Fragment的webView restoreState无法正常工作

Question

我正在尝试保存片段中webview的状态。

@Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        try {
            View view = inflater.inflate(R.layout.fragment_activity, container, false);

            browser = (WebView) view.findViewById(R.id.webview);
         if (browser != null) {
                //browser.setWebViewClient(new WebViewClient());

                if (webViewBundle == null || webViewBundle.isEmpty()) {
                  //  browser.setWebViewClient(new WebViewClient());
                    browser.getSettings().setLoadsImagesAutomatically(true);
                    browser.getSettings().setJavaScriptEnabled(true);

                    browser.setWebViewClient(new WebViewClient() {
                        public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
                            //Users will be notified in case there's an error (i.e. no internet connection)
                            Log.i("", "");
                        }

                        @Override
                        public void onPageStarted(WebView view, String url, Bitmap favicon) {
                            url = url;
                        }

                        public void onPageFinished(WebView view, String url) {
                            CookieSyncManager.getInstance().sync();
                            super.onPageFinished(view, url);
                        }

                        @Override
                        public boolean shouldOverrideUrlLoading(WebView view, String url)
                        {
                            view.loadUrl(url);
                            return true;
                        }

                    });
                    browser.loadUrl(url);
                } else {
                    browser.restoreState(webViewBundle);
                    webViewBundle.clear();
                }
            }
            return view;
        }
        catch (Exception ex)
        {
            ex.printStackTrace();
            return null;
        }
    }  

我正在压倒onPause：

@Override
public void onPause() {
    super.onPause();

    if (browser != null && webViewBundle.isEmpty()) {
        browser.saveState(webViewBundle);
    }
}  

我在viewPager上有4个这样的片段 但是当片段被导航回来时，webview会冻结。