Android Studio

Android Unreal Engine SDK Guide

Written by: Alex | Last updated on September 6, 2024
Android Studio
android-unreal-engine-sdk-guide
Source: Androidauthority.com

Introduction

Integrating game engines into Android applications has become increasingly popular in mobile app development. One such game engine that has gained significant attention is Unreal Engine, developed by Epic Games. This guide will walk you through setting up and using the Unreal Engine SDK in your Android projects. Whether you're a seasoned developer or just starting out, this comprehensive guide will help you understand the intricacies of integrating Unreal Engine into your Android apps.

Why Use Unreal Engine?

Unreal Engine is renowned for its powerful rendering capabilities, robust physics engine, and extensive toolset for creating high-quality 3D graphics. It is widely used in the gaming industry but also offers a lot of potential for mobile app development. By utilizing Unreal Engine's capabilities, you can create visually stunning and immersive experiences for your users.

Prerequisites

Before diving into the world of Unreal Engine and Android, ensure you have the following prerequisites:

  1. Android Studio: Install Android Studio from the official Android website.
  2. Unreal Engine: Download Unreal Engine from the official Epic Games website.
  3. Basic Knowledge of Java or Kotlin: Understanding the basics of Java or Kotlin is essential for integrating it with Android.
  4. XML and Android App Development Basics: Familiarity with XML and basic Android app development concepts is crucial for setting up your project.

Setting Up Your Environment

Installing Unreal Engine

To start using Unreal Engine, download and install it from the official Epic Games website:

  1. Visit the Unreal Engine Website: Go to the Unreal Engine website and click on the "Download" button.
  2. Choose Your Platform: Select the platform you're using (Windows, macOS, or Linux).
  3. Select the Edition: Choose the edition that suits your needs (e.g., Unreal Engine 4 or Unreal Engine 5).
  4. Download and Install: Follow the installation prompts to download and install Unreal Engine.

Installing Android Studio

Similarly, install Android Studio on your machine:

  1. Visit the Android Studio Website: Go to the Android Studio website.
  2. Download the IDE: Click on the "Download" button for the latest version of Android Studio.
  3. Follow Installation Prompts: Follow the installation prompts to download and install Android Studio.

Creating a New Project in Android Studio

Once you have both Unreal Engine and Android Studio installed, create a new project in Android Studio:

  1. Open Android Studio: Launch Android Studio.
  2. Create a New Project: Click on "Start a new Android Studio project."
  3. Choose a Template: Select an appropriate template for your project, such as "Empty Activity."
  4. Name Your Project: Give your project a name (e.g., "UnrealEngineSDK").
  5. Choose Save Location: Choose where you want to save your project.
  6. Select Language: Choose either Java or Kotlin as your programming language.
  7. Finish: Click "Finish," and Android Studio will set up your project.

Integrating Unreal Engine with Android

Setting Up Dependencies

To use Unreal Engine in your Android project, add some dependencies to your build.gradle file:

gradle
dependencies {
implementation 'com.epicgames.unreal:unreal-engine-sdk:1.0.0'
}

Replace 1.0.0 with the latest version of the Unreal Engine SDK available in the repository.

Adding Necessary Libraries

Add some additional libraries to handle the integration:

gradle
dependencies {
implementation 'com.epicgames.unreal:unreal-engine-sdk:1.0.0'
implementation 'androidx.appcompat:appcompat:1.2.0'
implementation 'androidx.recyclerview:recyclerview:1.1.0'
implementation 'androidx.cardview:cardview:1.0.0'
}

Sync your project to download these libraries.

Designing the Layout

Design the layout where you'll display the content from Unreal Engine:

  1. Open activity_main.xml: Open the activity_main.xml file in your project directory.
  2. Add a SurfaceView: Add a SurfaceView where you'll render the content from Unreal Engine.

Example:

xml

<SurfaceView
    android:id="@+id/surfaceView"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

Creating Data Model

Define a data model for the items you'll be displaying:

java
public class Item {
private String name;

public Item(String name) {
    this.name = name;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

}

Setting Up Adapter

Create an adapter for the RecyclerView to display the items:

java
public class ItemAdapter extends RecyclerView.Adapter<ItemAdapter.ViewHolder> {

private List<Item> itemList;

public ItemAdapter(List<Item> itemList) {
    this.itemList = itemList;
}

@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_layout, parent, false);
    return new ViewHolder(view);
}

@Override
public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
    Item item = itemList.get(position);
    holder.nameTextView.setText(item.getName());
}

@Override
public int getItemCount() {
    return itemList.size();
}

public class ViewHolder extends RecyclerView.ViewHolder {

    public TextView nameTextView;

    public ViewHolder(View itemView) {
        super(itemView);
        nameTextView = itemView.findViewById(R.id.name_text_view);
    }
}

}

Integrating with Unreal Engine

Integrate the Unreal Engine content into your Android app. This involves creating a plugin in Unreal Engine that will handle the rendering of the content on the SurfaceView.

