Source info: https://roadmap.sh/android
Here is the full version of the roadmap in a single image and after that we have the broken down version with the resources and links to learn more about each of the boxes.
Below is the broken down version of the roadmap with links and resources to learn more about each of the items listed in the complete roadmap above.
For the languages, you can develop android apps either by using Kotlin or Java.
Although, you can use both Kotlin and Java to develop native android apps, Google announced in 2019 to make Kotlin the preferred way of developing android applications. If you were to start learning android development today, Kotlin should be your language of choice.
Install the Android Studio and learn the basics of Kotlin to get started.
We have also listed down some free resources which you can use for the items listed in the image above. If you have some better ones, please do suggest. Also, you don't need to go through all of them, just go through them and pick what you like.
Version control systems record your changes to the codebase and allow you to recall specific versions later. There are multiple Version Control Systems available but Git is the most common one these days.
Here are some of the resources to get you started. Feel free to google and find something else that you find easier.
Here is the list of items that you are going to need when developing Android applications. Please note that, this is an exhaustive list, and you don't need to know it all from the get-go. Get an idea of the items listed, and just start building some apps and keep the items listed in the back of your mind and have a deep dive when using them.
To learn more about the items listed in the image above, here are the links to the relevant docs
I would highly recommend watching this free course from google on Developing Android Apps with Kotlin. Also, here are some of the resources to learn more about the topics listed above.