Java Android App Development Course, Creating Your First App

Android app development is a crucial field in modern software development. Android is one of the most widely used mobile operating systems worldwide, and various apps are being developed for it. In this course, we will take a detailed look at the process of creating our first Android app using the Java language.

1. Setting Up the Android App Development Environment

To start Android app development, you first need to set up the development environment. Android Studio is the officially supported IDE by Google and is the most commonly used tool for Android app development.

1.1 Installing Android Studio

The process of downloading and installing Android Studio is straightforward. Follow these steps:

  1. Visit the official Android Studio website.
  2. Download the installation file suitable for your operating system.
  3. Once the download is complete, run the installation file and follow the instructions to complete the installation.
  4. After the installation is complete, launch Android Studio and install the required SDK (Software Development Kit).

1.2 Configuring Android Studio

When you first run Android Studio, you will need to perform some configurations. In the initial setup wizard, specify the SDK path and proceed to install any additional necessary features. Once all settings are completed, you will be able to see the main screen of Android Studio.

2. Creating Your First Android App

Now, let’s create our first app. The app we will create is a simple “Hello World” app. This app has the functionality to display the text “Hello World” on the screen.

2.1 Creating a New Project

The method to create a new project in Android Studio is as follows:

  1. After launching Android Studio, select ‘Start a new Android Studio project’.
  2. Select ‘Phone and Tablet’, choose ‘Empty Activity’, and then click ‘Next’.
  3. Enter the project name. For example, type “HelloWorldApp” and set the package name as well.
  4. Select the save location, choose Java as the language, and then select the minimum SDK version. The recommended version is Android 5.0 (API 21), and click ‘Finish’.

2.2 Adding Layout

Once the project is created, open the ‘app/res/layout/activity_main.xml’ file to define the basic layout. This file is where you set up the app’s UI (User Interface). Modify it as follows to add the basic text:


<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        android:textSize="30sp"
        android:layout_centerInParent="true"/>

</RelativeLayout>

2.3 Writing Java Code

Now, navigate to the ‘MainActivity.java’ file and add the code as follows. This file controls the application’s logic.


package com.example.helloworldapp;

import android.os.Bundle;
import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
}

2.4 Running the App

Now you are ready to run the app. Click the run button (green arrow) on the top toolbar of Android Studio to select an emulator or connect a physical device to run it. You can easily test the app.

3. Deploying the App

If the app is fully functional, you are now ready to deploy it. The method for deploying an Android app is as follows:

  1. Select ‘Build’ from the top menu in Android Studio, then choose ‘Build Bundle(s)/APK(s)’ > ‘Build APK(s)’.
  2. The APK file will be built, and once the build is complete, a notification will appear where you can confirm the path of the APK file.
  3. You can use this APK file to install on a physical device or register it on the Google Play Store to deploy.

4. Future Learning Directions

In this course, we have looked at the basic steps to create a simple Android app using Java. However, Android development does not end here. For the next steps, consider exploring the following topics:

  • Using various UI components (buttons, images, lists, etc.)
  • Data storage (SQLite, SharedPreferences, etc.)
  • Network communication (API calls and JSON parsing)
  • Understanding Android Architecture Components (LiveData, ViewModel, etc.)

5. Conclusion

Android app development is a field with many possibilities. Even beginners can easily create their first app through Java, and by adding various features, it can evolve into a more complex app. I hope this course has helped you lay the groundwork for Android app development.

Wishing you the best on your future development journey!