Android Hello, World Video Tutorial

Check out my latest video Tutorial on YouTube!

In this video I show you how to:

• Create an Android Studio project
• Create an Android Virtual Device (AVD)
• Run the Hello World program
• Add custom behavior to the program
• Add a string resource to strings.xml

Below is the main source code for the project.

MainActivity.java:

package com.makotogo.mobile.helloworld;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

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

   // Add button
   Button helloButton = (Button)findViewById(R.id.helloButton);

   helloButton.setOnClickListener(new View.OnClickListener() {
     @Override
     public void onClick(View v) {
       TextView textView = (TextView)findViewById(R.id.textView);
       textView.setText(R.string.seriouslyHelloWorld);
     }
   });
 }
}

activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
   xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:paddingBottom="@dimen/activity_vertical_margin"
   android:paddingLeft="@dimen/activity_horizontal_margin"
   android:paddingRight="@dimen/activity_horizontal_margin"
   android:paddingTop="@dimen/activity_vertical_margin"
   tools:context="com.makotogo.mobile.helloworld.MainActivity">

 <TextView
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:text="@string/helloWorld"
   android:id="@+id/textView"
   android:layout_alignParentTop="true"
   android:layout_alignRight="@+id/helloButton"
   android:layout_alignEnd="@+id/helloButton"/>

 <Button
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:text="Click Me!"
   android:id="@+id/helloButton"
   android:layout_marginTop="76dp"
   android:layout_below="@+id/textView"
   android:layout_centerHorizontal="true"/>

</RelativeLayout>

strings.xml:

<resources>
  <string name="app_name">HelloWorld</string>
  <string name="helloWorld">Hello, World!</string>
  <string name="seriouslyHelloWorld">Seriously, HELLO, WORLD!!</string>
</resources>

I hope you enjoy the video!

–jsp

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