Single Activity by Example (Droidcon Italy 2019)

Slides for presentation given at Droidcon Italy 2019

Sample project here: https://github.com/remcomokveld/SingleActivity-DroidconIT

Transcript

3. Single Activity by Example By Remco Mokveld 2
4. Why this talk? Single Activity by Example 3
5. Disney Streaming Services –Twitter User “Until they really fix Backstack Management with fragments this is still going to be painful.” 4
6. Disney Streaming Services –Twitter User “Don’t get the Single Activity hype. It doesn’t scale.” 5
7. Disney Streaming Services –Twitter User “Big projects should be split up in feature modules, one Activity per feature.” 6
8. Disney Streaming Services –Twitter User “Single activity makes it too easy to create spaghetti, that is likely going to be what you get. Multiple activities force you to decouple better.” 7
9. Points to discuss • Fragment Back Stack • Single Activity Scalability 8
10. Disney Streaming Services 9
11. Disney Streaming Services 9
12. Disney Streaming Services 9
13. Disney Streaming Services 9
14. Disney Streaming Services 9
15. Disney Streaming Services 9
16. Disney Streaming Services 9
17. Disney Streaming Services 9
18. Disney Streaming Services 9
19. Disney Streaming Services 9
20. Disney Streaming Services 9
21. Disney Streaming Services 9
22. Fragment Navigation Back stack issues? 10
23. Disney Streaming Services 11 What is a backstack?
24. Disney Streaming Services What is a back stack? 11
25. Disney Streaming Services Stack of cards 12
26. Disney Streaming Services Only the top card is visible 13
27. Disney Streaming Services 13 Only the top fragment has a View
28. Disney Streaming Services All Fragments in the stack are CREATED 14
29. Disney Streaming Services 15
30. Disney Streaming Services 15
31. Disney Streaming Services 15
32. Disney Streaming Services 16 FragmentA
33. Disney Streaming Services 16 FragmentA onCreate
34. Disney Streaming Services 16 FragmentA onCreate CREATED
35. Disney Streaming Services 16 FragmentA CREATED onCreateView
36. Disney Streaming Services 16 FragmentA CREATED onStart
37. Disney Streaming Services 16 FragmentA onStart STARTED
38. Disney Streaming Services 16 FragmentA STARTED onResume
39. Disney Streaming Services 16 FragmentA onResume RESUMED
40. Disney Streaming Services 16 FragmentA FragmentB onResume RESUMED
41. Disney Streaming Services 16 FragmentA FragmentB RESUMED onPause
42. Disney Streaming Services 16 FragmentA FragmentB onPause STARTED
43. Disney Streaming Services 16 FragmentA FragmentB STARTED onStop
44. Disney Streaming Services 16 FragmentA FragmentB onStop CREATED
45. Disney Streaming Services 16 FragmentA FragmentB CREATED onDestroyView
46. Disney Streaming Services 16 FragmentA FragmentB CREATED onCreate
47. Disney Streaming Services 16 FragmentA FragmentB CREATED onCreate CREATED
48. Disney Streaming Services 16 FragmentA FragmentB CREATED CREATED onCreateView
49. Disney Streaming Services 16 FragmentA FragmentB CREATED CREATED onStart
50. Disney Streaming Services 16 FragmentA FragmentB CREATED onStart STARTED
51. Disney Streaming Services 16 FragmentA FragmentB CREATED STARTED onResume
52. Disney Streaming Services 16 FragmentA FragmentB CREATED onResume RESUMED
53. Disney Streaming Services 16 FragmentA FragmentB CREATED RESUMED onPause
54. Disney Streaming Services 16 FragmentA FragmentB CREATED onPause STARTED
55. Disney Streaming Services 16 FragmentA FragmentB CREATED STARTED onStop
56. Disney Streaming Services 16 FragmentA FragmentB CREATED onStop CREATED
57. Disney Streaming Services 16 FragmentA FragmentB CREATED CREATED onDestroyView
58. Disney Streaming Services 16 FragmentA FragmentB CREATED CREATED onDestroy
59. Disney Streaming Services 16 FragmentA FragmentB CREATED onDestroy DESTROYED
60. Disney Streaming Services 16 FragmentA CREATED
61. Disney Streaming Services 16 FragmentA CREATED onCreateView
62. Disney Streaming Services 16 FragmentA CREATED onStart
63. Disney Streaming Services 16 FragmentA onStart STARTED
64. Disney Streaming Services 16 FragmentA STARTED onResume
65. Disney Streaming Services 16 FragmentA onResume RESUMED
66. Disney Streaming Services Unnecessary view creation 17
