Simple Hello World Program

Let's start programming with Android Framework. Before you start writing your first programme using Android SDK, you have to make sure that you have set-up your Android development environment properly as explained in Android tutorial. I also assume that you have a little bit working knowledge with Android studio. So let's start writing a simple Android Application which will print "Hello World!". The first step is to create a simple Android Application using Android studio. When you start Android studio , it will show screen as shown below: 

select start a new android studio project option. In a new installation frame should ask Application name, package information and location of the project as shown below:

After entered application name, click on next button it ask on which API application runs on, here need to specify Minimum SDK, in our tutorial, I have choose as API 23: Android 6.0(Marshmallow):

After select API, click on next button it ask which Activity you want, I have choose a Empty Activity as shown below:

After select Activity, click on next button it ask to name activity By default it shows MainActivity, I have not change it.click finish Button.let Android Studio setup your Project.SomeTimes it takes Some time. be patience!! After that You Have A Following Screen:

the design view code that is MainActivity.xml is as shown below

<android .support.constraint.constraintlayout="" android:layout_height="match_parent" android:layout_width="match_parent" tools:context="hp.hello.MainActivity" xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools">

    <textview android:layout_height="wrap_content" 
                 android:layout_width="wrap_content" 
                 android:text="Hello World!" 
                 app:layout_constraintbottom_tobottomof="parent" 
                 app:layout_constraintleft_toleftof="parent" 
                 app:layout_constraintright_torightof="parent" 
                 app:layout_constrainttop_totopof="parent"/>
</constraintlayout">

Java file that is MainActivity.java is as shown below:

your pakage name;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

    @Override    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
}

You can see the launch Button( ) below the MenuBar it is used to run the app There is a two way to run your project

     In Emulator
     In Your device

Before Run your project Make sure that your  Emulator is created And its SDK Platform is  which you select at the time of project creation.