android/CONTRIBUTING.md

Nextcloud Android app

Index

1. Guidelines
   1. Issue reporting
   2. Labels
      1. Pull request
      2. Issue
      3. Bug workflow
2. Contributing to Source Code
   1. Developing process
      1. Branching model
      2. Android Studio formatter setup
      3. Build variants
      4. Git hooks
   2. Contribution process
      1. Fork and download android repository
      2. Create pull request
      3. Create another pull request
      4. Backport pull request
      5. Pull requests that also need changes on library
      6. Adding new files
      7. Testing
   3. File naming
      1. Menu files
   4. Translations
   5. Engineering practices
      1. Approach to technical debt
      2. Dependency injection
      3. Custom platform APIs
      4. Testing
3. Releases
   1. Types
      1. Stable
      2. Release Candidate
      3. Dev
   2. Version Name and number
      1. Stable / Release candidate
      2. Dev
   3. Release cycle
   4. Release Process
      1. Stable Release
      2. Release Candidate Release
      3. Development Dev

Guidelines

Issue reporting

• Report the issue and choose bug report or feature request. The template includes all the information we need to track down the issue.
• This repository is only for issues within the Nextcloud Android app code. Issues in other components should be reported in their own repositories, e.g. Nextcloud core
• Search the existing issues first, it's likely that your issue was already reported. If your issue appears to be a bug, and hasn't been reported, open a new issue.

Labels

Pull request

• 1 developing
• 2 to review
• 3 to release

Issue

• nothing
• approved
• PR exists (and then the PR# should be shown in first post)

Bug workflow

Every bug should be triaged in approved/needs info in a given time.

• approved: at least one other is able to reproduce it
• needs info: something unclear, or not able to reproduce
  • if no response within 1 months, bug will be closed
• pr exists: if bug is fixed, link to pr

Contributing to Source Code

Thanks for wanting to contribute source code to Nextcloud. That's great!

New contributions are added under AGPL version 3.

Developing process

We are all about quality while not sacrificing speed so we use a very pragmatic workflow.

• create an issue with feature request
  • discuss it with other developers
  • create mockup if necessary
  • must be approved --> label approved
  • after that no conceptual changes!
• develop code
• create pull request
• to assure the quality of the app, any PR gets reviewed, approved and tested by two developers before it will be merged to master

Branching model

• All contributions bug fix or feature PRs target the master branch
• Feature releases will always be based on master
• Bug fix releases will always be based on their respective feature-release-bug-fix-branches
• Bug fixes relevant for the most recent and released feature (e.g. 2.0.0) or bugfix (e.g. 2.0.1) release will be backported to the respective bugfix branch (e.g. 2.0.x or 2.1.x)
• Hot fixes not relevant for an upcoming feature release but the latest release can target the bug fix branch directly

Android Studio formatter setup

Our formatter setup is rather simple:

• Standard Android Studio
• Line length 120 characters (Settings->Editor->Code Style->Right margin(columns): 120)
• Auto optimize imports (Settings->Editor->Auto Import->Optimize imports on the fly)

Build variants

There are three build variants

• generic: no Google Stuff, used for FDroid
• gplay: with Google Stuff (Push notification), used for Google Play Store
• versionDev: based on master and library master, available as direct download and FDroid

Git hooks

We provide git hooks to make development process easier for both the developer and the reviewers. To install them, just run:

./gradlew installGitHooks

Contribution process

• Contribute your code in the branch 'master'. It will give us a better chance to test your code before merging it with stable code.
• For your first contribution start a pull request on master.

Fork and download android repository:

• Please follow SETUP.md to setup Nextcloud Android app work environment.

Create pull request:

• Commit your changes locally. Remember to sign off your commits (git commit -sm 'Your commit message').
• Push your changes to your GitHub repo: git push
• Browse to https://github.com/YOURGITHUBNAME/android/pulls and issue pull request
• Enter description and send pull request.

Create another pull request:

To make sure your new pull request does not contain commits which are already contained in previous PRs, create a new branch which is a clone of upstream/master.

