如何使用gomobile构建sdk-arr-libs访问Web？

I use gomobile bind generated an .arr file.

gomobile version
gomobile version +e154aff Wed Dec 2 14:48:43 2015 +0000 (android); androidSDK=D:\android\sdk\platforms\android-23

go version
go version go1.5.2 windows/amd64

Go code include a func which access to web.

client := &http.Client{}
req, err := http.NewRequest("GET", url, nil)
if err != nil {
    log.Fatal(err.Error())
}
resp, err := client.Do(req)

I add this .arr to my Android project in Android Studio, build and install a apk to Virtual Devices.

But the app can't access to web.

After running app it comes out:

 GoLog: Get www.google.com: unsupported protocol scheme ""

I must missed something, please help me.

It's nothing to do with gomobile. The url www.google.com should started with http://.