Android studio clean build

Put your Android Studio on a diet

How to make a deep clean of your Android Studio & Gradle junk files to fix up the mess.

Do you know that when you’re updating your Android Studio, Gradle or even dependencies, some old files are still present on your machine and can waste some disk free space?

On our laptops, disk space is limited and clearing those files will make you gain a lot of free space available. Having too many junk files may also slow down your machine and your builds!

In my case, I was also having strange build errors or gradle sync failures when it was working on my colleague’s machine.

It was time to do some deep cleaning and put our Android Studio on a diet by following some simple steps.

Clear your project directory

1. Obviously, try to clean your project from android studio : “ Build -> Clean Project”. This will clear your build folders.
2. Clear the cache of Android Studio using “ File -> Invalidate Caches / Restart” choose “ Invalidate and restart option” and close Android Studio.
3. Remove your .gradle directory from the root of your project. It contains some Gradle cache files.
4. Delete also the .idea directory ( make a backup before). It contains some project configuration files.
5. Restart Android Studio.

Big project directories can weight around 500MB to 1GB.

Gradle cleaning

Now let’s take a look at Gradle files. If none of the above suggestions fix your problem, try these:

/.gradle directory. This is the Gradle home directory, containing caches, daemons and wrappers files. This is a really huge one, mine was

Inside those directories, you’ll have sub-directories for each version of Gradle you’ve been using. So, the more projects you have with different Gradle versions, the more sub-directories you will have.
You can delete those 3 directories:

• caches: Gradle cache files.
• daemon: essentially logs files of Gradle daemons.
• wrapper: different distributions of Gradle downloaded on you machine.

Android Studio cleanup

1. Go to your Android home, usually

/.android and clear build-cache and cache directories. There are few MB to free here (

100MB for me)
In the

/Library/ directories, you will find the Android Studio preferences files, settings and plugins. You can clear the directories of previous version of Android Studio (> 1GB per version of AS). Starting with version 3.3, Android Studio will propose you to remove them after an update.

Android SDK cleaning

On Android Studio, check the SDK Manager and remove the following items:

• Old SDKs you don’t use anymore. I guess you’ll not miss the Android 3.0 SDK files.
• Remove the emulators you don’t use as they’re quite heavy ( some GB).
• I recommend to keep “Sources for Android xx” items as it will allow you to check the source code of the SDK from a previous version of Android & help you debugging.
• On the SDK Tools tab, click on “Show Packages Details” and uncheck the old build-tools or NDK versions.
• Delete unused emulators using the AVD.

You can gain easily 10GB with these steps.

Extra cleaning

There is some extra stuff you can clean too:

• Your download directory: you may have downloaded a lot of GIFs, video, Android Studio binaries that you can remove.
• Clear your local git branches that have been merged (don’t remove the ones that you still need!).
• Delete all those photoshopped pictures of your colleagues ( ͡° ͜ʖ ͡°).
• Clear your recycle bin.

That’s it ! You’ve gained some precious disk space on your machine and maybe fixed some weird issues with your Android Studio.

I don’t recommend to do a full clean everyday, you’ll waste time and your build time will be quite longer so you’ll be less productive. Take it only as a “spring cleaning” ritual.

I hope it helped you, and don’t forget to follow the Marie Kondo mantra and only keep things that spark joy.

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This page is obsolete. You’re being redirected to developer.android.com/studio/build/build-cache.html

• The build cache is now enabled by default.
• There is a new Gradle task called cleanBuildCache for you to more easily clean the build cache. You can use it by typing the following in your terminal: ./gradlew cleanBuildCache

Android Studio 2.2 Beta 3 introduces a new build cache feature that can speed up build times for clean builds by storing and reusing files/directories that were created in previous builds of the same or different Android project.

The build cache is meant to be used across all Android projects. The developer can enable/disable the build cache and specify its location in the gradle.properties file. Currently, the build cache contains only pre-dexed libraries; in the future, we will use it for caching other types of files as well.

Note that the build cache works independently of Gradle’s cache management (e.g., reporting up-to-date statuses). When a task is executed, whether the build cache is used or not during its execution will be unknown to Gradle (i.e., even when the cache is hit, Gradle’s profile report will not show the task as up-to-date). However, you should expect to get faster build times when the build cache is used.

Although there are currently no known issues, we would like to provide the community more time to provide feedback on it. This feature is currently considered to be experimental and is disabled by default (update: this feature enabled by default starting with Android Studio 2.3 Canary 1). With your feedback, we are aiming to graduate it to stable and enable it by default in Android Studio 2.3 or 2.4.

