i dont know how far i am right, but doesn't the context change when u instantiate a new activity object? >myact maobj=new myact(); hence the exception. jus move the code in open() to the line after dbhelper instatiation. it should work fine. there is no need to create a new activity object.
On Wed, Aug 5, 2009 at 5:02 PM, saptarshi chatterjee < [email protected]> wrote: > > Friends, > > In the following code the method "public void open() throws > SQLException " is throwing NullPointeeException. Please help me. > > Thanks & Regards > Saptarshi > > > > package com.outp.inp; > > > import android.app.Activity; > import android.content.Context; > import android.database.Cursor; > import android.database.SQLException; > import android.database.sqlite.SQLiteDatabase; > import android.database.sqlite.SQLiteOpenHelper; > import android.os.Bundle; > import android.util.Log; > import android.widget.Toast; > > > public class myact extends Activity { > > > public static final String KEY_ROWID = "_id"; > public static final String KEY_VEHICLE = "vehicle"; > public static final String KEY_ROUTE = "route"; > public static final String KEY_COUNTRY = "country"; > public static final String KEY_CITY = "city"; > private static final String TAG = "DBAdapter"; > > private static final String DATABASE_NAME = "publicTransport"; > private static final String DATABASE_TABLE = "vehicleTable"; > private static final int DATABASE_VERSION = 1; > > long id; > Cursor c; > > private static final String DATABASE_CREATE = > "create table vehicleTable (_id integer primary key > autoincrement, " > + "vehicle text not null, route text not null, " > + "country text not null,city text not null);"; > > > private final Context context=this; > private DatabaseHelper DBHelper; > private SQLiteDatabase sqlitedatabase; > > > > > > > > > /** Called when the activity is first created. */ > @Override > public void onCreate(Bundle savedInstanceState) { > super.onCreate(savedInstanceState); > setContentView(R.layout.main); > > DBHelper = new DatabaseHelper(context); > myact maobj=new myact(); > try{ > maobj.open();} > catch(Exception e){Toast.makeText(this, "misfunctioning > open"+e.toString(),Toast.LENGTH_LONG).show();} > > > } > > > > private static class DatabaseHelper extends SQLiteOpenHelper > { > DatabaseHelper(Context context) > { > super(context, DATABASE_NAME, null, DATABASE_VERSION); > > } > > > public void onCreate(SQLiteDatabase db) > { > > db.execSQL(DATABASE_CREATE); > > > } > > @Override > public void onUpgrade(SQLiteDatabase db, int oldVersion, > int newVersion) > { > Log.w(TAG, "Upgrading database from version " + > oldVersion > + " to " > + newVersion + ", which will destroy all old data"); > db.execSQL("DROP TABLE IF EXISTS titles"); > onCreate(db); > } > } > > > > > public void open() throws SQLException > { > > sqlitedatabase = DBHelper.getWritableDatabase(); > } > > > } > > > > > > > > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~----------~----~----~----~------~----~------~--~---
