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만약 이 글을 읽는 개발자가 GPGS의 Document에 따라서 잘 개발했다면(혹은 GPGS sample app을 다운받아서 디버깅할때) 마지막 남은 관문을 넘지 못해서 나오는 오류인 것이다.
GPGS는 디버깅시에 signed apk를 사용하여 디버깅해야만 한다.
GPGS 디버깅 방법
GPGS와 사용자의 google 계정 연결 혹은 업적과 같은 기능의 테스트를 위해서는 일반적인 Android studio의 RUN으로는 불가능하다. 해당 내용은 GPGS 공식홈페이지에도 아래와 같이 나와있다.
Choose Installed application as your Application type and select Android as the installed application type (these should be your only options).
In the Package name field, enter your Android application's package name.
Open a terminal and run the Keytool utility to get the SHA1 fingerprint of the certificate. You should get both the release and debug certificate fingerprints.
The keytool prompts you to enter a password for the keystore. The default password for the debug keystore is android. The keytool then prints the fingerprint to the terminal.
Paste the SHA1 fingerprint into the Signing certificate fingerprint (SHA1) field.
You should create two client IDs, one with the release certificate fingerprint and another with the debug certificate fingerprint. Make sure to use the same package name for both. This allows Google Play games services to recognize calls from your linked APKs that are signed with either certificate. For more information about certificate signing for Android, see Signing Your Application.
You can add more than one Android app to the same game entry in Google Play Console. However, this should only be done if there are different versions of thesamegame (for example, the free version and the paid version). In this case, always list the paid version before the free version (or the full version before the demo/trial version). Do not link different games to the same project as this may cause incorrect behavior. Instead, create a separate game entry in the Google Play Console for each game that you publish.