How to use the Build Cache

Step 0

Ensure that android.dexOptions.preDexLibraries is either not set or set to true; otherwise the libraries will not be pre-dexed and therefore the build cache will not be used.

Step 1

In an Android project, open the gradle.properties file and add the following parameters:

android.enableBuildCache= true # Set to true or false to enable or disable the build cache. If this parameter is not set, the build cache is disabled by default.

# Optional, specify the absolute path of the build cache directory. If you use a relative path, it will be relative to the root directory of the Android project. If this parameter is not set, the default build cache directory at /.android/build-cache will be used. Multiple Android projects can share the same cache if they specify the same build cache location (in that case, it is recommended that the default location or a location outside the projects is used, although it is still possible to use a location inside one of the projects). In any case, it is important that the build cache location is not in a “build” directory; otherwise, it would be erased after running a clean task. This parameter is ignored if android.enableBuildCache=false .

Step 2

Build your Android project (on the terminal, type ./gradlew assemble ) and check the following locations to see whether the build cache took effect.

The cached files are stored in the build cache directory set by the android.buildCacheDir parameter above. By default, this is /.android/build-cache.

The final pre-dexed files are stored in

/ module-dir> /build/intermediates/pre-dexed/debug and

/ module-dir> /build/intermediates/pre-dexed/release. You need to run the command line to see the “pre-dexed” directory; if you click the “Run” button from the Android Studio menu, you will not see this directory as it will be deleted.

Note: If you are using Multi-dex with minSdk >= 21, the dexed files will be stored directly into the

/build/intermediates/transforms/dex directory without being stored in

Cleaning the Build Cache

To clean the build cache, you can navigate to the build cache directory and delete all the files in that directory. Th e build cache directory is either located at the path specified by the android.buildCacheDir property in your gradle.properties file, or it is located at /.android/build-cache by default.

Update: starting with Android Studio 2.3 Canary 1, there is a now a Gradle task called cleanBuildCache that you can use to more conveniently clean the build cache. You can use it by typing the following in your terminal:

We encourage you to try this feature and to see how it’s working for you. Please file a bug to us if you find any issues or if you have other feedback about this feature for us. Thanks!

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Методы лечения различных ошибок в Android Studio при разработке проекта

Сегодня хотел бы поделиться своим анализом и способами лечением разных ошибок при разработке своего продукта в Android Studio. Лично я, не раз сталкивался с различными проблемами и ошибками при компиляции и/или тестировании мобильного приложения. Данный процесс, всегда однообразный и в 99% случаев и всегда нужно тратить n-колличество времени на его устранение. Даже, когда ты уже сталкивался с данной проблемой, ты все равно идешь в поисковик и вспоминаешь, как же решить ту или иную ситуацию.

Я для себя завел файлик, в котором отметил самые частые ошибки — потратив на это несколько часов и перечислил самые популярные ошибки (в дальнейшем планирую просто их запомнить), чтоб сократить свое время в дальнейшем.

Итак, начну по порядку с самой распространенной проблемы и дальше буду перечислять их по мере появления:

1) Если подчеркивает красным код, где используются ресурсы: R. — попробовать (но вероятно не поможет): Build -> Clean Project.

В принципе на Build -> Clean Project можно не терять времени, а лучше всего — слева переключиться на Project, открыть каталог .idea, затем каталог libraries и из него удалить все содержимое. Затем нажать кнопку Sync Project. А затем (если все еще красное, но скорее всего уже будет все ок ) Build -> Clean Project.

2) После внезапного выключения компьютера, после перезапуска может быть во всех проектах весь код красным. Перед этим может быть ошибка: Unable to create Debug Bridge: Unable to start adb server: Unable to obtain result of ‘adb version’. Есть три решения — первое помогло, второе нет (но может быть для другого случая), а третье — не пробовал:

а) File — Invalidate Caches/Restart — Invalidate and Restart

б) Закрыть студию. В корне папки проекта удалить файл(ы) .iml и папку .idea. Вновь запустить студию и импортировать проект.

в) Нажать Ctrl-Alt-O и запустить оптимизацию импорта.

Кстати, adb сервер можно проверить на версию (и работоспособность) и затем перезапустить:

3) Если Android Studio выдает приблизительно такую ошибку: Error:Execution failed for task ‘:app:dexDebug’.

Надо слева переключиться на опцию Project, найти и удалить папку build которая лежит в папке app, т.е. по пути app/build. Затем перестроить весь проект заново: Build -> Rebuild Project.

