Faster Android Development with Data Binding

Session at the Android Fortnightly Series by GDG Lagos.

A talk about how to use data binding in Android to improve development speed, performance and prevent redundant code.

1. Faster Android development with Data Binding Android Fortnightly Series, July 2016
2. Segun Famisa Software Engineer at Konga,KongaPay @segunfamisa segunfamisa.com
3. What is data binding?
4. What is data binding? • Simply put: binding data, to your layouts. • Changes in data are propagated to the views, and vice versa. • Does not necessarily use the `findViewById ()`
5. What is data binding? Regular Way of accessing views
6. What is data binding? So much boilerplate code Data binding helps bring an end to that. findViewById()
8. Data binding in your Android app
9. Data binding in Android ButterKnife Holdr Data binding library
10. Data binding in Android ButterKnife Holdr Data binding library
11. Data binding in Android ButterKnife Holdr Data binding library Holdr has been deprecated
12. Data binding in Android ButterKnife Holdr Data binding library
13. Why use data binding?
14. Why use data binding? Avoid boilerplate code Efficiency No Performance issues findViewById() Data binding makes the view id’s not useful in code, so, no need to findViewById. Avoid those ugly looking findViewById calls.
15. Why use data binding? Avoid boilerplate code Efficiency No Performance issues findViewById is an expensive call. It traverses the UI hierarchy only once. Data binding improves efficiency of by preventing numerous findViewById calls
16. Why use data binding? Avoid boilerplate code Efficiency No Performance issues Data binding does not use reflection. Every processing happens at compile time. #PerfMatters
17. How to use data binding in Android
18. How to use data binding in Android? What do I need to use data binding? • Android Studio 1.3+ • Gradle 1.5.0-alpha1 and above • Download the library from the Support repository in the Android SDK manager.
19. How to use data binding in Android? Enable data binding in the android block of your app’s build.gradle file android { ... dataBinding.enabled = true }
20. Writing your first data binding code
21. Your first data binding code Make <layout> outer tag Use DataBindingUtil a. Activity b. Fragment
22. Your first data binding code Make <layout> outer tag Use DataBindingUtil a. Activity b. Fragment
23. Your first data binding code Make <layout> outer tag Use DataBindingUtil a. Activity b. Fragment
24. Your first data binding code Make <layout> outer tag Use DataBindingUtil a. Activity b. Fragment
25. Your first data binding code Make <layout> outer tag Use DataBindingUtil a. Activity b. Fragment
26. Yasss, we did it. Let’s take it further!
27. Using variables
28. Using variables 1. Add <variable> tag 2. Set variable
29. Using variables 1. Add <variable> tag 2. Set variable The user variable within data describes a property that may be used within this layout.
30. Using variables 1. Add <variable> tag 2. Set variable
31. Let’s take it further, let’s handle events!
32. Add handler class & method Add handler variable to <data> tag Bind handler to view in code Handling events - Method references
33. Add handler class & method Add handler variable to <data> tag Bind handler to view in code Handling events - Method references
34. Add handler class & method Add handler variable to <data> tag Bind handler to view in code Handling events - Method references
35. Add handler class & method Add handler variable to <data> tag Bind handler to view in code Handling events - Method references
36. Layout details
37. Layout details Imports Expressions Includes Null coalescing
38. Layout details Imports Expressions Includes Null coalescing • Mathematical + - / * % • String concatenation + • Logical && || • Binary & | ^ • Unary + - ! ~ • Shift >> >>> << • Comparison == > < >= <=
39. Layout details Imports Expressions Includes Null coalescing • instanceof • Grouping () • Literals - character, String, numeric, null • Cast • Method calls • Field access • Array access [] • Ternary operator ?:
40. Layout details Imports Expressions Includes Null coalescing Expressions that aren’t supported: “new” “this” “super”
41. Layout details Imports Expressions Includes Null coalescing • You can embed include tags within your layout. • Each include must have an id for you to be able to access it from code. • An <include> tag cannot be the direct child of a <merge> tag
42. Layout details Imports Expressions Includes Null coalescing
43. Layout details Imports Expressions Includes Null coalescing The expression resolves to user.nickName if user. name is null and user. name otherwise
44. Under the hood How data binding works?
45. How data binding in Android works • Begin compilation • Process layout files ◦ Removing every data binding-related stuff in the layout. • Parse expressions • During compile, resolve dependencies • Find setters, and set attributes • Write data binding` Begin Compilation Process layout files Parse Expressions Resolve dependencies Find setters Write binders Java Compilation
46. How data binding in Android works Begin Compilation Process layout files Parse Expressions Resolve dependencies Find setters Write binders Java Compilation
47. How data binding in Android works Begin Compilation Process layout files Parse Expressions Resolve dependencies Find setters Write binders Java Compilation Removes all data binding-related code in the layout
48. Attribute setters Custom setters. Using @BindingAdapter annotation, you can bind custom attributes to static methods. TL;DR you can create your own attributes.
49. Attribute setters Custom setters. Using @BindingAdapter annotation, you can bind custom attributes to static methods.
50. Attribute setters Custom setters. Using @BindingAdapter annotation, you can bind custom attributes to static methods.
51. Resources & References • https://developer.android.com/topic/libraries/data- binding/index.html • https://www.youtube.com/watch?v=NBbeQMOcnZ0 • https://www.youtube.com/watch?v=DAmMN7m3wLU • https://realm.io/news/data-binding-android-boyar-mount/ • https://goo.gl/jwc921
52. We could go on and on and on..
53. Questions? @segunfamisa segunfamisa.com Thank you for listening.