public class MainActivity extends FragmentActivity implements LoaderManager.LoaderCallbacks<Cursor>{

      private SimpleCursorAdapter dataAdapter;

      @Override

      public void onCreate(Bundle savedInstanceState) {

       super.onCreate(savedInstanceState);

       setContentView(R.layout.activity_main); 

       displayListView();

       Button add = (Button) findViewById(R.id.add);

          add.setOnClickListener(new View.OnClickListener() {

               public void onClick(View v) {

                   ContentValues values = new ContentValues();

                   values.put(SensorsDb.KEY_TYPE, "wld");

                   values.put(SensorsDb.KEY_TITLE, "Basement Water Detector");

                   values.put(SensorsDb.KEY_SERIAL, "");

                   values.put(SensorsDb.KEY_VALUE, "NO WATER");

                    getContentResolver().insert(MyContentProvider.CONTENT_URI,values);

                    displayListView();

               }

              });

      }

      @Override

      protected void onResume() {

       super.onResume();

       //Starts a new or restarts an existing Loader in this manager

       getSupportLoaderManager().restartLoader(, null, MainActivity.this);

      }

      private void displayListView() {

       // The desired columns to be bound

       String[] columns = new String[] {

        SensorsDb.KEY_TITLE,

        SensorsDb.KEY_VALUE

       };

       // the XML defined views which the data will be bound to

       int[] to = new int[] {

         R.id.sensorTitle,

         R.id.sensorState

       };

       // create an adapter from the SimpleCursorAdapter

       dataAdapter = new SimpleCursorAdapter(this, R.layout.custom_row_view, null, columns, to, );

       //Ensures a loader is initialized and active.

       getSupportLoaderManager().initLoader(, null,  this);

       // get reference to the ListView

       ListView listView = (ListView) findViewById(R.id.sensorList);

       // Assign adapter to ListView

       listView.setAdapter(dataAdapter);

       getSupportLoaderManager().restartLoader(, null, MainActivity.this);

      }

      // This is called when a new Loader needs to be created.

      @Override

      public Loader<Cursor> onCreateLoader(int id, Bundle args) {

       String[] projection = {

         SensorsDb.KEY_ROWID,

         SensorsDb.KEY_TYPE,

         SensorsDb.KEY_TITLE,

         SensorsDb.KEY_SERIAL,

         SensorsDb.KEY_VALUE};

       CursorLoader cursorLoader = new CursorLoader(this,

         MyContentProvider.CONTENT_URI, projection, null, null, null);

       return cursorLoader;

      }

      @Override

      public void onLoadFinished(Loader<Cursor> loader, Cursor data) {

             dataAdapter.swapCursor(data);

      }

      @Override

      public void onLoaderReset(Loader<Cursor> loader) {

       dataAdapter.swapCursor(null);

      }

      @Override

      public boolean onCreateOptionsMenu(Menu menu) {

       getMenuInflater().inflate(R.menu.main, menu);

       return true;

      }

     }

有 MyContentProvider 类

public class MyContentProvider extends ContentProvider{

 private MyDatabaseHelper dbHelper;

 private static final int ALL_SENSORS = ;

 private static final int SINGLE_SENSOR = ;

 // authority is the symbolic name of your provider

 // To avoid conflicts with other providers, you should use

 // Internet domain ownership (in reverse) as the basis of your provider authority.

 private static final String AUTHORITY = "com.example.contproctest.contentprovider";

 // create content URIs from the authority by appending path to database table

 public static final Uri CONTENT_URI =

  Uri.parse("content://" + AUTHORITY + "/sensors");

 // a content URI pattern matches content URIs using wildcard characters:

 // *: Matches a string of any valid characters of any length.

    // #: Matches a string of numeric characters of any length.

 private static final UriMatcher uriMatcher;

 static {

  uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);

  uriMatcher.addURI(AUTHORITY, "sensors", ALL_SENSORS);

  uriMatcher.addURI(AUTHORITY, "sensors/#", SINGLE_SENSOR);

 }

 // system calls onCreate() when it starts up the provider.

 @Override

 public boolean onCreate() {

  // get access to the database helper

  dbHelper = new MyDatabaseHelper(getContext());

  return false;

 }

 //Return the MIME type corresponding to a content URI

 @Override

 public String getType(Uri uri) {

  switch (uriMatcher.match(uri)) {

  case ALL_SENSORS:

   return "vnd.android.cursor.dir/vnd.com.example.contproctest.contentprovider.sensors";

  case SINGLE_SENSOR:

   return "vnd.android.cursor.item/vnd.com.example.contproctest.contentprovider.sensors";

  default:

   throw new IllegalArgumentException("Unsupported URI: " + uri);

  }

 }

 // The insert() method adds a new row to the appropriate table, using the values

 // in the ContentValues argument. If a column name is not in the ContentValues argument,

 // you may want to provide a default value for it either in your provider code or in

 // your database schema.