Такое же решение если ошибка типа: «не могу удалить (создать) папку или файл» и указан путь, который в ведет в app/build. Тоже удаляем папку build и ребилдим проект.

4) В сообщении об ошибке упоминается heap — виртуальная память. А ошибка обычно вызвана ее нехваткой, т.е. невозможностью получить запрашиваемый объем. Поэтому этот запрашиваемый объем надо уменьшить, т.е. переписать дефолтное значение (обычно 2048 MB которое можно изменить в настройках), на меньшее 1024 MB.

В файле проекта gradle.properties пишем:

5) Android Studio пришет примерно такую ошибку: Plugin is too old, please update to a more recent version, or set ANDROID_DAILY_OVERRIDE environment variable to «83648b99316049d63656d7276cb19cc7e95d70a5»

Возможные причины (кроме необходимости регулярного обновления SDK):

а) Загруженный проект был скомпилирован с помощью уже несовместимого старого gradle плагина. В этом случае надо найти и подключить в своем build.gradle проекта этот более старый плагин. т.е. попробовать более старые версии, например: 1.1.3 (часто именно 1.1.x и подходит).

Найти все версии можно здесь.

б) Если в build.gradle проекта используется beta-версия плагина — это означает, что срок ее истек. Посмотреть последние релизы (продакшн и бета) можно также здесь:

6) Иногда при подключении сторонних библиотек могут дублироваться некоторые файлы (обычно связанные с лицензированием). В сообщении будет что-то содержащее слова: duplicate files. Решение — надо посмотреть в сообщении об ошибке или в документации подключенной сторонней библиотеки — какие именно файлы стали избыточными, и перечислить их в build.gradle модуля для исключения (exclude) из билда.

Это делается в директиве packagingOptions (которая, в свою очередь, находится в директиве android).

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Build and run your app

Android Studio sets up new projects to deploy to the Android Emulator or a connected device with just a few clicks. Once your app is installed, you can use Apply Changes to deploy certain code and resource changes without building a new APK.

To build and run your app, follow these steps:

In the toolbar, select your app from the run configurations drop-down menu.

From the target device drop-down menu, select the device that you want to run your app on.

If you don’t have any devices configured, then you need to either connect a device via USB or create an AVD to use the Android Emulator.

Click Run .

Change the run/debug configuration

When you run your app for the first time, Android Studio uses a default run configuration. The run configuration specifies whether to deploy your app from an APK or an Android App Bundle, the module to run, package to deploy, activity to start, target device, emulator settings, logcat options, and more.

The default run/debug configuration builds an APK, launches the default project activity, and uses the Select Deployment Target dialog for target device selection. If the default settings don’t suit your project or module, you can customize the run/debug configuration, or even create a new one, at the project, default, and module levels. To edit a run/debug configuration, select Run > Edit Configurations. For more information, see Create and Edit Run/Debug Configurations.

Change the build variant

By default, Android Studio builds the debug version of your app, which is intended for use only during development, when you click Run.

To change the build variant Android Studio uses, select Build > Select Build Variant in the menu bar.

For projects without native/C++ code, the Build Variants panel has two columns: Module and Active Build Variant. The Active Build Variant value for the module determines which build variant the IDE deploys to your connected device and is visible in the editor.

Figure 1. The Build Variants panel has two columns for projects that do not have native/C++ code

To switch between variants, click the Active Build Variant cell for a module and choose the desired variant from the list field.

For projects with native/C++ code, the Build Variants panel has three columns: Module, Active Build Variant, and Active ABI. The Active Build Variant value for the module determines the build variant that the IDE deploys to your device and is visible in the editor. For native modules, the Active ABI value determines the ABI that the editor uses, but does not impact what is deployed.

Figure 2. The Build Variants panel adds the Active ABI column for projects with native/C++ code

To change the build variant or ABI, click the cell for the Active Build Variant or Active ABI column and choose the desired variant or ABI from the list. After you change the selection, the IDE syncs your project automatically. Changing either column for an app or library module will apply the change to all dependent rows.

By default, new projects are set up with two build variants: a debug and release variant. You need to build the release variant to prepare your app for public release.

To build other variations of your app, each with different features or device requirements, you can define additional build variants.

Conflicts in Android Studio’s Build Variants dialog

In Android Studio’s Build Variants dialog, you might see error messages indicating conflicts between build variants, such as the following:

This error does not indicate a build issue with Gradle – it is only indicating that the Android Studio IDE itself cannot resolve symbols between the variants of the selected modules.

