android dev toolbox

Android dev toolboxAVGeeks, 2015

Shem Magnezi@shemag8 | shem8.wordpress.com

Part 1 Libraries

Why use external libraries?

▣Let others speed up your development▣Code that is heavily

used▣Small hidden bugs /

case you didn’t think of▣Help others

Why not?

▣Legal issues▣Old/ buggy code▣Your core functions

1.Basics

Support Library & Design Support Libraryset of code libraries that provide backward-compatible versions of Android framework APIs as well as features

that are only available through the library APIs.

● Fragment

● NotificationCompat

● LocalBroadcastManager

● ViewPager

● PagerTitleStrip

● PagerTabStrip

● DrawerLayout

SlidingPaneLayout

● Navigation View

● Floating labels

● FAB

● Snackbar

● CoordinatorLayout

● Collapsing Toolbars

● ...

Google Play Servicestake advantage of the latest, Google-powered features such as Maps, Google+, and more, with automatic

platform updates distributed as an APK through the Google Play store.

● Google+

● Google Account Login

● Google App Invites

● Google Analytics

● Google Cloud Messaging

● Google Fit

● Google Location

● Google Maps

ParcelerAndroid Parcelables made easy through code generation.

@Parcel

public class Example {

String name;

int age;

public Example(){ /*Required empty bean constructor*/ }

public Example(int age, String name) {

this.age = age;

this.name = name;

}

public String getName() { return name; }

public int getAge() { return age; }

}

Bundle bundle = new Bundle();

bundle.putParcelable("example", Parcels.wrap(example));

Example example = Parcels.unwrap(this.getIntent().getParcelableExtra("example"));

http://square.github.io/picasso/

IcepickAndroid library that eliminates the boilerplate of saving and restoring instance state.

class ExampleActivity extends Activity {

@State String username; // This will be automatically saved and restored

@Override public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

Icepick.restoreInstanceState(this, savedInstanceState);

}

@Override public void onSaveInstanceState(Bundle outState) {

super.onSaveInstanceState(outState);

Icepick.saveInstanceState(this, outState);

}

}

https://github.com/frankiesardo/icepick

Joda timeJoda-Time is the widely used replacement for the Java date and time classes.

public boolean isAfterPayDay(DateTime datetime) {

if (datetime.getMonthOfYear() == 2) { // February is month 2!!

return datetime.getDayOfMonth() > 26;

}

return datetime.getDayOfMonth() > 28;

}

public Days daysToNewYear(LocalDate fromDate) {

LocalDate newYear = fromDate.plusYears(1).withDayOfYear(1);

return Days.daysBetween(fromDate, newYear);

}

public boolean isRentalOverdue(DateTime datetimeRented) {

Period rentalPeriod = new Period().withDays(2).withHours(12);

return datetimeRented.plus(rentalPeriod).isBeforeNow();

}

public String getBirthMonthText(LocalDate dateOfBirth) {

return dateOfBirth.monthOfYear().getAsText(Locale.ENGLISH);

}

https://github.com/JodaOrg/joda-time

GuavaGoogle core libraries for Java 6+

@Override public String toString() {

return Objects.toStringHelper(this)

.add("name", name)

.add("nickname", nickname)

.add("favMovie", favMovie)

.toString();

}

public String preferredName() {

return Objects.firstNonNull(nickname, name);

}

String seriesId =

CharMatcher.DIGIT.or(CharMatcher.is('-'))

.retainFrom(input);

https://github.com/google/guava

2.Network

GsonConvert Java Objects into their JSON representation

Albums albums = new Albums();

albums.title = "Free Music Archive - Albums";

albums.message = "";

albums.total = "11259";

albums.total_pages = 2252;

albums.page = 1;

albums.limit = "5";

GsonBuilder builder = new GsonBuilder();

Gson gson = builder.create();

System.out.println(gson.toJson(albums));

System.out.println(gson.fromJson(gson.toJson(albums)));

https://github.com/google/gson

JacksonMulti-purpose Java library for processing JSON data format. Jackson aims to be the best possible combination

of fast, correct, lightweight, and ergonomic for developers.

