How to launch app from another app in Windows Phone 8.1 - windows-phone-8.1

Question

I want to launch my app from another app in the Windows Phone 8.1 environment. I followed the instructions in MSDN, but I cannot figure out how to call the first app from the second. This is the protocol I added in the first app's manifest file:
<Extensions>
<Extension Category="windows.protocol">
<Protocol Name="myapp">
<Logo>Assets\SmallLogo.scale-240.png</Logo>
<DisplayName>my App 1</DisplayName>
</Protocol>
</Extension>
</Extensions>
This is my call from the second app, that does absolutely nothing:
private async void btn_Click(object sender, RoutedEventArgs e)
{
await Windows.System.Launcher.LaunchUriAsync(new System.Uri("myapp:"));
}

Answer 1

Follow the steps in Auto-launching apps using file and URI associations for Windows Phone 8
And you have use use a class which is derived from UriMapperBase to handle the navigation and have to set it as RootFrame.UriMapper in the App.xaml.cs
private void InitializePhoneApplication()
{
if (phoneApplicationInitialized)
return;
// Create the frame but don't set it as RootVisual yet; this allows the splash
// screen to remain active until the application is ready to render.
RootFrame = new PhoneApplicationFrame();
RootFrame.Navigated += CompleteInitializePhoneApplication;
// Assign the URI-mapper class to the application frame.
RootFrame.UriMapper = new AssociationUriMapper();
******
}