android中wifi分为5个等级,对应的图标是0格,1格,2格,3格,4格.
那么对应的信号强度是多少呢?
根据wifimanager中的算法calculateSignalLevel可以算得:
0 rssi<=-100 1 (-100, -88] 2 (-88, -77] 3 (-66, -55] 4 rssi>=-55
public int getIcon(AccessPoint ap) {
int level = ap.getLevel();
return ICONS[level >= 0 ? level : 0];
}
frameworks/base/packages/SettingsLib/src/com/android/settingslib/wifi/AccessPoint.java
public int getLevel() {
return WifiManager.calculateSignalLevel(mRssi, SIGNAL_LEVELS);
}
关键函数:
/frameworks/base/wifi/java/android/net/wifi/WifiManager.java
private static final int MIN_RSSI = -100;
private static final int MAX_RSSI = -55;
public static final int RSSI_LEVELS = 5;
public static int calculateSignalLevel(int rssi, int numLevels) {
if (rssi <= MIN_RSSI) {
return 0;
} else if (rssi >= MAX_RSSI) {
return numLevels - 1;
} else {
float inputRange = (MAX_RSSI - MIN_RSSI);
float outputRange = (numLevels - 1);
return (int)((float)(rssi - MIN_RSSI) * outputRange / inputRange);
}
}