Before we start providing you with resources..

Android is a mobile operating system based on a modified version of the Linux kernel and other open source software.
Designed for:

• Smartphones & Tablets 📱
• Tv 📺
• Wear OS ⌚
• Android things 🔮

First of all we should learn a programming language from [java or Kotlin] and XML [for building the user interface(UI)]

• In my opinion most of apps built with java and if you worked somewhere at a company , how do you refactor or add new features to this app that built with java!
• Most of open source was written with java.
• There are much more Java tutorials and almost every solution for Android problems on pages like Stack Overflow from the last years have been written in Java.
• Understanding the syntax of a language is one thing, but to actually build apps you have to learn how to use the different framework and library APIs. You have to learn what classes you have to use and which methods you have to call in the different phases of your app. And for this you need practice and a lot of examples you can refer to.

Don't worry Java is not going to be obsolete 💪

Arabic
Abdullah Almehmadi:

1. Java 101
2. Java 102
3. Java 103
4. Java 104

English Crash course
Check this

• OOP.
• Looping (for - while - doWhile).
• Make a decision (if else - switch).
• Exception handling (try catch).
• Casting, static, final, generics.
• Using interface and abstraction and Anonynmous object.
• 👉 Build a simple project with java like ( Banking or Hotel or SuperMarket system).

Now you are ready to start with android

Now you are ready to build user interface using xml and write some java code at android studio.

English
Udacity:

1. Android Basics: User Interface ​ (due to 1 week)
   https://mena.udacity.com/course/android-basics-user-interface--ud834

2. Android Basics: User Input ​ (due to 2 weeks)
   https://mena.udacity.com/course/android-basics-user-input--ud836

3. Android Basics: Multiscreen Apps​ ​ (due to 1 Month)
   https://mena.udacity.com/course/android-basics-multiscreen-apps--ud839

After you have learned to use Relative and Linear layout.. there is another amazing thing called Constraint layout to build a responsive layout
check this playlist

Go a head and build a project and use the tools that you learned in basic level

Local: We use shared preference and room database(based on sqllite).

Remote: We can use firebase or some thing called API.

👉 Don't Worry right now about that, we 'll provide you with useful resources to learn that

Before that you should learn an important view called recycle view.. Why?
Most of android apps need to display a list of any type of data for users so the best way to handle that using recycler view.

1. check this tutorial

What is Database generally

2. simple tutorial

then start with learning sqllite commands before implement it with android studio:

3. ProgrammingKnowledge: check this

Additional but very useful:
To master sqllite check this Sqllite fully tutorial

Learn how to store data into your local database of your application by learning room database.

4. TODO Add a room db resources.

You should learn networking basics: (working with a remotely data)

Android Basics: Networking ​ (due to 5 weeks)

1. check this

So now you need to learn about recycler view, fargments, notification, room database and working with some libraries and more..

Udacity:
2. check this

Then you should learn the best libarary in android development that working with APIs called (Retrofit)

Coding in flow.
3. check this

Material is an adaptable system of guidelines, components, and tools that support the best practices of user interface design. Backed by open-source code, ...

Material Design for Android Developers:
4. check this

👉 Go a head and build a project and use the tools that you learned in basic level and Intermediate part 1&2

Alright, you need to add some more features for your app like playing music, integrate google maps into your app, push notification and more..

Advanced Android App Development.

1. check this

English
2. Kotlin crash course

After finishing this course above you should be sure that you are good at:

• val, var, lateinit
• inline function
• Scoped funs
• const VS val
• data class
• sealed class
• Higher order funs and lambda experssion

3. What is android jetpack?
   check this video
   Get hands dirty with Android Jet-pack.

4. Learn more about Architecture pattern (MVVM, MVP, MVI).

👉 Go a head and build a project and use the tools that you learned in the previous levels

• Now, you need to know more about retrofit and it's customization.
• Learn some design patterns (Builder, singleton, factory, prototype, observer, ...).
• Reactive programming.
• Kotlin coroutines.
• Dependency injection (DI).
• Jet-pack Compose
• Sensors.
• Security.
• Testing.

I think you need to keep learning more and more..