参考链接
本次迁移主要参考上面谷歌官方公众号文章,迁移背景建议点进文章进行查看,本文主要提及一些迁移过程和其中遇到的坑

重要提醒

迁移开始之前,不管你的项目用的是svn还是git 都确认本地代码无修改并且是分支上最新代码,建议在电脑上新建个文件夹,把分支上代码拉下来专门做androidX迁移,这样到时候既是迁移不成功,把该文件夹删掉就行了,跟你的小伙伴们商量好迁移的事项,像我这一个人的话,就随便了

如果你的项目不是使用AndroidStudio开发的本文中的一些步骤可能不太适用,确保AndroidStudio使用3.5+版本

关于Gradle版本问题

如果你的项目使用的是 美团的walle 打包,不要把gradle版本升级到最新的4.0,停留在3.63就行.问题一大堆了

如图

gradle配置参考

参考示例

项目的gradle文件
dependencies {
        classpath "com.android.tools.build:gradle:3.6.3"
    }

项目的gradle文件夹

gradle文件夹

distributionBase=GRADLE_USER_HOME
distributionPath=wrapper/dists
zipStoreBase=GRADLE_USER_HOME
zipStorePath=wrapper/dists
distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.4-all.zip

迁移步骤

迁移步骤示意图

1,将项目中所有的Support库升级到28

参考版本和示例

    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    implementation 'com.android.support:support-core-ui:28.0.0'
    implementation 'com.android.support:support-core-utils:28.0.0'
    implementation 'com.android.support:support-fragment:28.0.0'
    implementation 'com.android.support:support-vector-drawable:28.0.0'
    implementation 'com.android.support:animated-vector-drawable:28.0.0'
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support:support-v4:28.0.0'
    implementation 'com.android.support:design:28.0.0'
    implementation 'com.android.support:recyclerview-v7:28.0.0'
    implementation 'com.android.support:cardview-v7:28.0.0'

这一步应该没问题,无非就是涉及到一些Api的改动

2,开启 Jetifier

项目的gradle.properties添加

android.useAndroidX=true
android.enableJetifier=true

修改好之后,确保 clean rebuild run 都没问题 在进行下一步

3,将项目依赖的所有第三方库全部升级

个人认为这一步最重要,当然选择第三方sdk要适用于你的项目,比如okhttp4,rxjava3等底层都换了其实用rx2最新的版本就行,glide等改动不太大的直接升级最新版本就行

如果检测到第三方SDK还没有适配AndroidX,并且是项目必须依赖的,那么就此放弃,以下内容不用再看了!!!

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---3.1前方巨坑,坑了我两天

因为项目中使用了 支付宝sdk,微信支付登录sdk,大厂自然不用说,不存在一些java版本的兼容问题

但是 我们还是用了汇付宝

之前项目中一直使用的是汇付宝3.0的版本,最新的版本是4.0,这次升级sdk时遗漏了汇付宝的sdk升级 导致最终打包时一直报错,说某个方法不存在之类的,吭哧了两天 ,从头开始弄才得以解决

3.2升级Butterknife

butterknife从10.0开始已经支持androidx了,我们直接升级到最新的10.2.1版本即可,需要在app下的gradle中配置编译jdk版本

android {
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }

JDK8下载: 官网下载地址,不知道从几何时下载jdk也需要登录账号了,注册账号的流程又TM那么复杂,好在前人已经填坑了,直接给出的自己注册的账号

1772885836@qq.com 
OracleTest1234

或者
2696671285@qq.com 
密码：Oracle123

账号引用链接,再次感谢

3.3升级BaseRecyclerViewAdapterHelper

最新的3.0.4支持androidx并且用kotlin重写,但是一些api改动比较大,
像item中view的点击事件,加载更多等,一想到项目中那么多列表 我滴个亲娘嘞,没办法升级总是痛苦的,就是个复制粘贴的工作,干就得了奥利给!

