Xamarin Forms MediaElement

Some time ago I created a MediaElement control for Xamarin Forms for displaying video (and audio) content across the main mobile platforms and it’s been steadily improving and has been used in a number of projects.

After some discussions on GitHub I started the process of integrating the control into Xamarin Forms itself with a Pull request opened last week. There will be some API changes in the transition and I’ll be sure to keep the current control available until its fully integrated into a stable Xamarin Forms release.

Things are progressing well with some reviews and code changes, partly to fit the Xamarin coding style and partly having fresh eyes looking at the code pointing out some improvements. I’ve already created a new renderer for WPF which supports the basics (The WPF MediaElement doesn’t have built-in transport controls so this isn’t supported yet). It highlighted something as I was testing on iOS where the video just wouldn’t work. I later remembered that unless you explicitly request it in your info.plist the app will block any http resources. But you’ll not get an error, the video will simply be stuck in the ReadyToPlay state. Switching to an https target fixed the issue immediately. This lead me to create the following table showing supported URI types and how they map on each platform. These apply to both the InTheHand.Forms version and the Xamarin.Forms control although only the latter has WPF support:-

 

Uri Scheme Android iOS UWP WPF
HTTP/HTTPS Yes HTTPS only or set NSAppTransportSecurity in info.plist Yes Yes
file Yes Yes Yes Yes
ms-appx Yes. Items must have the build action AndroidResource and be located in the Resources/raw folder of the project Yes. Items must have the build action BundleResource Yes Maps to pack://application:,,,{localpath}
ms-appdata Yes (Local+Temp) Yes (Local+Temp) Yes (Local, Temp and Roaming) Yes (Local+Temp)

Azure IoT DevKit – External Connectivity

Beyond the sensors built into the board the possibilities are endless when you consider attaching external devices. As I mentioned in my previous post, the DevKit has an edge connector with a number of input/output pins as well as power. You’ll need an “edge connector breakout” like this to make use of them.

I found this excellent post by Jeremy Lindsay which included a table of the pin numbers and how they map to Arduino pin names – you need this so that you can refer to a physical pin on the edge connector breakout to a pin in your Arduino sketch.

From this it’s possible to rig up an LED or similar on a breadboard and set it from code. One of the things I wanted to try out was using an ultra-sonic distance sensor and this is where I hit a snag. Unlike many Arduino boards there is no 5v output (even though it is driven from a USB 5v input) and the sensor I am using requires one. I’ve had to order a few more parts before I can make progress on this project. Essentially I’ll need a separate 5v supply to my breadboard and will have to convert the output from the sensor down to the 3.3v expected by the DevKit board.

First Steps with Azure IoT DevKit

The Azure IoT DevKit is an Arduino compatible board which is ready to use in conjunction with Azure IoT Hub to build an end-to-end IoT system. Code running on the board is native C and you deploy to the board using Visual Studio Code over the included USB cable. Then your device uses WiFi to establish a connection back to Azure where you can process data received from the device in a number of ways. Two-way messaging is supported so you can respond to the device and send commands to control it. Basically the possibilities are endless!

mxkit

The board itself has a number of sensors – temperature, pressure, humidity, movement and an RGB LED and a small (but very clear) display for output. Other inputs and outputs are possible by attaching to the edge connector which is the same as the microbit. The package consists of the board and USB cable in a neat little cardboard box.

Everything you need software-wise is explained on this GitHub site along with a number of sample apps. It’s even possible to deploy the required IoT Hub and services to your Azure account automatically.

There are three suppliers listed on the “Get a Kit” page and at the time of looking only Plugable had stock but don’t ship internationally. Luckily I was able to find Mouser who had stock and ship to the UK. It only took a couple of days to ship from the US.

I’ll revisit this when I look at setting up the software and provisioning a working program.

 

Bluetooth with Xamarin Mac

I’ve been working on adding macOS support to 32feet.NET and there are two frameworks in macOS for Classic Bluetooth – IOBluetooth and IOBluetoothUI. I soon discovered that neither of these had bindings in the standard Xamarin.Mac package which is referenced by all Xamarin Mac applications. I decided to build binding libraries for both APIs and publish the code as part of 32feet.NET. This means you can either use the IOBluetooth lower-level APIs yourself or later use the platform-agnostic 32feet API.

Today I’ve published the first release of the InTheHand.IOBluetoothUI package. There are fewer APIs than IOBluetooth and I’ve already begun the manual process of simplifying and making it more “.NET friendly”. There is also documentation to add, though even Apple’s documentation on IOBluetooth is rather thin at best…

These are by no means final and there will be changes to the APIs as names are cleaned up and more is tested and fixed. If you’d like to try them in your projects please let me know your feedback via GitHub. Those NuGet packages are:-

https://www.nuget.org/packages/InTheHand.IOBluetooth/

https://www.nuget.org/packages/InTheHand.IOBluetoothUI/

 

Bluetooth from Unity

An ongoing issue with 32feet.NET is that it wouldn’t work inside Unity. The reason is that the System.Net.Sockets classes behave slightly differently in the Mono runtime to the desktop .NET framework and you can’t create a Socket using the Bluetooth specific address family.

In order to work around the issue it was necessary to P/Invoke into the native winsock functions, essentially rebuilding a subset of the Socket class. In parallel to this work I’ve been rebuilding 32feet with a more modern API which is less tied to Sockets (primarily just used on desktop Windows) and able to map onto a range of platforms. Another big change for this version is support for Bluetooth LE alongside classic Rfcomm on supported platform. Currently this library supports Xamarin Android and iOS along with UWP, Windows desktop .NET 4.6 and Mono .NET 2.0 for Unity. I’m working on a macOS implementation too. The API is essentially designed to be a more friendly version of the UWP API. In order to support such an old version of .NET, the Unity version is entirely synchronous whereas most of the API is normally async.

In order to test this I wrote a very simple script for Unity which picks a specific paired device, connects to a serial port service over Rfcomm and sends a string. Yes that’s right I have a 3d game that I can print from!

This is currently in preview (but available on NuGet now). There is a lot still to finish including generating the documentation. I’m hoping for some useful feedback, particularly on the Unity work but also any of the other current platforms. Feel free to join in the discussions on GitHub.

More on Xamarin Insights Migration

Since the original release of InTheHand.AppCenter.Insights just over a week ago there have been a few hundred installs, which is nice. There has also been a major change at App Center and logging handled exceptions is now supported. Therefore the latest update (version 1.5) takes full advantage of this and utilises this new API so we don’t lose vital stacktrace information and these are correctly shown as errors rather than events with some of the exception properties. This is a great move from Microsoft as it brings the App Center functionality into parity with Xamarin Insights which has just three weeks remaining before it is shut down.

If you have a project currently using Xamarin Insights I recommend you install my library to quickly switch over before the deadline. If you’re already using my library I highly recommend you update to the latest version for the full exception reporting support.