在mainactivity中写入super.loadUrl("file:///android_asset/www/login.html");
但是为什么提示Application Error The connection to the server was unsuccessful
http://stackoverflow.com/questions/12319809/application-error-the-connection-to-the-server-was-unsuccessful-file-andr
https://www.robertkehoe.com/2013/01/fix-for-phonegap-connection-to-server-was-unsuccessful/