Running database query in FragmentStatePagerAdapter NPE

I am trying to run a query against my database to get some data (which changes page to page) from my database. I am getting a NullPointerException at `Double balance = db.getSum();` Below is the full code of my fragmentstatepageradapter ``` import android.content.Context; import android.os.Bundle; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentManager; import android.support.v4.app.FragmentStatePagerAdapter; public class MyFragmentPagerAdapter extends FragmentStatePagerAdapter { int listSize; String[] tabNames; String tabName; protected Context mContext; /** Constructor of the class */ public MyFragmentPagerAdapter(FragmentManager fm, Context c) { super(fm); mContext = c; } /** This method will be invoked when a page is requested to create */ @Override public Fragment getItem(int arg0) { MainFragment mainFragment = new MainFragment(); final DatabaseHelper db = new DatabaseHelper(mContext); Double balance = db.getSum(); //NPE here******************* tabName = "[" + getPageTitle(arg0) + "]"; Bundle data = new Bundle(); data.putInt("current_page", arg0 + 1); data.putString("tabName", tabName); mainFragment.setArguments(data); return mainFragment; } /** Returns the number of pages */ @Override public int getCount() { return listSize; } @Override public CharSequence getPageTitle(int position) { return tabNames[position]; } public void setCount(int count){ listSize = count; } public void setNames(String[] names) { tabNames = names; } @Override public int getItemPosition(Object object) { return POSITION_NONE; } } ``` Here is my database getSum() ``` // GET SUM public Double getSum(){ SQLiteDatabase db = this.getReadableDatabase(); Cursor c = db.rawQuery("SELECT SUM(credit), SUM(debit) FROM " + TABLE_DEFAULT_ACCOUNT, null); if(c.moveToFirst()) { sum = (c.getDouble(0) - c.getDouble(1)); } return sum; } ``` And here is the error I am getting ``` 07-09 15:26:52.861 14874-14874/com.rcd.simpleregister D/AndroidRuntime﹕ Shutting down VM 07-09 15:26:52.865 14874-14874/com.rcd.simpleregister E/AndroidRuntime﹕ FATAL EXCEPTION: main Process: com.rcd.simpleregister, PID: 14874 java.lang.NullPointerException: Attempt to invoke virtual method 'android.database.sqlite.SQLiteDatabase android.content.Context.openOrCreateDatabase(java.lang.String, int, android.database.sqlite.SQLiteDatabase$CursorFactory, android.database.DatabaseErrorHandler)' on a null object reference at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:224) at android.database.sqlite.SQLiteOpenHelper.getReadableDatabase(SQLiteOpenHelper.java:188) at com.rcd.simpleregister.DatabaseHelper.getSum(DatabaseHelper.java:90) at com.rcd.simpleregister.MyFragmentPagerAdapter.getItem(MyFragmentPagerAdapter.java:31) at android.support.v4.app.FragmentStatePagerAdapter.instantiateItem(FragmentStatePagerAdapter.java:105) at android.support.v4.view.ViewPager.addNewItem(ViewPager.java:832) at android.support.v4.view.ViewPager.populate(ViewPager.java:982) at android.support.v4.view.ViewPager.populate(ViewPager.java:914) at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1436) at android.view.View.measure(View.java:16537) at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:719) at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:455) at android.view.View.measure(View.java:16537) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5135) at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) at android.view.View.measure(View.java:16537) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5135) at com.android.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:327) at android.view.View.measure(View.java:16537) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5135) at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2291) at android.view.View.measure(View.java:16537) at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1947) at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1137) at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1326) at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1024) at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5796) at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761) at android.view.Choreographer.doCallbacks(Choreographer.java:574) at android.view.Choreographer.doFrame(Choreographer.java:544) at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747) at android.os.Handler.handleCallback(Handler.java:733) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:136) at android.app.ActivityThread.main(ActivityThread.java:5102) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595) ``` Anyone see why I might be getting this? Thanks!