Android | 登录Google Api有时不起作用

Question

In my app, I've implemented the GoogleSignInApi, with this code:

in onCreate:

        GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
                .requestIdToken(getString(R.string.server_client_id))
                .requestEmail()
                .build();
        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .enableAutoManage(this /* FragmentActivity */, null /* OnConnectionFailedListener */)
                .addApi(Auth.GOOGLE_SIGN_IN_API, gso)
                .build();

in an AsyncTask

        if (mGoogleApiClient != null)
            mGoogleApiClient.connect();
        if (mGoogleApiClient != null) {
            ConnectionResult result = mGoogleApiClient.blockingConnect();
            if(result.isSuccess()){
                GoogleSignInResult googleSignInResult = Auth.GoogleSignInApi.silentSignIn(mGoogleApiClient).await();
                GoogleSignInAccount account = googleSignInResult.getSignInAccount();
                authToken = account.getIdToken();
            }else {
                return null;
            }
        }else{
            return null;
        }

The app crash with "Attempt to invoke virtual method 'java.lang.String com.google.android.gms.auth.api.signin.GoogleSignInAccount.getIdToken()' on a null object reference" (account is null!)
Now I've added if(account!=null) {get error}, but why account could be null, if "result.isSuccess()"?

Answer 1

result is only the variable containing the result of connecting to the API. This does not involve any authentication yet. Only once you are connected, you can sign in. However, the credentials may be wrong, so you get a null result.

Answer 2

    You can use the following code for Google login:

     protected void onActivityResult(int requestCode, int responseCode, Intent intent) {
            if (requestCode == RC_SIGN_IN) {
                    GoogleSignInResult result = Auth.GoogleSignInApi.getSignInResultFromIntent(intent);
                    if (result.isSuccess()) {
                    GoogleSignInAccount acct = result.getSignInAccount();
                    }
            }
        }

GoogleSignInAccount will give you all account details.