android數據庫

Question

我創建了一個帶有3個表格的數據庫。數據庫內容的檢索和顯示爲列表視圖在模擬器中正常工作。但在設備中，列表視圖是空的。 我用過「DBHelper」。爲什麼我無法查看設備中現有數據庫的內容？

public class DatabaseHelper{ 
    private static final String TAG = "DBAdapter";  
public static final String column_1="CategoryName"; 
public static final String row_id="_id"; 
public static final String wordcolumn="word"; 
public static final String row_idword="_id"; 
public static final String row_idfor="CategoryId"; 
private DatabaseHelperDB dDbhelper; 
private SQLiteDatabase dDb; 
private DatabaseAdapter dbAdapt; 
private static final String Database_CreateCat="create table if not exists categorys (_id integer primary key, CategoryName text not null);"; 
private static final String Database_CreateWord="create table if not exists wordss (_id integer primary key autoincrement, " 
    + "CategoryId integer, word text not null, foreign key(CategoryId) references categorys(_id));"; 
private static final String Database_Name="idea_generator_db2_1"; 
private static final String Database_TableCat="categorys"; 
private static final String Database_TableWord="wordss"; 
private final Context dctx; 
private static final int database_version=1; 

public DatabaseHelper(Context ctx) 
{ 
    this.dctx=ctx; 
    dDbhelper=new DatabaseHelperDB(ctx); 
} 
private static class DatabaseAdapter extends SQLiteOpenHelper 
{ 
    DatabaseAdapter(Context context) 
    { 
     super(context,Database_Name,null,database_version); 
    } 
    public void onCreate(SQLiteDatabase db) 
    { 
     try{ 
      db.execSQL(Database_CreateCat); 
      db.execSQL(Database_CreateWord); 
      //db.execSQL(sql) 
     }catch(SQLException e) 
     { 
      e.printStackTrace(); 
     } 
    } 
    public void onUpgrade(SQLiteDatabase db,int oldversion,int newversion) 
    { 
     Log.w(TAG, "Database upgradation from version "+oldversion+" to "+newversion); 
    db.execSQL("DROP TABLE IF EXISTS "+Database_TableCat); 
    db.execSQL("DROP TABLE IF EXISTS "+Database_TableWord); 
    onCreate(db); 
    } 
} 

public DatabaseHelper open()throws SQLException{ 
    dDbhelper= new DatabaseHelperDB(dctx); 
    dDb=dDbhelper.getWritableDatabase();   
    return this; 

} 

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

Answer 1

1）你把數據放在表中嗎？