3rd party libraries never seems to be documented enough. It’s the old truth that every software developer learns sooner or later. In most cases after dozens of hours spent on trying to figure out “what the hell is wrong with my/that code!?”. This post is about one of such “hidden features” in Microsoft oData client - Simple.OData.
Standard Xamarin.Forms Xamarin.Forms.Editor control offers edit capabilities similar to Entry but for multiline text. Unfortunately unlike Entry it doesn’t support displaying placeholder text out of the box. Implementing this functionality with custom renderers can be tricky. Let’s see how to do this on Android and iOS.
Most of iPhone and iPad users can easily recognize icon badges - the pattern for application notifications typically presented in app icon or navigation bar. People that got used to this pattern might want to have the same user experience in their Xamarin Forms application. This post describes how to customize the navigation toolbar in iOS to dynamically display such elements.
Adding tap/click handling to Xamarin.Forms Label is fairly easy. You can do it both in XAML or code behind using GesureRecognizers collection like it is described in this recipe. Unfortunately if you plan to use this solution intensively in your app it will add quite a lot of repeatable code for setting up those handlers (especially in XAML)
Microsoft Azure Active Directory Authentication Libraries (ADAL) is a popular set wrapper around Azure Active Directory API distributed in the form of platform and language specific components. It’s especially useful in multi-platform applications that integrate with various AD APIs such as Outlook or Graph API. It not only wraps the oAuth endpoints but automates the entire application flow for retrieving, refreshing and persisting tokens.
All the credits for solution described in this post goes my friend qbus. He saved few hours of my life and my sanity ;-)
ModernHttpClient is a great wrapper around native HTTP clients offered by Xamarin. It wraps NSURLSession on iOS and OkHttp on Android. As it deals pretty well with SSL/TLS stack (especially in uncommon scenarios) it’s often used instead of built-in types. I switched to ModernHttpClient because of weird errors on connections to the preproduction environment in Android.
When you build a multi-platform application in .NET, especially for the mobile, you typically choose between two approaches. One is to code the shared UI layer commonly with Xamarin.Forms (you will still need to have some parts to be placed in platform projects, like custom renderers or providers). The second is to put the entire UI code in platform-specific projects. In this approach you can use the full power of each platform features (like fragments on Android). Both solutions allow for sharing common business logic between all the platforms. On the other hand full implementation of MVVM pattern in the second approach can be tricky and time consuming. The solution is to use 3rd party library; and here comes the MvvmCross. It covers many more areas than the pure MVVM pattern:
Have you ever encountered an error: Error executing task BuildApk: .../bin/packaged_resources does not exist? If so you probably know that solving this issue can be sometimes quite tricky. It may be hard to track when and where the true bug was introduced in the code base. Although some suggestions can be found on the Xamarin Forum the solution usually differ case by case.
As it’s mentioned in MVVMCross documentation Android is quite specific in terms of navigation requirements. The entry point is statically indicated by MainLauncher = true attribute parameter on the activity. On rest of the platforms, specifically on iOS, this can be done dynamically by implementing IMvxAppStart class for registration in MvxApplication.Initialize().