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iTEC | Building a career in Android Development

iTEC | Building a career in Android Development

About OOP, Design Patterns, Clean Code, Java, Kotlin, Android Jetpack, how to build a learning plan with OKRs.

Magda Miu

March 05, 2021

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  1. Building a career in Android Development @magdamiu

  2. ABOUT ME • Squad Leader Developer @YOXO (Orange) • Android

    Google Developers Expert • Trainer & Speaker • Co-organiser GDG Pitesti & WTM Romania
  3. Employment history Web Developer Aug 2010 - Oct 2010 Android

    Developer Nov 2010 - Aug 2015 Android Technical Lead Sept 2015 - Dec 2019 Squad Lead Developer Jan 2019 - Present GDE Android Feb 2019 - Present
  4. OOP Q: What’s the object-oriented way to become wealthy? A:

  5. Cohesion

  6. Coupling

  7. Best case scenario Cohesion Coupling high loose

  8. • Don’t Repeat Yourself • Applicable whenever we copy /

    paste a piece of code D.R.Y.
  9. • Keep It Simple and Stupid • Whenever we want

    to implement a method to do all things K.I.S.S.
  10. • You Ain’t Gonna Need It • Don’t write code

    which is not yet necessary Y.A.G.N.I.
  11. • Single responsibility (SRP) • Open-closed (OCP) • Liskov substitution

    (LSP) • Interface segregation (ISP) • Dependency inversion (DIP) S.O.L.I.D.
  12. Design Patterns

  13. Java for Android Development • OOP • Variables • Loops

    • Conditionals • Arrays • Classes • Inheritance • Interfaces • Collections • Generics • Exceptions • Multithreading
  14. Learn Java

  15. Kotlin A modern and pragmatic language for the industry, not

    an academic one.
  16. None
  17. None
  18. • General-purpose • FP + OOP • Open source (Apache

    2.0) • Developed by JetBrains • Static typing What is Kotlin?
  19. Kotlin is 100% interoperable with Java *.kt *.java Kotlin compiler

    Java compiler *.class *.jar App Kotlin runtime
  20. None
  21. // Elvis operator val name: String? = null val lengthOfName

    = name?.length ?: -1 println(lengthOfName)
  22. // Elvis operator val name: String? = null val lengthOfName

    = name?.length ?: -1 println(lengthOfName) // => -1
  23. class Utility { // infix functions = functions with a

    single parameter infix fun String.onto(other: String) = Pair(this, other) } fun main(args: Array<String>) { val blueShoes = "blue".onto("shoes") val yellowScarf = "yellow" onto "scarf" println(blueShoes) // => (blue, shoes) println(yellowScarf) // => (yellow, scarf) }
  24. fun String.removeFirstLastChar(): String = this.substring(1, this.length - 1) Receiver type

    Receiver object // extension function
  25. Data classes are a concise way to create classes that

    just hold data. Data classes Function Price Getters and Setters 0 Lei equals() & hashCode() 0 Lei toString() 0 Lei componentN() 0 Lei copy() 0 Lei TOTAL FREE!
  26. Coroutines are lightweight threads

  27. co + routines coroutines Cooperation Functions

  28. Kotlin is about developer’s happiness and productivity.

  29. Clean Code “Clean code is readable. It tells a story.”

    Uncle Bob, Clean Code
  30. None
  31. None
  32. None
  33. Code quality “measure” WTFs/min Few WTFs Developer Many WTFs Developer

    WTF = What a Terrible Feature
  34. Use intention-revealing names Types Names Classes and Objects Customer, Account,

    WikiPage Methods postPayment, deleteAccount, displayPage Solution domain names AccountVisitor Problem domain names churnPerMonth Names

  36. Actor a1; System.out.println(a1.fn + " " + a1.ln); int length

    = a1.fn.length(); int theLength = a1.ln.length(); int sum = length + theLength; sout("The total length of the full name is " + sum);
  37. Actor actor; System.out.println(actor.firstName + " " + actor.lastName); int firstNameLength

    = actor.firstName.length(); int lastNameLength = actor.lastName.length(); int fullNameLength = firstNameLength + lastNameLength; sout("The total length of the full name is " + fullNameLength);
  38. private void message() { if (t % 7 == 0)

    { int w = t / 7; System.out.println(w + " week(s)"); } else { System.out.println(t + " days"); } }
  39. private void displayOfferExpirationTime() { if (daysUntilOfferEnds % numberOfDaysInWeek == 0)

    { int numberOfWeeks = daysUntilOfferEnds / numberOfDaysInWeek; System.out.println(numberOfWeeks + " week(s)"); } else { System.out.println(daysUntilOfferEnds + " days"); } }
  40. “Functions should do one thing. They should do it well.

    They should do it only.” Functions
  41. “The functions should be small. The functions should be smaller

    than that. “
  42. • Functions should hardly ever be 20 lines long. •

    For a nicer impact make a function not bigger than 4 lines of code. • The indent level of a function should not be greater than one or two. • The blocks within if, else and while should be one line long. • A long descriptive name is better than a short enigmatic name. About Functions
  43. • Zero (niladic) ◦ Ideal number of arguments • One

    (monadic) ◦ A good number of arguments • Two (dyadic) ◦ A good number of arguments • Three (triadic) ◦ Should be avoided where possible. • More than three (polyadic) ◦ Maybe we should wrap the arguments in a new type Function arguments
  44. System System Command Query Separation Command Query Output System Changed

    state Output (result) Changed state Output (result)
  45. Every time you write a comment, a cat cries somewhere...

