Question

I am working for the first time with ListFragments. I want to display data from a sqlite database.

My problem: I can’t retrieve the context.

I have tried this.getActivity() in my class which extends ListFragment- but the context is null.

Then I have tried to save the context of my first activity(the ui which is displayed after starting the app) of my application as a static variable. But is this the right context?

static Context context; 

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        //Setting the context
        context = this; 

        setContentView(R.layout.main);
    }

    public static Context getContext() {
        return context;
    } 

When I query the database I don’t get any exceptions but the cursor is always empty. I have looked into my sqlite database – I have three rows of data (so the cursor should not be empty).

My code for querying the data from the database:

Cursor cursor = null;
        try{
            open();
            cursor = database.rawQuery("select _id, surname, prename, street, zipcode, telephone, email from "+Database.getMyDbTable()+";", null);
        }catch(Exception ex){
            Log.e(TAG, "Could not get list");
            CharSequence text = "Die Liste kann nicht erstellt werden!";
            Toast toast = Toast.makeText(context, text, duration);
            toast.show();
        }
        Log.d(TAG, "Cursor "+cursor); 
        close(); 

How do I get the right context?

Answer 1

I found this tutorial, which was quite helpful (as I wanted to have a Tab Layout combined with a list):

https://github.com/artem-zinnatullin/Android-List-Fragment-Tutorial

I have modified the onCreate method:

@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);


        //Getting the data from the Database
        Context myContext = getActivity();           
        Log.d(TAG, "Context "+myContext);

        contactListManager = new ContactList(myContext);
        Log.d(TAG, "ContactListManager "+contactListManager);

        Cursor cursor =  contactListManager.fetchAllItems();
        Log.d(TAG, "Cursor "+cursor);

with this code I can access my database.