How to get the connection strength of Wifi access points?

Question

I am building an application reading the signal strength of each available Wifi access point.

I've written code like:

    wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);

    // Get WiFi status
    WifiInfo info = wifi.getConnectionInfo();
    textStatus.append("\n\nWiFi Status: " + info.toString());

    // List available networks
    List<WifiConfiguration> configs = wifi.getConfiguredNetworks();

However, I have two problems:

1. In debugging, configs only contains one connection. However, I can see that there are several APs available in the system's wifi setting. I.e. configs is an incomplete list.

2. I don't know how to get the signal strength in WifiConfiguration.

btw, I am using HTC Hero and Android 1.5.

Answer 1

According to the Android API documentation WifiManager.getConfiguredNetworks() does not fill the signal strength paramters. This data only represents the remembered access point settings, not the visible ones.

To get actually visible networks you must call WifiManager.startScan() to initiate WiFi radio scanning and WifiManager.getScanResults() after a while to get the scanning results.