CODEWITHSUNDEEP
androidxamarin.forms
David Shochet
David Shochet

Reputation: 5375

NullReferenceException on App.Current.MainPage

I have a Xamarin.Forms app that uses push notifications. For some reason, the following line:

(App.Current.MainPage as MainPage)?.AddMessage(body);

that is called from Android native OnMessageReceived(), throws NullReferenceException.

Why can this happen? Isn't App.Current to be accessible from the platform-specific project?

Edit:

Here is the full OnMessageReceived() code:

    public override void OnMessageReceived(RemoteMessage message)
    {
        base.OnMessageReceived(message);
        string messageBody;

        if (message.GetNotification() != null)
        {
            messageBody = message.GetNotification().Body;
        }

        // NOTE: test messages sent via the Azure portal will be received here
        else
        {
            messageBody = message.Data.Values.First();
        }

        // convert the incoming message to a local notification
        SendLocalNotification(messageBody);

        // send the incoming message directly to the MainPage
        SendMessageToMainPage(messageBody);
    }

Upvotes: 1

Views: 267

Answers (1)

Ivan I
Ivan I

Reputation: 9990

App.Current.MainPage may contain any Page, not necessary your type MainPage, for example it could be NavigationPage. As the result of casting is null it is clear that it is of some other type.

Also it could happen that nothing is assigned to it.

Upvotes: 2

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