Applying IAP for Android In Godot

What is In App Purchases and How Does it Work?

Today we’re going to talk about doing in-app purchases inside of Godot. so first we’re going to go through the process of explaining how in-app purchases operate, we’re going to go ahead, and download our plugin. From there we we will set up our scene and set up our project. We are going to then code our signals and our project itself, and then we’re going to go ahead and set up our application out on the Google Play Store so that we can do internal application testing. We will then download our app and test it and verify our results so that’s what I have in store for you guys today, so let’s go ahead and get started.

Getting The Plugin

Setting up Godot

Coding The Plugin

Go to your control node and right click -> Attach Script. Lets name it Billing Controller. (I do like my controllers) In our ready function we need to add our signals. We also need to make two varables that can hold our billing singleton and our item token.

var billing
var itemToken

func _ready():
	if Engine.has_singleton("GodotGooglePlayBilling"):
		billing = Engine.get_singleton("GodotGooglePlayBilling")
		billing.connect("connected", self, "connected") # fired when you connect to the google api
		billing.connect("disconnected", self, "disconnected") # fired when you disconnect 
		billing.connect("connect_error", self, "connect_error") # fired when you cant connect
		billing.connect("purchases_updated", self, "purchases_updated") # fired when you get your purchases
		billing.connect("purchase_error", self, "purchase_error") # fired when you cant get any purchases
		billing.connect("sku_details_query_completed", self, "sku_details_query_completed") # fired when you get your sku details
		billing.connect("sku_details_query_error", self, "sku_details_query_error") # fired when you cant get you sku details
		billing.connect("purchase_acknowledged", self, "purchase_acknowledged")# fired when you purchase something
		billing.connect("purchase_acknowledgement_error", self, "purchase_acknowledgement_error") # fired when you cant purchase something
		billing.connect("purchase_consumed", self, "purchase_consumed") #fired when you use an item
		billing.connect("purchase_consumption_error", self, "purchase_consumption_error") # fired when you cant consume something
		billing.startConnection()
	pass # Replace with function body.

From there we need to set up our connected function that our connected signal attaches to. The connected function will go out and query the SKU details. it takes in a list of strings in this case im going to put “testsku in our list of queried skus so we can get that from the Google API. The second option is used to determine if its a subscription or a in app purchase. We will be using inapp but if you want to use subscriptions you can use subs We also need to build out query completed function. In this case I don’t want to use anything that comes back but I will print it out for debugging.

func connected():
	billing.querySkuDetails(["testsku"], "inapp")

func sku_details_query_completed(details):
	print(details)

From there lets go ahead and finish setting up our buttons. Going out to our scene we need to connect our button signals. Click on the “Purchase Item” button on the right there is a button by the inspector that says “Node” click on that, Right click button_down() -> connect, click on your control node that has your BillingController script on it and click connect. this will open up your script add the following code to your function.

func _on_Puchase_Item_button_down():
	var response = billing.purchase("testsku")
	print("purchase has been attempted : result " + response.status)
	if response.status != OK:
		print("error purchasing item")
	pass # Replace with function body.

What this code does is it goes out and attempts to purchase the item using “testsku” as the item id you are purchasing. I log our response so I can debug any issues. From there I check if the status is ok if not I log the error so I can debug it. We also need to connect our signal for purchases updated. This signal is fired off when the user wants to purchase a item and the API acknowledged that they purchased the item. It should contain all the items a user has purchased. In this we loop though and check if they are acknowledged. Acknowledging a purchase is important so Google does not author another code for this item it will help fight fraud. We then need to check if the items we got back has anything and we pull our item token. YOU MUST HAVE YOUR ITEM TOKEN TO USE THAT ITEM. This is a unique code for each items use. I pull the last one on the list because it is the current one they just purchased.

func purchases_updated(items):
	for item in items:
		if !item.is_acknowledged:
			print("acknowledge Purchases: " + item.purchase_token)
			billing.acknowledgePurchase(item.purchase_token)
	if items.size() > 0:
		itemToken = items[items.size() - 1].purchase_token

Now we must hook up our acknowledge signel. This can be used to store there tokens in a db or something of that nature. Once its acknowledged it can be used.

func purchase_acknowledged(token):
	print("purchase was acknowledged! " + token)

Now, go back out to our scene. Click on the “Use Item” button on the right there is a button by the inspector that says “Node” click on that, Right click button_down() -> connect, click on your control node that has your BillingController script on it and click connect. this will open up your script add the following code to your function.

func _on_Use_Item_button_down():
	if itemToken == null:
		print("Error you need to buy this first")
	else:
		print("consuming item")
		billing.consumePurchase(itemToken)
	pass # Replace with function body.

