Please i need an example of using VpnService in Android 4.0 with PPTP VPN Server. I'm tried ToyVpnService but it's not using a username & passwd to connect to VPN server.
The VPNService API is not for configuring the system VPN Services but for implementing your own VPN solution. You can for example implement protocols that are not implemented by the system like OpenVPN.
To use pptp with the VPNService API you need to implement the PPTP protocol yourself (or port an existing implementation (should not be difficult))