Can't input text in Entry on iOS

Hello!
I use Xamarin.Forms, i have added in project basic and simple element Entry:

sview.Content = Content = new StackLayout
{
    Orientation = StackOrientation.Vertical,
    Children = {
        new Entry { Placeholder = "Username" , TextColor = Color.Black},
        new Entry { Placeholder = "Password", IsPassword = true , TextColor = Color.Black }
    }
};

And in Android Project Entry is active - i can print text, but in iOS Project i see element but I can't input text.

Help me please.
Thank you.