Xamarin.Forms And The Case of Failed NuGet Packages

When you create a Xamarin.Forms project, chances are there will be updates available for Xamarin.Forms libraries and associated packages. You can check for updates to NuGet packages manually or these will be restored before “build”.

The Problem:

When you create a new Xamarin.Forms app or open existing one, if you’ve fresh formatted machine with fresh VS and Xamarin installation, the build may last for longer than expected. The reason for this being, it downloads NuGet packages along with its dependencies like Android Support Packages. If in between, VS hangs or there are interruptions in network, you’ll see some errors in build like this:


The solution:

Well, at first you may think it is issue with Xamarin or Visual Studio or NuGet. But this all has to do with lot of NuGet packages and their dependencies download. So it all depends on machine config and network connectivity. If ever you see above errors follow the below steps:

1) Start from fresh. Close Visual Studio instances and delete everything under %appdata%local/Xamarin (e.g. C:\Users\mayur\AppData\Local\Xamarin)

2) Launch Visual Studio and open the solution. Right click each project and update NuGet packages. Android is the one which will take longer to update.


3) Wait till all packages are downloaded. Make sure the %appdata% folder contents all the necessary directories and files.


4) Build the solution. And if you still get issues about some missing some resources. Open Android SDK Manager from Tools > Android and make sure right API levels (in this case API Level 23) is installed.


Now run the project and it should run without any issues.


Mayur Tendulkar

Updating Mobile Development Environment

On 20th July, Microsoft released Visual Studio 2015. This release of Visual Studio includes improvements in terms of IDE features, Language features and even changes in underlying .NET framework. Along with this, Microsoft is also releasing Windows 10 on 29th July, which will add Universal Windows Platform (UWP) development capabilities to Visual Studio. In this blog post, I’m going to cover the features that are most important for us i.e. mobile developers. Having said that, if you want to build UWP apps on RTM, hold on till July 29th, as the SDK and tooling for UWP will be released on the same day. You can find that information here.

Install Selection

You can think Visual Studio 2015 as the most complete mobile development IDE. You can build any kind of mobile applications which can run on Android, iOS and Windows devices. To setup your environment for mobile development, while installing itself, make sure you select your required tools. For example, here I’ve selected Xamarin tools to build native mobile applications. In this case, Visual Studio will install the necessary SDKs and libraries e.g. Android SDKs & NDKs with different API levels, Java SDK, etc…

VS 2015 Install

If you’re already a Xamarin developer, you may want to install Xamarin Studio, which needs to be installed separately by downloading Xamarin Installer from the site. With open sourcing of .NET and Roslyn, even Xamarin Studio is using some of its benefits. You can read more about it from Miguel’s blog.

Xamarin Integration & Project Template

Previously (VS 2013 or prior), you had to install Xamarin to get Xamarin specific project templates. With VS2015, if you select above option during install, you’ll have Xamarin project templates in File > New Project Dialog.

VS 2015 Project Templates

Note: The difference between Blank App (Native Portable) & Blank App (Xamarin.Forms Portable) is literal. That means, later one has Xamarin.Forms NuGet and integration in all projects. First one, just creates 4 separate projects without Xamarin.Forms dependencies.

When you create a Xamarin project, Visual Studio will ask you to sign into your Xamarin account to use different features according to license.

VS 2015 Xamarin

Developer (aka God) Mode

As I mentioned above, if you want to build UWP apps on RTM, you’ll need to wait till 29th July. And to enable Windows Store apps development and debugging on your machine, you’ll need to enable a ‘Developer Mode’. When you create a new project you’ll get following dialog which can take you to next dialog, where you need to select ‘Developer Mode’ and you should be able to test your apps. Do the same thing in your Windows 10 mobile device, if you want to debug apps directly on mobile.

VS 2015 - Developer Mode

VS 2015 - Developer Mode Enabled

Accessing Tools

This is not new as such to Visual Studio 2015, but I want to add it here for your reference. You can find all the tools and setting related to Xamarin and mobility under Tools menu. So, if you want to download new API Level (for example Android M Preview) or monitor your Android app’s performance on device using Android Device Monitor, you know where to look for. We’ll cover tools and features exclusive for Windows 10 in next post.

