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Platform SDKby Adnan Begovic

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Background

What is CyanogenMod?

CyanogenMod (pronounced /saɪ.ˈæn.oʊ.ˌdʒɛn.mɒd/), usually abbreviated to CM, is an open-source operating system for smartphones and tablet computers, based on the Android mobile platform. It is developed as free and open source software based on the official releases of Android by Google, with added original and third-party code. It is based on a rolling release development model.

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Background

CyanogenMod User Base:● 50+ million users● Users in 190+ different countries● Localized to 50+ languages via automated crowdin

system

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Background

CyanogenMod Developer base:● Numerous active core developers/maintainers

○ Maintain devices○ Maintain documentation for features and device specs○ Maintain and manage their own user bases○ Maintain crowdin○ File and resolve bugs reported by community users

● ~163 devices supported● Receive a substantial amount of OSS contributions

from outside sources.

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Developer Base

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Crowdsourcing Android Development

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An Example Community Contribution

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Topics

● OS development is intimidating● Treehacks Hackathon learnings● Cyanogen Platform

○ Infrastructure○ Framework library○ SDK○ Resource Package

● Using the SDK (QST examples)● Contributing API’s

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Contributing to an OS

The Treehacks experience

Treehacks:● 500+ person hackathon with students from all over the country.● Workshops to get a meaningful contribution to the OSS project

CyanogenMod.● Open to Stanford students, external students, and outside developers.

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Treehacks Experience

Winning Project: CyanTranslate

Using CyanogenMod, the winners modified the Android operating system and created several new built-in features for manipulating text. By highlighting text and hitting a button, the user can take advantage of these features. The new features include:

Automatic translation between languages

● One-tap Google search● UrbanDictionary definition lookup● Book information lookup

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Treehacks Experience

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Treehacks FeedbackPositives Negatives

Open platform High ramp up time

Good infrastructure● Gerrit Code Review● Github mirroring

Massive code base● ~1281 github repos● 100+ android packages● 25+ Gb repo size

Build environment documentation● https://wiki.cyanogenmod.org

High barrier of entry in understanding Android’s core implementations

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Treehacks Experience

- How to decrease the barrier to entry?

- How to extend the CM experience for 3rd party developers?

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The Cyanogen Platform

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Cyanogen Platform

The new, more approachable, infrastructure:● CyanogenMod Platform Library● CyanogenMod Resource Package● CyanogenMod Platform SDK

Application

Cyanogen Platform SDK

Platform API Core

Resource Package

Android OS

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Cyanogen Platform Library

Framework library similar to Android’s Framework JAR.

● Contains System Binder Services that get spun up and managed by Android’s SystemServer.

● Contains the implementation, state management, and persisting of data for a specific API feature.

● Leveraging Android’s powerful IPC framework for interaction between an application and the system process.

Further information: Understanding the Structure

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Cyanogen Resource Package

Contains exported resources and CyanogenMod specific permissions to be leveraged by the Application and framework.

● ex: ○ cyanogenmod.permission.PUBLISH_CUSTOM_TILE○ cyanogenmod_system_label

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Cyanogen Platform SDK

A library that can be included in your application to interact with CM specific binder services to gain extra functionality.

● Provides objects, object builder’s, helper methods, and simple interfaces to push or receive data from the platform library.

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Using the SDK

Custom Quick Tiles API Example:● Allows your application to publish a Quick Tile to be hosted in the QS

Panel.○ Patterns similar to Notification and NotificationManager

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Exploration for an API

Bike O’Clock● Using Quick Settings Tiles to surface commonly

used actions.

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Bike O’Clock

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Using the SDK

Creating a CustomTile:

CustomTile customTile = new CustomTile.Builder(mContext)

.setLabel("custom label")

.setContentDescription("custom description")

.setOnClickIntent(pendingIntent)

.setOnSettingsClickIntent(intent)

.setOnClickUri(Uri.parse("custom uri"))

.setIcon(R.drawable.ic_launcher)

.build();

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Using the SDK

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Using the SDK

Publishing: CMStatusBarManager.getInstance(this)

.publishTile(CUSTOM_TILE_ID, mCustomTile);

Removing: CMStatusBarManager.getInstance(this)

.removeTile(CUSTOM_TILE_ID, mCustomTile);

Requires: <uses-permission android:name="cyanogenmod.permission.PUBLISH_CUSTOM_TILE" />

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Contributing

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Making a change

repo init -u git://github.com/CyanogenMod/android.git -b cm-12.1

repo sync

repo start changes vendor/cmsdk

https://www.github.com/CyanogenMod/cm_platform_sdk

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Contributing

Application

Cyanogen Platform SDK

Platform API Core

Community API Core

gerrit (code review, unit tests)

Interface Changes

Unit Tests

SDK Methods

CTS

SDK methods added to Platform SDK project

API added along side core

Interfaces added to nightly builds

API Council (Change Control Board)API Check-API

Android OS

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Contributing

Documentation generation is automated!● make org.cyanogenmod.platform.sdk-docs

● Published directly from gerrit merge to github pages

Docs: http://cyanogenmod.github.io/cm_platform_sdk/reference/packages.html

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Contribute New APIs & Write More Functional Apps

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Questions?

Join the G+ Community: http://bit.ly/1FC6lJI

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Appendix for QA

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Security

vendor/cm/overlay <!-- Defines external services to be started by the SystemServer at boot. The service itself

should publish as a binder services in its onStart -->

<string-array name="config_externalCMServices">

<item>org.cyanogenmod.platform.internal.CMStatusBarManagerService</item>

</string-array>

vendor/cm/sepolicy/servicecontexts cmstatusbar u:object_r:system_server_service:s0

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Security

Selinux service_contexts● service_contexts is used for translating service names into selinux labels.● MAC check to the svc_can_register function in

service_manager.

https://android.googlesource.com/platform/frameworks/native/+/69154df