Question

i yet really grasp this whole context thing we found a lot in android programming. so i tried creating a function to drop all my tables, and here’s a my partial code:

public class DBAdapter {
       private static class DbHelper extends SQLiteOpenHelper {
        private boolean databaseCreated = false;
        public DbHelper(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
        }

        public void deleteTables(){
        Log.d("DBAdapter","dlm drop tables pre");
        this.sqlDatabase.execSQL("DROP TABLE IF EXISTS ["+TABLE_TV+"];");
        this.sqlDatabase.execSQL("DROP TABLE IF EXISTS ["+TABLE_CAMERA+"];");
        this.sqlDatabase.execSQL("DROP TABLE IF EXISTS ["+TABLE_GPS+"];");
       }
}
}

and the part where i’m going to call the function deleteTables

public class UpdateDatabase {
     public void updateTable(String table,JSONObject jsonObject){
    DBAdapter db = new DBAdapter(this);
        db.deleteTables();
    }
}

but of course it will return an error, since DBAdapter expects a context. public class UpdateDatabase is not an activity class. Calling DbAdapter db = new DBAdapter(this) from activity class will work just find. So how do I find any fix for this problem?

thanks

Answer 1

You can add a constructor to UpdateDatabase that takes a Context and stores it so that it is available to be used by updateTable. Something like this:

public class UpdateDatabase {
    private final Context mContext;

    public UpdateDatabase(Context context){
        mContext = context;
    }

    public void updateTable(String table,JSONObject jsonObject){
        DBAdapter db = new DBAdapter(mContext);
        db.deleteTables();
    }
}

Now, whenever you do new UpdateDatabase() you will need to do new UpdateDatabase(..context..) instead. If you are doing this from an Activity, then you can do new UpdateDatabase(this).