67. Disney Streaming Services setReorderingAllowed 18
68. Disney Streaming Services 19
69. Disney Streaming Services 19
70. Disney Streaming Services onCreate onCreateView onStart onResume First Transaction onPause onStop onDestroyView Second Transaction onCreate onCreateView onStart onResume
71. Disney Streaming Services onCreate onCreateView onStart First Transaction onStop onDestroyView Second Transaction onCreate onCreateView onStart onResume onResume onPause
72. Disney Streaming Services onCreate onCreateView onStart First Transaction onStop onDestroyView Second Transaction onCreate onCreateView onStart onResume
73. Disney Streaming Services onCreate onCreateView First Transaction onDestroyView Second Transaction onCreate onCreateView onStart onResume onStart onStop
74. Disney Streaming Services onCreate onCreateView First Transaction onDestroyView Second Transaction onCreate onCreateView onStart onResume
75. Disney Streaming Services onCreate First Transaction Second Transaction onCreate onCreateView onStart onResume onCreateView onDestroyView
76. Disney Streaming Services onCreate First Transaction Second Transaction onCreate onCreateView onStart onResume
77. Disney Streaming Services 21 ScreenA
78. Disney Streaming Services 21 ScreenA onCreate CREATED
79. Disney Streaming Services 21 ScreenA ScreenB CREATED onCreate CREATED
80. Disney Streaming Services 21 ScreenA ScreenB CREATED CREATED onCreateView
81. Disney Streaming Services 21 ScreenA ScreenB CREATED onStart STARTED
82. Disney Streaming Services 21 ScreenA ScreenB CREATED onResume RESUMED
83. Disney Streaming Services 21 ScreenA ScreenB CREATED onPause STARTED
84. Disney Streaming Services 21 ScreenA ScreenB CREATED onStop CREATED
85. Disney Streaming Services 21 ScreenA ScreenB CREATED CREATED onDestroyView
86. Disney Streaming Services 21 ScreenA ScreenB CREATED onDestroy
87. Disney Streaming Services 21 ScreenA CREATED onCreateView
88. Disney Streaming Services 21 ScreenA onStart STARTED
89. Disney Streaming Services 21 ScreenA onResume RESUMED
90. Disney Streaming Services Primary Navigation Fragment 22
91. Disney Streaming Services 23 Splash Onboarding MainActivity FavoriteTeam Paywall SignIn MainApp MyTeam ScoreBoard ScoreBoard
92. Disney Streaming Services 23 Splash Onboarding MainActivity FavoriteTeam Paywall SignIn MainApp MyTeam ScoreBoard ScoreBoard
93. Disney Streaming Services 23 Splash Onboarding MainActivity FavoriteTeam Paywall SignIn MainApp MyTeam ScoreBoard ScoreBoard
94. Disney Streaming Services 23 Splash Onboarding MainActivity FavoriteTeam Paywall SignIn MainApp MyTeam ScoreBoard ScoreBoard
95. Disney Streaming Services 23 Splash Onboarding MainActivity FavoriteTeam Paywall SignIn MainApp MyTeam ScoreBoard ScoreBoard
96. Disney Streaming Services 23 Splash Onboarding MainActivity FavoriteTeam Paywall SignIn MainApp MyTeam ScoreBoard MatchDetail
97. Disney Streaming Services 23 Splash Onboarding MainActivity FavoriteTeam Paywall SignIn MainApp MyTeam ScoreBoard MatchDetail
98. Disney Streaming Services 23 Splash Onboarding MainActivity FavoriteTeam Paywall SignIn MainApp MyTeam ScoreBoard MatchDetail
99. Disney Streaming Services Required for nested back stacks 24
100. Disney Streaming Services 25
101. Disney Streaming Services 26
102. Disney Streaming Services 26
103. Disney Streaming Services 26
104. Disney Streaming Services 26
105. Disney Streaming Services 26
106. Disney Streaming Services 26
107. Disney Streaming Services 26 OUTDATED
108. Disney Streaming Services As of activity:1.0.0-alpha06 OnBackPressedDispatcher 27
109. Disney Streaming Services Two Fragment navigation functions 28
110. Disney Streaming Services 29
111. Disney Streaming Services 30
112. Scalability Single Activity by Example 31
113. Disney Streaming Services Activity is the single entry point of each app 32
114. Disney Streaming Services Fragment is the single entry point of each feature 33
115. Disney Streaming Services Activity represents an entire user session 34
116. Disney Streaming Services Fragments represent individual screens or flows 35
117. Disney Streaming Services Fragments represent individual screens or flows 36