修改好之后,确保 clean rebuild run 都没问题 在进行下一步

4,使用AndroidStudio 将Support库转换AndroidX

Migrate to AndroidX

AndroidStudio导航

过程中会提示你备份当前工程,备份一下就进行下一步,经过一段时间后成功了,

需要注意的是,AndroidStudio转换后有时候并没有把所有的XML布局都能转换成功,有一些布局文件会遗漏

这个时候就需要我们自己手动进行替换

4.1库替换

官方提供库的映射表,可以用Ctrl+F 在本页面查找.找到对应的库并且选择合适的版本

Old build artifact	AndroidX build artifact
android.arch.lifecycle:common-java8	androidx.lifecycle:lifecycle-common-java8
android.arch.lifecycle:compiler	androidx.lifecycle:lifecycle-compiler
android.arch.lifecycle:extensions	androidx.lifecycle:lifecycle-extensions
android.arch.lifecycle:livedata	androidx.lifecycle:lifecycle-livedata
android.arch.lifecycle:livedata-core	androidx.lifecycle:lifecycle-livedata-core
android.arch.lifecycle:reactivestreams	androidx.lifecycle:lifecycle-reactivestreams
android.arch.lifecycle:runtime	androidx.lifecycle:lifecycle-runtime
android.arch.lifecycle:viewmodel	androidx.lifecycle:lifecycle-viewmodel
android.arch.paging:common	androidx.paging:paging-common
android.arch.paging:runtime	androidx.paging:paging-runtime
android.arch.paging:rxjava2	androidx.paging:paging-rxjava2
android.arch.persistence.room:common	androidx.room:room-common
android.arch.persistence.room:compiler	androidx.room:room-compiler
android.arch.persistence.room:guava	androidx.room:room-guava
android.arch.persistence.room:migration	androidx.room:room-migration
android.arch.persistence.room:runtime	androidx.room:room-runtime
android.arch.persistence.room:rxjava2	androidx.room:room-rxjava2
android.arch.persistence.room:testing	androidx.room:room-testing
android.arch.persistence:db	androidx.sqlite:sqlite
android.arch.persistence:db-framework	androidx.sqlite:sqlite-framework
com.android.support.constraint:constraint-layout	androidx.constraintlayout:constraintlayout
com.android.support.constraint:constraint-layout-solver	androidx.constraintlayout:constraintlayout-solver
com.android.support.test.espresso.idling:idling-concurrent	androidx.test.espresso.idling:idling-concurrent
com.android.support.test.espresso.idling:idling-net	androidx.test.espresso.idling:idling-net
com.android.support.test.espresso:espresso-accessibility	androidx.test.espresso:espresso-accessibility
com.android.support.test.espresso:espresso-contrib	androidx.test.espresso:espresso-contrib
com.android.support.test.espresso:espresso-core	androidx.test.espresso:espresso-core
com.android.support.test.espresso:espresso-idling-resource	androidx.test.espresso:espresso-idling-resource
com.android.support.test.espresso:espresso-intents	androidx.test.espresso:espresso-intents
com.android.support.test.espresso:espresso-remote	androidx.test.espresso:espresso-remote
com.android.support.test.espresso:espresso-web	androidx.test.espresso:espresso-web
com.android.support.test.janktesthelper:janktesthelper	androidx.test.jank:janktesthelper
com.android.support.test.services:test-services	androidx.test:test-services
com.android.support.test.uiautomator:uiautomator	androidx.test.uiautomator:uiautomator
com.android.support.test:monitor	androidx.test:monitor
com.android.support.test:orchestrator	androidx.test:orchestrator
com.android.support.test:rules	androidx.test:rules
com.android.support.test:runner	androidx.test:runner
com.android.support:animated-vector-drawable	androidx.vectordrawable:vectordrawable-animated
com.android.support:appcompat-v7	androidx.appcompat:appcompat
com.android.support:asynclayoutinflater	androidx.asynclayoutinflater:asynclayoutinflater
com.android.support:car	androidx.car:car
com.android.support:cardview-v7	androidx.cardview:cardview
com.android.support:collections	androidx.collection:collection
com.android.support:coordinatorlayout	androidx.coordinatorlayout:coordinatorlayout
com.android.support:cursoradapter	androidx.cursoradapter:cursoradapter
com.android.support:customtabs	androidx.browser:browser
com.android.support:customview	androidx.customview:customview
com.android.support:design	com.google.android.material:material
com.android.support:documentfile	androidx.documentfile:documentfile
com.android.support:drawerlayout	androidx.drawerlayout:drawerlayout
com.android.support:exifinterface	androidx.exifinterface:exifinterface
com.android.support:gridlayout-v7	androidx.gridlayout:gridlayout
com.android.support:heifwriter	androidx.heifwriter:heifwriter
com.android.support:interpolator	androidx.interpolator:interpolator
com.android.support:leanback-v17	androidx.leanback:leanback
com.android.support:loader	androidx.loader:loader
com.android.support:localbroadcastmanager	androidx.localbroadcastmanager:localbroadcastmanager
com.android.support:media2	androidx.media2:media2
com.android.support:media2-exoplayer	androidx.media2:media2-exoplayer
com.android.support:mediarouter-v7	androidx.mediarouter:mediarouter
com.android.support:multidex	androidx.multidex:multidex
com.android.support:multidex-instrumentation	androidx.multidex:multidex-instrumentation
com.android.support:palette-v7	androidx.palette:palette
com.android.support:percent	androidx.percentlayout:percentlayout
com.android.support:preference-leanback-v17	androidx.leanback:leanback-preference
com.android.support:preference-v14	androidx.legacy:legacy-preference-v14
com.android.support:preference-v7	androidx.preference:preference
com.android.support:print	androidx.print:print
com.android.support:recommendation	androidx.recommendation:recommendation
com.android.support:recyclerview-selection	androidx.recyclerview:recyclerview-selection
com.android.support:recyclerview-v7	androidx.recyclerview:recyclerview
com.android.support:slices-builders	androidx.slice:slice-builders
com.android.support:slices-core	androidx.slice:slice-core
com.android.support:slices-view	androidx.slice:slice-view
com.android.support:slidingpanelayout	androidx.slidingpanelayout:slidingpanelayout
com.android.support:support-annotations	androidx.annotation:annotation
com.android.support:support-compat	androidx.core:core
com.android.support:support-content	androidx.contentpager:contentpager
com.android.support:support-core-ui	androidx.legacy:legacy-support-core-ui
com.android.support:support-core-utils	androidx.legacy:legacy-support-core-utils
com.android.support:support-dynamic-animation	androidx.dynamicanimation:dynamicanimation
com.android.support:support-emoji	androidx.emoji:emoji
com.android.support:support-emoji-appcompat	androidx.emoji:emoji-appcompat
com.android.support:support-emoji-bundled	androidx.emoji:emoji-bundled
com.android.support:support-fragment	androidx.fragment:fragment
com.android.support:support-media-compat	androidx.media:media
com.android.support:support-tv-provider	androidx.tvprovider:tvprovider
com.android.support:support-v13	androidx.legacy:legacy-support-v13
com.android.support:support-v4	androidx.legacy:legacy-support-v4
com.android.support:support-vector-drawable	androidx.vectordrawable:vectordrawable
com.android.support:swiperefreshlayout	androidx.swiperefreshlayout:swiperefreshlayout
com.android.support:textclassifier	androidx.textclassifier:textclassifier
com.android.support:transition	androidx.transition:transition
com.android.support:versionedparcelable	androidx.versionedparcelable:versionedparcelable
com.android.support:viewpager	androidx.viewpager:viewpager
com.android.support:wear	androidx.wear:wear
com.android.support:webkit	androidx.webkit:webkit

