Using Unity as a Library AR demo

This repository represents an example of using Unity's AR features in a library as part of a native iOS or Android app.

Unity version

Minimal Unity version 2019.3.0f1

Folder structure

• AndroidProject: The Android Studio project for the native Android component. Already preconfigured for a Unity output library built at /UnityAndroidLibrary.
• UnityProject: The Unity AR project.
• XcodeProject: The Xcode project for the native iOS component.
• both.xcworkspace: The workspace used to build the XcodeProject and the Unity iOS project.

Build instructions

Refer to Unity's documentation for more information.

• Unity as a library general info https://docs.unity3d.com/2019.3/Documentation/Manual/UnityasaLibrary.html
• Android details, sample
• iOS details. sample

Setting up the Unity as a library AR example for Android and iOS

Application Walkthrough

This is the Unity as a library demo menu screen:

There are two items to choose from: a mug and a shirt. There is a color cycle button for each item and a button to enter into the AR Demo, ie launch the embedded Unity project.

Upon pressing the Show in AR button the Unity AR Demo will initialize and launch. Follow the prompts to setup the AR environment. Once it is set up, a Tap to Place AR prompt will appear.

Tapping will place the selected item in the world with the selected color. After the item has been placed a color cycle button will appear.

The Back and Colour button are native buttons that are drawn over the Unity Activity.

The back button can be used to return to the shopfront. The Unload Unity button will now be active.

How to setup the demo in iOS and Android

Refer to "Build Instructions" section above for setup details.

Code snippets/examples

Launching Unity Activity

Android - Java

    // Start the Unity Activity.
    private void selectShopItem(int i) {
        CurrentSelectedItem = i;
        isUnityLoaded = true;
        Intent intent = new Intent(this, MainUnityActivity.class);
        intent.putExtra("product",CurrentSelectedItem+"");
        intent.putExtra("productColor", getColorStringForCurrentItem());
        intent.putExtra("nextProductColor",getNextColorForCurrentItem()+"");
        intent.setFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
        startActivityForResult(intent,1);
    }

iOS - Objective C

- (void)initUnity {
    if([self unityIsInitialized]) {
         [[self ufw] showUnityWindow];
         [self updateUnityShopItem];
        return;
    }
    
    [self setUfw: UnityFrameworkLoad()];
    // Set UnityFramework target for Unity-iPhone/Data folder to make Data part of a UnityFramework.framework and uncomment call to setDataBundleId
    // ODR is not supported in this case, ( if you need embedded and ODR you need to copy data )
    [[self ufw] setDataBundleId: "com.unity3d.framework"];
    [[self ufw] registerFrameworkListener: self];
    [NSClassFromString(@"FrameworkLibAPI") registerAPIforNativeCalls:self];
    
    [[self ufw] runEmbeddedWithArgc: gArgc argv: gArgv appLaunchOpts: appLaunchOpts];
    
    auto view = [[[self ufw] appController] rootView];
}

Sending a message to Unity from Native

The example of this is when cycling the item color within AR using the top right button.

Android - Java

 // Send messages to Unity to update the AR item.
    @Override
    protected void updateUnityShopItem() {
        mUnityPlayer.UnitySendMessage("AR Session Origin", "SetProduct", currentProduct);
        mUnityPlayer.UnitySendMessage("AR Session Origin", "SetColor",currentProductColor);
    }

iOS - Objective C

- (void)updateItem:(int)itemIndex {
    const char * itemString = [[NSString stringWithFormat:@"%d",currentItem] UTF8String ];
    [[self ufw] sendMessageToGOWithName: "AR Session Origin" functionName: "SetProduct" message: itemString];
    
    int itemColorIndex = colorIndex[itemIndex];
    const char * colorString = [ colorStringArray[itemColorIndex] UTF8String ];
    [[self ufw] sendMessageToGOWithName: "AR Session Origin" functionName: "SetColor" message: colorString];
    self.ColorBtn.tintColor = colorArray[(colorIndex[itemIndex] + 1) % colorArray.count];
}

Sending a message to native from Unity

This method is called from within the Unity Activity when it starts in order to update the item to display.

Unity - C#

  private void UpdateShopItem()
    {
#if UNITY_ANDROID
            try
            {
                AndroidJavaClass jc = new AndroidJavaClass("com.company.product.OverrideUnityActivity");
                AndroidJavaObject overrideActivity = jc.GetStatic<AndroidJavaObject>("instance");
                overrideActivity.Call("updateUnityShopItem");
            } 
            catch(Exception e)
            {
                Debug.LogError(e.Message);
            }
#elif UNITY_IOS
            NativeAPI.updateUnityShopItem();
#endif
    }

Closing the Unity Activity Android - Java

   public void unloadUnity(View view) {
        if(isUnityLoaded) {
            Intent intent = new Intent(this, MainUnityActivity.class);
            intent.setFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
            intent.putExtra("unload", true);
            startActivity(intent);
            isUnityLoaded = false;
        }
    }

iOS - Objective C

- (void)UnloadUnity
{
    if([self unityIsInitialized]){
        [UnityFrameworkLoad() unloadApplication];
    }
}