webView.setWebChromeClient(new WebChromeClient() {
    @Override
    public void onReceivedTitle(WebView view, String title) {
        if (title != null) {
            if (title.contains("404")) {
                //加载错误显示的页面
                showErrorPage();
            } else {
                //title为webview标题内容
                tvTitle.setText(title);
            }
        }
        super.onReceivedTitle(view, title);
    }
});