How to active scan WiFi in Android

Question

From the Android document we know that WiFiManager.startScan() invoke a passive WiFi scan. It usually takes more time than an active scan. As a result, I would like to invoke an active scan using the method below.

In the previous WiFiManager.java there is a hidden method called startScanActive. We cannot call it directly, but we can invoke it via java reflection. What does @hide mean in the Android source code?

However, this method disappeared in the Android 4.3+. Then, how to begin an active WiFi scan in Android 4.3+?

Thank you

http://stackoverflow.com/a/17056643/1137118 explains `@hide` — Pphoenix, Jul 10 '14 at 07:42

score 0 · Accepted Answer · edited May 23 '17 at 12:01

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AFAIK, Active Scan is not possible and so is removed from the later API levels.

It is a device and/or OS version dependent setting. On the Nexus One for example it takes roughly a second to scan whereas on the G1 it takes significantly longer (or get fresh results after a few scans).

Moreover, Android does passive scans, it listens for beacons. Doing an active scan can create a lot of congestion on the network by sending out probe requests and waiting for probe responses.

Refer: android-wifi-active-scans and WifiManager.

edited May 23 '17 at 12:01

Community

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answered Jul 10 '14 at 08:01

sjain

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Are you sure Android does passive scans? My HTC One M8 sends Probe Requests periodically, even when WiFi is turned off (but "scanning always available" option is enabled). – Alexandr Zarubkin Sep 24 '15 at 09:22

score -1 · Answer 2 · answered Jul 10 '14 at 07:51

-1

Then you can use the following in your activity class:

WifiManager wifiManager = (WifiManager) this.getSystemService(Context.WIFI_SERVICE); wifiManager.setWifiEnabled(true); wifiManager.setWifiEnabled(false);

answered Jul 10 '14 at 07:51

Guru

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Bwahahaha. You'd expect a `Guru` to provide a relevant answer. – TheRealChx101 Jan 19 '18 at 08:02

How to active scan WiFi in Android

2 Answers2