Hi all,
I'm new to Android, however I am experienced with C# and Java. I have
never had problems opening or communicating with a database until now.
Every time I try to open/create a database using SQLiteOpenHelper's
built-in getReadableDatabase or getWritableDatabase functions my
program crashes with a NullPointerException. Here is the relevant
code:
My SQLiteOpenHelper class:
-------------------------------------------
public class SQLHelper extends SQLiteOpenHelper{
public SQLHelper(Context context, String db_name)
{
super(context, db_name, null, 1);
}
public void onUpgrade(SQLiteDatabase db, int oldVersion, int
newVersion){}
public void onCreate(SQLiteDatabase db){}
public void onOpen(SQLiteDatabase db){}
}
--------------------------------------------
My main Activity class:
----------------------------------------------
public class BlackBook extends Activity{
private SQLHelper dbHelper;
private SQLiteDatabase db;
private ListProvider lp;
private TextView tv;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
tv = (TextView) findViewById(R.id.errorText);
lp = new ListProvider();
tv.setText(lp.Initiate());
}
public class ListProvider extends ContentProvider
{
/* All mandatory, unmodified overrides here.
Cut out for clarity of this discussion. */
public String Initiate()
{
dbHelper = new SQLHelper(getContext(), "LBB_DB.db");
try{
db = dbHelper.getReadableDatabase();
}catch (Exception e)
{return e.toString();}
finally{}
return "Success!";
}
}
----------------------------------------------
As you can see, I create a new ContentProvider class in order to
obtain a Context() to pass to the SQLiteOpenHelper. This is what I saw
in the NotePadProvider example, so please let me know if I've done
this wrong and it is causing this error.
This line does not throw an error:
dbHelper = new SQLHelper(getContext(), "LBB_DB.db");
But the very next line throws a NullPointerException error:
db = dbHelper.getReadableDatabase();
I have tried both getReadable and getWritable with no difference. I've
been pulling my hair out over this one for well over five hours now, I
would greatly appreciate some help pinpointing the source of the error
if possible.
Thanks for reading.
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