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Android application with Visual Studio and develop an understanding of the fundamentals of Android application development with Xamarin. You will create an application that translates an alphanumeric phone number entered by the user into a numeric phone number and display the numeric phone number to the user. The final application looks like this: Windows requirements To follow along with this walkthrough, you will need the following: Windows Visual Studio or Visual Studio version This walkthrough assumes that the latest version of Xamarin.

Android is installed and running on your platform of choice. For a guide to installing Xamarin. Android, refer to the Xamarin. Android Installation guides. Configuring emulators If you are using the Android emulator, we recommend that you configure the emulator to use hardware acceleration. Instructions for configuring hardware acceleration are available in Hardware Acceleration for Emulator Performance.

Create the project Start Visual Studio. In the New Project dialog, click the Android App template. After the new project is created, expand the Resources folder and then the layout folder in the Solution Explorer.

The default layout will be a RelativeLayout. From the Toolbox the area on the left , enter text into the search field and drag a Text Large widget onto the design surface the area in the center : With the Text Large control selected on the design surface, use the Properties pane to change the Text property of the Text Large widget to Enter a Phoneword:: Drag a Plain Text widget from the Toolbox to the design surface and place it underneath the Text Large widget.

Placement of the widget will not occur until you move the mouse pointer to a place in the layout that can accept the widget. Write some code The next step is to add some code to translate phone numbers from alphanumeric to numeric.

Insert the following code into this file: using System. Contains c return 2; else if "DEF". Contains c return 3; else if "GHI". Contains c return 4; else if "JKL". Contains c return 5; else if "MNO". Contains c return 6; else if "PQRS". Contains c return 7; else if "TUV". Contains c return 8; else if "WXYZ". Wire up the user interface The next step is to add code to wire up the user interface by inserting backing code into the MainActivity class.

Begin by wiring up the Translate button. In the MainActivity class, find the OnCreate method. The next step is to add the button code inside OnCreate, below the base.

First, modify the template code so that the OnCreate method resembles the following: using Android. App; using Android. OS; using Android. Runtime; using Android. TranslateButton ; Add code that responds to user presses of the Translate button. ToNumber phoneNumberText. Text ; if string. If there are errors, go through the previous steps and correct any mistakes until the application builds successfully.

If you get a build error such as, Resource does not exist in the current context, verify that the namespace name in MainActivity. If you still get build errors, verify that you have installed the latest Visual Studio updates. Expand the values folder inside the Resources folder and open the file strings. Click New Project Click Next.

In the Configure your Android app dialog, name the new app Phoneword and click Next. In the Configure your new Android App dialog, leave the Solution and Project names set to Phoneword and click Create to create the project. Create a layout Newer releases of Visual Studio support opening. After the new project is created, expand the Resources folder and then the layout folder in the Solution pad. Double-click Main. Button on the design surface and press the Delete key to remove it. From the Toolbox the area on the right , enter text into the search field and drag a Text Large widget onto the design surface the area in the center : With the Text Large widget selected on the design surface, you can use the Properties pad to change the Text property of the Text Large widget to Enter a Phoneword: as shown below: Next, drag a Plain Text widget from the Toolbox to the design surface and place it underneath the Text Large widget.

Write some code Now, add some code to translate phone numbers from alphanumeric to numeric. This creates a new empty C class for us. Remove all of the template code in the new class and replace it with the following code: using System. Ensure that there are no compile-time errors by rebuilding the solution.

Wire up the user interface The next step is to add code to wire up the user interface by adding the backing code into the MainActivity class. Double-click MainActivity. Begin by adding an event handler to the Translate button. Add the button code inside OnCreate, below the base. Main calls. Remove any existing button handling code i. Content; using Android. Views; using Android. Widget; using Android. Empty; translateButton. If the application compiles, you will get a success message at the top of Visual Studio for Mac: If there are errors, go through the previous steps and correct any mistakes until the application builds successfully.

If you still get build errors, verify that you have installed the latest Xamarin. Android and Visual Studio for Mac updates. Start by editing the Label for MainActivity. The Label is what Android displays at the top of the screen to let users know where they are in the application.

By default, Visual Studio for Mac will provide a default icon for the project. Delete these files from the solution, and replace them with a different icon. Expand the Resources folder in the Solution Pad. Notice that there are five folders that are prefixed with mipmap-, and that each of these folders contains a single Icon. Right click on each of Icon. Next, download and unzip Xamarin App Icons set. This zip file holds the icons for the application.

Each icon is visually identical but at different resolutions it renders correctly on different devices with different screen densities. The set of files must be copied into the Xamarin. Android project. Select Icon. In the Add File to Folder dialog box, select Copy the file into the directory and click OK: Repeat these steps for each of the mipmap- folders until the contents of the mipmap- Xamarin App Icons folders are copied to their counterpart mipmap- folders in the Phoneword project.

After all the icons are copied to the Xamarin. Android project, open the Project Options dialog by right clicking on the project in the Solution Pad. Congratulations on completing your first Xamarin. Android application! Next up is the Hello, Android Deep Dive. Related links.

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Next Page Let us start actual programming with Android Framework. Before you start writing your first example using Android SDK, you have to make sure that you have set-up your Android development environment properly as explained in Android - Environment Set-up tutorial. I also assume that you have a little bit working knowledge with Android studio. So let us proceed to write a simple Android Application which will print "Hello World! When you click on Android studio icon, it will show screen as shown below You can start your application development by calling start a new android studio project.

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Along the way, basic Android Application Building Blocks are introduced with a deeper dive into Android architecture. The final application will have a second screen that displays the numbers that were "translated", as illustrated by the screenshot on the right: The accompanying Deep Dive reviews what was built and discusses architecture, navigation, and other new Android concepts encountered along the way. Requirements Because this guide picks up where Hello, Android leaves off, it requires completion of the Hello, Android Quickstart. If you would like to jump directly into the walkthrough below, you can download the completed version of Phoneword from the Hello, Android Quickstart and use it to start the walkthrough. Start by opening the Phoneword application in Visual Studio and editing the Main. Tip Newer releases of Visual Studio support opening. This will cause the button to become darker on the design surface: Creating the second activity Create a second Activity to power the second screen.

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