android上带有get Google令牌的验证后端

我有一个问题，当我试图获得谷歌代币在android的Balidation后端。我创建Web应用程序客户端Id（我在url路径中使用）、Android客户端Id，并使用以下代码：

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

private static final String TAG = GoogleOAuthTask.class.getSimpleName();
Activity mActivity;
String mEmail;

private final static String SCOPE = "audience:server:client_id:XXXXXXXXXXXXXXXXXXXAAAAAXXXXXXXXXXX.apps.googleusercontent.com";

public GoogleOAuthTask(Activity activity, String email) {
    this.mActivity = activity;
    this.mEmail = name;
}

@Override
protected String doInBackground(Void... params) {
    String accountName = "myRandomValidEmail@gmail.com";
    Account account = new Account(accountName, GoogleAuthUtil.GOOGLE_ACCOUNT_TYPE);
    String scopes = "audience:server:client_id:XXXXXASASXXXXX.apps.googleusercontent.com"; // This is my Web Application Client Id
    try {
        return GoogleAuthUtil.getToken(mActivity, account, scopes);
    } catch (IOException e) {
        Log.e(TAG, "Error retrieving ID token.", e);
        return null;
    } catch (GoogleAuthException e) {
        Log.e(TAG, "Error retrieving ID token.", e);
        return null;
    }
}
}

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问题是AsyncTask中的线程池

Could not find method android.app.Notification$Builder.setLocalOnly