如何使用：
- 添加依赖库：
fluttertoast: ^2.1.1 - 导入：
import 'package:fluttertoast/fluttertoast.dart'; - 示例：
Fluttertoast.showToast(
msg: "This is Center Short Toast",
toastLength: Toast.LENGTH_SHORT,
gravity: ToastGravity.CENTER,
timeInSecForIos: 1,
bgcolor: "#e74c3c",
textcolor: '#ffffff'
);
Fluttertoast.showToast(
msg: "网络连接错误",
toastLength: Toast.LENGTH_SHORT,
gravity: ToastGravity.BOTTOM,
timeInSecForIos: 1,
bgcolor: "#9E9E9E",
textcolor: '#ffffff');
}