public static String getIMEI(Context context) {
    String deviceId = null;
    try {
      TelephonyManager tm = (TelephonyManager) context
          .getSystemService(Context.TELEPHONY_SERVICE);
      deviceId = tm.getDeviceId();
      if (deviceId == null || "".equals(deviceId)) {
        return getLocalMacAddress(context);
      }
    } catch (Exception e) {
      e.printStackTrace();
      if (deviceId == null || "".equals(deviceId)) {
        return getLocalMacAddress(context);//獲取Mac地址，在Android 9 P版本中，地址會隨機變化，不可用作唯一標(biāo)識，可去掉。
      }
    }

    return deviceId;
  }

public static String getIMEI(Context context) {
    String deviceId = null;
    try {
      TelephonyManager tm = (TelephonyManager) context
          .getSystemService(Context.TELEPHONY_SERVICE);
      if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
        deviceId = Settings.System.getString(context.getContentResolver(), Settings.Secure.ANDROID_ID);
      } else {
        // request old storage permission
        if (ActivityCompat.checkSelfPermission(context, Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) {
          // TODO: Consider calling
          //  ActivityCompat#requestPermissions
          // here to request the missing permissions, and then overriding
          //  public void onRequestPermissionsResult(int requestCode, String[] permissions,
          //                     int[] grantResults)
          // to handle the case where the user grants the permission. See the documentation
          // for ActivityCompat#requestPermissions for more details.
          return null;
        }
        deviceId = tm.getDeviceId();
      }
      if (deviceId == null || "".equals(deviceId)) {
        return getLocalMacAddress(context);
      }
    } catch (Exception e) {
      e.printStackTrace();
      if (deviceId == null || "".equals(deviceId)) {
        return getLocalMacAddress(context);
      }
    }

    return deviceId;
  }