VS 2015 Tools

By the way, if you ever face any issues with Xamarin and need to contact support, Xamarin logs can help you to share more information about your issues with Support guys. Even, you can go through them and find issues/reasons. You can find them easily under Help > Xamarin

If you want to check where exactly platform SDKs are installed, you can find in Tools > Options and at two different selections

VS 2015 - SDK Location - 1

VS 2015 - SDK Location - 2

More Resources

Now, if you want to know more about Visual Studio 2015 and .NET Framework, Microsoft Channel 9 has Connect On-Demand series on it. Some of the most important videos are here

What’s new in C# 6
New Coding Experiences for C# and Visual Basic
What’s New for .NET 2015
Developing iOS and Android Apps in C# with Visual Studio
Xamarin.Forms: Leaveraging XAML to Build iOS, Android, and Windows Apps
Wearables in C#: Highlighting Apple Watch, Android Wear, and Microsoft Band
GitHub Extensions for Visual Studio

I’ll update tendulkar-uvāca series with new tools and technologies once they are released i.e. after 29th July. Till then, download the Visual Studio 2015 and enjoy the new IDE & tooling.

By the way, have I told you: You get Visual Studio 2015 Community Edition free for specific use cases and along with it, you get Xamarin Starter for free. If you’re a student, you can get more benefit through Microsoft DreamSpark program.

Mayur Tendulkar


tendulkar-uvāca : Episode 2

In previous episode of tendulkar-uvāca, we’ve seen how we can setup our development environment using Visual Studio and Xamarin.
In this episode, we’re going to see how we can use emulators to test and debug our applications.

iOS simulators will get installed with XCode is installed.
For Android emulator, install Xamarin Android Player from here
Windows Phone emulators can be installed while installing Visual Studio 2013 Update 3.

Do let me know your feedback and suggestions.

Mayur Tendulkar

Plugin 05: Accelerometer

In our series on plugins, today we’re going to cover plugin which can help us to work with Accelerometer sensor. This sensor is responsible to detect X, Y, Z co-ordinates of the devices. Using data received from this sensor, you can build games like TempleRun, where users can collect the coins by tilting the device.

There are different APIs for different platform and their usage is different too. First, lets see how we can use this sensor in different platform and then we’ll use plugin in Xamarin.Forms application.

Being Windows Runtime API, the API and its usage is same in Windows and Windows Phone. Here, you create object of the sensor and register for ‘ReadingChanged’ event. Whenever device position is changed, it is reported through that event and UI can be updated using Dispatcher.

In case of Android, it is again similar to Windows platform. Create object of SensorManager and register for SensorChanged event.

iOS is not any different. You create object of CMMotionManager and then listen to sensor for changes.

As you can see, for three different platforms the APIs are totally different. But with Plugins for Xamarin.Forms it becomes easy. You can use DeviceMotion plugin which can work across all these platforms. And the code for same looks like:

In this series on plugin we’ve seen how particular concept can be implemented in all the three platforms and how we can use plugin to make life easier. This will be be last post in this series, but there are many plugins available which you can explore and use in your projects. Do let me know if you want to cover any specific plugin. We’ll start with a new series in couple of weeks. Till then… happy coding :)

Mayur Tendulkar

Plugin 04: FileIO

In continuation to blog posts in this series on plugins, today we’ll cover a plugin/library to perform FileIO.

There are different APIs on different platforms to perform FileIO. Having said that, Xamarin already makes life easier by implementing System.IO which is available in Android and iOS.

Following code can be used in Android to create a file and then read contents from it.FileIO - Android

Similarly, following code can be used in case of iOS application. FileIO - iOS

In case of Windows, using WinRT APIs, the case is little bit different as shown below:FileIO - Windows

Now to make life easier, there is a NuGet from Daniel Plaisted, which can help you to use same code on different platforms. You can find more information about the library from here: https://www.nuget.org/packages/PCLStorage/FileIO - Forms

This way, you can use one code (in C#) across all the three different platforms.

Hope you’re enjoying this series. Do let me know your feedback if you want to include any specific libraries/features.

Mayur Tendulkar

Plugin 03: Phone Calling

In continuation to blog posts in this series on plugins, today we’ll cover a plugin to make phone calls.

As we understood before, all platforms support phone calling (just like emailing, texting, etc…) and Xamarin makes it easier with one common language – C#. However, developers still need to learn

In case of Windows Phone, one can initiate a phone call by using following code. In this case, Windows Phone has special class which allow developers to perform this task.

Screenshot 2015-02-23 10.53.12

In case of Android, developers can use ‘Intent’ and ‘URI activation’ to start a new phone call.

Screenshot 2015-02-23 10.56.09

In case of iOS, same concept of URI activation can be applied. As shown below in the code, developers can create a URI with telephone number and it will launch default application to make a phone call.

Screenshot 2015-02-23 11.13.09

Now, in case of Xamarin.Forms developers can use same Messaging Plugin for Xamarin and Windows plugin to implement phone functionality across the platforms.

Screenshot 2015-02-23 12.31.23

This way, developers can utilize the power of plugins to write one code which can work across different platforms, without bothering about underlying APIs.

Mayur Tendulkar