Android : List view

Android has ListView and ExpandableListView classes capable of displaying scrollable list of items. The ExpandableListView supports a scrollable list of items. 

An Adapter manages the data model and adapts to the individual rows in the list view. An Adapter extends the BaseAdapter class. 

Every line in the list view consists of a layout and application can choose the complexity of it. 

Adapters 

An Adapter manages the data model and adapts to the individual rows in the list view. An adapter extends the BaseAdapter class. The Adapter would inflate the layout for each row in its getView method and assign data to the individual views in the row. 

The Adapter is assigned to the ListView via the setAdapter method in the ListView object. 

the default normal adapters provided by the system are ArrayAdapters and CursorAdapter 

A sample of ListView with ArrayAdapter 

- First of all make the layout in the xml like below 

android:id="+id/listview"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

/>

By default if Application provides a simple array adapter, each element n the array adapter array will be taken as the row item and display it in the list view 

Applications can create a list view row with own layout. A sample given below which shows an image view and a text view in a row 

android:layout_width="wrap_content"

android:layout_height="wrap_content"

>

…

/>

android:id="+id/textview"

…

…

/>

After this, in the code, the below can be done 

String[] values = new String[]{"Android" , "iPhone", "WindowsMobile", "Blackberrty" , "WebOS" };

ArrayAdapter adapter = new ArrayAdapter (this, R.layout.rowlayout, R.id.label, values);

setLlistAdapter (adapter)

Application can create an Own adapter as well. Below sample code shows the 

extends from the Simple Adapter such as array adapter overrider the getView method 

public class MySimpleCustomAdapter extends ArrayAdapter

{

private final Context context; 

private final String[] values;

public MySimpleCustomAdapter (Context context, String[] values)

{

super(context, R.layout.rowlayout, values);

this.context = context; 

this.values = values;

}

@override

public View getView(int position, View convertView, ViewGroup parent)

{

LayoutInflator inflator = (LayoutInflator) context.getSystemService(Context.LAYOUT_INFLATOR_SERVICE);

View rowView  = inflator.inflate(R.layout.rowLayout,parent,false);

TextView tview = (TExtView)rowView.findViewById(R.id.label);

ImageView view = (ImageView) rowView.findViewById(R.id.imageview);

tview.setText(values[position]);

view.setImageResource(R.drawble.mycustomimage);

}

}

references: 

http://www.vogella.com/tutorials/AndroidListView/article.html

http://developer.android.com/guide/topics/ui/layout/listview.html