Google登录按钮未弹出

Question

我遵循了firebase的官方文档，android的google登录按钮未显示弹出，最初用于直接登录，后来在另一个系统中运行相同的代码后，它仅针对第一次登录时，它不是在询问允许或拒绝之类的权限。

    gsignin = (SignInButton) findViewById(R.id.googlesign);
    GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
            .requestIdToken(getString(R.string.default_web_client_id))
            .requestEmail()
            .build();

    mGoogleSignInClient = GoogleSignIn.getClient(this, gso);mAuth=FirebaseAuth.getInstance();
    gsignin.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent signInIntent = mGoogleSignInClient.getSignInIntent();
            startActivityForResult(signInIntent, RC_SIGN_IN);
        }
    });



  public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    // Result returned from launching the Intent from GoogleSignInApi.getSignInIntent(...);
    if (requestCode == RC_SIGN_IN) {
        Task<GoogleSignInAccount> task = GoogleSignIn.getSignedInAccountFromIntent(data);
        try {
            // Google Sign In was successful, authenticate with Firebase
            GoogleSignInAccount account = task.getResult(ApiException.class);
            firebaseAuthWithGoogle(account);
        } catch (ApiException e) {
            // Google Si
            Toast.makeText(this, "Google sign in failed", Toast.LENGTH_SHORT).show();
        }
    }
}


private void firebaseAuthWithGoogle(GoogleSignInAccount acct) {

    AuthCredential credential = GoogleAuthProvider.getCredential(acct.getIdToken(), null);
    mAuth.signInWithCredential(credential)
            .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                @Override
                public void onComplete(@NonNull Task<AuthResult> task) {
                    if (task.isSuccessful()) {
                        Toast.makeText(MainActivity.this, "Sign in Success", Toast.LENGTH_SHORT).show();

                        Intent i = new Intent(MainActivity.this,LandingActivity.class);
                        startActivity(i);
                        finish();
                    } else {
                        // If sign in fails, display a message to th
                        Toast.makeText(MainActivity.this, "Authentication Failed", Toast.LENGTH_SHORT).show();
                    }

                    // ...
                }
            });
}


   @Override
    public void onStart()
{
    super.onStart();
    // Check if user is signed in (non-null) and update UI accordingly.
    FirebaseUser currentUser = mAuth.getCurrentUser();
    if(currentUser!=null){
        if(currentUser.isEmailVerified()) {
            Intent i = new Intent(MainActivity.this, LandingActivity.class);
            startActivity(i);
            finish();
        }
  //            FirebaseAuth.getInstance().signOut();
    }
}

主要问题是Google登录按钮未在登录时询问允许或拒绝之类的权限