Question

我遇到sqlite open helper的问题我收到此错误：

sqlite3_open_v2（“/ data / data / lam.ztl.lamztlbologna / databases / ztlBolo.db”，＆amp; handle，2，NULL）失败无法打开数据库。关闭它。 android.database.sqlite.SQLiteCantOpenDatabaseException：无法打开数据库文件我不明白为什么会收到这个错误。

My Open助手类是：

enter code here



public class DBHelper extends SQLiteOpenHelper {
    private final static String DATABASE_NAME = "ztlBolo.db";
    static SQLiteDatabase db;
    //private  static String DB_PATH = "/data/data/lam.ztl.lamztlbologna/databases/";
    static Context context;
    private  static String DB_PATH = "/data/data/"+context.getPackageName()+"/databases/";



    private final static String TABLE_NAME = "manageZtlStreet";
    private final static String SQL_PATH = "databaseZtlBolo.sql";
    MapsActivity ma = new MapsActivity();
    Double LATITUDE= 0.0;
    Double LONGITUDE = 0.0;
    private final Context myContext;
    private final String CREATE_TABLE_ZTL_STREET = "CREATE TABLE manageZtlstreet ("
            + " via text not null,"
            +"latitude DOUBLE," 
            + "longitude DOUBLE);";

    public DBHelper(Context context,int version) {

        super(context, DBHelper.DATABASE_NAME,null,1);
        this.myContext = context;
    }

    @Override
    public void onCreate(SQLiteDatabase database) {
        //  database.openOrCreateDatabase(database.getPath(), null);
        database=SQLiteDatabase.openDatabase(database.getPath(), null, SQLiteDatabase.NO_LOCALIZED_COLLATORS|SQLiteDatabase.OPEN_READWRITE|SQLiteDatabase.CREATE_IF_NECESSARY);
        database.execSQL(this.CREATE_TABLE_ZTL_STREET);

        //DB_PATH = db.getPath();
        try {

            copyDataBase(database);
            Log.e("copy","copy");

        } catch (IOException e) {

            throw new Error("Error copying database");

        }
        database.close();
    }






    /**
     * Copies your database from your local assets-folder to the just created empty database in the
     * system folder, from where it can be accessed and handled.
     * This is done by transfering bytestream.
     * */
    private void copyDataBase(SQLiteDatabase db) throws IOException{


        //Open your local db as the input stream
        InputStream myInput = myContext.getAssets().open(SQL_PATH);
        /*leggo il file*/
        BufferedReader buffread =  new BufferedReader(new InputStreamReader(myInput));
        String line = null;

        while((line = buffread.readLine()) != null) {

            //Log.e("line",""+line);
            //db.execSQL(line);!
            if(!line.equals(new String(""))){
                db.execSQL(line);
            }
        }

        myInput.close();
    }

        public void openDataBase() throws SQLException{
        SQLiteDatabase myDataBase = null;
        String myPath = DATABASE_NAME;
        myDataBase = SQLiteDatabase.openDatabase( DB_PATH+DATABASE_NAME, null, SQLiteDatabase.OPEN_READWRITE);
        Log.e("path",""+myDataBase);

    }

    @Override
    public synchronized void close() {

        /*  if(myDataBase != null)
            myDataBase.close();
         */
        super.close();

    }


    @Override
    public void onUpgrade(SQLiteDatabase database, int oldVersion, int newVersion) {
        database.execSQL("DROP TABLE IF EXISTS manageZtlStreet;");
        //database.close();
        this.onCreate(database);
    }


    public Cursor getZtlStreet(){
        String query = "select latitude ,longitude from manageZtlstreet";

        SQLiteDatabase rdb = getWritableDatabase();
        /** Cursor cursor=rdb.rawQuery(query,null);
        rdb.close();
        return cursor;*/return null;
    }

Answer 1

您不应直接使用文件ztlBolo.db。

糟糕的主意：private static String DB_PATH = "/data/data/"+context.getPackageName()+"/databases/";

我的实施：

public class UtilDB {

private static final String DATABASE_NAME = "cool_db.db";
private static final int DATABASE_VERSION = 1;

private final String SQL_CREATE_MY_COOL_TABLE = "CREATE  TABLE `cool_table` ...";


private SQLiteDatabase mDB = null;
private MyDBHelper mDBHelper = null;
private static UtilDB mInstance = null;

//Using pattern singleton
public static UtilDB getInstance(Context context) {
    if (mInstance == null) {
        mInstance = new UtilDB(context);
    }

    mInstance.open();

    return mInstance;
}

private UtilDB(Context context) {       
    mDBHelper = new MyDBHelper (context, DATABASE_NAME, null, DATABASE_VERSION);
}

private void open() throws SQLException {
    //If connection to db is not open then will open connection
    if ((mDB == null) || (!mDB.isOpen())) {
        mDB = mDBHelper.getWritableDatabase();
    }
}

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


private class MyDBHelper extends SQLiteOpenHelper {

    public MyDBHelper (Context context, String name, CursorFactory factory, int version) {
        super(context, name, factory, version);
    }

    @Override
    public void onCreate(SQLiteDatabase _db) {
        _db.execSQL(SQL_CREATE_MY_COOL_TABLE );
    }

    @Override
    public void onUpgrade(SQLiteDatabase _db, int oldVersion, int newVersion) {
        _db.execSQL("DROP TABLE IF EXISTS \"cool_table\"");

        onCreate(_db);
    }
}

}

SQLite没有在android中打开数据库

1 个答案: