CODEWITHSUNDEEP
androidsqlitenullpointerexception
Sami
Sami

Reputation: 19

Android Application SQlite Access

Accessing the SQlite DB from activity works fine eg.

    public class MainActivity extends Activity {

     DatabaseHelper db;
     protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        db = new DatabaseHelper(getApplicationContext());

        // Creating tags
        Tag tag1 = new Tag("Shopping");
        Tag tag2 = new Tag("Important");
        Tag tag3 = new Tag("Watchlist");
        Tag tag4 = new Tag("Androidhive");

        // Inserting tags in db
        long tag1_id = db.createTag(tag1);
        long tag2_id = db.createTag(tag2);
        long tag3_id = db.createTag(tag3);
        long tag4_id = db.createTag(tag4);

        Log.d("Tag Count", "Tag Count: " + db.getAllTags().size());
        setContentView(R.layout.activity_main);
                if (savedInstanceState == null) {
            getFragmentManager().beginTransaction()
                    .add(R.id.container, new        PlaceholderFragment()).commit();
        }
    }

but as soon as I take the DB code in Activity and call this in Application Constructor, I get null pointer. eg

public class MainClass extends Application {
// Database Helper
private DatabaseHelper db;
private static final String LOG = MainClass.class.getName();

public MainClass()  {
    Log.d(LOG, "MainClass Init");
    db = new DatabaseHelper(getApplicationContext());

What am I missing ?

Upvotes: 0

Views: 41

Answers (1)

laalto
laalto

Reputation: 152827

Application classes don't need an explicit constructor.

At object instantiation phase when the constructor is called, the Application is not set up as a Context yet. getApplicationContext() won't work.

You can use the Application as a Context only in onCreate() or later.

Upvotes: 3

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