A Pirate's Guidelines for Android

Fragments suck. State is hard. Android is hostile. How can you write a crashfree, bug free app on such a buggy, fragmented OS? In the spirit of Jack Sparrow, I’ve come up with some guidelines for making Android development less of a headache. Talk would basically be about how we’ve adapted and used each of these in the Electric Objects companion app.

- There is a one to one correspondence between a wireframe screen and an Activity.
- Every Activity has it's own layout file.
- Reusable View code belongs in a View class.
- Fragments are not simple. Don't use fragments.
- Embrace state machines.
- Corollary: Every Activity is a State Machine.
- Override on configuration changed at your own peril (aka never)
- Retain nothing but state (and hardware adapters)

This talk was first given at DroidCon NYC 2015.
http://droidcon.nyc/2015/dcnyc/10/

Transcript

1. Android Development The Pirate's CODE
4. Android Development The Pirate's Guidelines
5. Where did these come from?
6. Where did these come from? How Do I Start An Android App?
10. How Do I Start An Android App?
11. How do I map these mock ups to Android 'Pieces'?
16. Pirate Guideline #1
17. Pirate Guideline #1 There is a one to one correspondence between a wireframe screen and an Activity
18. Super easy to get started writing a new application
22. OkayActivity.java setContentView(R.layout.activity_generic.xml); SuccessActivity.java setContentView(R.layout.activity_generic.xml);
25. luke: hey lisa! !
26. luke: hey lisa! ! lisa: hey! !!
27. luke: the app's looking really great! !!
28. luke: the app's looking really great! !! lisa: /me blushes ☺️
29. luke: just one thing
30. luke: just one thing luke: *explains how someone could get stuck*
31. luke: we need a logout button
34. lisa: /me prepares diatribe on the Android Back Button
35. lisa: /me realizes she is vastly outnumbered by iOS devices
37. lisa: /me ctrl-C; ctrl-V
38. OkayActivity.java setContentView(R.layout.activity_generic.xml); SuccessActivity.java setContentView(R.layout.activity_slightly_less_generic.xml);
39. Pirate Guideline #2
40. Pirate Guideline #2 Every Activity has its own layout file
43. PRGRAMMING BSET PRACTICES PRINCIPAL 101
44. PRGRAMMING BSET PRACTICES PRINCIPAL 101 DRY: Don't Repeat Yourself
46. Pirate Guideline #3
47. Pirate Guideline #3 Reusable View code belongs in a View class
50. PRGRAMMING BSET PRACTICES PRINCIPAL 101
51. PRGRAMMING BSET PRACTICES PRINCIPAL 101 Favor composition over inheritance
56. Pirate Guideline #3A Reusable View attributes belong in a style
68. !""""
69. Pirate Guideline #4
70. Pirate Guideline #4 Fragments are not simple. Don't use fragments.*
71. Pirate Guideline #4 Fragments are not simple. Don't use fragments.* *unless it is absolutely necessary
73. @Override public void onConfigurationChanged(Configuration newConfig) { super.onConfigurationChanged(newConfig); }
74. @Override public void onConfigurationChanged(Configuration newConfig) { super.onConfigurationChanged(newConfig); \\ ~~something real hacky~~ }
75. —languages not changing correctly
76. —languages not changing correctly —views not resizing properly
77. —languages not changing correctly —views not resizing properly —strange invocations to .onSaveInstanceState() in onConfigurationChanged
78. —BUGGY —HARD TO TEST —HARD TO FIX
79. Pirate Guideline #5
80. Pirate Guideline #5 Never override configuration changed.*
81. Pirate Guideline #5 Never override configuration changed.* * for view code
82. setRetainState(true);
83. setRetainState(true); How well do you really know the Activity Lifecycle?
85. @Override protected void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); // save my state! }
86. Pirate Guideline #6 Retain nothing but state*
87. Pirate Guideline #6 Retain nothing but state* *and hardware adapters
88. CAVEAT:
89. CAVEAT: headless fragments
93. Pirate Guideline #7
94. Pirate Guideline #7 Embrace state machines
95. A State Machine —States are explicitly defined —Can only do certain things in each state —Where you can go next depends on where you are now
100. Android Development A Pirate's Guidelines
101. —There is a one to one correspondence between a wireframe screen and an Activity —Every Activity has its own layout file —Reusable View code belongs in a View class —Fragments are not simple. Don't use fragments.* —Never override configuration changed* —Retain nothing but state* —Embrace state machines
102. ~thank you~
103. Lisa Neigut work @electricobjects me on the internet, @niftynei