Android loader-Example

This example shows the complete implementation of a listview in fragment. The listview contains the query results for the address book content provider. It uses a cursorloader to manage queries based on the content provider.

Because this application accesses the user's address book, its list file must contain the read_contacts license.

Public static class cursorloaderlistfragment extends listfragment
Implements onquerytextlistener, loadermanager. loadercallbacks <cursor> {

// This is the adapter being used to display the list's data.
Simplecursoradapter madapter;

// If non-null, this is the current filter the user has provided.
String mcurfilter;

@ Override public void onactivitycreated (bundle savedinstancestate ){
Super. onactivitycreated (savedinstancestate );

// Give some text to display if there is no data. In a real
// Application this wocould come from a resource.
Setemptytext ("No phone numbers ");

// We have a menu item to show in action bar.
Sethasoptionsmenu (true );

// Create an empty adapter we will use to display the loaded data.
Madapter = new simplecursoradapter (getactivity (),
Android. R. layout. simple_list_item_2, null,
New String [] {contacts. display_name, contacts. contact_status },
New int [] {Android. R. Id. text1, Android. R. Id. text2}, 0 );
Setlistadapter (madapter );

// Prepare the loader. either re-connect with an existing one,
// Or start a new one.
Getloadermanager (). initloader (0, null, this );
}

@ Override public void oncreateoptionsmenu (menu, menuinflater Inflater ){
// Place an action bar item for searching.
Menuitem item = menu. Add ("Search ");
Item. seticon (Android. R. drawable. ic_menu_search );
Item. setshowasaction (menuitem. show_as_action_if_room );
Searchview SV = new searchview (getactivity ());
Sv. setonquerytextlistener (this );
Item. setactionview (SV );
}

Public Boolean onquerytextchange (string newtext ){
// Called when the action bar search text has changed. Update
// The search filter, and restart the loader to do a new Query
// With this filter.
Mcurfilter =! Textutils. isempty (newtext )? Newtext: NULL;
Getloadermanager (). restartloader (0, null, this );
Return true;
}

@ Override public Boolean onquerytextsubmit (string query ){
// Don't care about this.
Return true;
}

@ Override public void onlistitemclick (listview L, view V, int position, long ID ){
// Insert desired behavior here.
Log. I ("fragmentcomplexlist", "item clicked:" + id );
}

// These are the contacts rows that we will retrieve.
Static final string [] contacts_summary_projection = new string [] {
Contacts. _ id,
Contacts. display_name,
Contacts. contact_status,
Contacts. contact_presence,
Contacts. photo_id,
Contacts. lookup_key,
};
Public loader <cursor> oncreateloader (int id, bundle ARGs ){
// This is called when a new loader needs to be created. This
// Sample only has one loader, so we don't care about the ID.
// First, pick the base URI to use depending on whether we are
// Currently filtering.
Uri baseuri;
If (mcurfilter! = NULL ){
Baseuri = URI. withappendedpath (contacts. content_filter_uri,
Uri. encode (mcurfilter ));
} Else {
Baseuri = contacts. content_uri;
}

// Now create and return a cursorloader that will take care
// Creating a cursor for the data being displayed.
String select = "(" + contacts. display_name + "notnull) and ("
+ Contacts. has_phone_number + "= 1) and ("
+ Contacts. display_name + "! = ''))";
Return new cursorloader (getactivity (), baseuri,
Contacts_summary_projection, select, null,
Contacts. display_name + "collate localized ASC ");
}

Public void onloadfinished (loader <cursor> loader, cursor data ){
// Swap the new cursor in. (The framework will take care of closing
// Old cursor once we return .)
Madapter. swapcursor (data );
}

Public void onloaderreset (loader <cursor> loader ){
// This is called when the last cursor provided to onloadfinished ()
// Above is about to be closed. We need to make sure we are no
// Longer using it.
Madapter. swapcursor (null );
}