WifiManager.getScanResults（） - 澄清（自动扫描，睡眠等） [英] WifiManager.getScanResults() - clarifications (automatic scans, sleep etc)

问题描述

我想一些澄清的行为 WifiManager.getScanResults（），即：

I would like some clarifications on the behavior of WifiManager.getScanResults(), namely :

当无线启用的

1. 是否在一个固定的时间间隔接入点的android扫描？可以在一个查询/修改时间？一个人能查询上次扫描的时间呢？对于讨论，请参阅此回答
2. 当无线电关闭时会发生什么情况（休眠） - 无线上网的同时仍启用 - 将 getScanResults（）走在返回的最后一次扫描的结果？一个人怎么会知道，如果它的时间为 startScan（）？

1. Does android scan for access points on a fixed interval ? Can one query/change the interval ? Can one query the time of the last scan ? For a discussion see this answer
2. What happens when the wireless radio is turned off (sleeps) - while wifi is still enabled - will getScanResults() go on returning the last scan results ? How would one know if it's time for startScan()?

无线时禁用的

1. getScanResults（）将返回上次扫描结果？一个空列表？或空（它有时返回null，这不是90％张贴在这样的片段的处理）？
2. 答案1甚至会重新启动（手机启动与WiFi关闭）？
在真

1. getScanResults() would return the last scan results ? Or an empty List ? Or null (it does return null at times and this is not handled by 90% of the snippets posted in SO) ?
2. The answer to 1 would be true even after a reboot (the phone booting with wifi off) ?

我想问的原因是我需要定期获得的可用接入点列表，我宁愿放弃 getScanResults（）一次，比 WifiManager.startScan（）然后 getScanResults（）如果我真的没有 - 因为这涉及到收购的WiFi锁等，并是相当微妙的。我不是也知道有多少千万的API级别和手机硬件发挥作用。

The reason I ask is I need to get the list of the available access points periodically and I'd rather call getScanResults() at once, than WifiManager.startScan() and then getScanResults() if I really do not have to - as this involves acquiring wifi locks and the like and is rather subtle. I am not also sure how much do the API level and phone hardware come into play.

有关困难了良好的讨论，请参阅该<一href="http://stackoverflow.com/questions/14862018/startscan-has-result-after-10-min-when-phone-get-into-idle-state/14910918#14910918">answer

For a good discussion of difficulties see this answer

推荐答案

无线时禁用的

1. getScanResults（）返回空 ...
2. ...即使重新启动（这是可以预料的 - 这将是有争议的，如果它没有在第一时间返回null）

1. getScanResults() will return null...
2. ...even after a reboot (that's to be expected - this would be disputed if it did not return null in the first place)

编辑：当无线启用的

2.Surprisingly足够 getScanResults（）返回空一段时间后（在Nexus One的，安卓2.3 .7氰MOD - 但我怀疑这是不是真的有关）。所以，是的，显然一个人无论以启动无线状态的扫描

2.Surprisingly enough getScanResults() will return null after some time (on a Nexus One, Android 2.3.7, Cyanogen mod - but I suspect this is not really relevant). So yes, apparently one has to initiate a scan irrespective of the wireless status

我想这是事实也是如果状态 WIFI_STATE_DISABLING

I guess this is true also if the state is WIFI_STATE_DISABLING

我仍然有兴趣在无线的情况下，答案已启用 - 尤其是第2个问题，如果该设备是睡着了。谷歌集团不会让我上传（提示）

I am still interested in the answer in the case wireless is enabled - in particular question 2, if the device is asleep. Google groups won't let me post (hint)

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