android - android WifiManager中的Rssi是什么意思

Question

我正在尝试使用 getRssi() 获取当前 wifi 连接的信号强度

private void checkWifi(){
    ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo Info = cm.getActiveNetworkInfo();
    if (Info == null || !Info.isConnectedOrConnecting()) {
        Log.i("WIFI CONNECTION", "No connection");
    } else {
        int netType = Info.getType();
        int netSubtype = Info.getSubtype();

        if (netType == ConnectivityManager.TYPE_WIFI) {
            wifiManager = (WifiManager)getApplicationContext().getSystemService(Context.WIFI_SERVICE);
            int linkSpeed = wifiManager.getConnectionInfo().getLinkSpeed();
            int rssi = wifiManager.getConnectionInfo().getRssi();
            Log.i("WIFI CONNECTION", "Wifi connection speed: "+linkSpeed + " rssi: "+rssi);


        //Need to get wifi strength
        } 
    }
}

问题是我得到了 -35 或 -47 等数字。我不理解它们的值。我查看了 android 文档及其所有内容:

public int getRssi ()

Since: API Level 1 Returns the received signal strength indicator of the current 802.11 network.

This is not normalized, but should be!

Returns the RSSI, in the range ??? to ???

有人可以解释如何“归一化”或理解这些结果吗？

Answer 1

我在 WifiManager.java 中找到了这个:

/** Anything worse than or equal to this will show 0 bars. */
private static final int MIN_RSSI = -100;

/** Anything better than or equal to this will show the max bars. */
private static final int MAX_RSSI = -55;

android 上的相关 rssi 范围在 -100 和 -55 之间。

有这个静态方法WifiManager.calculateSignalLevel(rssi,numLevel)将为您计算信号电平:

int wifiLevel = WifiManager.calculateSignalLevel(rssi,5);

返回一个 0 到 4 之间的数字(即 numLevel-1):您在工具栏中看到的条数。

编辑 API 30+

静态方法现已弃用，您应该使用 instance method

wifiManager.calculateSignalLevel(rssi)

主要区别在于级别数现在由 wifiManager.getMaxSignalLevel() 给出