IONIC - Android Studio Error : ":processDebugGoogleServices" Please fix the version conflict either by updating the version of the google-services plugin

IONIC - Android Studio Error :
":processDebugGoogleServices"
Please fix the version conflict either by updating the version of the google-services plugin

이 질문이 진짜 많다
저 오류로 고생하는 이들이 엄청나단건데
한국어로 블로깅된 내용이 없어서 정리해봅니다

1. 원인
cordova-plugin-fcm
cordova-plugin-googleplus
위 두개의 플러그인을 사용할 경우 발생한다

1. Cause 

cordova-plugin-fcm

cordova-plugin-googleplus
Occurs when two plugins are used

2. 해결방법 (Solutions)

1) build.gradle(Module:android) OPEN

2) dependencies modify

buildscript {

repositories {

mavenCentral()

}

// Switch the Android Gradle plugin version requirement depending on the

// installed version of Gradle. This dependency is documented at

// http://tools.android.com/tech-docs/new-build-system/version-compatibility

// and https://issues.apache.org/jira/browse/CB-8143

dependencies {

classpath 'com.android.tools.build:gradle:1.5.0'

classpath 'com.google.gms:google-services:3.1.0'

}

}

// Allow plugins to declare Maven dependencies via build-extras.gradle.

repositories {

mavenCentral()

}

3) REMOVE >> // apply from: "cordova-plugin-fcm/willy-FCMPlugin.gradle"

4) compile dependencies modify ('+' to 10.2.0)

dependencies {

compile fileTree(dir: 'libs', include: '*.jar')

// SUB-PROJECT DEPENDENCIES START

debugCompile project(path: "CordovaLib", configuration: "debug")

releaseCompile project(path: "CordovaLib", configuration: "release")

compile "com.android.support:support-v4:24.1.1+"

compile "com.soundcloud.android:android-crop:1.0.0@aar"

compile "com.google.android.gms:play-services-auth:11.0.1"

compile "com.google.android.gms:play-services-identity:11.0.1"

compile "com.google.firebase:firebase-core:11.0.1"

compile "com.google.firebase:firebase-messaging:11.0.1"

// SUB-PROJECT DEPENDENCIES END

}



5) Adding to last line

apply plugin: 'com.google.gms.google-services'

6) project.properties open and modify

cordova.system.library.1=com.google.firebase:firebase-core:11.0.1

cordova.system.library.2=com.google.firebase:firebase-messaging:11.0.1

cordova.system.library.3=com.google.android.gms:play-services-auth:11.0.1

cordova.system.library.4=com.google.android.gms:play-services-identity:11.0.1

끝!
END!