android 去叹号

从Android 5.0 (Lollipop)开始，安卓为了检测各种需要登录的Wifi服务，提供了captive_portal_detection_enabled和captive_portal_server这两个设置，分别作为检测的开关和服务器。

去叹号

settings delete global captive_portal_server
settings delete global captive_portal_http_url
settings delete global captive_portal_https_url
settings put global captive_portal_https_url https://developers.google.cn/generate_204