  46. Android Jetpack A set of libraries, tools and guides to

    help make app building quick and easy.
  47. Android Jetpack Follow best practices Fewer crashes and less memory

    leaks with backwards-compatibility baked in. No boilerplate code You can focus on what makes your app great. Reduce fragmentation Reduce complexity with libraries that work consistently across Android versions and devices.
  48. Android Jetpack UI Jetpack Compose Foundation AndroidX, Android KTX Architecture

    LiveData, ViewModel, Lifecycle, Room, Navigation, Paging, Hilt Behaviour Slices, Security, Permissions
  49. *Recommended app architecture Activity / Fragment Model Room Remote Data

    source Retrofit SQLite REST API ViewModel LiveData Repository
  50. Architecture Components: Room for databases Components Entity, Dao, Database “Relations”

    @Embedded, @Relation, @ForeignKey Queries @Insert, @Update, @Delete, @Query, @RawQuery
  51. 🛠Tools for Android development CI/CD Pipeline

  52. Learning Plan “A goal without a plan is just a

    wish.” Antoine de Saint-Exupéry
  53. Achievable Learning Plan @Work Code review & Pull Request @Home

    SWOT & OKRs
  54. Achievable Learning Plan @School OOP, Database, Unit Testing, etc @Home

    SWOT & OKRs
  55. @Work Code review & Pull Request

  56. <Code> Reviewer Author

  57. Author

  58. Writing the code • Make sure you understand your task

    • Refactor the code if it’s unreadable • Write tests and follow the team conventions • Format your code before commit it
  59. The boy scout rule Leave the campground cleaner than you

    found it.
  60. Before the code review • Add relevant commit comments •

    Send pull requests often • Have minimum 2 reviewers (one is senior)
  61. After the code review • Be humble • You are

    on the same side with your reviewer(s) • Know when to unlearn the old habits
  62. Reviewer

  63. Use I… comments • I think… • I would… •

    I believe… • I suggest...
  64. Ask questions • Have you consider using… ? • What

    do you think about… ? • Have you tried to… ?
  65. It’s about the code, not about the coder • This

    code… • This function… • This line of code...
  66. Feedback equation* Observation of a behavior Impact of the behavior

    Question or Request I observed this function has 60 lines. This makes it difficult for me to understand the logic. I suggest extracting a part of the code into other functions and give them relevant names. * Defined by Lara Hogan
  67. @Home SWOT & OKRs

  68. The “process” SWOT Where I am now Retro How it

    was and what’s next OKRs What I want to achieve Review What I achieved 01 02 04 03
  69. Personal SWOT Analysis ME Weaknesses Skills that should be improved

    (technical or work habits) Threats Impediments at work, changes, weaknesses lead to threats Strengths Advantages like: skills, achievements, certifications, education, connections Opportunities Events, conferences, new role/project, industry growing
  70. • Goal setting in a collaborative way • Objective =>

    WHAT • Key results => HOW • “It’s not a key result unless it has a number” OKRs
  71. • Superpower #1 => focus and commit to priorities •

    Superpower #2 => align and connect for teamwork • Superpower #3 => track for accountability • Superpower #4 => stretch for amazing OKRs superpowers
  72. • 0.7 to 1.0 = green (we delivered) • 0.4

    to 0.6 = yellow (we made progress, but fell short of completion) • 0.0 to 0.3 = red (we failed to make real progress) Scoring @Google
  73. OKR sample Learn Kotlin for Android Development 6 months /

    weekly review Quantity Goal Quality Goal Result 1 Kotlin Koan per week Learn specific features of the language => 1 feature / week Exercise often and on a set of Koans proposed by JetBrains Write one detailed article about a specific topic per month Improve my writing skills and learn by teaching to others Learn new things, help the community and get feedback 3 code samples runned per week Get a repo with samples that I can re-check (use ktlint) Gain real experience in programming using Kotlin
  74. • Score your results • Keep notes of your accomplishments

    • Look for feedback because development is continuous • Surround yourself with people who motivate and inspire you • Find a mentor Review
  75. • Did I accomplish all of my objectives? ◦ YES

    => what contributed to my success? ◦ NO => what obstacles did I encounter? • If I were to rewrite a goal achieved in full, what would I change? • What have I learned that might alter my approach to the next cycle’s OKRs? • Understand what is your WHY • Repeat the process Retrospective
  76. 📃Official Documentation from Google 🌐Blogs and Websites 💻Code Examples (Codelabs

    & GitHub) 📰Newsletters 📚Books & Online Courses From where to learn more... 🎞Videos & Youtube Channels 📻Podcasts 👨‍💻👩‍💻Twitter 🎤Conferences & Meetups 🚨Troubleshooting
  77. From where to learn more...

  78. • Define your objectives and track the progress • Identify

    your learning style • Focus on your strengths • Search for resources and organise them in a plan • Start learning and track your progress • Focus to understand how the things are working • If it is difficult, take a break, and start over My summary in 7 steps
  79. CREDITS: This presentation template was created by Slidesgo, including icons

    by Flaticon, images from Unsplash, and infographics & images by Freepik. THANKS! magdamiu.com @magdamiu