Android Programming Jumpstart – 6

  This is lab 6 in my ongoing series of jumpstart Android programming tutorials.
  This lab will focus on selectable ListViews.

Here are some terms that you’ll need to understand to work with ListViews:

• Context
  
  • Interface to information about an application environment
  • Typically when a context parameter is needed for your app you will use (this)
• Adapters
  
  • The bridge between a View and the data for that view
  • Provides access to the data items
• ArrayAdapter
  
  • The ArrayAdapter constructor takes three parameters:
    
    • The Context to use (this)
    • The resource ID of a view to use
    • The actual array or list of items to show
  • By default, the ArrayAdapter will invoke toString() on the objects in the list and wrap each of those strings in the view designated by the supplied resource.
  • android.R.layout.simple_list_item_1
    
    • a built in resource that turns those strings into TextView objects styled in a particular way.
  • Definitions for some built in resources can be found here
    
    • http://developer.android.com/reference/android/R.layout.html
• Listeners
  
  • Interface to setup callbacks for actions on your widgets
  • Use to set up link between a button and onClick

• ListView
  
  • To use you will need to define one in your layout
    
    • android.R.layout.simple_list_item_1
    • android.R.layout.simple_list_item_single_choice
    • android.R.layout.simple_list_item_multiple_choice
  • Assign data to it using setAdapter()
  • Assign functionality to catch users selections using a Listener using setOnItemClickListener()
  • If your View is really just your list, you can make things easier on yourself by having your activity extend ListActivity
    
    • It will then construct the full screen list for you
    • You must name your ListView @android:id/list

Check out the two different ways of working with a ListView below.  In this first example everything is setup in onCreate().

In this example everything we have broken it out.
 

Here are some different types of usage for a ListView. 
It is quite versatile and can be used for single or multi selections.