运行项目报下面的错，请问这个怎么办啊，我的adt和sdk都是刚刚更新的
2015-10-31 17:08:38 - b] Android Launch!
[2015-10-31 17:08:38 - b] adb is running normally.
[2015-10-31 17:08:38 - b] Performing com.example.b.MainActivity activity launch
[2015-10-31 17:08:38 - b] Automatic Target Mode: Unable to detect device compatibility. Please select a target device.
[2015-10-31 17:10:51 - b] Launch canceled!