JsonFactory jsonFactory = new JsonFactory(); // or, for data binding,

org.codehaus.jackson.mapper.MappingJsonFactory

JsonGenerator jg = jsonFactory.createJsonGenerator(file, JsonEncoding.UTF8); // or Stream, Reader

TokenBuffer buffer = new TokenBuffer();

// serialize object as JSON tokens (but don't serialize as JSON text!)

objectMapper.writeValue(buffer, myBean);

// read back as tree

JsonNode root = objectMapper.readTree(buffer.asParser());

// modify some more, write out

String jsonText = objectMapper.writeValueAsString(root);

https://github.com/FasterXML/jackson

VolleyVolley is an HTTP library that makes networking for Android apps easier and most importantly, faster.

RequestQueue queue = Volley.newRequestQueue(this);

String url ="http://www.google.com";

// Request a string response from the provided URL.

StringRequest stringRequest = new StringRequest(Request.Method.GET, url,

new Response.Listener<String>() {

@Override

public void onResponse(String response) {

// Display the first 500 characters of the response string.

mTextView.setText("Response is: "+ response.substring(0,500));

}

}, new Response.ErrorListener() {

@Override

public void onErrorResponse(VolleyError error) {

mTextView.setText("That didn't work!");

}

});

// Add the request to the RequestQueue.

queue.add(stringRequest);

http://developer.android.com/training/volley/index.html

OkHttpAn HTTP & SPDY client for Android and Java applications

public static final MediaType JSON = MediaType.parse("application/json; charset=utf-8");

OkHttpClient client = new OkHttpClient();

String post(String url, String json) throws IOException {

RequestBody body = RequestBody.create(JSON, json);

Request request = new Request.Builder()

.url(url)

.post(body)

.build();

Response response = client.newCall(request).execute();

return response.body().string();

}

http://square.github.io/okhttp/

FlatBuffersMemory Efficient Serialization Library

ByteBuffer bb = ByteBuffer.wrap(data);

Monster monster = Monster.getRootAsMonster(bb);

short hp = monster.hp();

Vec3 pos = monster.pos();

https://github.com/google/flatbuffers

RetrofitA type-safe HTTP client for Android and Java

public interface GitHubService {

@GET("/users/{user}/repos")

Call<List<Repo>> listRepos(@Path("user") String user);

}

Retrofit retrofit = new Retrofit.Builder()

.baseUrl("https://api.github.com")

.build();

GitHubService service = retrofit.create(GitHubService.class);

Call<List<Repo>> repos = service.listRepos("octocat");

http://square.github.io/retrofit/

3.Basics

ORMLiteActiveAndroid allows you to save and retrieve SQLite database records without ever writing a single SQL

statement.

@DatabaseTable(tableName = "accounts")

public class Account {

@DatabaseField(id = true)

private String name;

@DatabaseField(canBeNull = false)

private String password;

}

// create an instance of Account

String name = "Jim Smith";

Account account = new Account(name, "_secret");

// persist the account object to the database

accountDao.create(account);

// retrieve the account

Account account2 = accountDao.queryForId(name);

http://ormlite.com/

ActiveAndroidActiveAndroid allows you to save and retrieve SQLite database records without ever writing a single SQL

statement.

@Table(name = "Categories")

public class Category extends Model {

@Column(name = "Name")

public String name;

}

@Table(name = "Items")

public class Item extends Model {

@Column(name = "Name")

public String name;

@Column(name = "Category")

public Category category;

}

Category restaurants = new Category();

restaurants.name = "Restaurants";

restaurants.save();

new Select()

.from(Item.class)

.where("Category = ?", category.getId())

.orderBy("Name ASC")

.execute();

http://www.activeandroid.com/

GreenDAOgreenDAO is an open source project to help Android developers working with data stored in SQLite.

List joes = userDao.queryBuilder()

.where(Properties.FirstName.eq("Joe"))

.orderAsc(Properties.LastName)

.list();

QueryBuilder<User> queryBuilder = userDao.queryBuilder();

queryBuilder.join(Properties.addressId, Address.class)

.where(AddressDao.Properties.Street.eq("Sesame Street"));

List<User> users = queryBuilder.list();

List orders = customer.getOrders();

daoSession.delete(newOrder);

orders.remove(newOrder);

http://greendao-orm.com/

SquidbSquiDB is a SQLite database layer for Android.

