Hello World Application in Xamarin

First you must install Xamarin for Android.

Let's Start

1. Go to File -> New -> Project.

2.  Select Android Application -> Give it a Name.

 

Before starting, have a look at Solution Explorer. An Android Application contains Properties, References, Assets and Resources and so on. Properties contain AssemblyInfo (the same as you saw in the C# project). The References folder contains Assembly Files (DLL files). The Mono.Android DLL assembly contains the C# binding to the Android API.

 

The resources folder contains a Drawable folder (that contains icons and images for the application), Layout (provides a designer surface for the application). Resource.Designer.cs contains auto generated code. As we will start from the basics, delete the main.axml layout and the Activity1.cs file from the project.

3. Right-click on Layout then seelct Add -> New Item.



4. Add an Android Layout (named Main.axml) then click on Add and select it.

5. Drop a Button control from the Toolbox.



Set the Button text as "Click Me!" and id as "@+id/btn_Hello".

Main.axml code: 

1. <?xml version="1.0" encoding="utf-8"?>  
2. <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  
3.     android:orientation="vertical"  
4.     android:layout_width="fill_parent"  
5.     android:layout_height="fill_parent"  
6.     android:minWidth="25px"  
7.     android:minHeight="25px">  
8.     <Button  
9.         android:text="Click Me!"  
10.         android:layout_width="fill_parent"  
11.         android:layout_height="wrap_content"  
12.         android:id="@+id/btn_Hello" />  
13. </LinearLayout>  

6. Add a new item then select Activity then click on Add.

Activity1.cs Code: 

1. using System;  
2. using System.Collections.Generic;  
3. using System.Linq;  
4. using System.Text;  
5.   
6. using Android.App;  
7. using Android.Content;  
8. using Android.OS;  
9. using Android.Runtime;  
10. using Android.Views;  
11. using Android.Widget;  
12.   
13. namespace Hello_World_Application  
14. {  
15.     //Set the Label = "Hello World Application" which is displayed on the Top of the Application(in Title)  
16.     //Set MainLauncher = true makes this Activity as a Main Activity and Applicationstarts from this Activity. 
17.     //Set Icon using Icon = "@drawable/icon"  
18.     [Activity(Label = "Hello World Application", MainLauncher = true, Icon = "@drawable/icon")]  
19.     public class Activity1 : Activity  
20.     {  
21.         //Creating Instance of Button  
22.         Button btn_Hello;  
23.         protected override void OnCreate(Bundle bundle)  
24.         {  
25.             base.OnCreate(bundle);  
26.   
27.             //SetContentView  
28.             SetContentView(Resource.Layout.Main);  
29.             //Get btn_Hello Button control from the Manin.axml Layout.  
30.             btn_Hello = FindViewById<Button>(Resource.Id.btn_Hello);  
31.             //Creating Click event of btn_Hello  
32.             btn_Hello.Click += btn_Hello_Click;  
33.         }  
34.         //btn_Hello Click Event  
35.         void btn_Hello_Click(object sender, EventArgs e)  
36.         {  
37.             //Display a Toast Message on Clicking the btn_Hello  
38.             Toast.MakeText(this, "Hello World Application by Anoop", ToastLength.Short).Show();  
39.         }  
40.     }  
41. }  

7. Build and run the application. Start an emulator image if not started. Select the Running devices and then click on OK.

Note: the Emulator takes a lot of time to start. Enable USB Debugging on your Android Device and run your application on the Device directly; that is much faster compared to debugging on an emulator.

Final preview:



I hope you like it. Thanks.