Since you have not specified you are connected to a server from the device or emulator so I guess you are using your application in the emulator.
If you are referring your localhost on your system from the Android emulator then you have to use http://10.0.2.2:8080/
Because Android emulator runs in a Virtual Machine therefore here 127.0.0.1
or localhost
will be emulator’s own loopback address.
Refer: Emulator Networking