webview miss network

if ( !isNetworkAvailable() ) { // loading offline
        main_webView.getSettings().setCacheMode( WebSettings.LOAD_CACHE_ELSE_NETWORK );
    }



   // WebView main_webView;
    main_webView = (WebView) findViewById(R.id.webView);
    main_webView.setWebViewClient(new MyWebViewClient());
    main_webView.loadUrl("http://www.lialpa.org/CM3/app.html");
    //end of webview setup




private boolean isNetworkAvailable() {
    ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService( CONNECTIVITY_SERVICE );
    NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
    return activeNetworkInfo != null && activeNetworkInfo.isConnected();
}