WIFI扫描记录

一、应用扫描限制（官网描述）

WLAN 扫描功能概览  |  Connectivity  |  Android Developers

二、系统扫描 

Android Wifi的扫描机制_安卓wifi扫描频次-CSDN博客

WifiConnectivityManager.java

handleScreenStateChanged-->startConnectivityScan-->startPeriodicScan-->startPeriodicSingleScan

WifiNetworkFactory.java

这里有个间隔10s的扫描，还需要看是否可以调用到

public static final int PERIODIC_SCAN_INTERVAL_MS = 10 * 1000; // 10 seconds

public static final int NETWORK_CONNECTION_TIMEOUT_MS = 30 * 1000; // 30 seconds

public static final int USER_SELECTED_NETWORK_CONNECT_RETRY_MAX = 3; // max of 3 retries.

private void scheduleNextPeriodicScan() {

mAlarmManager.set(AlarmManager.ELAPSED_REALTIME_WAKEUP,

mClock.getElapsedSinceBootMillis() + PERIODIC_SCAN_INTERVAL_MS,

TAG, mPeriodicScanTimerListener, mHandler);

mPeriodicScanTimerSet = true;

}