List View Introduction

1. Prof. Neeraj Bhargava
Vishal Dutt
Department of Computer Science, School of
Engineering & System Sciences
MDS University, Ajmer

2. What is a list view?
 A ViewGroup that displays scrollable items.

3. 3 Parts of a ListView
 The ListView itself
 aka a ViewGroup
 List items
 Each row/item in the list. Each item is a layout
consisting of a View or ViewGroup.
 Data for each item

4. ListItem
 Since the ListItem can be a ViewGroup, we have the
power to display very simple or extremely complex
layouts for each item.
 A TextView
 A TextView and ImageView
 A TextView and CheckBox
 A TextView and Button
 A TextView, ImageView, CheckBox, Button, and
RatingBar, etc

5. Where does the data come from?
 ListViews receive data via Adapters.
 The Adapter behaves as the middleman between the
data source and the ListView.

6. The job of an Adapter
 The Adapter fetches data from the source.
 Creates the layout that represents each list item.
 Takes the data fetched from the source places it into
the list item layout.
 Returns a list item to the ListView.

7. How an Adapter Works
Array<String> mMovies = { "Bill and Ted's Excellent Adventures", "Teen
Wolf", "Honey I shrunk the kids", "Texas Chainsaw Massacre",
"Puppet Master" }
Adapter
Bill and Ted’s
Excellent…
Teen Wolf
Honey I shrunk…
Texas Chainsaw
Mas…
Pupper Master
Bill and Ted…
ListView

8. Data source for Adapters
1. Arrays
2. Content Provider
 Used to get Calendar and Contact info from phone.
3. Database Cursor

9. Types of Adapters
 ArrayAdapter
 Works with Arrays
 Can handle any Java Object as input
 Uses the .toString() method of the JavaObject to obtain
text for list item.
 SimpleCursorAdapter
 Works with a Content Provider and Database Cursor