Category : Android Cross Platform Mobile App iOS Visual Studio Windows Phone Xamarin
Customizing Listview display in Xamarin
February 19, 2015
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As the usual behavior of ListView to display the items in a list and it contains a single column. The ItemSource property of Listview accepts the list of data to be displayed and render the same on screen.
The code for a simple list to display the Students of a class would like as in the following pic.
Now let’s customize this ListView in a way to display the Student Name along with the Class and School they belongs to.
As in the image above, the data contains a single record. So to accommodate the data in a single record, Let’s create a Student model class.
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public class Student { public string StudentName { get; set; } public string Class { get; set; } public string School { get; set; } } |
In order to customize the ListView display, we need to override the ViewCell class.
What’s new in Xamarin.Forms 1.3 : Inherited App Class
With the new release of Xamarin.Forms 1.3 version, the App Class has its new Avatar. The Older version of App Class was just a class with static methods. Unlike the older version, the new version is an inherited class from the Xamarin.Forms.Application class. Summary of improvements Addition of new life cycle events : We can
Consuming RESTFul web Service in XamarinForms project Using HttpClient
Web service is an important part of the mobile app. I am trying to consume a RESTFul web service in Xamarin using HttpClient. Prerequisites : – Microsoft.Net.Http – Newtonsoft.Json In this example, let’s display the name of the places for a given postal code. We will use the http://api.geonames.com webservice to get the places. Call
Configure Xamarin.Forms XAML intellisense in Visual Studio
There is a plugin available for Visual Studio to enable intellisense for Xamarin.Forms XAML.
Don’t believe me. Here is how I saw before the XAML intellisense is installed.
Let’s configure it in Visual Studio.
Xamarin.Forms.DependencyService platform tweaks
What is DependencyService in Xamarin ?
DependencyService is a static class under Xamarin.Forms namespace. Shared or Portable projects can access the platform based tweaks that are done in any specific platform projects by using DependencyService.
How it works?
The key point is by defining an Interface.
- Declare an Interface in the Shared / Portable project.
- Implement the interface in platform specific projects.
- Register the class under DependencyService Assembly with Dependency attribute.
- Call the DependencyService.get method with the Interface. It will identify the platform and executes the implementation
Xamarin.Mobile : Cross platform component for Device APIs
Xamarin.Mobile is a component from Xamarin to write a commonly used code to consume the device API. What I meant by the commonly used code is, the same code that will can access device specific APIs and behave accordingly depending upon the platform in which it is running.
More than a month back newest release of Xamarin.Mobile is still in its preview release mode.
As of now, it supports the following device APIs for iOS, Android and Windows Phone.
- Contacts
- Geolocation
- Media
How it compiles in Xamarin
What we must agree is, different platforms have different ways of understanding the assemblies. They execute and run the app in the same way. So Xamarin compiles the app in relevance to the platforms basing upon their nature and behavior of executing the assemblies. So that the app assembly fits to the platform acceptable format and run.
Compiling for iOS
iOS runs on ARM architecture. So the nature of iOS is, it understands the assembly language for ARM. It never allows the code to be generated dynamically during run time. So to respect the same, Xamarin did it exactly. It uses the Ahead Of Time (AOT) compilation process in order to generate ARM assemblies from the static code. This is a process to generate the pre-compiled code. Unlike the traditional on-demand execution approach, it compiles the code before hand. During the linking process, it links the .Net framework and the relevant assemblies only. It removes all others, which are no longer in use.
[Proved] Xamarin Forms Content page can contain a single view
Xamarin Content page can contain a single view in it without any layout. Yes, that’s correct. But sometimes crazy thoughts strike to mind . Why should I believe unless I try that out?
You believe ??? But let me check before I agree with you
I am going to create a new Xamarin.Forms.Portable project using Visual Studio. Let me name this as “TryContentPage”. It will create 4 different projects out of which one is the Xamarin.Forms.Portable project and rest three of them are for platforms like iOS, Android and Windows Phone individually.
For now let’s ignore the other projects and concentrate on the Portable project only. To start with our experiment, let me add a XAML Form to that project and name it as “MyFirstPage” .
How to setup Xamarin Build Host with Visual Studio
The cross platform app development with Xamarin Forms allows to create multiple platform development projects under a single Visual Studio solution. It is easy to build app for Android and Windows Phone in Windows with Xamarin using Visual Studio. But for the iOS development we need XCode, which can only be installed in a MAC
Different pages in Xamarin
Pages are the basic components for application building. Pages when compiled to the iOS native app gets converted to UIViewController, Activities for Android and Pages for Windows Phone. Xamarin supports following type of pages.
Content page
- Creates a simple page with single view
- Contains scrollview or stack layout
- Most commonly used type page