如何访问需要先登录的Google表单

Question

我有一个Google表单，要求用户通过Google登录才能访问该表单。如何通过api访问表单？我已经尝试通过示例驱动器api gist（上传照片的那个）登录后向表单发送一个get请求，但它仍然给我一个禁止的响应代码。

这是Google在GoogleSignIn上的快速入门：

// [START configure_signin]
    // Configure sign-in to request the user's ID, email address, and basic
    // profile. ID and basic profile are included in DEFAULT_SIGN_IN.

    GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
            .requestEmail()
            .requestScopes(new Scope("https://www.googleapis.com/auth/drive"), new Scope("https://www.googleapis.com/auth/plus.login"), new Scope("https://www.googleapis.com/auth/plus.me"), new Scope("https://www.googleapis.com/auth/forms"))
    // [END configure_signin]

    // [START build_client]
    // Build a GoogleApiClient with access to the Google Sign-In API and the
    // options specified by gso.

    mGoogleApiClient = new GoogleApiClient.Builder(this)
            .enableAutoManage(this /* FragmentActivity */, this /* OnConnectionFailedListener */)
            .addApi(Auth.GOOGLE_SIGN_IN_API, gso)
            .build();
    mGoogleApiClient.connect();
    // [END build_client]

这是来自尝试连接到表单的AsyncTask（需要首先登录：

public class RetrieveTokenTask extends AsyncTask<String, Void, String> {

Context mContext;

public RetrieveTokenTask(Context context){
    mContext = context;
}

@Override
protected String doInBackground(String... email) {

    try{
        URL api = new URL("https://docs.google.com/forms/d/___FORMID/formResponse?entry.209165355=1&entry.1433596447=1&entry.2073901950=1");

        HttpURLConnection conn = (HttpURLConnection) api.openConnection();
        conn.setRequestMethod("POST");
        conn.setInstanceFollowRedirects(true);
        conn.setRequestProperty("Authorization","Bearer " + GoogleAuthUtil.getToken(mContext,email[0],"oauth2:https://www.googleapis.com/auth/forms"));
        Log.wtf("Response", conn.getResponseCode()+"-"+conn.getResponseMessage());
        return null;

    }catch(Exception e ){
        Log.wtf("FAILED",e.getMessage());
    }

    return null;
}

}