title: Cannot resolve symbol default_web_client_id in Firebase's Android Codelab
body: <p>I am trying to learn Firebase, so I went through the Android Codelab. The project they gave me however, had an error:</p>
  
  <blockquote>
    <p>Cannot resolve symbol default_web_client_id</p>
  </blockquote>
  
  <p>And I didn't know how to solve it, since I didn't know the value of <code>default_web_client_id</code> or what it is. It is in the <code>onCreate()</code> method:
  <strong>SigninActivity.java</strong></p>
  
  <pre><code>@Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_sign_in);
      mFirebaseAuth = FirebaseAuth.getInstance();
  
      // Assign fields
      mSignInButton = (SignInButton) findViewById(R.id.sign_in_button);
  
      // Set click listeners
      mSignInButton.setOnClickListener(this);
  
      // Configure Google Sign In
      GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
              .requestIdToken(getString(R.string.default_web_client_id))
              .requestEmail()
              .build();
      mGoogleApiClient = new GoogleApiClient.Builder(this)
              .enableAutoManage(this /* FragmentActivity */, this /* OnConnectionFailedListener */)
              .addApi(Auth.GOOGLE_SIGN_IN_API, gso)
              .build();
  }
  </code></pre>
  
  <p>I have no idea what it is, what's its value is, and why is it giving me this error. I haven't changed anything so far except for adding the <code>google-services.json</code>. I have added my <a href="http://en.wikipedia.org/wiki/SHA-1" rel="noreferrer">SHA-1</a> and enabled Google in the console.</p>