// This is a table schema

@TableModelSpec(className = "Person", tableName = "people")

public class PersonSpec {

public String firstName;

public String lastName;

@ColumnSpec(name = "creationDate")

public long birthday;

}

// This is how you'd work with the generated model

Person newPerson = new Person()

.setFirstName("Sam")

.setLastName("Bosley")

.setBirthday(System.currentTimeMillis());

db.persist(newPerson);

long ageCutoff = System.currentTimeMillis() - (DateUtil.YEAR_IN_MILLIS * 18);

Query peopleWhoCanVote = Query.select().where(Person.BIRTHDAY.lt(ageCutoff));

// This becomes select * from people where people.birthday < ? where ? is the age cutoff arg

SquidCursor<Person> voters = db.query(Person.class, peopleWhoCanVote);

https://github.com/yahoo/squidb

RealmRealm is a mobile database that runs directly inside phones, tablets or wearables

// Define you model class by extending the RealmObject

public class Dog extends RealmObject {

@Required private String name;

private int age;

}

public class Person extends RealmObject {

@Required private String name;

private String imageUrl;

private RealmList<Dog> dogs;

}

// Use them like regular java objects

Dog dog = new Dog();

dog.setName("Rex");

Realm realm = Realm.getInstance(context);

realm.beginTransaction();

realm.copyToRealm(dog);

realm.commitTransaction();

// Get a Realm instance for this thread

Realm realm = Realm.getInstance(context);

Dog dog = realm.where(Dog.class).equalTo("name", "Rex").findFirst();

https://github.com/realm/realm-java

4.Images

Universal image loaderUIL aims to provide a powerful, flexible and highly customizable instrument for image loading, caching and

displaying.

ImageLoader imageLoader = ImageLoader.getInstance(); // Get singleton instance

// Load image, decode it to Bitmap and display Bitmap in ImageView (or any other view

// which implements ImageAware interface)

imageLoader.displayImage(imageUri, imageView);

// Load image, decode it to Bitmap and return Bitmap to callback

imageLoader.loadImage(imageUri, new SimpleImageLoadingListener() {

@Override

public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {

// Do whatever you want with Bitmap

}

});

// Load image, decode it to Bitmap and return Bitmap synchronously

Bitmap bmp = imageLoader.loadImageSync(imageUri);

https://github.com/nostra13/Android-Universal-Image-Loader

PicassoA powerful image downloading and caching library for Android

Picasso.with(context).load("http://i.imgur.com/DvpvklR.png").into(imageView);

Picasso.with(context)

.load(url)

.resize(50, 50)

.centerCrop()

.into(imageView);

Picasso.with(context)

.load(url)

.placeholder(R.drawable.user_placeholder)

.error(R.drawable.user_placeholder_error)

.into(imageView);

http://square.github.io/picasso/

GlideAn image loading and caching library for Android focused on smooth scrolling

// For a simple view:

@Override

public void onCreate(Bundle savedInstanceState) {

ImageView imageView = (ImageView) findViewById(R.id.my_image_view);

Glide.with(this).load("http://goo.gl/gEgYUd").into(imageView);

}

// For a simple image list:

@Override

public View getView(int position, View recycled, ViewGroup container) {

...

String url = myUrls.get(position);

Glide.with(myFragment)

.load(url)

.centerCrop()

.placeholder(R.drawable.loading_spinner)

.crossFade()

.into(myImageView);

return myImageView;

}

https://github.com/bumptech/glide

5.Utils

EventBussimplifies the communication between components

public class MessageEvent { /* Additional fields if needed */ }

eventBus.register(this);

public void onEvent(AnyEventType event) {/* Do something */};

eventBus.post(event);

http://square.github.io/otto/

OttoOtto is an event bus designed to decouple different parts of your application while still allowing them to

communicate efficiently.

Bus bus = new Bus();

bus.post(new AnswerAvailableEvent(42));

bus.register(this);

@Subscribe

public void answerAvailable(AnswerAvailableEvent event) {

// TODO: React to the event somehow!

}

http://square.github.io/otto/

Dagger 2A fast dependency injector for Android and Java

class Thermosiphon implements Pump {

private final Heater heater;

@Inject

Thermosiphon(Heater heater) {

this.heater = heater;

}

}

class CoffeeMaker {

@Inject Heater heater;

@Inject Pump pump;

}

@Provides Heater provideHeater() {

return new ElectricHeater();

}

CoffeeShop coffeeShop = DaggerCoffeeShop.builder()

.dripCoffeeModule(new DripCoffeeModule())

.build();

http://google.github.io/dagger/

RoboguiceGoogle Guice on Android

@ContentView(R.layout.main)

class RoboWay extends RoboActivity {

@InjectView(R.id.name)

