We struggle a lot learning small, basic and specific concepts. Here is my list of resources which may help you understand Android in a better way. A repository containing link/resources to small, basic as well as specific Android concepts.

• Is Java pass by reference or value?

  Link 1

  Link 2

• Desugaring in Java

• Understanding Overloading and Overriding in Java

• Practive Overloading and Overriding Java

• When to use Static class and when Singleton?

  Link 1

  Link 2

• OnClickListener Internals

  Link 1

  Link 2

• Hashmap Internals

• ArrayList Internals

• LinkedList Internals

  Link 2

• Reflection in Java

  Link 1

  Link 2

• Garbage Collection

• Why Java is platform independent?

  Link 1

  Link 2

• Implements Runnable vs extends Thread

  Link 1

  Link 2

• Sparse Array vs Hashmap

• Static vs Singleton

• Lambda vs Anonymous Classes

• Stack vs Heap Memory

• When to use Handler/thread?

• Handler Internals

• Java to Kotlin

• D8 vs R8

• ART vs Dalvik

• Android 11 Features

• FAQ on Scoped Storage

• Launch Modes

• Recent changes in Play store

• Activity Life Cycle

• Fragment LifeCycle

• Fragment Transition

• MVP vs MVVM vs MVI

  Link 1

  Link 2

• How MVI works

• How MVI works?

• Mediator vs Mutable Live Data

• Why and when to use Mediator Live Data

• Livedata transformations and Mdeiatot LiveData

• LiveData vs Observable Field

• Sealed Classes

• Data Classes

• setValue vs PostValue

• Exceptions vs Error

• Memory Leaks

• Solve OOM

• How to find OOM through hProf

• Understanding MultiDex

• Hardware Acceleration

  Link 2

• Understanding Webview methods

• Memory Leak in WebView

• WebView Best Practices

• WebView vs ChromeTab

• Custom Tab - What, How, When, Why

• Under FCM concepts for Foreground and Background

• Memory Management

  Link 2

  Link 3

• Understanding Job Scheduler

• If u need all-time location access, what should you do?

• LayoutAnimation attribute for recyclerView not working for some devices?

• RecyclerView Internals

  Link 2

  Link 3

• Migration to Paging 3

  Link 2

• WorkManager vs JobScheduler

• Why & How DiffUtil?

• Lifecycle View in Android

  Link 2

• Kotlin Flow

• The SOLID Principles for Android Developers

• Kotlin Quick tips

• Jetpack Navigation between top-level destinations using Dagger-Hilt

• OkHttp vs Retrofit

• Understanding Android New Results API

• RecyclerView Tips

• LiveData with Coroutines and Flow

• Why @JvmOverloads in Kotlin

• Understanding Elvis Operator pitfalls

• Understanding Scoped Storage

• Understanding Android AllowBackup

• Understanding JSON Web Token

• ConstraintLayout

• Should we use largeHeap attribute in Android manifest

• Coroutines vs RxJava

• Mockito vs Mockk

• Best practices to test Static Methods

• Writing Testable Code

• JUnit Annotations

• Why Mockito can't mock static methods

• apply vs let vs run in Kotlin

• Improve recyclerView Performance

• Understand Clean Architecture

• Memory management and Leaks

• Which context to use

• Steps to Build a quality app

• DDMS vs Android Profiler

• Activity Process LifeCycle

• System vs Data Notification - FCM

• Scheduler vs Dispatcher

• ViewModelFactory

• Custom Chrome Tabs

• Progressive vs Native App

• SDK vs Non SDK interfaces

• View Life Cycle

• How Vector drawable works

• Dagger vs Koin

• Handler vs HandlerThread vs Looper

• Enum vs Sealed Classes

• Understand Vector drawable path commands

• Custom Views performance

• Know About Memory Leaks

• FindViewById vs Synthetic Binding

• How Enums Impact performance

• Parcelable Interface implementation

• Android Vitals

• Rx with Retrofit with sample

• Understand Android DataBinding : https://www.raywenderlich.com/7711166-data-binding-in-android-getting-started

• How recyclerView works internally? : https://medium.com/1mgofficial/how-recyclerview-works-internally-71290de5d2c4

• Annotation Processor : https://aitorvs.medium.com/annotation-processing-in-android-studio-7042ccb83024

• Design Pattern : https://www.raywenderlich.com/18409174-common-design-patterns-and-app-architectures-for-android

• Kotlin Questionnaire : https://imstudio.medium.com/kotlin-interview-questions-part-2-4f2f2b05063b

• Coroutine Exception Handling CheatSheet : https://www.lukaslechner.com/coroutines-exception-handling-cheat-sheet/