• git fetch upstream
• git checkout -b my_new_master_branch upstream/master
• If you want to rename that branch later: git checkout -b my_new_master_branch_with_new_name
• Push branch to server: git push -u origin name_of_local_master_branch
• Use GitHub to issue PR

Backport pull request:

Use backport-bot via "/backport to stable-version", e.g. "/backport to stable-3.7". This will automatically add "backport-request" label to PR and bot will create a new PR to targeted branch once the base PR is merged. If automatic backport fails, it will create a comment.

Pull requests that also need changes on library

For speeding up developing, we do use a master snapshot of nextcloud-library, provided by jitpack.io. This means that if a breaking change is merged on library, master branch of the app will fail. To limit this risk please follow this approach:

• on app PR: first use a reference to your library branch in build.gradle: ext -> androidLibraryVersion, e.g. androidLibraryVersion = "changeSearch-SNAPSHOT"
• on library PR: use label "client change required" to indicate that this is breaking change. This will prevent GitHub from merging it.

Once both PRs are reviewed and ready to merge:

• on library PR: remove label and merge it (for a short time now master cannot be built!)
• on app PR: change androidLibraryVersion back to "master-SNAPSHOT"
• wait for CI and then merge

With this approach the "downtime" of not building master is limited to the timestamp between merge lib PR and merging app PR, which is only limited by CI.

Adding new files

If you create a new file it needs to contain a license header. We encourage you to use the same license (AGPL3+) as we do. Copyright of Nextcloud GmbH is optional.

Source code of library:

/*
 * Nextcloud Android Library
 *
 * SPDX-FileCopyrightText: 2024 Your Name <your@email.com>
 * SPDX-License-Identifier: MIT
 */

Source code of app:

/*
 * Nextcloud - Android Client
 *
 * SPDX-FileCopyrightText: 2024 Your Name <your@email.com>
 * SPDX-License-Identifier: AGPL-3.0-or-later OR GPL-2.0-only
 */

XML (layout) file:

<!--
 ~ Nextcloud Talk - Android Client
 ~ 
 ~ SPDX-FileCopyrightText: 2024 Your name <your@email.com>
 ~ SPDX-License-Identifier: AGPL-3.0-or-later OR GPL-2.0-only
-->

Testing

• testing is very important, but is lacking a lot on this project. Starting with 2020 we aim to write tests for every new pull request.
• Code coverage can be found here.

Unit tests

• small, isolated tests, with no need of Android SDK
• code coverage can be directly shown via right click on test and select "Run Test with Coverage"

Instrumented tests

• tests to see larger code working in correct way

• tests that require parts of Android SDK

• best to avoid server communication, see https://github.com/nextcloud/android/pull/3624

• run all tests ./gradlew createGplayDebugCoverageReport -Pcoverage=true

• run selective test class: ./gradlew createGplayDebugCoverageReport -Pcoverage=true -Pandroid.testInstrumentationRunnerArguments.class=com.owncloud.android.datamodel.FileDataStorageManagerTest

• run multiple test classes:

  • separate by ","
  • ./gradlew createGplayDebugCoverageReport -Pcoverage=true -Pandroid.testInstrumentationRunnerArguments.class=com.owncloud.android.datamodel.FileDataStorageManagerTest,com.nextcloud.client.FileDisplayActivityIT

• run one test in class: ./gradlew createGplayDebugCoverageReport -Pcoverage=true -Pandroid.testInstrumentationRunnerArguments.class=com.owncloud.android.datamodel.FileDataStorageManagerTest#saveNewFile

• JaCoCo results are shown as html: firefox ./build/reports/coverage/gplay/debug/index.html

UI tests

We use shot for taking screenshots and compare them

• check screenshots: ./gradlew gplayDebugExecuteScreenshotTests

• update/generate new screenshots: scripts/updateScreenshots.sh

  • in this script are samples how to only execute a given class/test
  • this will fire up docker & emulator to ensure that screenshots look the same

• creating own UI comparison tests:

  • add IntentsTestRule for launching activity directly:

  @Rule public IntentsTestRule<SettingsActivity> activityRule = new IntentsTestRule<>(SettingsActivity.class,
                                                                                      true,
                                                                                      false);
  

  • in test method:

  Activity activity = activityRule.launchActivity(null); 
  …do something, e.g. navigate, create folder, etc. … 
   Screenshot.snapActivity(activity).record();
  

  • best practice is to first create test with emulator too see behaviour and then create screenshots

File naming

The file naming patterns are inspired and based on Ribot's Android Project And Code Guidelines.