Creating a Plugin in Unreal Engine

  1. Open Unreal Engine: Open Unreal Engine and create a new project.
  2. Create a Plugin: Go to File > Plugin Development > New Plugin.
  3. Choose Android: Select "Android" as the target platform.
  4. Name Your Plugin: Name your plugin (e.g., "AndroidIntegrationPlugin").

Setting Up the Plugin

In your plugin, create a class that will handle the rendering of the content on the SurfaceView. Example:

cpp
#include "CoreMinimal.h"
#include "AndroidJniWrapper.h"
#include "AndroidJniUtil.h"
#include "AndroidSurfaceView.h"

class AAndroidIntegrationPlugin : public IModuleInterface
{
public:
virtual void StartupModule() override
{
// Initialize the plugin
UE_LOG(LogTemp, Log, TEXT("Initializing Android Integration Plugin"));

    // Get the SurfaceView instance from Android
    FAndroidSurfaceView* SurfaceView = FAndroidSurfaceView::GetSurfaceView();

    // Set up the rendering context
    SurfaceView->SetRenderContext();

    // Start rendering
    SurfaceView->StartRendering();
}

virtual void ShutdownModule() override
{
    // Clean up the plugin
    UE_LOG(LogTemp, Log, TEXT("Shutting down Android Integration Plugin"));

    // Stop rendering
    FAndroidSurfaceView* SurfaceView = FAndroidSurfaceView::GetSurfaceView();
    SurfaceView->StopRendering();
}

};

Handling JNI Calls

Handle JNI calls to communicate between Java and C++. Example:

cpp
#include "CoreMinimal.h"
#include "AndroidJniWrapper.h"
#include "AndroidJniUtil.h"

extern "C" JNIEXPORT void JNICALL
Java_com_epicgames_unreal_UnrealEngineSDK_RenderFrame(JNIEnv* env, jobject obj)
{
// Get the SurfaceView instance from Android
FAndroidSurfaceView* SurfaceView = FAndroidSurfaceView::GetSurfaceView();

// Render the frame
SurfaceView->RenderFrame();

}

Handling JNI Registration

Register the JNI functions in your plugin:

cpp
#include "CoreMinimal.h"
#include "AndroidJniWrapper.h"
#include "AndroidJniUtil.h"

extern "C" JNIEXPORT void JNICALL
Java_com_epicgames_unreal_UnrealEngineSDK_Initialize(JNIEnv* env, jobject obj)
{
// Initialize the plugin
UE_LOG(LogTemp, Log, TEXT("Initializing Android Integration Plugin"));

// Register JNI functions
RegisterJniFunctions(env);

}

extern "C" JNIEXPORT void JNICALL
Java_com_epicgames_unreal_UnrealEngineSDK_Shutdown(JNIEnv* env, jobject obj)
{
// Clean up the plugin
UE_LOG(LogTemp, Log, TEXT("Shutting down Android Integration Plugin"));

// Unregister JNI functions
UnregisterJniFunctions(env);

}

Handling JNI Registration in Java

Register the JNI functions in your Java code:

java
public class UnrealEngineSDK {
public native void Initialize();
public native void Shutdown();
public native void RenderFrame();

static {
    System.loadLibrary("unreal-engine-sdk");
}

}

Calling JNI Functions from Android Code

Call the JNI functions from your Android code:

java
public class MainActivity extends AppCompatActivity {

private UnrealEngineSDK unrealEngineSDK;

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

    // Initialize the Unreal Engine SDK
    unrealEngineSDK = new UnrealEngineSDK();
    unrealEngineSDK.Initialize();

    // Start rendering
    new Thread(() -> {
        while (true) {
            unrealEngineSDK.RenderFrame();
            try {
                Thread.sleep(16); // 16ms = 60fps
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }).start();
}

@Override
protected void onDestroy() {
    super.onDestroy();

    // Shutdown the Unreal Engine SDK
    unrealEngineSDK.Shutdown();
}

}

Additional Tips

Debugging

Debugging can be challenging when dealing with native code and JNI calls. Here are some tips to help you debug:

  1. Use Log Statements: Use log statements in both C++ and Java to track the flow of your code.
  2. Use Android Debug Bridge (ADB): Use ADB to debug your app on an emulator or physical device.
  3. Use Unreal Engine Debugging Tools: Use Unreal Engine's built-in debugging tools to debug the plugin.

Performance Optimization

Performance optimization is crucial when dealing with complex graphics rendering. Here are some tips to help you optimize performance:

  1. Profile Your App: Use profiling tools to identify performance bottlenecks.
  2. Optimize Rendering Code: Optimize your rendering code to reduce overhead.
  3. Use Multi-Threading: Use multi-threading to handle tasks concurrently.

By following these tips and guidelines, you can create high-performance Android apps that integrate seamlessly with Unreal Engine, providing an exceptional user experience.

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