• StateFlow vs SharedFlow : https://proandroiddev.com/should-we-choose-kotlins-stateflow-or-sharedflow-to-substitute-for-android-s-livedata-2d69f2bd6fa5

• Kotlin Flows : https://elizarov.medium.com/exceptions-in-kotlin-flows-b59643c940fb

• When to use Coroutines.unconfined? : https://stackoverflow.com/questions/55169711/when-should-i-use-dispatchers-unconfined-vs-emptycoroutinecontext#:~:text=or%20null%20objects.-,Dispatchers.,code%20from%20blocking%20world%20callbacks

• Lateinit vs Lazy : https://blog.mindorks.com/learn-kotlin-lateinit-vs-lazy

• Activity result API : https://proandroiddev.com/is-onactivityresult-deprecated-in-activity-results-api-lets-deep-dive-into-it-302d5cf6edd#:~:text=The%20new%20Activity%20Result%20API,other%20third%20party%20library%20anymore

• Lifecycle aware components : https://developer.android.com/topic/libraries/architecture/lifecycle

• ViewModel under the hood : https://blog.mindorks.com/android-viewmodels-under-the-hood

• SavedState Handle : https://developer.android.com/topic/libraries/architecture/viewmodel-savedstate

• WorkManager under the hood : https://medium.com/android-news/androidx-workmanager-%EF%BE%89-%EF%BE%89-some-details-under-the-hood-a5ca1099c93

• Shared Preference under the hood : https://proandroiddev.com/shared-preferences-101-aee26c13e4

• Fragment vs Custom View : https://stackoverflow.com/questions/31236020/fragment-vs-custom-view-in-android

• RecyclerView ViewHolder : https://jonfhancock.com/your-viewholders-are-dumb-make-em-not-dumb-82e6f73f630c

• Ktx Extensions : https://developer.android.com/kotlin/ktx

• merge vs include in layout : https://alltechsolution.wordpress.com/2012/06/13/difference-between-merge-includeand-tag-in-android/

• Okhttp interceptors under the hood : https://blog.codavel.com/how-to-create-an-http-interceptor-for-an-android-app-using-okhttp3

• Retrofit under the hood : https://www.ekchang.com/breakdown/2016/06/11/retrofit-breakdown.html

• Create your own livedata : https://medium.com/androidiots/how-i-made-my-own-livedata-1faf4a45520

• Enum vs sealed class : https://blog.kotlin-academy.com/enum-vs-sealed-class-which-one-to-choose-dc92ce7a4df5

• ViewModel Best Practices : https://medium.com/androiddevelopers/viewmodels-and-livedata-patterns-antipatterns-21efaef74a54

• Pros/cons of Multiple processes on Android : https://stackoverflow.com/questions/19744906/what-are-pros-and-cons-of-using-multiple-processes-within-android-application#:~:text=Cons%3A,and%20the%20perhaps%20application%20performance

• How room works internally? : https://blog.mindorks.com/how-does-room-work-internally

• How leak Canary Works? : https://square.github.io/leakcanary/fundamentals-how-leakcanary-works/

• Mockito vs Mockk : https://stackshare.io/stackups/mockito-vs-mockk

• Mock vs Stub vs spy in Unit Testing : https://www.javatpoint.com/mock-vs-stub-vs-spy#:~:text=Mocks%20are%20used%20to%20create,used%20in%20large%20test%20suites

• Mockito vs PowerMock : https://stackoverflow.com/questions/6036450/powermock-mockito-vs-mockito-alone

• Developer Guide: https://developer.android.com/guide
• Codelabs: https://codelabs.developers.google.com/
• Udacity: https://www.udacity.com
• Scaler Topics: https://www.scaler.com/topics/
• MindOrks: https://mindorks.com
• Ray Wenderlich: https://www.raywenderlich.com/
• CodingWithMitch: https://www.youtube.com/channel/UCoNZZLhPuuRteu02rh7bzsw
• Awesome Learning Resources: https://github.com/androiddevnotes/awesome-android-learning-resources
• Best Practices: https://proandroiddev.com/android-development-best-practices-7278e9cdbbe9
• Interview Questions: https://github.com/niharika2810/android-interview-questions
• Refactoring : https://www.amazon.in/dp/8131734668/ref=cm_sw_r_wa_apa_fab_XPmEFb2A4W4TJ
• Clean Code : https://github.com/ontiyonke/book-1/blob/master/%5BPROGRAMMING%5D%5BClean%20Code%20by%20Robert%20C%20Martin%5D.pdf

Will be updating (once/twice a week) with more after sorting them out. Please contribute if you have more so that I can also learn. :-)

Enjoy Reading!!