android 获取本机IP地址

private String getLocalIPAddress() throws SocketException{  
    for(Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces();en.hasMoreElements();){  
        NetworkInterface intf = en.nextElement();  
        for(Enumeration<InetAddress> enumIpAddr = intf.getInetAddresses(); enumIpAddr.hasMoreElements();){  
            InetAddress inetAddress = enumIpAddr.nextElement();  
            if(!inetAddress.isLoopbackAddress())){  
                return inetAddress.getHostAddress().toString();  
            }  
        }  
    }  
    return "null";  
}

但是，在android4.0以上系统中，上面的代码仅能够返回一个ipv6的地址，如果需要获取ip v4的地址，可以这么更改：

private String getLocalIPAddress() throws SocketException{  
    for(Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces();en.hasMoreElements();){  
        NetworkInterface intf = en.nextElement();  
        for(Enumeration<InetAddress> enumIpAddr = intf.getInetAddresses(); enumIpAddr.hasMoreElements();){  
            InetAddress inetAddress = enumIpAddr.nextElement();  
            if(!inetAddress.isLoopbackAddress() && <strong>(inetAddress instanceof Inet4Address)</strong>){  
                return inetAddress.getHostAddress().toString();  
            }  
        }  
    }  
    return "null";  
}