It's all about ListViews

     One of the most frequent components used in an android application is a ListView, it's basically a UI component which displays a list of items (simple String items or richer items), with an adapter which can be bound to a ListView and a collection of some sort.

What do we need in order to create a ListView?

Two main options:

1. within the context of an Activity which extends the Activity Class

2. Within the context of an Activity which extends ListActivity (that being said if the whole activity is a 

    list)

We’ll look at the first option

1. Create an Activity, and a matching Xml layout file.

    In the layout file, add a ListView control using <ListView></ListView>, don't forget to give it   

    layout_width,layout_height,id.

    for example:

    <ListView

          android:id="@+id/your_listview_id"

          android:layout_width="fill_parent"

          android:layout_height="wrap_content">

    </ListView>

2. In the Activity, get A reference to the ListView by:

    ListView myListView = (ListView)findViewById(R.id.your_listview_id);

3. Create the actual data that should be populated in the ListView

     for example : 

      String[] names = {"John","Benny","Sharon","Sharona","Simona","Bill"};

      (perhaps a more comfortable way is to create a <string-array> in the resource file under 

      res/values/string.xml).

4. Ok, so far we have an Empty ListView and a collection of data stored in a String Array, we 
    need to be      

    able to bind that data to the listView, for this we will need an adapter:

    ArrayAdapter<String> adapter  =  

                     new ArrayAdapter<String>
                     (this,android.R.layout.simple_list_item_1,names); 

    let's see what are the components:

    1. this - the context

    2. android.R.layout.simple_list_item_1 - this is an id for a single layout of an item in the 
        list (taken by reference directly from the resources of the android SDK, we can see this by 
        the syntax "android.R.layout.simple_list_item_1).

    3. name -  the string array which we've defined.

    

5. finally, we connect the ListView to the adapter by using:

    myListView.setAdapter(adapter);

On the next post, we'll see how we create rich ListView's where each item on the list contains various controls.