如何从Android应用程序中的Facebook SDK获取电子邮件ID？

Question

private FacebookCallback<LoginResult> callback = new FacebookCallback<LoginResult>() {
    @Override
    public void onSuccess(LoginResult loginResult)
    {


        GraphRequest.newMeRequest(
                loginResult.getAccessToken(), new GraphRequest.GraphJSONObjectCallback() {

                    public void onCompleted(JSONObject me, GraphResponse response) {
                        if (response.getError() != null) {
                            textView.setText("Error");
                        } else {
                            String email = me.optString("email").toString();
                            textView1.setText(email);

                        }
                    }
                }).executeAsync();


    }