This document provides instructions for migrating an Android project to use AndroidX instead of the legacy support library. It outlines the steps to upgrade support libraries, migrate dependencies to AndroidX, replace package names, fix errors, and handle limitations. Key points include upgrading the gradle plugin, setting flags in gradle.properties to enable migration, running a script to replace package names, fixing unresolved and deprecated errors, dealing with merge conflicts by rerunning the script, and handling dependencies that haven't migrated yet.

1. X: First Class
Kami
#AndroidTaipei

2. Ref: https://developer.android.com/jetpack/androidx/migrate

3. KEEP
CALM
AND
ROID
X

4. Why AndroidX ?
The support library artifacts are being deprecated and
all feature development is going into AndroidX.

6. Step
1. Upgrade support library v28.0.0↑
2. Upgrade 3rd library version before supporting X
3. Modify gradle.properties
4. Migrate all dependencies supporting X
5. Replace X package
6. Fix unresolved or deprecated things
7. Follow X progress of libraries haven’t support X

7. gradle.properties
android.useAndroidX=true
android.enableJetifier=true

8. #!/usr/bin/env bash
MAPPING_FILE=path/to/androidx-class-mapping.csv
PROJECT_DIR=path/to/android/project
replace=""
while IFS=, read -r from to
do
replace+="; s/$from/$to/g"
done <<< "$(cat $MAPPING_FILE)"
find $PROJECT_DIR ( -name "*.kt" -o -name "*.java" -o -name "*.xml" ) -type f -not -path '*/.git*' -print0 |
xargs -0 gsed -i "$replace"
Ref: https://gist.github.com/dlew/5db1b780896bbc6f542e7c00a11db6a0

9. Ref: https://issuetracker.google.com/issues/119776865

10. import androidx.gridlayout.widget.GridLayoutManager
recyclerview
e.g. unresolved - 1

11. Ref:
https://github.com/googlesamples/android-architecture/commit/4d435d28f020ea45b6746e05efdff97d0c357b26#diff-2
4e499d4a814ef202cf522debced827a
e.g. unresolved - 2

12. import androidx.test.runner.AndroidJUnit4
import androidx.test.ext.junit.runners.AndroidJUnit4
e.g. deprecated - 1
androidTestImplementation "androidx.test.ext:junit:${version}"

13. import androidx.test.InstrumentationRegistry
import androidx.test.platform.app.InstrumentationRegistry
e.g. deprecated - 2

14. Merge Nightmares
Just re-run the script

15. Jetifier Limitations

16. Ref: https://issuetracker.google.com/issues/115738511

17. Ref: https://issuetracker.google.com/issues/123060356

18. gradle.properties (After X… )
android.useAndroidX=true
android.enableJetifier=false

19. $ ./gradlew :app:dependencies > a.txt

20. +--- com.google.dagger:dagger-android-support:2.16
| +--- com.google.dagger:dagger:2.16 (*)
| +--- com.google.dagger:dagger-android:2.16
| | +--- com.google.dagger:dagger:2.16 (*)
| | +--- com.android.support:support-annotations:25.0.0 -> 26.1.0
| | --- javax.inject:javax.inject:1

21. Ref: https://github.com/google/dagger/issues/1181

22. Ref: https://android-developers.googleblog.com/2019/06/google-play-services-and-firebase.html

23. Thanks