// Android 6.0之前的版本可以用的方法（模拟器可以使用） 
  private String getMacAddrOld() 
  { 
    String macString = ""; 
    WifiManager wifimsg = (WifiManager)getSystemService(Context.WIFI_SERVICE); 
    if (wifimsg != null) 
    { 
      if (wifimsg.getConnectionInfo() != null) 
      { 
        if (wifimsg.getConnectionInfo().getMacAddress() != null) 
        { 
          macString = wifimsg.getConnectionInfo().getMacAddress(); 
        } 
      } 
    } 
    return macString; 
  }

public static String getMacAddr() { 
    try { 
      List<NetworkInterface> all = Collections.list(NetworkInterface.getNetworkInterfaces()); 
      for (NetworkInterface nif : all) { 
        if (!nif.getName().equalsIgnoreCase("wlan0")) continue; 
        byte[] macBytes = nif.getHardwareAddress(); 
        if (macBytes == null) { 
          return ""; 
        } 
        StringBuilder res1 = new StringBuilder(); 
        for (byte b : macBytes) { 
          res1.append(String.format("X:",b)); 
        } 
        if (res1.length() > 0) { 
          res1.deleteCharAt(res1.length() - 1); 
        } 
        return res1.toString(); 
      } 
    } catch (Exception ex) { 
    } 
    return "02:00:00:00:00:00"; 
  }

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