For example, if you have a module M1 that depends on variant v1 of module M2 , but M2 has variant v2 selected in the IDE, you have unresolved symbols in the IDE. Let’s say that M1 depends on a class Foo which is only available in v1 . When v2 is selected, that class is not known by the IDE and it will fail to resolve it and show errors in the code of M1 .

These error messages appear because the IDE cannot load code for multiple variants simultaneously. In terms of your app’s build, however, the variant selected in this dialog will have no effect because Gradle builds your app with the source code specified in your Gradle build recipes, not based on what’s currently loaded in the IDE.

Build your project

The Run button builds and deploys your app to a device. However, to build your app to share or upload to Google Play, you’ll need to use one of the options in the Build menu to compile parts or all of your project. Before you select any of the build options listed in table 1, make sure you first select the build variant you want to use.

Table 1. Build options in the Build menu.

Builds an APK of all modules in the current project for their selected variant. When the build completes, a confirmation notification appears, providing a link to the APK file and a link to analyze it in the APK Analyzer.

If the build variant you’ve selected is a debug build type, then the APK is signed with a debug key and it’s ready to install. If you’ve selected a release variant, then, by default, the APK is unsigned and you must manually sign the APK. Alternatively, you can select Build > Generate Signed Bundle / APK from the menu bar.

Android Studio saves the APKs you build in project-name / module-name /build/outputs/apk/ .

Builds an Android App Bundle of all modules in the current project for their selected variant. When the build completes, a confirmation notification appears, providing a link to the app bundle and a link to analyze it in the APK Analyzer.

If the build variant you’ve selected is a debug build type, then the app bundle is signed with a debug key, and you can use bundletool to deploy your app from the app bundle to a connected device. If you’ve selected a release variant, then the app bundle is unsigned by default and you must manually sign it using jarsigner . Alternatively, you can select Build > Generate Signed Bundle / APK from the menu bar.

Android Studio saves the APKs you build in project-name / module-name /build/outputs/bundle/ .

Menu Item	Description
Make Module	Compiles all source files in the selected module that have been modified since the last build, and all modules the selected module depends on recursively. The compilation includes dependent source files and any associated build tasks. You can select the module to build by selecting either the module name or one of its files in the Project window.
Make Project	Makes all modules.
Clean Project	Deletes all intermediate/cached build files.
Rebuild Project	Runs Clean Project for the selected build variant and produces an APK.
Build Bundle(s) / APK(s) > Build APK(s)
Build Bundle(s) / APK(s) > Build Bundle(s)
Brings up a dialog with a wizard to set up a new signing configuration, and build either a signed app bundle or APK. You need to sign your app with a release key before you can upload it to the Play Console. For more information about app signing, see Sign your app.

Note: The Run button builds an APK with testOnly=»true» , which means the APK can only be installed via adb (which Android Studio uses). If you want a debuggable APK that people can install without adb, select your debug variant and click Build Bundle(s) / APK(s) > Build APK(s).

For details about the tasks that Gradle executes for each command, open the Build window as described in the next section. For more information about Gradle and the build process, see Configure Your Build.

Monitor the build process

You can view details about the build process by clicking View > Tool Windows > Build (or by clicking Build in the tool window bar). The window displays the tasks that Gradle executes in order to build your app, as shown in figure 3.

Figure 3. The Build output window in Android Studio

Build tab: Displays the tasks Gradle executes as a tree, where each node represents either a build phase or a group of task dependencies. If you receive build-time or compile-time errors, inspect the tree and select an element to read the error output, as shown in figure 4.

Figure 4. Inspect the Build output window for error messages

Sync tab: Displays tasks that Gradle executes to sync with your project files. Similar to the Build tab, if you encounter a sync error, select elements in the tree to find more information about the error.

Restart: Performs the same action as selecting Build > Make Project by generating intermediate build files for all modules in your project.

Toggle view: Toggles between displaying task execution as a graphical tree and displaying more detailed text output from Gradle—this is the same output you see in the Gradle Console window on Android Studio 3.0 and earlier.

If your build variants use product flavors, Gradle also invokes tasks to build those product flavors. To view the list of all available build tasks, click View > Tool Windows > Gradle (or click Gradle in the tool window bar).

If an error occurs during the build process, Gradle may recommend some command-line options to help you resolve the issue, such as —stacktrace or —debug . To use command-line options with your build process:

1. Open the Settings or Preferences dialog:
   • On Windows or Linux, select File >Settings from the menu bar.
   • On Mac OSX, select Android Studio >Preferences from the menu bar.
2. Navigate to Build, Execution, Deployment >Compiler.
3. In the text field next to Command-line Options, enter your command-line options.
4. Click OK to save and exit.

