26.02.2017 - Externe Sqlite 'Benutzer' Tabelle nicht gefunden, aber DB wurde kopiert. [Android]

Question

Ein großes Hallo an die Stackoverflow Gemeinschaft,

ich zur Zeit auf einem Login-Formular arbeitete in Android Studio und zu versuchen, zu einer externen SQLite DB zu verbinden, aber ich habe ein Problem bin die Begegnung, wo es zu sein scheint keine Tabelle in der kopierten DB. Für eine ausgewählte auf dem Tisch Benutzer, führen in der folgenden erro:

*E/SQLiteLog: (1) no such table: User* 

Auch wenn meine Datenbank kopiert wurde und geöffnet wird:

Database is open 

Kann mir bitte jemand sagen, was ich falsch mache? Ich habe den Code hinzugefügt verwende ich in meiner Databasehelper Klasse:

public class DatabaseHelper extends SQLiteOpenHelper { 

    private Context mycontext; 
    Connection sqliteConnection; 
    // Database Version 
    private static final int DATABASE_VERSION = 1; 

    //Database Path 
    private static String DB_PATH ="/data/data/"+ BuildConfig.APPLICATION_ID+"/databases/"; 


    // Database Name 
    private static final String DATABASE_NAME = "mystockdb.db"; 

    // User table name 
    private static final String TABLE_USER = "User"; 

    // User Table Columns names 
    private static final String COLUMN_USER_ID = "user_id"; 
    private static final String COLUMN_USER_NAME = "name"; 
    private static final String COLUMN_USER_PASSWORD = "user_password"; 

    public SQLiteDatabase myDataBase; 


    public DatabaseHelper(Context context) { 
     super(context, DATABASE_NAME, null, DATABASE_VERSION); 
     this.mycontext=context; 
     boolean dbexist = checkdatabase(); 
     if (dbexist) { 
      System.out.println("Database exists"); 
      opendatabase(); 
     } else { 
      System.out.println("Database doesn't exist"); 
      createdatabase(); 
     } 
    } 
    private void copydatabase() throws IOException { 
     //Open your local db as the input stream 
     InputStream myinput = mycontext.getAssets().open(DATABASE_NAME); 

     // Path to the just created empty db 
     String outfilename = DB_PATH + DATABASE_NAME; 

     //Open the empty db as the output stream 
     OutputStream myoutput = new FileOutputStream(outfilename); 

     // transfer byte to inputfile to outputfile 
     byte[] buffer = new byte[1024]; 
     int length; 
     while ((length = myinput.read(buffer))>0) { 
      myoutput.write(buffer,0,length); 
     } 

     //Close the streams 
     myoutput.flush(); 
     myoutput.close(); 
     myinput.close(); 
    } 

    private boolean checkdatabase() { 

     boolean checkdb = false; 
     try { 
      String myPath = DB_PATH + DATABASE_NAME; 
      File dbfile = new File(myPath); 
      checkdb = dbfile.exists(); 
     } catch(SQLiteException e) { 
      System.out.println("Database doesn't exist"); 
     } 
     return checkdb; 
    } 
    public void opendatabase() throws SQLException { 
     //Open the database 
     String mypath = DB_PATH + DATABASE_NAME; 
     System.out.println(DB_PATH); 
     myDataBase = SQLiteDatabase.openDatabase(mypath, null, SQLiteDatabase.OPEN_READWRITE); 
     if (myDataBase.isOpen()) { 
      System.out.println("Database is open"); 

     } 

    } 

    public void createdatabase() { 
     boolean dbexist = checkdatabase(); 
     if(dbexist) { 
      System.out.println(" Database exists."); 

     } else { 
      this.getReadableDatabase(); 
      try { 
       copydatabase(); 
      } catch(IOException e) { 
       throw new Error("Error copying database"); 
      } 
     } 
    } 


    @Override 
    public void onCreate(SQLiteDatabase db) { 

    } 

    @Override 
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
     if (newVersion >oldVersion){ 
      try{ 
       copydatabase(); 
      }catch (IOException e) { 
       e.printStackTrace(); 
      } 
     } 
    } 

    /** 
    * This method will return if user is in db or not 
    * 
    * @param name 
    * @param password 
    * @return true/false 
    */ 
    public boolean checkUser(String name, String password) { 


     // array of columns to fetch 
     String[] columns = { 
       COLUMN_USER_ID 
     }; 
     opendatabase(); 
     myDataBase = getReadableDatabase(); 
     // selection criteria 
     String selection = COLUMN_USER_NAME + " = ?" + " AND " + COLUMN_USER_PASSWORD + " = ?"; 

     // selection arguments 
     String[] selectionArgs = {name, password}; 

     // query user table with conditions 
     /** 
     * Here query function is used to fetch records from user table this function works like we use sql query. 
     * SQL query equivalent to this query function is 
     * SELECT user_id FROM user WHERE user_email = 'jack@androidtutorialshub.com' AND user_password = 'qwerty'; 
     */ 
     Cursor cursor = myDataBase.query(TABLE_USER, //Table to query 
       columns,     //columns to return 
       selection,     //columns for the WHERE clause 
       selectionArgs,    //The values for the WHERE clause 
       null,      //group the rows 
       null,      //filter by row groups 
       null);      //The sort order 

     int cursorCount = cursor.getCount(); 

     cursor.close(); 
     myDataBase.close(); 
     if (cursorCount > 0) { 
      return true; 
     } 

     return false; 
    } 

}

Answer 1

ich entschieden hat, json zu verwenden, anstatt meine Daten zu speichern, die die Nutzer über WLAN zugreifen.