Android開發——數據存儲之ContentProvider(2)

2、創建自定義ContentProvider 創建內容供應器，需要繼承ContentProvider   示例代碼三：

   1:  

   2: /**

   3:  * 內容提供者

   4:  * @author 張漢國

   5:  */

   6: public class TodoListProvider extends ContentProvider {

   7:  

   8:     private static final String TAG = TodoListProvider.class.getSimpleName();

   9:  

  10:     //數據庫名

  11:     private static final String DATABASE_NAME = "todolist.db";

  12:     //版本

  13:     private static final int DATABASE_VERSION = 1;

  14:     //表名

  15:     private static final String TABLE_NAME = "todos";

  16:     //屬性表

  17:     private static HashMap<String, String> sTodosProjectionMap;

  18:  

  19:     private static final int TODOS = 1;

  20:     private static final int TODO_ID = 2;

  21:  

  22:     //uri匹配器

  23:     private static final UriMatcher uriMatcher;

  24:  

  25:     private DataBaseHelper dataBaseHelper;

  26:  

  27:     static {

  28:         //數據初始化

  29:         uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);

  30:         uriMatcher.addURI(TodoList.AUTHORITY, "todos", TODOS);

  31:         uriMatcher.addURI(TodoList.AUTHORITY, "todos/#", TODO_ID);

  32:  

  33:         sTodosProjectionMap = new HashMap<String, String>();

  34:         sTodosProjectionMap.put(Todo._ID, Todo._ID);

  35:         sTodosProjectionMap.put(Todo.TITLE, Todo.TITLE);

  36:         sTodosProjectionMap.put(Todo.CONTENT, Todo.CONTENT);

  37:         sTodosProjectionMap.put(Todo.CREATED_DATE, Todo.CREATED_DATE);

  38:         sTodosProjectionMap.put(Todo.MODIFIED_DATE, Todo.MODIFIED_DATE);

  39:     }

  40:  

  41:     private static class DataBaseHelper extends SQLiteOpenHelper {

  42:  

  43:         public DataBaseHelper(Context context) {

  44:             super(context, DATABASE_NAME, null, DATABASE_VERSION);

  45:         }

  46:  

  47:         //創建表

  48:         @Override

  49:         public void onCreate(SQLiteDatabase db) {

  50:             Log.d(TAG, "create table :"   TABLE_NAME);

  51:             db.execSQL("CREATE TABLE IF NOT EXISTS "   TABLE_NAME   "("   Todo._ID   " INTEGER PRIMARY KEY,"   Todo.TITLE

  52:                       " TEXT,"   Todo.CONTENT   " TEXT,"   Todo.CREATED_DATE   " INTEGER,"   Todo.MODIFIED_DATE

  53:                       " INTEGER)");

  54:             ContentValues values = new ContentValues();

  55:             values.put(Todo.TITLE, "test");

  56:             values.put(Todo.CONTENT, "dddddddd");

  57:             db.insert(TABLE_NAME, "title", values);

  58:         }

  59:  

  60:         //更新數據庫表

  61:         @Override

  62:         public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

  63:             Log.w(TAG, "Upgrading database from version "   oldVersion   " to "   newVersion

  64:                       ", which will destroy all old data");

  65:             db.execSQL("DROP TABLE IF EXISTS "   TABLE_NAME);

  66:             onCreate(db);

  67:         }

  68:  

  69:     }

  70:  

  71:     //刪除數據操作

  72:     @Override

  73:     public int delete(Uri uri, String selection, String[] selectionArgs) {

  74:         SQLiteDatabase db = dataBaseHelper.getWritableDatabase();

  75:         int count = 0;

  76:         //判斷uri類型

  77:         switch (uriMatcher.match(uri)) {

  78:         case TODOS:

  79:             //如果以"/todo"結尾，則刪除整個表數據

  80:             count = db.delete(TABLE_NAME, selection, selectionArgs);

  81:             break;

  82:         case TODO_ID:

  83:             //如果以“/todo/1”結尾，則刪除ID=1的數據

  84:             String todoId = uri.getPathSegments().get(1);

  85:             count = db.delete(TABLE_NAME, Todo._ID   "="   todoId

  86:                       ((TextUtils.isEmpty(selection)) ? "" : " AND "   selection), selectionArgs);

  87:             break;

  88:         default:

  89:             throw new IllegalArgumentException("Unknown URI :"   uri);

  90:         }

  91:         getContext().getContentResolver().notifyChange(uri, null);

  92:         return count;

  93:     }

  94:     ......

  95:     ......

  96:     //其他方法省略

至此我們就創建了一個ContentProvider了

3、Provider的配置，在AndroidMainfest.xml配置

示例代碼三：

   1: <?xml version="1.0" encoding="utf-8"?>

   2: <manifest xmlns:android="http://schemas.android.com/apk/res/android"

   3:     package="com.halzhang.android.provider" android:versionCode="1"

   4:     android:versionName="1.0">

   5:     <application android:icon="@drawable/icon" android:label="@string/app_name">

   6:         <!-- 

   7:     name屬性為繼承ContentProvider的類

   8:     authorities屬性為屬性對象路徑

   9:      -->

  10:         <provider android:name=".TodoListProvider"

  11:             android:authorities="com.halzhang.android.provider.TodoList"></provider>

  12:         <activity android:name=".ContentProviderDemo" android:label="@string/app_name">

 

OK，至此我們就創建了一個ContentProvider了。

轉自：http://www.cnblogs.com/halzhang/archive/2010/05/28/1746589.html