 @Override

 public Uri insert(Uri uri, ContentValues values) {

  SQLiteDatabase db = dbHelper.getWritableDatabase();

  switch (uriMatcher.match(uri)) {

  case ALL_SENSORS:

   //do nothing

   break;

  default:

   throw new IllegalArgumentException("Unsupported URI: " + uri);

  }

  long id = db.insert(SensorsDb.SQLITE_TABLE, null, values);

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

  return Uri.parse(CONTENT_URI + "/" + id);

 }

 // The query() method must return a Cursor object, or if it fails,

 // throw an Exception. If you are using an SQLite database as your data storage,

 // you can simply return the Cursor returned by one of the query() methods of the

 // SQLiteDatabase class. If the query does not match any rows, you should return a

 // Cursor instance whose getCount() method returns 0. You should return null only

 // if an internal error occurred during the query process.

 @Override

 public Cursor query(Uri uri, String[] projection, String selection,

   String[] selectionArgs, String sortOrder) {

  SQLiteDatabase db = dbHelper.getWritableDatabase();

  SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();

  queryBuilder.setTables(SensorsDb.SQLITE_TABLE);

  switch (uriMatcher.match(uri)) {

  case ALL_SENSORS:

   //do nothing

   break;

  case SINGLE_SENSOR:

   String id = uri.getPathSegments().get();

   queryBuilder.appendWhere(SensorsDb.KEY_ROWID + "=" + id);

   break;

  default:

   throw new IllegalArgumentException("Unsupported URI: " + uri);

  }

  Cursor cursor = queryBuilder.query(db, projection, selection,

    selectionArgs, null, null, sortOrder);

  return cursor;

 }

 // The delete() method deletes rows based on the seletion or if an id is

 // provided then it deleted a single row. The methods returns the numbers

 // of records delete from the database. If you choose not to delete the data

 // physically then just update a flag here.

 @Override

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

  SQLiteDatabase db = dbHelper.getWritableDatabase();

  switch (uriMatcher.match(uri)) {

  case ALL_SENSORS:

   //do nothing

   break;

  case SINGLE_SENSOR:

   String id = uri.getPathSegments().get();

   selection = SensorsDb.KEY_ROWID + "=" + id

   + (!TextUtils.isEmpty(selection) ?

     " AND (" + selection + ')' : "");

   break;

  default:

   throw new IllegalArgumentException("Unsupported URI: " + uri);

  }

  int deleteCount = db.delete(SensorsDb.SQLITE_TABLE, selection, selectionArgs);

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

  return deleteCount;

 }

 // The update method() is same as delete() which updates multiple rows

 // based on the selection or a single row if the row id is provided. The

 // update method returns the number of updated rows.

 @Override

 public int update(Uri uri, ContentValues values, String selection,

   String[] selectionArgs) {

  SQLiteDatabase db = dbHelper.getWritableDatabase();

  switch (uriMatcher.match(uri)) {

  case ALL_SENSORS:

   //do nothing

   break;

  case SINGLE_SENSOR:

   String id = uri.getPathSegments().get();

   selection = SensorsDb.KEY_ROWID + "=" + id

   + (!TextUtils.isEmpty(selection) ?

     " AND (" + selection + ')' : "");

   break;

  default:

   throw new IllegalArgumentException("Unsupported URI: " + uri);

  }

  int updateCount = db.update(SensorsDb.SQLITE_TABLE, values, selection, selectionArgs);

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

  return updateCount;

 }

}

解决方法 :

你不需要调用 restartLoader 后在 CP 中插入新的数据，因为 CursorLoader 可以听您的数据和 (ContentProvider) 的数据源中发生更改时自动更新。尝试在调用 cursor.setNotificationUri() 之前返回 Cursor 从你 CP 的查询方法。

@Override

public Cursor query(Uri uri, String[] projection, String selection,

 String[] selectionArgs, String sortOrder) {

  SQLiteDatabase db = dbHelper.getWritableDatabase();

  SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();

  queryBuilder.setTables(SensorsDb.SQLITE_TABLE);

  switch (uriMatcher.match(uri)) {

  case ALL_SENSORS:

   //do nothing

   break;

  case SINGLE_SENSOR:

   String id = uri.getPathSegments().get();

   queryBuilder.appendWhere(SensorsDb.KEY_ROWID + "=" + id);

   break;

  default:

   throw new IllegalArgumentException("Unsupported URI: " + uri);

  }

  Cursor cursor = queryBuilder.query(db, projection, selection,

    selectionArgs, null, null, sortOrder);

  cursor.setNotificationUri(getContext().getContentResolver(), uri);

  return cursor;

}