https://stackoverflow.com/questions/54557479/flutter-and-google-sign-in-plugin-platformexceptionsign-in-failed-com-google
1、add google-service
A：add classpath 'com.google.gms:google-services:4.2.0'
%app%/android/build.gradle
buildscript {
repositories {
google()
jcenter()
}
dependencies {
classpath 'com.android.tools.build:gradle:3.2.1'
classpath 'com.google.gms:google-services:4.2.0'
}
}
B：add apply plugin: 'com.google.gms.google-services'
%app%/android/app/build.gradle
apply plugin: 'com.android.application'
apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
apply plugin: 'com.google.gms.google-services'
2、 get google-service.json
https://firebase.google.com/docs/flutter/setuphttps://developers.google.com/android/guides/client-auth
create app
A：create test project
go https://console.firebase.google.com/
B：create application
Where get app name
Open %app%/android/app/build.gradle find applicationId
defaultConfig {
// TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
applicationId "com.example.flutter_sqlite"
minSdkVersion 16
targetSdkVersion 28
versionCode flutterVersionCode.toInteger()
versionName flutterVersionName
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
Here is com.example.flutter_sqlite
put com.example.flutter_sqlite in app name, then next.
Download google-service.json
next next...
Copy google.service.json to %app%/android/app/
C：test app in local emu need to fingerprint.
find java jdk\bin\keytoolpassword use： android
C:\Program Files\Java\jdk1.8.0_201\bin>keytool -list -v -alias androiddebugkey -keystore %USERPROFILE%\.android\debug.keystore
copy sha1 to here
Run your flutter app. Now is ok.