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Android Widget – ListView

Android ListView is a view which groups several items and display them in vertical scrollable list. The list items are automatically inserted to the
list using an Adapter that pulls content from a source such as an array or database.

An adapter actually bridges between UI components and the data source that fill data into UI Component. Adapter holds the data and send the data
to adapter view, the view can takes the data from adapter view and shows the data on different views like as spinner, list view, grid view etc.

The ListView and GridView are subclasses of AdapterView and they can be populated by binding them to an Adapter, which retrieves data from an
external source and creates a View that represents each data entry. Android provides several subclasses of Adapter that are useful for retrieving different kinds of data and building views for an AdapterView
( i.e. ListView or GridView). The common adapters are ArrayAdapter,Base Adapter, CursorAdapter, SimpleCursorAdapter,SpinnerAdapter and WrapperListAdapter.

Following is the content of the modified main activity ListDisplay.java. This file can include each of the fundamental life cycle methods.

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.ArrayAdapter;
import android.widget.ListView;
public class ListDisplay extends Activity {
   // Array of strings...
   String[] mobileArray = {"Android","IPhone","WindowsMobile","Blackberry","WebOS","Ubuntu","Windows7","Max OS X"};
   protected void onCreate(Bundle savedInstanceState) {
      ArrayAdapter adapter = new ArrayAdapter<string>(this, R.layout.activity_listview, mobileArray);
      ListView listView = (ListView) findViewById(R.id.mobile_list);

Following will be the content of res/layout/activity_main.xml file :-

<linearlayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical"tools:context=".ListActivity">
   <listview android:id="@+id/mobile_list"android:layout_width="match_parent"android:layout_height="wrap_content">

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