captive portal

    // Default configuration values for captive portal detection probes.
    // TODO: append a random length parameter to the default HTTPS url.
    // TODO: randomize browser version ids in the default User-Agent String.
    private static final String DEFAULT_HTTPS_URL     = "https://www.google.com/generate_204";                                                                                                                    
    private static final String DEFAULT_HTTP_URL      =
            "http://connectivitycheck.gstatic.com/generate_204";

    private static String getCaptivePortalServerHttpsUrl(Context context) {
        return getSetting(context, Settings.Global.CAPTIVE_PORTAL_HTTPS_URL, DEFAULT_HTTPS_URL);                                                                                                                  
    }

    public static String getCaptivePortalServerHttpUrl(Context context) {
        return getSetting(context, Settings.Global.CAPTIVE_PORTAL_HTTP_URL, DEFAULT_HTTP_URL);
    }

　　

adb shell "settings put global captive_portal_http_url http://captive.v2ex.co/generate_204"
adb shell "settings put global captive_portal_https_url https://captive.v2ex.co/generate_204"