1. ANDROID LISTS

2. Android Lists (Introduction)
Items can be placed in a list from which the user can scroll through the items
The selection of a list item might (and often does) start another activity or fragment
Or display detail data
Adapters manage the data model
We connect the list to an array or other data type

3. Adapter Pattern Adapters are just another design pattern
The adapter design pattern makes incompatible things compatible
Adapters are structural patterns
Intent:
Convert the interface of a class into another one
Wrap a class with a new interface

4. Arrays as Resources We can create array resources
<string-array> is an array of strings
<integer-array> is an array of integers

5. Arrays as Resources (Example)

6. Reading an Array Resource
Remember that getResources() is used to get a resource
getStringArray() gets a string resource array
getIntArray() gets an integer resource array

7. Reading an Array Resource (Example)
Get the string array named adobe_products and store the result in the String array variable adobe_products
Use R.array.array_name
String[] adobe_products = getResources().getStringArray(
R.array.adobe_products);

8. Creating the ArrayAdapter (1)
The constructor we will use accepts 4 arguments:
The first contains a reference to the current context (this)
The second contains the resource ID for a layout (R.layout.list_item)
The third contains the id of the TextView within the layout to be populated
The last contains the array of objects

9. Creating the ArrayAdapter (2)

10. Working with the Lists (Method 1)
Derive an Activity from ListActivity
Use this method when implementing a full screen list
ListActivity manages the complexities of the list itself
Such as providing a default full screen layout
It’s possible to create a custom layout though

11. Working with the Lists (Method 2)
The ListView widget is used when you need a custom screen layout
There are requirements
The layout MUST contain a ListView object

12. Working With Lists (Method 1)

13. The ListView (Introduction)
The ListView is a view group that displays a list of scrollable items
The ExpandableListView class supports a grouping of items
Items are added using an adapter that pulls content from a source (commonly called the data model)
An array (ArrayAdapter)
Or database query (CursorAdapter)

14. Referencing the ListView
The getListView method applies to the ListActivity class. It gets the activity’s ListView widget
The control is built-in to ListActivity

15. Wiring onItemClick
The ListView has an OnItemClickListener

16. Wiring onItemClick (Example)

17. Implementing the ListView
In the layout file, you need to create the ListView itself

18. Implementing the ListView
Next, wire he ListView to the Adapter
Note here we are using an inline array rather than a resource