Content Provider in Android (Part 1)

 Today, I will introduce about Content Provider in Android.

What's is Content Provider?

- Content Provider store and retrieve data. Content Provider will make data accessible to all applications. This is unique way to share data across applications.
- Android provide a number of Content Provider for common data types (audio, video, images, bookmarks, contact,...). Query these providers for the data contained. (although, for some, must acquire the proper permission to read/write data).

There're 2 ways to make data public:

- Create your own Content Provider.
- Add your data to existing Content Provider.

Example 1: Displays Bookmark of System Browser.

- Permission is required to access Browser Content. Declare 2 below lines in AndroidManifest.xml file:

<uses-permission android:name="com.android.browser.permission.READ_HISTORY_BOOKMARKS">
<uses-permission android:name="com.android.broswer.permission.WRITE_HISTORY_BOOKMARKS"> 

 - Retrieve data and display them in List view. Create a ListActivity:

package com.jbohn.contentprovider;

import android.app.ListActivity;
import android.database.Cursor;
import android.os.Bundle;
import android.provider.Browser;
import android.widget.SimpleCursorAdapter;

public class ContentProviderBrowserActivity extends ListActivity
{

 @Override
 public void onCreate( Bundle savedInstanceState )
 {
  super.onCreate( savedInstanceState );
  setContentView( R.layout.activitybrowser );
  
  //Projection for the interesting columns of a Bookmark
  String[] projection = new String[] { Browser.BookmarkColumns._ID,
    Browser.BookmarkColumns.TITLE, Browser.BookmarkColumns.URL };
  
  //Do query to retrieve data(bookmarks) from Browser
  Cursor cursor = managedQuery( android.provider.Browser.BOOKMARKS_URI,
    projection, null, null, null );
  
  //Put data to a List Activity
  String[] displayFields = new String[] { Browser.BookmarkColumns.TITLE,
    Browser.BookmarkColumns.URL };
  int[] displayViews = new int[] { android.R.id.text1, android.R.id.text2 };
    
  setListAdapter( new SimpleCursorAdapter( this,
    android.R.layout.simple_list_item_2, cursor, displayFields,
    displayViews ) );
 }
}

Tobe continue... 

(http://jbohn.blogspot.com)