118. Onboarding flow Single Activity by Example 37
119. Disney Streaming Services IAP back behavior 38
120. Disney Streaming Services IAP back behavior 38 FollowTeam
121. Disney Streaming Services IAP back behavior 38
122. Disney Streaming Services IAP back behavior 38 FollowTeam
123. Disney Streaming Services IAP back behavior 38 FollowTeam SignUp
124. Disney Streaming Services Lots of different screens 39
125. Disney Streaming Services Complex back logic 40
126. Disney Streaming Services OnboardingActivity? 41
127. Disney Streaming Services Is onboarding done? 42
128. Disney Streaming Services 43 LoginFragment SignUpFragment OnboardingFragment FollowTeamFragment IAPFragment PaywallFragment
129. Disney Streaming Services replaceStack(OnboardingFragment()) 44
130. Disney Streaming Services class NHLActivity : Activity(), OnboardingHost 45
131. Disney Streaming Services 46
132. Disney Streaming Services “Type a quote here.” 47
133. Disney Streaming Services Find interface in parents 48
134. Disney Streaming Services 49
135. Disney Streaming Services 49
136. Disney Streaming Services 49
137. Disney Streaming Services 49
138. Disney Streaming Services 49
139. Disney Streaming Services 49
140. Disney Streaming Services What about that custom back behavior? 50
141. Disney Streaming Services 51
142. Bottom Navigation Single Activity by Example 52
143. Disney Streaming Services (Almost) According to material.io (as of today) 53
144. Disney Streaming Services Builds a stack within each tab 54 MyTeam
145. Disney Streaming Services Builds a stack within each tab 54 MyTeam
146. Disney Streaming Services Switching tabs should reset the back stack 55 MyTeam
147. Disney Streaming Services Switching tabs should reset the back stack 55 MyTeam
148. Disney Streaming Services Switching tabs should reset the back stack 55 MyTeam
149. Disney Streaming Services Back on first tab closes the app 56
150. Disney Streaming Services Back on first tab closes the app 56
151. Disney Streaming Services Back on first tab closes the app 56
152. Disney Streaming Services Pressing back on second and third top-level tab takes you to the first 57 MyTeam
153. Disney Streaming Services Pressing back on second and third top-level tab takes you to the first 57 MyTeam
154. Disney Streaming Services Pressing tab item while on top level resets content 58
155. Disney Streaming Services Pressing tab item while on top level resets content 58
156. Disney Streaming Services 59
157. Startup checks Single Activity by Example 60
158. Disney Streaming Services Needs to be done on every startup 61
159. Disney Streaming Services Pre fetch data 62
160. Disney Streaming Services Lapsed subscription check 63
161. Disney Streaming Services Fetch A/B Configs 64
162. Disney Streaming Services SplashActivity? 65
163. Disney Streaming Services SingleActivity.onCreate 66
164. Disney Streaming Services 67
165. Disney Streaming Services 68
166. Key Takeaways & Tips Single Activity by Example 69
167. Disney Streaming Services Nesting Fragments is good 70
168. Disney Streaming Services Every UI feature can be built in a Fragment 71
169. Disney Streaming Services If a feature becomes too big, split your Fragment into multiple (child) Fragments 72
170. Disney Streaming Services Fragments should never depend on their host 73
171. Disney Streaming Services Fragments should depend on their host implementing an interface 74
172. Disney Streaming Services Always use Primary Navigation Fragment 75
173. Disney Streaming Services Always use setReorderingAllowed 76
174. Disney Streaming Services Single Activity gives you full control over your back stack 77
175. Fragment Caveats Single Activity by Example 78
176. Disney Streaming Services Only do initial navigation when savedInstanceState == null 79
177. Disney Streaming Services Don’t mixup fragmentManager and childFragmentManager 80
178. Disney Streaming Services For navigation screens always: Add to back stack Or Replace the back stack 81
179. Disney Streaming Services Transitions support is… 82
180. Disney Streaming Services bit.ly/droidcon-it-single-activity 83
181. Thank you! Questions?