1. Android Development: Advanced Widgets using Adapters
Richard S. Stansbury
2015

2. Adapters ListView Spinner GridView ExpandableListView Gallery
These all extend AdapterView

3. Adapters
Adapters store content that are then displayed by the AdapterView classes
e.g.
ArrayAdapter
CursorAdapter
ListAdapter
SpinnerAdapter

4. ArrayAdapter
ArrayAdapter (Context context, int resource, T [] objects)
context – context from which you are building the ArrayAdapter
resource – R.id.<identifier> specifies the view that is used to encapsulate the data
objects – objects to be displayed
toString() is performed on each item in the object array and the appropriate TextView derivative is generated
Example:
ArrayAdapter a = new ArrayAdapter(this, android.R.Layout.simple_list_item_1, items);

5. ListView Displays a list of strings
List items can be selected or clicked
extending ListActivity is an easy approach, but requires a different type of ID
XML
<ListView
android:id = “android:id/list”
android:layout_width = “fill_parent”
android:layout_height = “wrap_content”
>

6. ListView (continued) Java setAdapter(…) setOnItemSelectedListener(…)
Sets the adapter to display
setOnItemSelectedListener(…)
Sets the listener for when an item is selected
setOnItemClickListener(…)
Sets the listener for an item being clicked
setOnScrollListener(…)
Records scroll event
getSelectedItem()
Returns the object for the currently selected item.

7. Example How do we specify a list?
Ignore the multiple lines per item…this was a default of the layout viewer

8. ListView: Selection Modes
As an alternative to tracking clicks
Single selection or multiple selection
Java: setChoiceMode(mode)
mode = {CHOICE_MODE_SINGLE, CHOICE_MODE_MULTIPLE}
XML: android:choiceMode = “multipleChoice”
Resource ID:
android.R.layout.simple_list_item_single_choice
android.R.simple_list_item_multiple_chioce

9. Example

10. Spinner A fancy term for a drop down menu
i.e. a List View that is initially collapsed and when clicked expands providing a scrollable view of the list
<spinner
android:layout_width = “fill_parent”
android:layout_height = “fill_parent”
/>

11. Spinner (continued) Java setAdapter setOnItemSelectedListener
setDropDownViewResource - used to configure the adapter (not spinner)

12. Example

13. Example

14. Challenge Build / Demo
Note: cropped from full portrait view to fit on slides.