id, Toast.LENGTH_SHORT)
                .show();
    }
}

Refs

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