4.2包名替换

快捷键 Ctrl + Shift + R 进行全局搜索替换

Old build artifact	AndroidX build artifact
android.support.annotation.NonNull	androidx.annotation.NonNull
android.support.annotation.Nullable	androidx.annotation.Nullable
android.support.constraint.ConstraintLayout	androidx.constraintlayout.widget.ConstraintLayout
android.support.v4.widget.NestedScrollView	androidx.core.widget.NestedScrollView
android.support.v7.widget.RecyclerView	androidx.recyclerview.widget.RecyclerView
android.support.v7.widget.LinearLayoutManager	androidx.recyclerview.widget.LinearLayoutManager
android.support.v7.widget.DefaultItemAnimator	androidx.recyclerview.widget.DefaultItemAnimator
android.support.v7.widget.GridLayoutManager	androidx.recyclerview.widget.GridLayoutManager
android.support.constraint.Guideline	androidx.constraintlayout.widget.Guideline
android.support.v7.widget.CardView	androidx.cardview.widget.CardView
android.support.v4.view.ViewPager	androidx.viewpager.widget.ViewPager
android.support.v4.view.PagerAdapter	androidx.viewpager.widget.PagerAdapter
android.support.v4.app.FragmentManager	androidx.fragment.app.FragmentManager
android.support.v4.app.FragmentTransaction	androidx.fragment.app.FragmentTransaction
android.support.v7.app.AppCompatDialog	androidx.appcompat.app.AppCompatDialog
android.support.design.widget.CoordinatorLayout	androidx.coordinatorlayout.widget.CoordinatorLayout
android.support.design.widget.AppBarLayout	com.google.android.material.appbar.AppBarLayout
android.support.design.widget.CollapsingToolbarLayout	com.google.android.material.appbar.CollapsingToolbarLayout
android.support.v4.widget.Space	Space

本次替换用到了这些,如果有新的 再往里面添加吧

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到这一步基本上就完成迁移了

5,确认问题环节

1. 确保 clean rebuild run 都没问题
2. 使用迁移后的代码打release包,在真机上运行无误

下班吧 迁移完成了 GO! GO! GO!