Android Sqlite always null even after calling getWritableDatabase()

Asked Sep 09 '16 at 14:39

Active Sep 09 '16 at 14:53

Viewed 118 times

Good morning stackoverflow lovers :) i wrote my Sqlite class , but there is an error "Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.database.sqlite.SQLiteDatabase.execSQL(java.lang.String)' on a null object reference"

I know it is because (db) is null , but i already gave it a value of getWritableDatabase() and here is my code

    public class sqlite extends SQLiteOpenHelper{
    public SQLiteDatabase db;
    public sqlite(Context context , String db_name , int db_version){
    super(context, db_name, null, db_version, null);
    this.db=db();
    }


   public SQLiteDatabase db(){
       if(this.db==null){try{this.db=getWritableDatabase();}catch(Exception e){this.db=getReadableDatabase();}}
       return this.db;
   }

   public void test(table){
        db.execSQL("CREATE TABLE IF NOT EXISTS "+table); ***//ERROR db is null , why????***

}
}

edited Sep 09 '16 at 14:41

asked Sep 09 '16 at 14:39

Sherif Eldeeb

Can you please add the detailed code, the whole class where you create the db? – sumandas Sep 09 '16 at 14:41
the whole code is already attached , any other details do you need? – Sherif Eldeeb Sep 09 '16 at 14:42
Those two nulls you are passing to the super constructor look like a smoking gun to me :) – lance-java Sep 09 '16 at 14:42
if db is null you should create a db and not try to write or read, i think that is the problem – Antonios Tsimourtos Sep 09 '16 at 14:44
http://stackoverflow.com/questions/3037767/create-sqlite-database-in-android – Antonios Tsimourtos Sep 09 '16 at 14:45
@SherifEldeeb I don't see any database created, that is why asking if that is all code? Please read the sql lite tutorials for help. http://www.tutorialspoint.com/android/android_sqlite_database.htm – sumandas Sep 09 '16 at 14:49
From where are you calling the test method? – Gaurav Singla Sep 09 '16 at 14:55
Also, from where are you creating an instance of your `sqlite` class. Show that line. I think trying to use `getWriteableDatabase` before your activity has run its onCreate leads to this type of issue (where `getWriteableDatabase` returns null). – trooper Sep 09 '16 at 14:57
@LanceJava I doubt it. check the API, `null` is the default value for both of those parameters. – trooper Sep 09 '16 at 15:10
I'm tired to say it... EVERY NPE IS THE SAME. – Phantômaxx Sep 09 '16 at 17:02

Android Sqlite always null even after calling getWritableDatabase()

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