Develop Reference

How to track from button click on website of app through Google Play up to in-app purchase in Android app?

I would like to get information: How many people who went through the app website made an in-app purchase?
Funnel: Click to "Get it on Google Play" button on the website of app > install app via Google Play > in-app purchase in Android app.
Android app uses Firebase SDK. (I am advanced.)
App website uses Google Analytics v4. (I am beginner -- I set it up yesterday.)
Is it possible to connect/keep tracking from website of app via Google Play to Android app?
It would be great to see in Google Analytics: n% of people made in-app purchase after click to Download button on app website.
or
The similar information in Firebase.
Thank you.

solution for your purpose is to handle Dynamic Link with Deep link
declare your app launcher can open some dynamic link, e.g. yourapp://tracking.key/ (so also yourapp://tracking.key/<secret_key>)
then construct dynamic link (e.g. manually), which will pass user to Play Store if app not installed. after installation and "Open" button press app will be opened with your deep link in intent and then you have "connection" between web click (cookie) and installed app (<secret_key>). then just track in app purchases reporting also obtained in app <secret_key>
if you don't want such precision you may just declare deep link as follow: yourapp://tracking.key/web_click

How to validate my android app as new app?

I have created an app which aggregates news using News.org API. That means my app is a news app.
Google asking to declare whether my app is news app or not.
https://support.google.com/googleplay/android-developer/answer/9949730
An app that declares itself as a "News" app on Google Play must be
able to show clear ownership of the app and provide ownership
information about in-app news content. if your app aggregates news published from other sources, you must indicate the original publisher of each article.
The website of the news publisher explicitly links to the
corresponding news app
App developer has claimed and verified the a
news publishers’ website domain
Documentation that validates an app
developer’s credentials as a news publisher (e.g., prior work, your
verifiable association with the press industry)
But I am an ordinary developer, it's not feasible for me to get relationships with the news sources.
I am showing news sources in my app, but Google rejected it and stopped me from updating my app.
What should I do now ? Did I miss anything or misunderstood ?

What is app indexing how to integrate it in android app and test the indexing?

I want an example of google app indexing as I am implementing the sdk following the link Google App Indexing but didn't get the app in search?

App Indexing puts your app in front of users who use Google Search.
It works by indexing the URL patterns you provide in your app manifest and using API calls from your app to make content within your app available to both existing and new users.
Specifically, when you support URLs for your app content, Android and iOS users can go directly to it from Search results on their device.
Finally, Google uses App Indexing API calls from your app as a ranking signal for your URLs.
Details you can find from here https://developers.google.com/app-indexing/

How to see where the user installed my app from

How my app was installed, how to track where the downloads are coming from, through which partner (advertising publisher)?
For example, I created ads in Facebook or in AdMob. User saw the ads, clicked on them, was redirected to the Google Play Store where he downloaded my app. How can I know that this user downloaded my app by clicking on the Facebook or AdMob ads? Does Google Analytics track and show this info?

You can easily set up install tracking for Mobile Apps:
Enable app install tracking in your account.
Install tracking is automatically enabled in Google Analytics for Android apps. You don’t have to do anything!
Update your Google Analytics SDK.
You need to change a few lines in their manifest file. Refer to the Developer Guide for Android for specific example on how to do this.
Set up Custom Campaigns.
Custom Campaigns are a Google Analytics feature that add parameters to the URL of your marketplace page where users download your app. It’s these parameters that tell Google Analytics what marketplaces your traffic comes from. Get an overview of Custom Campaigns in Google Analytics and how they work. You must set up Custom Campaigns for each platform you’re using.
Analyze your data using the Mobile App Sources report.
If you complete the steps outlined above, your data will appear in the Mobile App Sources report. Use this report to find out what brings users to your download page in each marketplace.
Reference: https://support.google.com/analytics/answer/3389142

Register/Login user using their Google Account?

I want my users to login with their Google accounts.
SwiftKey and Catch Notes do it by opening a WebView in their apps. I don't want to do that. I want to use AccountManager.
Tasks Free from Team Tasks uses it and loads your Google tasks easily. The official Google Reader app also uses it and loads your Google Reader feeds.
But I don't want to get any data of the user from Google except their name, email, etc. I only want to register the user and log them back in easily.
How do I register them with OAuth tokens etc?
All the examples I have found either use WebView or only load data from Google (not register).

When I first asked this question, it was really really hard to do. You had to use the Google Java API definitely not built for Android.
But there is now Google Play Services and this task is very easy to do.
Anyone can follow the below links:
https://developers.google.com/+/mobile/android/sign-in
https://developer.android.com/google/play-services/index.html

Google I/O 2011 covered Android + App Engine, which uses Google accounts for authentication. The Android client uses AccountManager. Here's the screenshot.
You may want to look at AccountsActivity in the source code.