/**
* 获取设备的mac地址
*
* @param ac
* @param callback
*      成功获取到mac地址之后会回调此方法
*/
public static void getMacAddress(final Activity ac, final SimpleCallback callback) {
    final WifiManager wm = (WifiManager) ac .getSystemService(Service.WIFI_SERVICE);
    // 如果本次开机后打开过WIFI，则能够直接获取到mac信息。立刻返回数据。
    WifiInfo info = wm.getConnectionInfo();
    if (info != null && info.getMacAddress() != null) {
      if (callback != null) {
        callback.onComplete(info.getMacAddress());
      }
      return;
    }
    // 尝试打开WIFI，并获取mac地址
    if (!wm.isWifiEnabled()) {
      wm.setWifiEnabled(true);
    }
    new Thread(new Runnable() {
      @Override
      public void run() {
        int tryCount = 0;
        final int MAX_COUNT = 10;
        while (tryCount < MAX_COUNT) {
          final WifiInfo info = wm.getConnectionInfo();
          if (info != null && info.getMacAddress() != null) {
            if (callback != null) {
              ac.runOnUiThread(new Runnable() {
                @Override
                public void run() {
                  callback.onComplete(info.getMacAddress());
                }
              });
            }
            return;
          }
          SystemClock.sleep(300);
          tryCount++;
        }
        // 未获取到mac地址
        if (callback != null) {
          callback.onComplete(null);
        }
      }
    }).start();
}

public interface SimpleCallback {
  void onComplete(String result);
}