将sqlite数据库复制到android会创建空数据库

Question

我正在尝试将现有的sqlite数据库复制到我的Android应用程序，然后从android数据库文件夹中使用它。但在复制数据库后，它会在android data/data//databases文件夹中创建空数据库（而不是具有现有数据的文件夹） 这是我的databasehelper课程。任何人都可以帮助我吗？

public class DatabaseHelper extends SQLiteOpenHelper{


    private Context mycontext;
    private String DB_PATH = "data/data/com.channa.saralawadana/databases/";
    private static String DB_NAME = "english_sinhala.sqlite";
    public SQLiteDatabase myDataBase;

    public DatabaseHelper(Context context) {
        super(context, DB_NAME, null, 1);
        this.mycontext = context;
        boolean dbexist = checkdatabase();
        if (dbexist) {
        } else {
            System.out.println("Database doesn't exist");
            try {
                createDataBase();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

    }

    public void createDataBase() throws IOException {
        boolean dbexist = checkdatabase();
        if (dbexist) {
        } else {
            this.getReadableDatabase();
            try {
                copydatabase();
            } catch (IOException e) {
                throw new Error("Error copying database");
            }
        }
    }

    private boolean checkdatabase() {
        boolean checkdb = false;
        try {
            String myPath = DB_PATH + DB_NAME;
            File dbfile = new File(myPath);
            checkdb = dbfile.exists();
        } catch (SQLiteException e) {
            System.out.println("Database doesn't exist");
        }

        return checkdb;
    }

    private void copydatabase() throws IOException {

        // Open your local db as the input stream
        InputStream myinput = mycontext.getAssets().open(DB_NAME);
        // Path to the just created empty db
        @SuppressWarnings("unused")
        String outfilename = DB_PATH + DB_NAME;

        // Open the empty db as the output stream
        OutputStream myoutput = new FileOutputStream(
                "data/data/com.channa.saralawadana/databases/english_sinhala");

        // 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();

    }

    public void openDataBase() {
        // Open the database
        String mypath = DB_PATH + DB_NAME;
        myDataBase = SQLiteDatabase.openDatabase(mypath, null,
                SQLiteDatabase.OPEN_READWRITE);

    }

    public synchronized void close() {
        myDataBase.close();
        super.close();
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub

    }



}