Overview of Android Infrastructure

Overview of Android
Infrastructure
Alexey Buzdin

@AlexeyBuzdin

alex.buzdin@gmail.com

LArchaon

Requirement:
Support as many android
devices as you can
(including tablets)

4.1–4.2
4.0

2.1
3.0 2.2

2.3

Google data, March 2013

Ain't that good for a developer

Is there is someone who
could help us?

Layers

Presentation

Application logic

Domain

Presentation

Application logic

Domain

Missing in Android 2.2
●
ActionBar
●
Support for tablets
●
Decent ListView support for server communication

Compatability libraries
Android Support library
ActionBarSherlock
etc

Support Library
http://developer.android.com/tools/extras/support-
library.html

Fragments
Async Stuff
Experimental stuff

ActionBarSherlock

http://actionbarsherlock.com/

Pull to Refresh

https://github.com/chrisbanes/Andro
id-PullToRefresh

Android Runtime
On Android you develop in Java
... but Android does not run Java Bytecode !

DalvikVM
Dalvik Virtual Machine
– Custom VM optimized for mobile devices
– Register-based JVM
– More efficient and compact
– Use memory efficiently
– Dalvik Executable Code (.dex)
● 30% fewer instructions

● 35% fewer code units

● 35% more bytes

– Trace JIT compiler (since 2.2)

Android Runtime
Android Java = Java language + Dalvik + Apache Harmony
Android Java API = Java SE – AWT/Swing + Android API
Sun-Java = Java language + JVM + JDK

36

Activity
public class MyActivity extends Activity {

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}

}

Context
●
Context of current state of the
application/object

Context
●
Context of current state of the
application/object
●
Context is a handle to the system it
provides services like
– resolving resources
– obtaining access to databases and
preferences

Important
any resource taken from context will
leave as long as Context does

Context problem

@Override
String appName = getString(R.string.appName);
}

}

Passing Context
public class MyStringProvider {

Context context;

public MyStringProvider(Context context) {
this.context = context;
}

public String getString(){
return context.getString(R.string.app_name);
}

}

Context problem

@Override
String appName = getString(R.string.appName);
}

}
Presentation

Application logic

Domain

Injection libraries
Dependency Injection
●
RoboGuice
●
Dagger

RoboGuice

●
Based on Google Guice
●
Lightweight
●
Multifunctional (has resource injection)

RoboGuice
public class MyActivity extends RoboActivity {

@Inject MyStringProvider stringProvider;

@Override

((TextView) findViewById(R.id.textView))
.setText(stringProvider.getString());
}

}

RoboGuice

Context context;

@Inject
}

return context.getString(R.string.app_name);
}
}

Optimezed context injection
public class MyActivity extends RoboActivity {

int i;

@Inject MyStringProvider stringProvider;

@Override

i = 1;
}

}

RoboGuice

Context context;

@Inject
}

return context.getString(R.string.app_name) + ((MyActivity)context).i;
}
}

Dagger
public class DaggerActivity extends DaggerBaseActivity {

@Inject DaggerStringProvider stringProvider;

@Override

}

}

Dagger
public class DaggerBaseActivity extends Activity {

@Inject
Bus bus;

@Override protected void onCreate(Bundle state) {
super.onCreate(state);

DaggerApplication.inject(this);
}

@Override protected void onResume() {
super.onResume();
bus.register(this);
}

@Override protected void onPause() {
super.onPause();
bus.unregister(this);
}
}

Dagger
public class DaggerApplication extends Application {

private static ObjectGraph objectGraph;

@Override public void onCreate() {
super.onCreate();

objectGraph = ObjectGraph.create(new DaggerModule(this));
}

public static <T> void inject(T instance) {
if(objectGraph != null) objectGraph.inject(instance);
}
}

@Module(
entryPoints = { DaggerApplication.class, DaggerActivity.class}
)
public class DaggerModule {
private final Context appContext;

public DaggerModule(Context appContext) {
this.appContext = appContext.getApplicationContext();
}

@Provides @Singleton Bus provideBus() {
return new Bus();
}

@Provides Context provideContext() {
return appContext;
}

}

Summary
Dagger
●
More customizable
●
Easy communicates with other libraries
●
Requires more code

RoboGuice
●
Simpler
●
Out of Box functionality

Other “Injection” libraries
Resource and View “Injection”
●
RoboGuice
●
ButterKnife
●
AndroidAnnotations

