Getting NullPointerException while reading Sqlite database

Question

I have to read values from SQLite database but getting NullPointerException when I execute

   private final String DB_NAME = "UserDb";
   private final String TABLE_NAMES = "tbluser"; 
   SQLiteDatabase sampleDB;
   Cursor c=null;
   String deviceDec;  
   c= sampleDB.rawQuery("SELECT * from " +TABLE_NAMES+" where did='"+deviceDec+"' ",null);

Please suggest me why I am getting the exception because in one function it is running but in other it is not and also I am getting the deviceDec value that I have checked in Log.

this is how i am creating the database sampleDB.execSQL("CREATE TABLE IF NOT EXISTS " +TABLE_NAME + " (id INTEGER PRIMARY KEY, did TEXT, idate DATE, edate DATE)"); sampleDB.execSQL("INSERT INTO " +TABLE_NAME +"(did,idate,edate) Values ('"+IMEI+"','"+fDate+"','"+feDate+"');"); — CodingDecoding
– CodingDecoding, Commented Oct 31, 2012 at 5:07
but the problem is In the activity where i am creating the database is working file but in other activity i have to just read the database there it is throwing null pointer exception — CodingDecoding
– CodingDecoding, Commented Oct 31, 2012 at 5:09

Niranj Patel · Accepted Answer · 2012-10-31 05:00:06Z

1

May be your sampleDB; is null.

so first you have init that object like as

SQLiteDatabase sampleDB = new SQLiteDatabase(Your Param);

answered Oct 31, 2012 at 5:00

Niranj Patel

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Kalpesh Lakhani · Accepted Answer · 2012-10-31 05:12:55Z

1

you need to initiate DB..

SQLiteDatabase sampleDB=context.getReadableDatabase();

answered Oct 31, 2012 at 5:12

Kalpesh Lakhani

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Sanket Kachhela · Accepted Answer · 2012-10-31 05:30:19Z

1

open database before selecting data from it.

public SQLiteDatabase openDataBase() throws SQLException {
    String myPath = DB_PATH + DB_NAME;
    myDataBase = SQLiteDatabase.openDatabase(myPath, null,
            SQLiteDatabase.OPEN_READWRITE);

    return myDataBase;
}

this will return dataabase.. and then use returnedDb.rawQuery("");

answered Oct 31, 2012 at 5:30

Sanket Kachhela

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