1.project相关
在创建项目的时候会自动创建.ignore文件，如果没有，可在project内新增文件。ignore文件与git相关，与studio无关，所以需首先安装git。
2.module相关
一般在module下也会有相关ignore文件，内容如下：
/build
3.一份完整的ignore文件（project下）。
# Created by .ignore support plugin (hsz.mobi)
### Android template
# Built application files
*.apk
*.aar
*.ap_
*.aab
# Files for the ART/Dalvik VM
*.dex
# Java class files
*.class
# Generated files
bin/
gen/
out/
# Uncomment the following line in case you need and you don't have the release build type files in your app
# release/
# Gradle files
.gradle/
build/
# Local configuration file (sdk path, etc)
local.properties
# Proguard folder generated by Eclipse
proguard/
# Log Files
*.log
# Android Studio Navigation editor temp files
.navigation/
# Android Studio captures folder
captures/
# IntelliJ
*.iml
.idea/
.idea/workspace.xml
.idea/tasks.xml
.idea/gradle.xml
.idea/assetWizardSettings.xml
.idea/dictionaries
.idea/libraries
# Android Studio 3 in .gitignore file.
.idea/caches
.idea/modules.xml
# Comment next line if keeping position of elements in Navigation Editor is relevant for you
.idea/navEditor.xml
# Keystore files
# Uncomment the following lines if you do not want to check your keystore files in.
#*.jks
#*.keystore
# External native build folder generated in Android Studio 2.2 and later
.externalNativeBuild
.cxx/
# Google Services (e.g. APIs or Firebase)
# google-services.json
# Freeline
freeline.py
freeline/
freeline_project_description.json
# fastlane
fastlane/report.xml
fastlane/Preview.html
fastlane/screenshots
fastlane/test_output
fastlane/readme.md
# Version control
vcs.xml
# lint
lint/intermediates/
lint/generated/
lint/outputs/
lint/tmp/
# lint/reports/
#.gitignore
.gradle/6.1.1/
.gradle/buildOutputCleanup/
.gradle/checksums/
.gradle/vcs-1/
4.如果添加ignore文件后，commit还是有相关build文件，多是因为缓存，可进行如下操作
git rm -r --cached .
git add .
git commit -m '.gitignore'