RoboGuice Views Injection
public class RoboGuiceActivity extends RoboActivity {

@Inject RoboGuiceStringProvider stringProvider;
@InjectView(R.id.textView) TextView textView;

@Override

textView.setText(stringProvider.getString());
}

}

Butterknife
public class DaggerActivity extends DaggerBaseActivity {

@Inject DaggerStringProvider stringProvider;
@InjectView(R.id.textView) TextView textView;

@Override
Views.inject(this);

textView.setText(stringProvider.getString());
}

}

AndroidAnnotations
@EActivity(R.layout.translate) // Sets content view to R.layout.translate
public class TranslateActivity extends Activity {
@ViewById // Injects R.id.textInput
EditText textInput;
@ViewById(R.id.myTextView) // Injects R.id.myTextView
TextView result;
@AnimationRes // Injects android.R.anim.fade_in
Animation fadeIn;
@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);
}
}

Data Source
Android has built in SQLite

Data Source
... but lacks ORM

Alternatives:
– GreenDAO
– ORMLite

ORMLite
@DatabaseTable(tableName = "accounts")
public class Account {
@DatabaseField(id = true) private String name;

@DatabaseField(canBeNull = false) private String password;

Account() {
// all persisted classes must define a no-arg constructor with at least package
visibility
}

}

ORMLite
// you get the SQLiteOpenHelper from your Android Activity
ConnectionSource connectionSource = new AndroidConnectionSource(sqliteOpenHelper);

// instantiate the DAO to handle Account with String id
Dao<Account,String> accountDao = BaseDaoImpl.createDao(connectionSource, Account.class);

TableUtils.createTable(connectionSource, Account.class);

String name = "Jim Smith";
Account account = new Account(name, "_secret");
accountDao.create(account)

Account account2 = accountDao.queryForId(name);
connectionSource.close();

Testing
●
DVM or JVM
●
Automation or Unit Tests

DVM
●
Requires a separate Test Project
●
android.test or Robotium

Android.test
public class SimpleActivityTestStandard extends
ActivityUnitTestCase<SimpleActivity> {
public SimpleActivityTestStandard() {
super(SimpleActivity.class);
}

public void setUp() throws Exception {
startActivity(new
Intent(getInstrumentation().getTargetContext(),
SimpleActivity.class), null, null);
}

public void testLayout() {
SimpleActivity activity = getActivity();
assertNotNull(activity.findViewById(R.id.button1));
Button view = (Button) activity
.findViewById(com.example.test.target.R.id.button1);
assertEquals("My Button 1", view.getText());
}
}

Robotium
public void testPreferenceIsSaved() throws Exception {
Solo solo = new Solo(getInstrumentation(), getActivity());
solo.sendKey(Solo.MENU);
solo.clickOnText("More");
solo.clickOnText("Preferences");
solo.clickOnText("Edit File Extensions");
assertTrue(solo.searchText("rtf"));

solo.clickOnText("txt");
solo.clearEditText(2);
solo.enterText(2, "robotium");
solo.clickOnButton("Save");
solo.goBack();
solo.clickOnText("Edit File Extensions");

assertTrue(solo.searchText("application/robotium")
solo.finishOpenedActivities();
);

JVM
public class RoboGuiceActivityTest {

@Test
public void shouldHaveISet() throws Exception {
RoboGuiceActivity activity = new RoboGuiceActivity();
assertThat(activity.getI(), equalTo(1));
}
}

We have Mockito!
lets mock something
in our Activity ...

Robolectric to the rescue

Allows you to run
you android code
on JVM

Robolectric
@RunWith(RobolectricRoboTestRunner.class)
public class RoboGuiceActivityTest {

@Test
public void shouldHaveISet() throws Exception {
RoboGuiceActivity activity = new RoboGuiceActivity();
activity.onCreate(null);
assertThat(activity.getI(), equalTo(1));
}
}

Testing
●
DVM or JVM
●
Automation or Unit Tests
●
Robotium or Robolectric
●
Or both

Android Bootstrap
●
Fragments,Fragment Pager
●
android-maven-plugin, Dagger
●
ActionBarSherlock
●
ViewPagerIndicator
●
http-request, GSON
●
Robotium

http://www.androidbootstrap.com/

Build Systems
● Gradle
● Maven

https://github.com/LArchaon/android
_mvn_template/

Overview of Android Infrastructure

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