使用editText和simpleCursorAdapter过滤listview

Question

我正在尝试过滤listView中的项目，但它无法正常工作。似乎我的代码没有响应我的editText中输入的文本。

这是我的SearchActivity类（MainActivity）

public class SearchActivity extends Activity {

    private DatabaseHelper myDatabaseHelper;

      /* Called when the activity is first created. */
      @Override
      public void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.search_layout);
          ListView listContent = (ListView)findViewById(R.id.contentlist);
          myDatabaseHelper = new DatabaseHelper(this);

          try {
            myDatabaseHelper.createDataBase();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
          myDatabaseHelper.openDataBase();
          Cursor cursor = myDatabaseHelper.queueAll();
          startManagingCursor(cursor);

          String[] from = new String[]{DatabaseHelper.KEY_CONTENT};
          int[] to = new int[]{R.id.text1};
          final SimpleCursorAdapter cursorAdapter =
           new SimpleCursorAdapter(this, R.layout.row, cursor, from, to);

          listContent.setAdapter(cursorAdapter);
          listContent.setFastScrollEnabled(true);
          listContent.setTextFilterEnabled(true);

          EditText etext=(EditText)findViewById(R.id.editText1);
          etext.addTextChangedListener(new TextWatcher() {
              public void onTextChanged(CharSequence s, int start, int before, int count) {
              }

              public void beforeTextChanged(CharSequence s, int start, int count, int after) {
              }

              public void afterTextChanged(Editable s) {
                  ListView listContent2 = (ListView)findViewById(R.id.contentlist);
                  SimpleCursorAdapter filterAdapter = (SimpleCursorAdapter)listContent2.getAdapter();
                  filterAdapter.getFilter().filter(s.toString());
              }
          });

          cursorAdapter.setFilterQueryProvider(new FilterQueryProvider() {
              public Cursor runQuery(CharSequence constraint) {
                  return myDatabaseHelper.getDirectoryList(constraint);
              }
          });

          myDatabaseHelper.close();

这是我的getDirectoryList

public Cursor getDirectoryList (CharSequence constraint)  {
    SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
    queryBuilder.setTables(DB_NAME);

    String[] columns = new String[]{KEY_ID, KEY_CONTENT, KEY_DESCRIPTION, KEY_NETWORKING, KEY_HARDWARE, KEY_SOFTWARE, KEY_INTERNET, KEY_TECHNOLOGY};

    if (constraint == null  ||  constraint.length () == 0)  {
        //  Return the full list
            Cursor cursor = myDataBase.query("MY_TABLE", 
             columns, null, null, null, null, null);
            return cursor;
    }  else  {
            String value = constraint.toString()+"%";
            Cursor cursor2 = myDataBase.query("MY_TABLE", columns, "KEY_CONTENT like ?", new String[]{value}, null, null, null);
            return cursor2;
        }
    }
}