Menu files

Similar to layout files, menu files should match the name of the component. For example, if we are defining a menu file that is going to be used in the UserProfileActivity, then the name of the file should be activity_user_profile.xml. Same pattern applies for menus used in adapter view items, dialogs, etc.

Component	Class Name	Menu Name
Activity	UserProfileActivity	activity_user_profile.xml
Fragment	SignUpFragment	fragment_sign_up.xml
Dialog	ChangePasswordDialog	dialog_change_password.xml
AdapterView item	---	item_person.xml
Partial layout	---	partial_stats_bar.xml

A good practice is to not include the word menu as part of the name because these files are already located in the menu directory. In case a component uses several menus in different places (via popup menus) then the resource name would be extended. For example, if the user profile activity has two popup menus for configuring the users settings and one for the handling group assignments then the file names for the menus would be: activity_user_profile_user_settings.xml and activity_user_profile_group_assignments.xml.

Translations

We manage translations via Transifex. So just request joining the translation team for Android on the site and start translating. All translations will then be automatically pushed to this repository, there is no need for any pull request for translations.

If you need to change a translation, do not change it, but give it new key. This way the translation stays backward compatible as we automatically backport translated strings to last versions.

When submitting PRs with changed translations, please only submit changes to values/strings.xml and not changes to translated files. These will be overwritten by next merge of transifex-bot and increase PR review.

Engineering practices

This section contains some general guidelines for new contributors, based on common issues flagged during code review.

Approach to technical debt

TL;DR Non-Stop Litter Picking Party!

We recognize the importance of technical debt that can slow down development, make bug fixing difficult and discourage future contributors.

We are mindful of the Broken Windows Theory and we'd like actively promote and encourage contributors to apply The Scout's Rule: "Always leave the campground cleaner than you found it". Simple, little improvements will sum up and will be very appreciated by Nextcloud team.

We also promise to actively support and mentor contributors that help us to improve code quality, as we understand that this process is challenging and requires deep understanding of the application codebase.

Dependency injection

TL;DR Avoid calling constructors inside constructors.

In effort to modernize the codebase we are applying Dependency Injection whenever possible. We use 2 approaches: automatic and manual.

We are using Dagger 2 to inject dependencies into major Android components only:

• Activity
• Fragment
• Service
• BroadcastReceiver
• ContentProvider

This process is fairly automatic, with @Inject annotation being sufficient to supply properly initialized objects. Android lifecycle callbacks allow us to do most of the work without effort.

For other application sub-components we prefer to use constructor injection and manually provide required dependencies.

This combination allows us to benefit from automation when it provides most value, does not tie rest of the code to any specific framework and stimulates continuous code modernization through iterative refactoring of all minor elements.

Custom platform APIs

TL;DR Avoid Android platform APIs.

Nextcloud Android application provides some replacements for native Android APIs to facilitate testing and expose higher-level, business-specific APIs.

Generally, whenever you need:

• account management
• application preferences
• background task scheduling
• device hardware information
• media playback
• networking
• logging
• notifications management

we have something more suitable.

Our transition to new APIs is a continuous process. Contributors might be asked by code reviewers to refrain from using specific Android APIs considered problematic and to use Nextcloud APIs instead. In extreme cases we might decide to put specific features on hold until we provide platform API replacement.

If in doubt, ask Nextcloud developers. App undergoes a process of intense refactoring and situation changes frequently.

Testing

TL;DR If we can't write a test for it, it's not good.

Test automation is challenging in mobile applications in general. We try to improve in this area and thereof we'd ask contributors to be mindful of their code testability:

1. new code submitted to Nextcloud project should be provided with automatic tests
2. contributions to existing code that is currently not covered by automatic tests should at least not make future efforts more challenging
3. whenever possible, testability should be improved even if the code is not covered by tests

Performance

If you're interested in improving the app's performance, please check the official documentation for ways you can inspect and improve performance.

