Dealing with the System UI on iOS in Xamarin.Forms

Dealing with the System UI on iOS in Xamarin.Forms

Having written a few applications with Xamarin.Forms by now, there was always the one part where you have to go platform specific. Over time, this part got easier as the collection of Platform-specifics in the Xamarin.Forms package was growing and growing.

This post will show (my) most used implementations leveraging the comfort of Platform-specifics as well as some other gotchas I collected over time. At the end of this post, you will also find a link to a demo project on my Github.

Large page title

Let’s start on top (literally). With iOS 11, Apple introduced large title’s that go back to small once the user is scrolling the content.

To make your app use this feature, you need two perform two steps. The first step is to tell your NavigationPage instance to prefer large titles. I often do this when creating my apps MainPage in App.xaml.cs:

public App()

    var navigationPage = new Xamarin.Forms.NavigationPage(new MainPage())
        BarBackgroundColor = Color.DarkGreen,
        BarTextColor = Color.White


    MainPage = navigationPage; 

This opens the door to show large titles on all pages that are managed by this NavigationPage instance. Sometimes, however, you need to actively tell the page it should use the large title (mostly happened to me in my base page implementation – never was able to nail it down to a specific point. I just opted in to always explicitly handle it on every page. In the sample application for this post, you will find a switch to toggle and untoggle the large title on the app’s MainPage:

On<iOS>().SetLargeTitleDisplay(_useLargeTitle ? 
LargeTitleDisplayMode.Always : 

You can read more in the documentation.

StatusBar text color

Chances are high that we are customizing the BarBackgroundColor and BarTextColor properties. Of course, it makes absolutely sense that the StatusBar text follows the BarTextColor. Luckily, there is a Platform-specific for that as well:

if (this.Parent is Xamarin.Forms.NavigationPage navigationPage)
    navigationPage.On<iOS>().SetStatusBarTextColorMode(_statusBarTextFollowNavBarTextColor ? 
                             StatusBarTextColorMode.MatchNavigationBarTextLuminosity : 

The documentation ends here. However, I always need to add/change the Info.plist file as well:


Only after adding this value the above-mentioned trick for the StatusBar text works.

On iOS, the NavigationBar has a separator on its bottom. If you want to hide this separator (which always disturbs the view), you can leverage another Platform-specific on your page:

if (this.Parent is Xamarin.Forms.NavigationPage navigationPage)

Home indicator visibility

All iPhones after the iPhone 8 (except the SE 2) do not have the home button. Instead, they have a home indicator on the bottom of the device (at least in app). If you are trying to set the color on it, I have bad news for you: you can’t (read on to learn why).

You can hide the indicator in your app, however. Just use this Platform-specific:


Home indicator background color

Hiding the home indicator is a hard measure. Most users do not even really recognize the indicator if it is incorporated into the app’s UI. To better understand how the home indicator works, I absolutely recommend to read Nathan Gitter’s great post on the topic.

The home indicator is adaptive to its surroundings. Most probably using a matching background color is all it needs to integrate the indicator nicely in your app(s).

Safe area

Thanks to the notch and the home indicator, putting content of our apps got trickier than before. However, Xamarin.Forms has you covered as well. All we have to do is to use the SetUseSafeArea Platform-specific – it will allow us to just use the area where we are not covering any System UI like the StatusBar or the home indicator:



Even though iOS has some specialties when it comes to the System UI, Xamarin.Forms has the most important tools built in to deal with them. I absolutely recommend creating a base page for your applications and set the most common specifics there. You can find the promised demo project here on Github. Like always, I hope this post is helpful for some of you.

Until the next post, happy coding, everyone!

Posted by msicc in Dev Stories, iOS, Xamarin, 2 comments

My experiences with Xamarin.Forms


As I have finished my first iOS app with Xamarin.Forms, I want to share my experience that I made during writing it.

It sounds great. Build the code once, run it on Android, iOS and Windows Phone (8). Xamarin is using the well known PCL to achieve this goal, or a shared asset project.

As I am familiar with the PCL structure, I decided to go with this one. The application I wrote for Telefónica had already their Windows Phone and Android counterpart. My thought was to bring together all three after finishing the iOS app into the Xamarin.Forms project to make it easier to maintain them (that was before it was clear that I would leave, but that’s another story). In the end, I focused on the iOS platform and implementation, leaving the other two out.

It was far easier to start a new iOS app with Xamarin.Forms than in the traditional way. Although there are some XAML gotchas (like Nicolò wrote already on his blog), it is pretty easy to get started with it.

The number one tip I can give you is to wrap everything in a principal Grid and set you ColumnWidth (also if you have only one single Column). This will help you to better position your controls on the page.

One really annoying thing is the missing IntelliSense support when you’re writing your XAML code. What does that mean? It means your will spend a lot of time with trial and error as well as reading the documentation in the beginning.

One thing that is solved in a good way is the access to native functions that are not implemented in the Forms project. Connecting through interfaces and Xamarin’s DependencyService, you can write the implementation you need in the native project and call the function from the Forms PCL. I will cover this in another blog post.

Often, you want/need your app to be designed in a different way (like I had to for Telefónica). Some basic modifications are possible from the XAML part. But the most effective way to achieve this goal for the whole app is to use Custom Renderer. This will be another post’s topic in the coming days.

Overall, Xamarin.Forms is already impressive. But you need to know that you will work with some workarounds when you start. If you are willing to do this, you might be able write a cross platform app in little time.

If you do not want to dig into the documentation or use the techniques I wrote about, Xamarin.Forms might not yet be your starting point for your cross platform app.

One last tip: To make it easier for you, there is the Xamarin.Forms Lab project. This community project has already extended Xamarin.Forms, and is worth a look and a second thought if you truly want to do a cross platform app with Xamarin.

Happy coding, everyone!

Posted by msicc in Dev Stories, Xamarin, 2 comments