how to get current wifi connection info in android

Most probably you have already found answer: currentWifi.getSSID() is quoted in most cases where scanResult.SSID is not (and of course you must not use == on strings :)).

Try something like this, it returns current SSID or null:

public static String getCurrentSsid(Context context) {
  String ssid = null;
  ConnectivityManager connManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
  NetworkInfo networkInfo = connManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
  if (networkInfo.isConnected()) {
    final WifiManager wifiManager = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
    final WifiInfo connectionInfo = wifiManager.getConnectionInfo();
    if (connectionInfo != null && !StringUtil.isBlank(connectionInfo.getSSID())) {
      ssid = connectionInfo.getSSID();
    }
  }
  return ssid;
}

also permissions are required:

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

StringUtil is not a standard Android class, so you can use TextUtils instead. The code then looks like this:

public static String getCurrentSsid(Context context) {
  String ssid = null;
  ConnectivityManager connManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
  NetworkInfo networkInfo = connManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
  if (networkInfo.isConnected()) {
    final WifiManager wifiManager = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
    final WifiInfo connectionInfo = wifiManager.getConnectionInfo();
    if (connectionInfo != null && !TextUtils.isEmpty(connectionInfo.getSSID())) {
      ssid = connectionInfo.getSSID();
    }
  }
  return ssid;
}