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.

Transcript

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: Inheritance
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.
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
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
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
35. “UNCLEAN” CODE CLEAN CODE
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... Comments
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