最近項目轉入AndroidX，期間參考了幾篇博客，做了一下總結：
注意，轉移AndroidX之前先備份下，但如果是版本控制的項目則不需要。
1.執行遷移之前，請先將應用更新到最新版本。我們建議您將項目更新爲使用支持庫的最終版本：版本 28.0.0。這是因爲，1.0.0 版本的 AndroidX 工件是與支持庫 28.0.0 工件等效的二進制文件。
2.必須將AndroidStudio升級到3.2以上，建議升級到3.6.1版本。使用 Android Studio 3.2 及更高版本，您只需從菜單欄中依次選擇 Refactor > Migrate to AndroidX，即可將現有項目遷移到 AndroidX。
重構命令使用兩個標記。默認情況下，這兩個標記在 gradle.properties 文件中都設爲 true：
android.useAndroidX=true
Android 插件會使用對應的 AndroidX 庫而非支持庫。
android.enableJetifier=true
3.舊依賴包名與新包名對照表（建議使用Ctrl + F搜索）
執行Migrate to AndroidX完成之後，雖然常用的support包都會被轉成對應的androidx裏的包名，gradle或者maven裏的部分依賴但還是有可能會未能轉換成功，這時候需要我們手動修改。
原包名 新包名
android.arch.core:common androidx.arch.core:core-common
android.arch.core:core androidx.arch.core:core
android.arch.core:core-testing androidx.arch.core:core-testing
android.arch.core:runtime androidx.arch.core:core-runtime
android.arch.lifecycle:common androidx.lifecycle:lifecycle-common
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:media2:1.0.0-alpha03
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
如有其他未列出的依賴，請參考
https://developer.android.google.cn/jetpack/androidx/migrate/artifact-mappings和https://developer.android.google.cn/jetpack/androidx/migrate/class-mappings