Android应用RAW目录存JSON凭证仍提示默认凭证不可用问题

Let’s break down exactly what’s going wrong here:

1. You’re Using the Wrong Method to Load Service Account Credentials #

The GoogleCredential.FromJson(json) method isn’t designed to parse raw service account JSON files. It’s meant to deserialize a pre-serialized GoogleCredential object (i.e., JSON that was generated by serializing an existing GoogleCredential instance).

Your service account JSON has a specific structure (with fields like "type": "service_account", "client_email", "private_key", etc.) that FromJson() doesn’t recognize. When this method fails to create a valid credential, the library falls back to trying to load Application Default Credentials (ADC)—which don’t exist in a typical Android environment—hence the error you’re seeing.

2. Correct Approach to Load Service Account Credentials on Android #

Instead of FromJson(), you need to use the credential stream loader that’s built to handle service account JSON files. Here’s how to fix your code:

// Get input stream from your RAW directory credential file
InputStream credStream = getResources().openRawResource(R.raw.your_service_account_json);

// Load credentials from the stream, add required scopes
GoogleCredentials credentials = GoogleCredentials.fromStream(credStream)
    .createScoped(Arrays.asList("https://www.googleapis.com/auth/your_target_scope"));

// If you specifically need a GoogleCredential object (for older API compatibility)
GoogleCredential googleCredential = ((ServiceAccountCredentials) credentials).toBuilder()
    .build();

This method properly parses the service account JSON structure and initializes the credential correctly, avoiding the fallback to ADC.

内容的提问来源于stack exchange，提问作者Pablo