「沒有這樣的表錯誤」當試圖顯示SQLite數據庫

Question

我想在一個活動中顯示我的SQlite數據庫，它告訴我有沒有這樣的表：sfdnull。我知道表存在，因爲我可以在我的DDMS上看到它。我的代碼位於我的dbhelper類和我的viewswimmerprofile類的下方，用於顯示錶「sfd」。我希望有人提出一些建議！

public class dbhelper extends SQLiteOpenHelper { 

    public static final String DATABASE_NAME = "swimmers"; 
    public static final String TABLE_SWIMMERS = "sfd"; 

    public static final String C_ID = "id"; 
    public static final String NAME = "name"; 
    public static final String TEAM = "team"; 
    public static final String NOTES = "notes"; 

    public static final int VERSION = 1; 

    public dbhelper(Context context) 
    { 
     super(context, DATABASE_NAME, null, VERSION); 
    } 

    @Override 
    public void onCreate (SQLiteDatabase db) 
    { 
     String createdb = "create table " + TABLE_SWIMMERS + "(" 
       + C_ID + " integer primary key autoincrement, " 
       + NAME + " text, " 
       + TEAM + " text, " 
       + NOTES + " text); "; 

     db.execSQL(createdb); 
    } 

    @Override 
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) 
    { 
     db.execSQL("drop table " + TABLE_SWIMMERS); 
     onCreate(db); 
    } 

    //add new entry 
    void addSwimmer(Swimmer swimmer){ 

     SQLiteDatabase db = this.getWritableDatabase(); 
     ContentValues values = new ContentValues(); 

     values.put(NAME, swimmer.getname()); 
     values.put(TEAM, swimmer.getteam()); 
     values.put(NOTES, swimmer.getnotes()); 

     db.insert(TABLE_SWIMMERS, null, values); 
     db.close(); 
    } 

    //Getting single swimmer 
    Swimmer getSwimmer(int id){ 
     SQLiteDatabase db = this.getReadableDatabase(); 

     Cursor cursor = db.query(TABLE_SWIMMERS, new String[] { C_ID, NAME, TEAM, NOTES}, C_ID + "=?", 
       new String[] { String.valueOf(id) }, null, null, null, null); 
     if (cursor !=null) 
      cursor.moveToFirst(); 

     Swimmer swimmer = new Swimmer (Integer.parseInt(cursor.getString(0)), 
       cursor.getString(1), cursor.getString(2), null); 
     return swimmer; 
    } 

    public int updateSwimmer(Swimmer swimmer){ 
     SQLiteDatabase db = this.getWritableDatabase(); 
     ContentValues values = new ContentValues(); 

     values.put(NAME, swimmer.getname()); 
     values.put(TEAM, swimmer.getteam()); 
     values.put(NOTES, swimmer.getnotes()); 

     return db.update(TABLE_SWIMMERS, values, C_ID + " = ?", new String[] { String.valueOf(swimmer.getID()) });   
    } 

    //delete single contact 
    public void deleteSwimmer(Swimmer swimmer){ 
     SQLiteDatabase db = this.getWritableDatabase(); 
     db.delete(TABLE_SWIMMERS, C_ID + " = ?", new String[] { String.valueOf(swimmer.getID()) });   
     db.close(); 
    } 

    //get contacts count 
    public int getSwimmersCount(){ 
     String countQuery = "SELECT * FROM " + TABLE_SWIMMERS; 
     SQLiteDatabase db = this.getReadableDatabase(); 
     Cursor cursor = db.rawQuery(countQuery, null); 
     cursor.close(); 
     return cursor.getCount(); 
    } 

    public List<Swimmer> getAllSwimmers() { 
     List<Swimmer> swimmerList = new ArrayList<Swimmer>(); 
     // Select All Query 
     String selectQuery = "SELECT * FROM " + TABLE_SWIMMERS; 

     SQLiteDatabase db = this.getWritableDatabase(); 
     Cursor cursor = db.rawQuery(selectQuery, null); 

     // looping through all rows and adding to list 
     if (cursor.moveToFirst()) { 
      do { 
       Swimmer swimmer = new Swimmer(); 
       swimmer.setID(Integer.parseInt(cursor.getString(0))); 
       swimmer.setname(cursor.getString(1)); 
       swimmer.setnotes(cursor.getString(2)); 
       // Adding swimmer to list 
       swimmerList.add(swimmer); 
      } while (cursor.moveToNext()); 
     } 

     // return swimmer list 
     return swimmerList; 
    } 

} 

public class ViewSwimmerProfile extends ListActivity { 

private ArrayList<String> results = new ArrayList<String>(); 
private String TABLE_SWIMMERS = dbhelper.TABLE_SWIMMERS; 
private SQLiteDatabase newDB; 

@Override 
public boolean onCreateOptionsMenu(Menu menu) 
{  
     getMenuInflater().inflate(R.menu.activity_sfdmain, menu); 
     return true; 
    } 

@Override 
public void onCreate (Bundle savedInstanceState){ 
    super.onCreate(savedInstanceState); 
    Log.i("viewProfileActivity", "Intent Text"); 
    setContentView(R.layout.viewprofile); 
    openAndQueryDatabase(); 
    displayResultList(); 
} 

    private void displayResultList() { 

       setListAdapter(new ArrayAdapter<String>(this, 
         android.R.layout.simple_list_item_1, results)); 
       getListView().setTextFilterEnabled(true); 
     } 

    private void openAndQueryDatabase() { 
      try { 
      dbhelper dbHelper = new dbhelper(this.getApplicationContext()); 
      newDB = dbHelper.getWritableDatabase(); 
      Cursor c = newDB.rawQuery("SELECT NAME, TEAM FROM " + 
       TABLE_SWIMMERS + 
       null, null); 

       if (c != null) { 
       if (c.moveToFirst()) { 
       do { 
       String NAME = c.getString(c.getColumnIndex("NAME")); 
       String TEAM = c.getString(c.getColumnIndex("TEAM")); 
       results.add("NAME: " + NAME + ",TEAM: " + TEAM); 
       }while (c.moveToNext()); 
       } 
       } 
      } catch (SQLiteException se) { 
       Log.e(getClass().getSimpleName(), "Could not create or Open the database"); 
       } finally { 
       if (newDB != null) 
        newDB.execSQL("DELETE FROM " + TABLE_SWIMMERS); 
        newDB.close(); 
       } 

     } 
} 

謝謝！

Answer 1

錯誤消息告訴您它試圖從表sfdnull而不是sfd讀取。

這可能是從這個代碼，在那裏你追加一個null表名：

Cursor c = newDB.rawQuery("SELECT NAME, TEAM FROM " + 
    TABLE_SWIMMERS + 
    null, null);