Clean architecture: Android

Clean architecture: Android

Michał Szczepanik

WroDroid

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I have a Dream...

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What a Terrible Failure!

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What is Architecture?

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Architecture is About Intent, not Frameworks„

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Our goal(s)

● Architecture focused on use cases and main system function

● Clear use cases first!● Easy to maintain● Fast to test● Easy to test● Very cohesive● Decoupled

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Step 0 (setup?)

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Architect role

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Team Role

14Android best practices ?

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Entities

The business objects of the application

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Use Cases

Use Cases orchestrate the flow of data to and from the entities.

They are also called Interactors.

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Interface Adapters

This set of adapters convert data from the format most convenient for the use cases and entities.

Presenters and Controllers belong here.

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Frameworks and Drivers

This is where all the details go: UI, tools, frameworks, etc.

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How to be clean ?

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App architecture – android view

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App architecture – developer view

Presentation Layer

Domain/BusinessLayer

DataLayer

Entities Layer

Inte

ract

ors

Boun

d aries

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Domain (Business) Layer

● Application business rules● All use cases (interactors)

● Android independent

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Domain (Business) Layer

Domain/BusinessLayer

Entities LayerInte

ract

ors

Inte

rfa

ces

Repos itory (D

ata access) In terfa ce

● Interactors Implementation● Use entities objects

● Most tests are here● (JUnit plus mockito)

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Entities Layer

● Basic (minimal) business object● Object's structure● Low-level rules ● General truths

● Android independent● Framework independent

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Entities Layer

● Basic java object● No frameworks

● Test for business objects● No mocks and stubs

Domain/BusinessLayer

Entities Layer

Inte

ract

ors

Bound

aries

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Presentation Layer

● Logic related to UI (view and animation)● Logic related to Activity and application lifecycle● Fragments and Activities are only views!● Design: MVP/MVC/MVVM pattern

● Strongly connected with Android SDK

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Presentation Layer

● Frameworks

● Integration (platform) tests● UI tests● (Android Instrumentation)● (Robotium/Espresso)● (Robolectric)

Presentation Layer

Inte

ract

ors

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Data Layer

● Deliver data needed by app● Cache● Service● Design: with Repository Pattern

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Data Layer● Repository Pattern

● Integration tests● Unit tests● (JUnit plus mockito)● (Robolectric)

Implementation

Repos ito

ry Interf ace

Memory(cache)

Disk(DB/File)

Cloud

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Testing

● Low-level tests are fast ● High-level tests are slow

● UI testing sucks ?● Self testing code ?

● new bug = new test

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QA Team

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Monkey

adb shell monkey [options] <event-count>

-s <seed>

-v <verbosity level>

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Android Tips

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65K

Unable to execute dex: method ID not in [0, 0xffff]: 65536

Conversion to Dalvik format failed: Unable to execute dex: method ID not in [0, 0xffff]: 65536

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How to solve it

● Find reason– dex-method-counts

● jarjar● Shrinking libs via Proguard● Multidex

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Dalvik / ART

● Dalvik:– Register-based machine

– Just in time (JIT): 2.3+

● ART– Ahead-of-time (AOT)

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Tools?

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Lint

● Static Code Analysis● Layouts tips and optimization

● Missing translations ● Layout performance problems ● Unused resources● Inconsistent array sizes ● Accessibility and internationalization problems ● Icon problems ● Usability problems ● Manifest errors

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Dependency Injections

● Dagger

● RoboGuice

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Injections● ButterKnife

● AndroidAnnotations

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Injectionsclass 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...

}

}

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Proguard / Dexguard

● Shrinking● Optimize ● Obfuscate

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Developer options

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Clean Architecture

● Easy to maintain● Easy to test● Very cohesive● Decoupled

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WroDroidhttp://www.meetup.com/WroDroid/

Clean Architecture by Unkle Bobhttp://goo.gl/Z4zMHG

Architecting Android…The clean wayhttp://goo.gl/MF13E1

Effective Android UIhttp://goo.gl/1dZxfb

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Thank you for your attention

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Questions ?

[email protected]