Building complex apps easily

Building a good app is hard and you don't need to solve problems that have already been solved before. This talk covers a bunch of libraries that make your life as an Android developer easier and help you focus on implementing your actual idea and not worry about mundane stuff.

Code shown in this talk can be found here - github.com/mustafa01ali/Sherlock

Transcript

1. Building complex apps easily Mustafa Ali
2. Building a good app is hard
3. “If I have seen farther than others, it is by standing on the shoulders of giants.” - Isaac Newton Mt. St. Helens Crater Rim by brookehoyer (CC-BY SA)
4. Writing boilerplate code sucks
5. Butter Knife View “injection” library for Android Eliminates boilerplate code Performs annotation-based code generation No reflection Can “inject” listeners as well jakewharton.github.io/butterknife
6. Butter Knife Usage public class ExampleActivity extends Activity { @InjectView(R.id.title) TextView title; @InjectView(R.id.subtitle) TextView subtitle; @InjectView(R.id.footer) TextView footer; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.simple_activity); ButterKnife.inject(this); // TODO Use "injected" views... } } public void inject(ExampleActivity a) { a.subtitle = (android.widget.TextView) a.findViewById(2130963232); a.footer = (android.widget.TextView) a.findViewById(21309685455); a.title = (android.widget.TextView) a.findViewById(21309686566); }
7. Butter Knife Usage @OnClick(R.id.submit) public void sayHi(Button button) { button.setText("Live long and prosper"); } @OnClick({ R.id.door1, R.id.door2, R.id.door3 }) public void pickDoor(DoorView door) { if (door.hasPrizeBehind()) { Toast.makeText(this, "You win!", LENGTH_SHORT).show(); } else { Toast.makeText(this, "DIE DIE DIE!", LENGTH_SHORT).show(); } } @OnItemSelected(R.id.list_view) void onItemSelected(int position) { // Do something with the “chosen one” } @OnItemSelected(value = R.id.maybe_missing, callback = NOTHING_SELECTED) void onNothingSelected() { // Y u no select anything? }
8. Integrating APIs is tricky GET, PUT, POST …. WUT???
9. Retrofit Type-safe REST client for Android and Java Turns your REST API into a Java interface Each HTTP verb is represented by an annotation Requests can be both synchronous & asynchronous Automatic deserialization using GSON, Simple, etc square.github.io/retrofit
10. Retrofit Usage public interface GoogleBooksService { @GET("/books/v1/volumes") void search(@Query("q") String query, Callback<SearchResults> callback); } GET https://www.googleapis.com/books/v1/volumes?q=android RestAdapter restAdapter = new RestAdapter.Builder() .setEndpoint("https://www.googleapis.com") .setLogLevel(RestAdapter.LogLevel.FULL) .build(); GoogleBooksService service = restAdapter.create(GoogleBooksService.class);
11. Synchronous SearchResult result = service.search(query); Retrofit Usage Asynchronous service.search(query, callback); private Callback<SearchResults> callback = new Callback<SearchResults>() { @Override public void success(SearchResults searchResults, Response response) { displayResults(searchResults); } @Override public void failure(RetrofitError error) { displayError(error); } };
12. Image Loading
13. Picasso Hassle-free image downloading and caching Handles ImageView recycling automatically Performs download cancellations automatically Allows complex image transformations Automatic memory and disk caching square.github.io/picasso
14. Picasso Usage Picasso.with(context).load("http://i.imgur.com/DvpvklR.png").into(imageView); Picasso.with(context) .load(url) .resize(50, 50) .centerCrop() .placeholder(R.drawable.user_placeholder) .error(R.drawable.user_placeholder_error) .into(imageView) Picasso.with(context).load(R.drawable.landing_screen).into(imageView1); Picasso.with(context).load("file:///android_asset/DvpvklR.png").into(imageView2); Picasso.with(context).load(new File(...)).into(imageView3);
15. Microsavings Small things, big benefits
16. Timber Logger built on top of android.util.Log Small and extensible API Automatic smart tagging No logging in production, ever! jakewharton.github.io/timber
17. Timber Usage public class SherlockApplication extends Application { @Override public void onCreate() { super.onCreate(); if (BuildConfig.DEBUG) { Timber.plant(new Timber.DebugTree()); } else { Timber.plant(new CrashReportingTree()); } } } Timber.i("A button with ID %s was clicked to say '%s'.", button.getId(), button.getText()); Timber.e("Search failed with error: " + error.getKind());
18. Timber Usage private static class CrashReportingTree extends Timber.HollowTree { @Override public void i(String message, Object... args) { // TODO e.g., Crashlytics.log(String.format(message, args)); } @Override public void i(Throwable t, String message, Object... args) { i(message, args); // Just add to the log. } @Override public void e(String message, Object... args) { i("ERROR: " + message, args); // Just add to the log. } @Override public void e(Throwable t, String message, Object... args) { e(message, args); // TODO e.g., Crashlytics.logException(t); } }
19. Demo
20. Q & A Ask me questions! Code available at - github.com/mustafa01ali/Sherlock
21. Thank you! You can reach out to me at @mustafa01ali