For additional analysis, set the perfAnalysis property in your Gradle build:

./gradlew installGplayDebug -P perfAnalysis

This will install the app with LeakCanary and StrictMode enabled and configured. These tools can help find memory leaks, foreground operations that should be in background, and other performance problems.

Releases

At the moment we are releasing the app in two app stores:

• Google Play Store
• f-droid

Types

We do differentiate between three different kinds of releases:

Stable

Play store and f-droid releases for the masses. Pull Requests that have been tested and reviewed can go to master. After the last release candidate is out in the wild for ~2 weeks and no errors get reported (by users or in the developer console) the master branch is ready for the stable release. So when we decide to go for a new release we freeze the master feature wise.

Release Candidate

stable beta releases done via the Beta program of the Google Play store and f-droid. Whenever a PR is reviewed/approved we put it on master. Before releasing a new stable version there is at least one release candidate. It is based on the current master and during this phase the master is feature freezed. After ~2 weeks with no error a stable version will be released, which is identical to the latest release candidate.

Dev

Done as a standalone app that can be installed in parallel to the stable app. Any PR which is labelled "ready for dev" will be automatically included in the dev app. This label should only set by the main developers. Same applies for the android-library. This repository also has a branch called dev which includes all upcoming features. The dev branch on this repository must always use the android-library dev branch.

Version Name and number

Stable / Release candidate

For stable and release candidate the version name follows the semantic versioning schema and the version number has several digits reserved to parts of the versioning schema inspired by the jayway version numbering, where:

• 2 digits for beta code as in release candidates starting at '01'
• 2 digits for hot fix code
• 3 digits for minor version code
• n digits for mayor version code

Examples for different versions:

• 1.0.0 10000099
• 8.12.2 80120200
• 9.8.4-rc18 90080418

beware, that beta releases for an upcoming version will always use the minor and hotfix version of the release they are targeting. So to make sure the version code of the upcoming stable release will always be higher stable releases set the 2 beta digits to '99' as seen above in the examples. For major versions, as we're not a library and thus 'incompatible API changes' is not something that happens, decisions are essentially marketing-based. If we deem a release to be very impactful, we might increase the major version number.

Dev

For dev the version name is in format YYYYMMDD. It is mainly as a reference for reporting bugs and is not related to stable/release candidates as it is an independent app.

Release cycle

• Releases are planned every ~2 months, with 6 weeks of developing and 2 weeks of stabilising
• after feature freeze a public release candidate on play store and f-droid is released
• ~2 weeks testing, bug fixing
• release final version on f-droid and play store
• Bugfix releases (dot releases, e.g. 3.2.1) are released 4 weeks after stable version from the branch created with first stable release (stable-3.2.x). If changes to the library are required, we do the same: create a branch from the version used in stable release (e.g. 1.1.0) and then release a dot release (1.1.1).

Hotfixes as well as security fixes are released via bugfix releases (dot releases) but are released on demand in contrast to regular, scheduled bugfix releases.

To get an idea which PRs and issues will be part of the next release simply check our milestone plan

Release process

Stable Release

Stable releases are based on the git master.

1. Bump the version name and version code in the AndroidManifest.xml, see chapter 'Version Name and number'.
2. Create a release/tag in git. Tag name following the naming schema: stable-Mayor.Minor.Hotfix (e.g. stable-1.2.0) naming the version number following the semantic versioning schema

Release Candidate Release

Release Candidate releases are based on the git master and are done between stable releases.

1. Bump the version name and version code in the AndroidManifest.xml, see below the version name and code concept.
2. Create a release/tag in git. Tag name following the naming schema: rc-Mayor.Minor.Hotfix-betaIncrement (e.g. rc-1.2.0-12) naming the version number following the semantic versioning schema

Developement Release

Dev releases are based on the master branch and are done independently from stable releases for people willing to test new features and provide valuable feedback on new features to be incorporated before a feature gets released in the stable app.

The deployment/build is done once a day automatically. If code has changed a new apk will be published here and it will, with a little delay, be available on Fdroid.