TextView name;

@InjectView(R.id.thumbnail)

ImageView thumbnail;

@InjectResource(R.drawable.icon)

Drawable icon;

@InjectResource(R.string.app_name) String myName;

@Inject

LocationManager loc;

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

name.setText( "Hello, " + myName );

}

}

https://github.com/roboguice/roboguice

Butter KnifeField and method binding for Android views

class ExampleActivity extends Activity {

@Bind(R.id.title) TextView title;

@Bind(R.id.subtitle) TextView subtitle;

@Bind(R.id.footer) TextView footer;

@Override public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.simple_activity);

ButterKnife.bind(this);

}

@BindString(R.string.title) String title;

@BindDrawable(R.drawable.graphic) Drawable graphic;

@BindColor(R.color.red) int red; // int or ColorStateList field

@BindDimen(R.dimen.spacer) Float spacer; // int (for pixel size) or float (for exact value)

@OnClick(R.id.submit)

public void submit(View view) {

// TODO submit data to server...

}

}

http://jakewharton.github.io/butterknife/

AndroidAnnotationsan Open Source framework that speeds up Android development. It takes care of the plumbing, and lets you

concentrate on what's really important.

@EActivity(R.layout.translate) // Sets content view to R.layout.translate

public class TranslateActivity extends Activity {

@ViewById EditText textInput; // Injects R.id.textInput

@ViewById(R.id.myTextView) TextView result; // Injects R.id.myTextView

@AnimationRes Animation fadeIn; // Injects android.R.anim.fade_in

@Click //When R.id.doTranslate button is clicked

void doTranslate() {

translateInBackground(textInput.getText().toString());

}

@Background //Executed in a background thread

void translateInBackground(String textToTranslate) {

String translatedText = callGoogleTranslate(textToTranslate);

showResult(translatedText);

}

@UiThread //Executed in the ui thread

void showResult(String translatedText) {

result.setText(translatedText);

result.startAnimation(fadeIn);

}

}

https://github.com/excilys/androidannotations

NineOldAndroidsAndroid library for using the Honeycomb (Android 3.0) animation API on all versions of the platform back to 1.0!

ObjectAnimator.ofFloat(myObject, "translationY", -myObject.getHeight()).start();

ValueAnimator colorAnim = ObjectAnimator.ofInt(this, "backgroundColor",0xFFFF8080, 0xFF8080FF);

colorAnim.setEvaluator(new ArgbEvaluator());

colorAnim.setRepeatCount(ValueAnimator.INFINITE);

colorAnim.setRepeatMode(ValueAnimator.REVERSE);

colorAnim.start();

AnimatorSet set = new AnimatorSet();

set.playTogether(

ObjectAnimator.ofFloat(myView, "rotationX", 0, 360),

ObjectAnimator.ofFloat(myView, "rotationY", 0, 180),

ObjectAnimator.ofFloat(myView, "rotation", 0, -90),

ObjectAnimator.ofFloat(myView, "translationX", 0, 90),

ObjectAnimator.ofFloat(myView, "translationY", 0, 90),

ObjectAnimator.ofFloat(myView, "scaleX", 1, 1.5f),

ObjectAnimator.ofFloat(myView, "scaleY", 1, 0.5f),

ObjectAnimator.ofFloat(myView, "alpha", 1, 0.25f, 1)

);

set.setDuration(5 * 1000).start();

animate(myButton).setDuration(2000).rotationYBy(720).x(100).y(100);

http://nineoldandroids.com/

Priority Jobqueue A Job Queue specifically written for Android to easily schedule jobs (tasks) that run in the background, improving

UX and application stability.

jobManager.addJobInBackground(new PostTweetJob(status));

public class PostTweetJob extends Job {

public static final int PRIORITY = 1;

public PostTweetJob(String text) {

// This job requires network connectivity,

// and should be persisted in case the application exits before job is completed.

super(new Params(PRIORITY).requireNetwork().persist());

}

@Override

public void onAdded() {

}

@Override

public void onRun() throws Throwable {

webservice.postTweet(text);

}

@Override

protected RetryConstraint shouldReRunOnThrowable(Throwable throwable, int runCount, int

maxRunCount) {

return RetryConstraint.createExponentialBackoff(runCount, 1000);

}

@Override

protected void onCancel() {

}

}

https://github.com/yigit/android-priority-jobqueue

TapeTape is a collection of queue-related classes for Android and Java by Square, Inc.