Gradle applies these command-line options the next time you try building your app.

Apply Changes

In Android Studio 3.5 and higher, Apply Changes lets you push code and resource changes to your running app without restarting your app—and, in some cases, without restarting the current activity. This flexibility helps you control how much of your app is restarted when you want to deploy and test small, incremental changes while preserving your device’s current state. Apply Changes uses capabilities in the Android JVMTI implementation that are supported on devices running Android 8.0 (API level 26) or higher. To learn more about how Apply Changes works, see Android Studio Project Marble: Apply Changes.

Requirements

Apply Changes actions are only available when you meet the following conditions:

• You build the APK of your app using a debug build variant.
• You deploy your app to a target device or emulator that runs Android 8.0 (API level 26) or higher.

Use Apply Changes

Use the following options when you want to deploy your changes to a compatible device:

Apply Changes and Restart Activity

Attempts to apply both your resource and code changes by restarting your activity but without restarting your app. Generally, you can use this option when you’ve modified code in the body of a method or modified an existing resource.

You can also perform this action by pressing Ctrl+Alt+F10 (or Control+Shift+Command+R on macOS).

Apply Code Changes

Attempts to apply only your code changes without restarting anything. Generally, you can use this option when you’ve modified code in the body of a method but you have not modified any resources. If you’ve modified both code and resources, use Apply Changes and Restart Activity instead.

You can also perform this action by pressing Ctrl+F10 (or Control+Command+R on macOS).

Run

Deploys all changes and restarts the app. Use this option when the changes that you have made cannot be applied using either of the Apply Changes options. To learn more about the types of changes that require an app restart, see Limitations of Apply Changes.

Enable Run fallback for Apply Changes

After you’ve clicked either Apply Changes and Restart Activity or Apply Code Changes, Android Studio builds a new APK and determines whether the changes can be applied. If the changes can’t be applied and would cause Apply Changes to fail, Android Studio prompts you to Run your app again instead. However, if you don’t want to be prompted every time this occurs, you can configure Android Studio to automatically rerun your app when changes can’t be applied.

To enable this behavior, follow these steps:

Open the Settings or Preferences dialog:

• On Windows or Linux, select File > Settings from the menu bar.
• On macOS, select Android Studio > Preferences from the menu bar.

Navigate to Build, Execution, Deployment > Deployment.

Select the checkboxes to enable automatic Run fallback for either of the Apply Changes actions.

Click OK.

Platform-dependent changes

Some features of Apply Changes depend on specific versions of the Android platform. To apply these kinds of changes, your app must be deployed to a device running that version of Android (or higher).

Type of change	Minimum platform version
Adding a method	Android 11

Limitations of Apply Changes

Apply Changes is designed to speed up the app deployment process. However, there are some limitations for when it can be used. If you encounter any issues while using Apply Changes, file a bug.

Code changes that require app restart

Some code and resource changes cannot be applied until the app is restarted, including the following:

• Adding or removing a field
• Removing a method
• Changing method signatures
• Changing modifiers of methods or classes
• Changing class inheritance
• Changing values in enums
• Adding or removing a resource
• Changing the app manifest
• Changing native libraries (SO files)

Libraries and plugins

Some libraries and plugins automatically make changes to your app’s manifest files or to resources that are referenced in the manifest. These automatic updates can interfere with Apply Changes in the following ways:

• If a library or plugin makes changes to your app’s manifest, you can’t use either Apply Code Changes or Apply Changes and Restart Activity and have to restart your app before you can see your changes.
• If a library or plugin makes changes to your app’s resource files, you can’t use Apply Code Changes , and you must use Apply Changes and Restart Activity to see your changes.

You can avoid these limitations by disabling all automatic updates for your debug build variants.

For example, Crashlytics updates app resources with a unique build ID during every build, which prevents you from using Apply Code Changes and requires you to restart your app’s activity to see your changes. You can disable this behavior so that you can use Apply Code Changes alongside Crashlytics with your debug builds.

Code that directly references content in an installed APK

If your code directly references content from your app’s APK that’s installed on the device, that code can cause crashes or misbehave after clicking Apply Code Changes . This behavior occurs because when you click Apply Code Changes, the underlying APK on the device is replaced during installation. In these cases, you can click Apply Changes and Restart Activity or Run , instead.

Content and code samples on this page are subject to the licenses described in the Content License. Java is a registered trademark of Oracle and/or its affiliates.

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