Learn Mobile App Dev & Mobile DevOps Here

DevOps Meme

My friend Prachi tagged me on this meme on Facebook and I couldn’t agree more with her. When I started my career, my entire version control was folders – zipped, tagged and stored on multiple hard-disks. But then things changed. My guru Raj, enlightened me about advantages of version control systems. I learned about how multiple people can collaborate on projects or how errors can be reversed by going through code history if version controls like Team Foundation Server or GitHub are used. I started using those and these days, all my projects and samples are either in Visual Studio Team Services or in GitHub repository.  Going one step ahead, I’m using Visual Studio Mobile Center for DevOps along with these version control systems.

But what is this all about? How it helps in building successful mobile applications? And I thought about answering these questions in a video series. The goal is to explain mobile DevOps and different steps in mobile DevOps in small (less than 10 mins) videos.  After completing this series, you’ll be able to build cross-platform Xamarin.Forms mobile application, which will consume Microsoft Cognitive Service and set-up mobile DevOps for the same.

To follow along with this series, I’m recommending following minimum hardware/software combination:

  • Intel i5, 8GB, 50GB machine with Hyper-V support & Windows 10 Professional
  • MacBook or MacMini with i5, 4GB, 50GB for compiling iOS apps
  • Visual Studio 2017 Community Preview

With these hardware/software additional services used in this series are:

Watch the 1st video here about activating these tools & services to set-up mobile DevOps.

In 2nd video learn about how to setup build automation, using Visual Studio Mobile Center.

I’ll update this blog post in coming weeks with the 3rd video in this series, which will be about building mobile applications.

Stay tuned and subscribe to my blog/channel :)

Namaste.
Mayur Tendulkar

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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:

XF-NUGET-02

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.

XF-NUGET-03

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

XF-NUGET-04

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.

XF-NUGET-05

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

XF-NUEGT-06

Namaste,
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.

Namaste
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 :)

Namaste
Mayur Tendulkar

Don’t Re-Invent the Wheel: Use Components or Plugins In Your Apps

Xamarin provides native, cross-platform mobile application development using language we all know and love – C#. However, it is still required to learn concepts of each platform. For example to send text message (SMS) in all these three platforms there are different set of APIs.

Below API is for Android, which uses SmsManager to send the text message. There is another way to do this using Intents.

image 

In case of Windows Phone, ChatMessage allows us to declare and send text message. This API is available in WinRT platform. In case of SL based apps, we need to use Launchers/Choosers.

image

In case of iOS as shown below, there is no API as such. But we use URL to launch default messaging app. In this case, we cannot set the message body, which we want to send out.

image

Life will be much simpler if there will be just one API on all these platforms which will take care of sending text messages and as I developer we don’t need to bother about on which platform it is being called. Here comes components and plugins. My friend James has written a nice blog about ‘What Exactly is a Plugin for Xamarin?’. You can read it here

In our case, we’re going to use Messaging Plugin for Xamarin and Windows which allow us to use same API to send text messages. Below code is written once in a Xamarin.Forms project which depending on platform on which code is executing, send the message using that platform’s APIs.

image

Using this plugin, it becomes easier to send text messages on Android, iOS and Windows. And this is the magic of Plugins for Xamarin.

In future posts, we’ll cover some of the best plugins and components which can help you build cross-platform mobile applications with single code-base.

I hope you’ve enjoyed this.

Namaste
Mayur Tendulkar

Xamarin.Forms for Windows Phone –Differences You Must Know

Xamarin.Forms is cross platform solution to create native apps. Whilst Xamarin allows us to build native apps for each platform (Android, iOS and Windows) with maximum code sharing, Xamarin.Forms goes one step ahead and allows UI code sharing as well. That means, I can create a TabbedPage and it will be rendered natively on each platform as ActionBar, UITabView and Pivot.

Xamarin.Forms allows creating UI in both C# as well as XAML. To keep things simple and less confusing across different platforms, there are new properties, new elements. XAML as a language is still the same. So we get to create objects from XAML, initialize them using InitializeComponent(). Everything is still the same. You just need to know the small differences. For example there is no Margin property, but there is Spacing property <grin>

While you can add a XAML page from XAML project template category, you should add one from Code -> Forms Xaml Page

image

The first thing to notice here is namespace

image

And this actually makes the difference. The two lines define the XAML page. First two are for Xamarin.Forms whereas last two are for normal XAML page in Windows app.

When creating User Interface, Xamarin.Forms provides Views (controls in our language) which abstract away the different controls in different platform. So, to create a TextBox on Windows Phone and a button which will be right aligned within StackPanel, following code will do the magic:

image

As you can see here, rather than StackPanel, StackLayout is used to represent controls positioned in stack (horizontal or vertical) and to avoid confusion with any stack in these platforms. This StackLayout will internally render native Stack of controls on each platform.

Also, in above code, Entry element is used, which is new to us. However, this entry represents a single line text-input control. That is, on Windows Phone it will become a TextBox.

Along with control names, some properties are named differently. For example Margin is now Spacing. We have left 25px space from each side in our code. Padding is still the same.  HorizontalAlignment is changed to HorizontalOptions. And possible values for that will be: Start [Left], Center and End [Right], with option to mention Expand which will take-up the space available. It also has FillAndExpand option, which is similar to Stretch mode.

While working with Font, usually we’ve different properties for FontFamily, FontSize, FontWeight etc. In Xamarin.Forms, we get one Font property which accepts multiple values (comma separated), which is parsed at runtime (Type Converters). So, below code can render TextBlock (label) with specified font details:

image

One thing to notice here is OnPlatform element. This element helps to override certain values (in above code, label renders with different font setting on different platform) for specific platform. There is a Device class with methods to work on platform specific code in XAML or C#.

The data binding concept is still the same as it was in traditional XAML.

image

The code above mentioned, with details is available at ‘An Introduction to Xamarin.Forms’ i.e.: http://bit.ly/1l1zg06 on Xamarin.com site.

Having said that XAML syntax is still the same. The features like code behind in partial class (with InitializeComponent), Type Converters, Property Element syntax, Attached Property syntax, Content properties, external library declarations (xmlns : somedifferentype=”uri”), adding event handlers, ResourceDictionary, StaticResources, etc… are still the same.

With this, I’m sure Xamarin.Forms will help C# and XAML developers to do Rapid Application Development on multiple platforms.

You can read more here at:

  1. An Introduction to Xamarin.Forms
  2. Getting Started with Xamarin.Forms: Basics
  3. Xamarin.Forms Samples
  4. XForms Labs (Open Source Project)

Happy Coding & Namaste
Mayur Tendulkar