在SQLite數據庫中檢測加載器的更改

Question

我一直在構建一個簡單的便箋應用程序，並已成功SQlite數據庫和加載器來加載列表視圖上的數據。接下來我想要做的是當我添加，更改或刪除數據庫中的備註但不知道如何時，使加載程序自動重新加載。我搜索，但主要是教程是內容提供商，我讀了這個：http://developer.android.com/reference/android/content/AsyncTaskLoader.html#q=addAll 但不是很瞭解，因爲他們使用BroadcastReceiver獲得SD卡上的變化。 我所有的耳朵都有任何建議和感謝提前的任何幫助！

這是我的代碼：WhiteNote.java

public class WhiteNote extends Fragment implements LoaderManager.LoaderCallbacks<ArrayList<NoteItems>> { 
private NoteDatabase note_database; 
private int i=0; 
public Context context; 
public NoteListAdapter noteListAdapter; 
public ListView note_listview_container; 
public SQLiteDatabase note_sqldb; 
public Cursor c; 

@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, 
     Bundle savedInstanceState) { 
    final View rootView = inflater.inflate(R.layout.white_note, container, false); 

    context=getActivity(); 
    note_database = new NoteDatabase(context); 

    final EditText text_ed_1; 
    final EditText text_ed_2; 
    Button button_addNote; 
    Button button_listallNote; 
    Button button_delallNote; 

    text_ed_1 = (EditText)rootView.findViewById(R.id.textedit1); 
    text_ed_2 = (EditText)rootView.findViewById(R.id.textedit2); 
    button_addNote = (Button)rootView.findViewById(R.id.button1); 
    button_listallNote = (Button)rootView.findViewById(R.id.button2); 
    button_delallNote = (Button)rootView.findViewById(R.id.button3); 
    note_listview_container=(ListView)rootView.findViewById(R.id.note_listview); 
    noteListAdapter=new NoteListAdapter(context, new ArrayList<NoteItems>()); 

    note_database.open(); 
    getLoaderManager().initLoader(0, null,WhiteNote.this); 
    note_database.close(); 

    button_addNote.setOnClickListener(new OnClickListener() {  
     @Override 
     public void onClick(View v) { 
      note_database.open(); 

      note_database.createData(text_ed_1.getText().toString(),text_ed_2.getText().toString()); 
      //i++; 
      note_database.close(); 
     } 
    }); 

    button_listallNote.setOnClickListener(new OnClickListener(){ 
     @Override 
     public void onClick(View v) { 
      note_database.open(); 

      note_database.get_NoteListAdapter(); 
      note_listview_container.setAdapter(note_database.dbnoteListAdapter); 

      note_database.close(); 
      //note_list.setText(ds); 
     } 
    }); 

    button_delallNote.setOnClickListener(new OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      note_database.open(); 
      note_database.deleteAllNote(); 
      note_database.close(); 
     } 
    }); 
    return rootView; 
} 

@Override 
public Loader<ArrayList<NoteItems>> onCreateLoader(int id, Bundle args) { 
    return new NoteItemsLoader(context,note_database); 
} 

@Override 
public void onLoadFinished(Loader<ArrayList<NoteItems>> loader, 
         ArrayList<NoteItems> data) { 
    note_listview_container.setAdapter(new NoteListAdapter(context, data)); 
} 

@Override 
public void onLoaderReset(Loader<ArrayList<NoteItems>> loader) { 
    note_listview_container.setAdapter(null); 
} 
} 

class NoteItemsLoader extends AsyncTaskLoader<ArrayList<NoteItems>> { 
    private ArrayList<NoteItems> loader_noteitems= new ArrayList<NoteItems>(); 
    private NoteDatabase loader_db; 

    public NoteItemsLoader(Context context, NoteDatabase db) { 
     super(context); 
     loader_db = db; 
     loader_noteitems=loader_db.get_NoteListArray(loader_noteitems,loader_db); 
    } 

    @Override 
    protected void onStartLoading() { 
     if (loader_noteitems != null) { 
      deliverResult(loader_noteitems); // Use the cache 
     } 
     else 
      forceLoad(); 
    } 

