Correspondence between Android wifi signal strength and icons

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. There are 5 levels of wifi in android. The corresponding icons are 0 grid, 1 grid, 2 grid, 3 grid, 4 grid.

So what is the corresponding signal strength?

According to the algorithm calculateSignalLevel in wifimanager, it can be calculated:

0 rssi<=-100
1 (-100, -88]
2 (-88, -77]
3 (-66, -55]
4 rssi>=-55

Let’s look at the Google code implementation:
/frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/policy/AccessPointControllerImpl.java

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);
 }

Key functions:

/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);
    }
}