What is Adapter?
Adapters in Android is a link between the AdapterView and underlying data for that view. The Adapter provides the opportunity to use data items.
Here is What Developers Guide tells about Adapters
AdapterView Class:
The adapter view is a derived class of view group. Adapter view accesses the data through adapter object indirectly, Adapter view is also called as view group.
Responsibilities of AdapterView
- Handling the user selection
- Filling the layout data through the adapter
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There are the some normally used Adapter in Android to execute the data in the UI Components.
- Base Adapter
- ArrayAdapter
- List Adapter
- Cursor Adapter
- Grid view
Now we discuss each Adapters one by one in detail:
Base Adapter
It is a common base class for an adapter that can be used in a Listview and Spinner. If we have need ofcustomized list in a list view we able to create our own adapter and extend base adapter. To create a custom Adapter for Showing a custom list item from extended by Base Adapter.
Custom Adapter extends the BaseAdapter code:
public class CustomAdapter extends BaseAdapter {
@Override
public int getCount() {
return 0;
}
ArrayAdapter
Array adapter is an adapter if ever had a list of single item which is backed by an array. For Example, List of Contacts or Names.
Here is How ArrayAdapter looks:
ArrayAdapter(Context context, int resources, int textViewResourcesId, T[] objects)
List Adapter
The ListAdapter has contained the data and a ListView that displaying the data. The List View can show any data type provided it’s wrapped in a ListAdapter.
A ListView is a ViewGroup that displays a scrollable item as a list. Items are inserted in the list using an Adapter.
The Adapter gets the data from a source such as an array and it turns each item into a view and places the view in the list.
CursorAdapter
A CursorAdapter is a Cursor’s data to a ListView. You must include the database’s _id column as it’s used in processing the list item’s selection.
The SimpleCursorAdapter is a subclass of CursorAdapter. The SimpleCursorAdapter is much easier to use while the CursorAdapter, it needs better work but allows more customization.
GridView
A GridView is a ViewGroup that displays items in a 2-dimensional scrollable grid.
An Adapter gets the items from a data source, creates a view to Surrounded the item and then added the view in the parent grid.