    @Override 
    protected void onStopLoading() { 
     cancelLoad(); 
    } 

    @Override 
    public ArrayList<NoteItems> loadInBackground() {    
     loader_db.open(); 

     ArrayList<NoteItems> note_items = new ArrayList<NoteItems>(); 
     loader_db.get_NoteListArray(note_items,loader_db); 

     loader_db.close(); 
     return note_items; 
    } 

    @Override 
    public void deliverResult(ArrayList<NoteItems> data) { 
     if (isReset()) { 
      if (data != null) { 
       onReleaseResources(data); 
      } 
     } 
     ArrayList<NoteItems> oldNotes = loader_noteitems; 
     loader_noteitems = data; 

     if (isStarted()) { 
      super.deliverResult(data); 
     } 

     if (oldNotes != null) { 
      onReleaseResources(oldNotes); 
     } 
    } 

    @Override 
    protected void onReset() { 
     super.onReset(); 
     onStopLoading(); 
     loader_noteitems = null; 
    } 

    @Override 
    public void onCanceled(ArrayList<NoteItems> data) { 
     super.onCanceled(data); 
     loader_noteitems = null; 
    } 

    protected void onReleaseResources(ArrayList<NoteItems> data) {} 

} 

我NoteDatabase.java

public class NoteDatabase { 
private static final String DATABASE_NAME = "DB_NOTE"; 
private static final int DATABASE_VERSION = 1; 
public static final String TABLE_NOTE = "NOTE"; 
public static final String COLUMN_ID = "_id"; 
public static final String COLUMN_TOPIC = "Topic"; 
public static final String COLUMN_NOTECONTENT = "Content"; 
public static final String COLUMN_NAME = "Name"; 

public NoteListAdapter dbnoteListAdapter; 

private static Context my_context; 
static SQLiteDatabase note_sqldb; 
private OpenHelper noteopenHelper; 

public NoteDatabase(Context c){ 
    NoteDatabase.my_context = c; 
} 

public NoteDatabase open() throws SQLException{ 
    noteopenHelper = new OpenHelper(my_context); 
    note_sqldb = noteopenHelper.getWritableDatabase(); 
    return this; 
} 

public void close(){ 
    noteopenHelper.close(); 
} 

public long createData(String chude_note, String noidung_note) { 
    ContentValues cv = new ContentValues(); 
    cv.put(COLUMN_TOPIC, chude_note); 
    cv.put(COLUMN_NOTECONTENT, noidung_note); 
    cv.put(COLUMN_NAME, "by Black"); 
    return note_sqldb.insert(TABLE_NOTE, null, cv); 
} 

public String getData() { 
    String[] columns = new String[] {COLUMN_ID,COLUMN_TOPIC,COLUMN_NOTECONTENT,COLUMN_NAME}; 
    Cursor c = note_sqldb.query(TABLE_NOTE, columns, null, null, null, null, null); 
    /*if(c==null) 
     Log.v("Cursor", "C is NULL");*/ 
    String result=""; 
    int iRow = c.getColumnIndex(COLUMN_ID); 
    int iTopic = c.getColumnIndex(COLUMN_TOPIC); 
    int iContent = c.getColumnIndex(COLUMN_NOTECONTENT); 
    int iOwner = c.getColumnIndex(COLUMN_NAME); 
    for(c.moveToFirst(); !c.isAfterLast(); c.moveToNext()){  
     result = result +" \n"+ c.getString(iRow) 
       + "\n - Topic: " + c.getString(iTopic) 
       + "\n - Content: " + c.getString(iContent) 
       + "\n - Owner: " + c.getString(iOwner) + "\n"; 
    } 
    c.close(); 
    //Log.v("Result", result); 
    return result; 
} 

public Cursor selectQuery(String query) { 
     Cursor c1 = null; 
     try { 

     if (note_sqldb.isOpen()) { 
      note_sqldb.close(); 

