Yeah I think a lot of this are getting this now. Having the same problem too.
Google pushed an update out yesterday
https://developers.google.com/android/guides/releases
(why this breaks ionic/cordova so quickly is kind of amazing).
The original problem seems to do with something with firebase updated and some new version came out.
Once that gets updated then things because out of sync. Using android 26 or 17 but the new code I think it expecting 28.
What @helpmelearn says is correct. I know it’s a default policy of Google to introduce breaking changes and only support the Android ecosystem, so all plugin maintainers have to keep their plugins up-to-date.
But what is the right course of action here for us developers? Should we follow the releases of say e.g. Firebase and be prepared for breaking changes? This seems like a counter-intuitive way of plugins to depend on --> independent maintainers (you guys are doing god’s work) who depend on --> Google’s breaking changes?
We suddenly have a breaking build in our pipeline and we can’t release our app.
There should be a way to force a Firebase / PlayServices version that is stil compatible with SDK version 27 (and so Ionic 3) - any clue?
I’m having the same problem and I’ve been trying to solve it all day without success. Has anyone found a solution?
Same issue + 1
No solution so far…
On the same boat, been trying all day to fix this issue. Any help would be appreciated.
Finally found a solution, based on a response from SO:
I may have deleted platforms folder beforehand
ionic cordova platform rm android
ionic cordova platform add android@8.0.0
ionic cordova plugin add cordova-plugin-androidx
ionic cordova plugin add cordova-plugin-androidx-adapter
cdvMinSdkVersion=19
project.ext { defaultBuildToolsVersion="28.0.3" //String defaultMinSdkVersion=19 //Integer - Minimum requirement is Android 4.4 defaultTargetSdkVersion=28 //Integer - We ALWAYS target the latest by default defaultCompileSdkVersion=28 //Integer - We ALWAYS compile with the latest by default }
<preference name="android-minSdkVersion" value="19" />
This person explains the problem pretty well on his answer, so i encourage you to read it.
This has worked! Many thanks
thanks dude!. you saved my life 
this method works, thank you very much.
UnhandledPromiseRejectionWarning: Error [ERR_UNHANDLED_ERROR]: Unhandled error. (The platform “android” does not appear to be a valid cordova platform. It is missing API.js. android not supported.)
@JorgeU i am getting the above error while rrunning the app. do i need to update anyother plugin?
Did you not get any error related to the Crashlytics / Firebase / Fabric?:
ERROR - Crashlytics Developer Tools error.
java.lang.IllegalArgumentException: Crashlytics found an invalid API key: null.
What version of Firebase are you using now?
Yes i got the Crashlytics error as well
Using this version of firebase plugin works for me
run this commande :
ionic cordova plugin add https://github.com/dpa99c/cordova-plugin-firebase#GH-1057-April-05-android-build-issue
https://github.com/arnesson/cordova-plugin-firebase/issues/1084#issuecomment-503433000
I am using angularfire 2 , and i did not use firebase plugin directly but getting the fontvariantSettings issue.
What version of google-services are you using?
Also had this and got fixed in google-services 4.2.0
I now reverted to these steps: https://github.com/arnesson/cordova-plugin-firebase/issues/1081#issuecomment-503135862, only had to remove and add the android platform again after I added his version of the cordova-plugin-firebase. Then these versions were in android/build.gradle:
classpath 'com.google.gms:google-services:4.2.0' // google-services dependency from cordova-plugin-firebase
classpath 'io.fabric.tools:gradle:1.25.4' // fabric dependency from cordova-plugin-firebase
I can finally build again but I am worried about who will maintain the fixed cordova-plugin-firebase
For me the simplest working solution without modifying any plugins or cordova-android was to add the following to the build gradle (or to build-extras.gradle):
configurations.all {
resolutionStrategy {
force 'com.android.support:support-v4:27.1.1'
force 'com.google.android.gms:play-services-tagmanager:16.0.8'
force 'com.google.android.gms:play-services-base:16.1.0'
force 'com.google.android.gms:play-services-tasks:16.0.1'
force 'com.google.android.gms:play-services-basement:16.2.0'
force 'com.google.android.gms:play-services-gcm:16.1.0'
force 'com.google.android.gms:play-services-stats:16.0.1'
force 'com.google.android.gms:play-services-location:16.0.0'
force 'com.google.android.gms:play-services-auth:16.0.1'
force 'com.google.android.gms:play-services-identity:16.0.0'
}
}
it forces your apk to work as it did before the google breaking changes which I think is the safest way not to break other plugins.
getting like this
Could not find any version that matches androidx.annotation:annotation:28.+.
Versions that do not match:
- 1.1.0
- 1.1.0-rc01
- 1.1.0-beta01
- 1.1.0-alpha02
- 1.1.0-alpha01
- + 8 more
Required by:
project :app
Could not find any version that matches androidx.legacy:legacy-support-v4:28.+.
Versions that do not match:
- 1.0.0
- 1.0.0-rc02
- 1.0.0-rc01
- 1.0.0-beta01
- 1.0.0-alpha3
- + 1 more
Required by:
project :app
Could not find any version that matches androidx.appcompat:appcompat:28.+.
Versions that do not match:
- 1.1.0-beta01
- 1.1.0-alpha05
- 1.1.0-alpha04
- 1.1.0-alpha03
- 1.1.0-alpha02
- + 9 more
Required by:
project :app
Hello,
I am trying to implement this solution but I am having some trouble.
What gradle version are you using? What version of Android Studio?
I’ve implemented all the steps indicated above, in addition to replacing the cordova firebase plugin with this:
ionic cordova plugin add https://github.com/dpa99c/cordova-plugin-firebase#GH-1057-April-05-android-build-issue
I am getting this error in Android Studio:
Error:(40, 0) Minimum supported Gradle version is 4.10.1. Current version is 4.1.
Please fix the project's Gradle settings.
<a href="fixGradleVersionInWrapper">Fix Gradle wrapper and re-import project</a><br><a href="openGradleSettings">Gradle settings</a>
In /platforms/android/gradle/gradle.wrapper.properties I have:
#Wed Jun 19 13:26:40 BST 2019
distributionBase=GRADLE_USER_HOME
distributionPath=wrapper/dists
zipStoreBase=GRADLE_USER_HOME
zipStorePath=wrapper/dists
distributionUrl=https\://services.gradle.org/distributions/gradle-4.1-all.zip
UPDATE:
Manage to solve the issues with mzepeda’s answer below.