LiveFolders

Class Overview

A LiveFolder is a special folder whose content is provided by a ContentProvider. To create a live folder, two components are required:

• An activity that can respond to the intent action ACTION_CREATE_LIVE_FOLDER. The activity is responsible for creating the live folder.
• A ContentProvider to provide the live folder items.

Lifecycle

When a user wants to create a live folder, the system looks for all activities with the intent filter action ACTION_CREATE_LIVE_FOLDER and presents the list to the user. When the user chooses one of the activities, the activity is invoked with the ACTION_CREATE_LIVE_FOLDER action. The activity then creates the live folder and passes it back to the system by setting it as an activity result. The live folder is described by a content provider URI, a name, an icon and a display mode. Finally, when the user opens the live folder, the system queries the content provider to retrieve the folder's content.

Setting up the live folder activity

The following code sample shows how to write an activity that creates a live folder:

 public static class MyLiveFolder extends Activity {
     public static final Uri CONTENT_URI = Uri.parse("content://my.app/live");

     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);

         final Intent intent = getIntent();
         final String action = intent.getAction();

         if (LiveFolders.ACTION_CREATE_LIVE_FOLDER.equals(action)) {
             setResult(RESULT_OK, createLiveFolder(this, CONTENT_URI, "My LiveFolder",
                     R.drawable.ic_launcher_contacts_phones));
         } else {
             setResult(RESULT_CANCELED);
         }

         finish();
     }

     private static Intent createLiveFolder(Context context, Uri uri, String name,
             int icon) {

         final Intent intent = new Intent();

         intent.setData(uri);
         intent.putExtra(LiveFolders.EXTRA_LIVE_FOLDER_NAME, name);
         intent.putExtra(LiveFolders.EXTRA_LIVE_FOLDER_ICON,
                 Intent.ShortcutIconResource.fromContext(context, icon));
         intent.putExtra(LiveFolders.EXTRA_LIVE_FOLDER_DISPLAY_MODE, LiveFolders.DISPLAY_MODE_LIST);

         return intent;
     }
 }
 

The live folder is described by an Intent as follows:

Setting up the content provider

The live folder's content provider must, upon query, return a Cursor whose columns match the following names:

Summary

[Expand] Inherited Constants
From interface android.provider.BaseColumns String _COUNT The count of rows in a directory. String _ID The unique ID for a row.

[Expand] Inherited Methods

From class java.lang.Object Object clone() Creates and returns a copy of this Object. boolean equals(Object o) Compares this instance with the specified object and indicates if they are equal. void finalize() Called before the object's memory is reclaimed by the VM. final Class<? extends Object> getClass() Returns the unique instance of Class that represents this object's class. int hashCode() Returns an integer hash code for this object. final void notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up. final void notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up. String toString() Returns a string containing a concise, human-readable description of this object. final void wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object. final void wait(long millis, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires. final void wait(long millis) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.