     } 
     note_sqldb = noteopenHelper.getWritableDatabase(); 
     c1 = note_sqldb.rawQuery(query, null); 

     } catch (Exception e) { 

     System.out.println("DATABASE ERROR " + e); 

     } 
     return c1; 

    } 

public void get_NoteListAdapter() { 

    ArrayList<NoteItems> noteList = new ArrayList<NoteItems>(); 
    noteList.clear(); 


    open(); 
    String[] columns = new String[] {NoteDatabase.COLUMN_ID,NoteDatabase.COLUMN_TOPIC,NoteDatabase.COLUMN_NOTECONTENT,NoteDatabase.COLUMN_NAME}; 
    note_sqldb = noteopenHelper.getWritableDatabase(); 
    Cursor c1 = note_sqldb.query(NoteDatabase.TABLE_NOTE, columns, null, null, null, null, null); 
    int iRow = c1.getColumnIndex(NoteDatabase.COLUMN_ID); 
    int iTopic = c1.getColumnIndex(NoteDatabase.COLUMN_TOPIC); 
    int iContent = c1.getColumnIndex(NoteDatabase.COLUMN_NOTECONTENT); 
    int iOwner = c1.getColumnIndex(NoteDatabase.COLUMN_NAME); 
    for(c1.moveToFirst(); !c1.isAfterLast(); c1.moveToNext()){  
     NoteItems one_rowItems = new NoteItems(); 

     one_rowItems.set_rowTopic(c1.getString(iTopic)); 
     one_rowItems.set_rowContent(c1.getString(iContent)); 
     one_rowItems.set_rowOwner(c1.getString(iOwner)); 

     noteList.add(one_rowItems); 
    } 
    c1.close(); 

    close(); 

    dbnoteListAdapter = new NoteListAdapter(my_context, noteList); 

} 

public ArrayList<NoteItems> get_NoteListArray(ArrayList<NoteItems> noteitems_list,NoteDatabase db) { 

     noteitems_list.clear(); 

     db.open(); 
     String[] columns = new String[] {NoteDatabase.COLUMN_ID,NoteDatabase.COLUMN_TOPIC,NoteDatabase.COLUMN_NOTECONTENT,NoteDatabase.COLUMN_NAME}; 
     note_sqldb = noteopenHelper.getWritableDatabase(); 
     Cursor c1 = note_sqldb.query(NoteDatabase.TABLE_NOTE, columns, null, null, null, null, null); 
     int iRow = c1.getColumnIndex(NoteDatabase.COLUMN_ID); 
     int iTopic = c1.getColumnIndex(NoteDatabase.COLUMN_TOPIC); 
     int iContent = c1.getColumnIndex(NoteDatabase.COLUMN_NOTECONTENT); 
     int iOwner = c1.getColumnIndex(NoteDatabase.COLUMN_NAME); 
     for(c1.moveToFirst(); !c1.isAfterLast(); c1.moveToNext()){  
      NoteItems one_rowItems = new NoteItems(); 

      one_rowItems.set_rowTopic(c1.getString(iTopic)); 
      one_rowItems.set_rowContent(c1.getString(iContent)); 
      one_rowItems.set_rowOwner(c1.getString(iOwner)); 

      noteitems_list.add(one_rowItems); 
     } 
     c1.close(); 
     db.close(); 

     return noteitems_list; 

} 

public int deleteNote(String topic) { 
    return note_sqldb.delete(TABLE_NOTE, COLUMN_TOPIC + "='" + topic + "'", null); 
} 

public int deleteAllNote() { 
    return note_sqldb.delete(TABLE_NOTE, null, null); 
} 
} 

Answer 1

我想要做的下一件事就是讓程序的時候，我加入自動重新加載，更改或刪除數據庫中的一個筆記，但不知道如何。

沒有辦法使這種情況自動發生。或者：

• 東西告訴改變了數據加載器，所以它知道重裝，或者

• 的Loader是做「添加，更改的情況，或者在數據庫中刪除便箋「

我去了後一種方法與my CWAC-LoaderEx project及其SQLiteCursorLoader。