This will send the token out to the API and tell it we are consuming this item and to remove it from the users account. We must check if its null first we dont want to crash out Googles api by sending a null item to them. from there we go ahead and use our item. Finally we connect our signal for consuming this item. This is used to give the users its affect eg the power up or more lives in my case ill just log that it was consumed.

func purchase_acknowledged(token):
	print("purchase was acknowledged! " + token)

Final Code

With this it should work! Here’s the final code!

extends Control


# Declare member variables here. Examples:
# var a = 2
# var b = "text"
var billing
var itemToken

# Called when the node enters the scene tree for the first time.
func _ready():
	if Engine.has_singleton("GodotGooglePlayBilling"):
		billing = Engine.get_singleton("GodotGooglePlayBilling")
		billing.connect("connected", self, "connected") # fired when you connect to the google api
		billing.connect("disconnected", self, "disconnected") # fired when you disconnect 
		billing.connect("connect_error", self, "connect_error") # fired when you cant connect
		billing.connect("purchases_updated", self, "purchases_updated") # fired when you get your purchases
		billing.connect("purchase_error", self, "purchase_error") # fired when you cant get any purchases
		billing.connect("sku_details_query_completed", self, "sku_details_query_completed") # fired when you get your sku details
		billing.connect("sku_details_query_error", self, "sku_details_query_error") # fired when you cant get you sku details
		billing.connect("purchase_acknowledged", self, "purchase_acknowledged")# fired when you purchase something
		billing.connect("purchase_acknowledgement_error", self, "purchase_acknowledgement_error") # fired when you cant purchase something
		billing.connect("purchase_consumed", self, "purchase_consumed") #fired when you use an item
		billing.connect("purchase_consumption_error", self, "purchase_consumption_error") # fired when you cant consume something
		billing.startConnection()
	pass # Replace with function body.

func connected():
	billing.querySkuDetails(["testsku"], "inapp")
# Called every frame. 'delta' is the elapsed time since the previous frame.
#func _process(delta):
#	pass
func sku_details_query_completed(details):
	print(details)
	
func purchases_updated(items):
	for item in items:
		if !item.is_acknowledged:
			print("acknowledge Purchases: " + item.purchase_token)
			billing.acknowledgePurchase(item.purchase_token)
	if items.size() > 0:
		itemToken = items[items.size() - 1].purchase_token

func purchase_acknowledged(token):
	print("purchase was acknowledged! " + token)

func purchase_consumed(token):
	print("item was consumed " + token)

func _on_Puchase_Item_button_down():
	var response = billing.purchase("testsku")
	print("purchase has been attempted : result " + response.status)
	if response.status != OK:
		print("error purchasing item")
	pass # Replace with function body.


func _on_Use_Item_button_down():
	if itemToken == null:
		print("Error you need to buy this first")
	else:
		print("consuming item")
		billing.consumePurchase(itemToken)
	pass # Replace with function body.

Exporting Your App

Creating Our Release Key

From here we need to export our app and put it out for internal testing. To upload to Google Console we first need to build our release key. Open a command prompt and navigate to your project. From here generate your release key: keytool -v -genkey -keystore mygame.keystore -alias mygame -keyalg RSA -validity 10000 . This will tell Androids keytool that you want to generate a release key. It will prompt you for a few things.

Google Console

Creating Our App

Setting Up Our Testing Track

Lets run though this quickly App access is asking if you need any special access to use this app. In our case no we do not Ads is asking if your app contains ads also in this case no we do not have ads. Content rating wants you to fill out your email address what category it is and what your content rating is so run though it for the most part all the answers but in app purchases is a no.

Target audience is what audience is being targeted with your app. In our case we are going to say 13-15 16-17 and 18 and over. For store presence we will say no its not targeted to children.

Creating Your In App Purchase

Downloading Your App From Google Play

Click on testers and click on copy link.

From here paste that in a new tab in your browser and you will be greeted with:

Using The App

From here we can now open our app. I suggest we connect our phone to our computer and open up a command prompt and type adb logcat. You do not have to do this but it will allow you to have your logs you created earlier in the tutorial!

Conclusion

Well that’s all there is to it if you have any questions throw them in the comments below because this is a very complicated system. I don’t want you guys to get completely lost, so go ahead and just throw a comment below if you have questions, I’m more than happy to sit down and help you guys out. If you have any suggestions or anything that you guys want me to cover in the future also throw that in the comments below because this was a viewer suggested tutorial and I take your suggestions very seriously and ill make tutorials of things you want to see, but that’s all I have for you today, so thank you very much for watching. I mean reading, and ill see you next time.

Thanks

Companion Youtube Video