如何获得Wifi接入点的连接强度？

Question

我正在构建一个应用程序，以读取每个可用Wifi接入点的信号强度。

我写的代码是这样的：

    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();

但是，我有两个问题：

1. 在调试中， configs仅包含一个连接。 但是，我可以看到系统的wifi设置中有几个AP。 即configs是不完整的列表。

2. 我不知道如何在WifiConfiguration获得信号强度。

顺便说一句，我正在使用HTC Hero和Android 1.5。

Answer 1

根据Android API文档， WifiManager.getConfiguredNetworks（）不会填充信号强度参数。 此数据仅代表记住的访问点设置，而不代表可见的访问点设置。

要获取实际可见的网络，必须过一会儿调用WifiManager.startScan（）来启动WiFi无线电扫描， 然后调用WifiManager.getScanResults（）以获取扫描结果。

Answer 2

下面的代码将有助于获得无线上网的酒吧：

registerReceiver(new BroadcastReceiver() {

        @Override
        public void onReceive(Context context, Intent intent) {
            final WifiManager wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
            int state = wifi.getWifiState();
            if(state == WifiManager.WIFI_STATE_ENABLED) {
                List<ScanResult> results = wifi.getScanResults();

                for (ScanResult result : results) {
                    if(result.BSSID.equals(wifi.getConnectionInfo().getBSSID())) {
                        int level = WifiManager.calculateSignalLevel(wifi.getConnectionInfo().getRssi(),
                                result.level);
                        int difference = level * 100 / result.level;
                        int signalStrangth= 0;
                        if(difference >= 100)
                            signalStrangth = 4;
                        else if(difference >= 75)
                            signalStrangth = 3;
                        else if(difference >= 50)
                            signalStrangth = 2;
                        else if(difference >= 25)
                            signalStrangth = 1;
                        tv.setText(tv.getText() + "\nDifference :" + difference + " signal state:" + signalStrangth);

                    }

                }
            }
        }
    }, new IntentFilter(WifiManager.RSSI_CHANGED_ACTION));

Answer 3

mainWifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
receiverWifi = new WifiReceiver();
    registerReceiver(receiverWifi, new IntentFilter(
            WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
class WifiReceiver extends BroadcastReceiver {
    public void onReceive(Context c, Intent intent) {

        List<ScanResult> wifiList = mainWifi.getScanResults();
        ArrayList<WifiConnectionBean> m4MessagesList = new ArrayList<WifiConnectionBean>();
        for (int i = 0; i < wifiList.size(); i++) {
            ScanResult scanResult = wifiList.get(i);
            WifiConnectionBean bean = new WifiConnectionBean();
            bean.setConnectionName(scanResult.SSID); // + "--" +
                                                        // scanResult.frequency);
            bean.setDescription(scanResult.capabilities);
            bean.setId(scanResult.SSID);
            bean.setLevel(String.valueOf(scanResult.level));
            bean.setSignalStrength(String.valueOf(scanResult.BSSID));
            m4MessagesList.add(bean);
        }
        if (m4MessagesList == null) {
            Toast.makeText(WifiIdentificationActivity.this,
                    "WifiConnection not available", Toast.LENGTH_SHORT)
                    .show();
        } else {
            String message = "Scanning complete. " + m4MessagesList.size()
                    + " connections found!";
        }
        pd.dismiss();

    }
}

其中scanResult.SSID给出信号强度。

Answer 4

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

            if (netType == ConnectivityManager.TYPE_WIFI) {
                Log.i(TAG, "Wifi connection");
                WifiManager wifiManager = (WifiManager) getApplication().getSystemService(Context.WIFI_SERVICE);
                List<ScanResult> scanResult = wifiManager.getScanResults();
                for (int i = 0; i < scanResult.size(); i++) {
                    Log.d("scanResult", "Speed of wifi"+scanResult.get(i).level);//The db level of signal 
                }


                // Need to get wifi strength
            } else if (netType == ConnectivityManager.TYPE_MOBILE) {
                Log.i(TAG, "GPRS/3G connection");
                // Need to get differentiate between 3G/GPRS
            }
        }
    }

Answer 5

    WifiManager wifiManager = (WifiManager)
    MonitorActivity.this.getSystemService(Context.WIFI_SERVICE);

    wifiManager.addNetwork(conf);

    int numberOfLevels = 5;
    WifiInfo wifiInfo = wifiManager.getConnectionInfo();
    int level = WifiManager.calculateSignalLevel(wifiInfo.getRssi(), numberOfLevels);

    Log.e("level", "" + level);
    // you will get the levels. Using these levels you can calculate strenghts.