Android Architectures and Clean Code

Transcript

1. Android Architectures and Clean Code
8. Slide google maps tablet search result
10. // manager made me do it // hack for release 1.2.4 // this should never happen // TODO: fix me before Sunday // WTF???
13. A definition Clean Code min(X) / X = WTF / LINE_OF_CODE
17. Object calisthenics - One level of indentation per method - Don’t use the ELSE keyword - Wrap all primitives and String - First class collections - One dot per line - Don’t abbreviate - Keep all entities small - No classes with more than two instance variables - No getters and setters
19. Correctness by design Order[] ordersWithinRange(String startDate, String endDate) {...}
20. Correctness by design Order[] ordersWithinRange(Calendar startDate, Calendar endDate) {...}
21. Correctness by design Order[] ordersWithinRange(DateRange range) {...}
22. Kill the boilerplate code Intent intent = new Intent(this, VideoActivity.class); intent.putExtra("video", mVideo); intent.setFlags(FLAG_ACTIVITY_SINGLE_TOP); this.startActivity(intent);
23. Kill the boilerplate code navigate(this) .clearingBackStack() .toVideoActivity() .withVideo(mVideo);
24. Bonus project: Icepick @Icicle String username; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); Bundles.restoreInstanceState(this, savedInstanceState); } public void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); Bundles.saveInstanceState(this, outState); }
25. Mutability class Event { @JsonName("o_name") void setName(String name) {...} @JsonName("D_address") void setAddress(String date) {...} @JsonName("valid_for") void setExpires(String duration) {...} }
26. Mutability class Event { final String name; final Address address; final DateRange duration; Event(String name, Address address, DateRange duration) {...} static class Address {...} static class DateRange {...} }
27. Mutability String doSomething() { StringBuffer buffer = new StringBuffer(); if (buffer.size() == 0) { buffer.append("("); } // Share a mutable instance. // Potential bugs will lurk here. return doSomethingElse(buffer); }
28. Mutability String doSomething() { String partialResult = ""; if (partialResult.length() == 0) { partialResult += "("; } // String is immutable. // Sharing won't cause troubles to the caller. return doSomethingElse(partialResult); }
29. Bonus project: clj-ds - Persistent Stack - Persistent Vector - Persistent Set - Persistent Map - … and many more!
32. A definition (cont.) Clean Architecture min(Y) / Y = WTF / DATA_FLOW
37. The way Content Provider: - Loaders - Cursors - Database - SyncAdapter
39. The way Dagger: - Modules - In-memory singletons - Event bus - Mortar/Flow
41. The way RxJava: - Composition - Observable state - Subscriptions
44. Information flow
45. Sync flow On New day: fetch products and offers On App opening: sync basket, user data, orders On Delivery screen: sync available slots On Basket changed: sync basket
46. The lean way Remix: - SyncAdapter + BG ThreadPoolExecutor - Loaders for each piece of info - In-memory mutable data - RxJava for composition (Basket + Products) - Separate syncing from displaying
49. Questions? @frankiesardo +Frankie Sardo frankiesardo