How to change backGround color in Xamarin forms NavigationPage
Just set the BarBackgroundColor property of the NavigationPage instance:
new NavigationPage(new LoginPage()) { BarBackgroundColor = Color.Green };
If you want to setup a global style in xaml, you could something similar to this:
<?xml version="1.0" encoding="utf-8" ?>
<Application xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="Sample.App">
<Application.Resources>
<ResourceDictionary>
<Style TargetType="NavigationPage">
<Setter Property="BarBackgroundColor" Value="#ff5733"/>
<Setter Property="BarTextColor" Value="White"/>
</Style>
</ResourceDictionary>
</Application.Resources>
</Application>