1. Android Lists and Fragments

2. Lecture Overview Introduction to Android lists (ListView)
Using a simple ArrayAdapter
Handling list events
Creating a custom adpater

3. <ListView> Introduction
The <ListView> widget displays a scrollable list of items
Each item can be rendered using “default” layout or a custom layout
Layouts are bound to data via an Adapter
Note that grids work similarly
The OnItemClickListener() callback fires when the user clicks an item
The GridView works similarly

4. <ListView> Illustration

5. <ListView> Attributes
android:divider – color to draw between list items
android:dividerHeight – to set the height of the divider
android:footerDividersEnabled – Boolean to draw divider before footer row
android:headerDividersEnabled – Boolean to draw divider after header row

6. <ListView> Methods (1)
Call setAdapter() to associate a ListView with an adapter
Call setDivider() to draw color between list items
Call setDividerHeight() to set the height of the divider drawn between list items

7. <ListView> Methods (2)

8. Introduction to Adapters
An adapter connects (binds) a ListView to a data source
An ArrayAdapter binds to an array
A SimpleCursorAdapter binds to a Cursor (dabase)

9. ArrayAdapter (Introduction)
Use this adapter to bind to an array
By default, toString() is called on each array item and the contents placed into a TextView
This behavior can be changed using custom adapters

10. ArrayAdapter (Constructor)
The ArrayAdapter constructor requires three arguments
The application context
A layout that contains a TextView
A String array

11. ArrayAdapter (Constructor - Example)
The argument (this) references the context
android.R.layout.simple_list_item_1 references a list item (TextView) from the global Android R file
myStringArray contains the string array to be rendered
<string> is the data type of the list items

12. ArrayAdapter (Associating)
Call setAdapter() passing the adapter as an argument
Each array item is bound and rendered as an item in the list

13. ArrayAdapter (Handling Click Events)
The OnItemClickLIstenter interface and onItemClick event fires when the user clicks a list item
To get the list item, call getItemAtPosition on the list view

14. ArrayAdapter (Handling Click Events)
listView.setOnItemClickListener(new OnItemClickListener() public void onItemClick(AdapterView<?> parent, View view, int position, long id) { int itemPosition = position; String itemValue = (String) listView.getItemAtPosition(position); } });

15. Creating a Custom Adapter (Introduction)
It’s a multi-step process
Create the class that will store each data time
Weather in our example
Crate a class that derives from ArrayAdapter
Override the getView() event to get the View
Create a class to store the object reference (Holder)

16. Creating the Data Class
Each list item will contain an icon reference an a string description

17. Creating the Custom Adapter
Create a class that derives from ArrayAdapter

18. Override GetView()

19. Configure the ListView

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