public class ImageQueueServiceListener implements ObjectQueue.Listener<ImageUploadTask> {

@Override public void onAdd(ObjectQueue<ImageUploadTask> queue, ImageUploadTask task) {

context.startService(new Intent(context, ImageQueueService.class));

}

@Override public void onRemove(ObjectQueue<ImageUploadTask> queue) {}

}

public class ImageQueueService extends Service implements ImageUploadTask.Callback {

private TaskQueue<ImageUploadTask> queue;

@Override public int onStartCommand(Intent intent, int flags, int startId) {

executeNext();

return START_STICKY;

}

public void executeNext() {

ImageUploadTask task = queue.peek();

if (task != null) {

task.execute(this);

return;

}

stopSelf(); // We're done for now.

}

@Override public void imageUploadComplete() {

queue.remove();

executeNext();

}

}

http://square.github.io/tape/

RetrolambdaBackport of Java 8's lambda expressions to Java 7, 6 and 5

button.setOnClickListener(v -> log("Clicked"));

https://github.com/orfjackal/retrolambda

BoltsBolts is a collection of low-level libraries designed to make developing mobile apps easier.

findAsync(query).continueWithTask(new Continuation<List<ParseObject>, Task<Void>>() {

public Task<Void> then(Task<List<ParseObject>> results) throws Exception {

// Collect one task for each delete into an array.

ArrayList<Task<Void>> tasks = new ArrayList<Task<Void>>();

for (ParseObject result : results) {

// Start this delete immediately and add its task to the list.

tasks.add(deleteAsync(result));

}

// Return a new task that will be marked as completed when all of the deletes are finished.

return Task.whenAll(tasks);

}

}).onSuccess(new Continuation<Void, Void>() {

public Void then(Task<Void> ignored) throws Exception {

return null; // Every comment was deleted.

}

});

Uri targetUrl = AppLinks.getTargetUrlFromInboundIntent(getIntent());

if (targetUrl != null) {

AppLinkNavigation.navigateInBackground(getContext(), targetUrl);

} else {

// Not an applink, your existing code goes here.

}

https://github.com/BoltsFramework/Bolts-Android

RxJava (and RxAndroid)RxJava is a Java VM implementation of Reactive Extensions: a library for composing asynchronous and event-

based programs by using observable sequences.

public static void hello(String... names) {

Observable.from(names).subscribe(new Action1<String>() {

@Override

public void call(String s) {

System.out.println("Hello " + s + "!");

}

});

}

hello("Ben", "George");

Hello Ben!

Hello George!

Observable.just("one", "two", "three", "four", "five")

.subscribeOn(Schedulers.newThread())

.observeOn(AndroidSchedulers.mainThread())

.subscribe(/* an Observer */);

https://github.com/ReactiveX/{RxJava,RxAndroid}

6.UI

Ultimate RecyclerViewA RecyclerView with refreshing,loading more,animation and many other features.

https://github.com/cymcsg/UltimateRecyclerView

Sticky headers recyclerviewSticky Headers decorator for Android's RecyclerView

https://github.com/timehop/sticky-headers-recyclerview

PagerSlidingTabStripAn interactive indicator to navigate between the different pages of a ViewPager

https://github.com/jpardogo/PagerSlidingTabStrip

Android BootstrapBootstrap style widgets for Android, with Glyph Icons

https://github.com/Bearded-Hen/Android-Bootstrap

Photo viewImplementation of ImageView for Android that supports zooming, by various touch gestures.

https://github.com/chrisbanes/PhotoView

DialogPlusAdvanced dialog solution for android

https://github.com/orhanobut/dialogplus

https://github.com/PhilJay/MPAndroidChart

MPAndroidChartA powerful Android chart view / graph view library, supporting line- bar- pie- radar- bubble- and candlestick

charts as well as scaling, dragging and animations.

WilliamChartAndroid library to create charts.

https://github.com/diogobernardino/WilliamChart

ObservableScrollViewAndroid library to observe scroll events on scrollable views. It's easy to interact with the Toolbar introduced in

Android 5.0 Lollipop and may be helpful to implement look and feel of Material Design apps.

http://ksoichiro.github.io/Android-ObservableScrollView/

Thanks!Any questions?

You can find this presentation at:shem8.wordpress.com

smagnezi8@gmail.com

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