flutter 自定义load

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter_screenutil/flutter_screenutil.dart';  //  这个可以不用， 该依赖主要做适配
import 'package:loading_indicator_view/loading_indicator_view.dart'; // 添加 loading_indicator_view  依赖

class Loading {
  OverlayEntry _overlayEntry;

  show(BuildContext context, {String message}) {
    _cancelToast();
    _overlayEntry = OverlayEntry(builder: (BuildContext context) {
      return Material(
        color: Colors.transparent,
        child: SafeArea(
          child: Center(
            child: Container(
              width: ScreenUtil().setSp(100.25),
              height: ScreenUtil().setSp(100.25),
              child: Stack(
                children: [
                  Align(
                    alignment: Alignment(0, 0),
                    child: Opacity(
                      opacity: 0.5,
                      child: Container(
                        height: 100,
                        width: 100,
                        decoration: BoxDecoration(color: Colors.black, borderRadius: BorderRadius.circular(5.0)),
                      ),
                    ),
                  ),
                  Align(alignment: Alignment(0, -0.3), child: LineSpinFadeLoaderIndicator()),
                  Align(
                    // alignment: Alignment(0, 1),
                    alignment: Alignment(0, 0.7),
                    child: Text(message, style: TextStyle(color: Colors.white, fontSize: 13, decoration: TextDecoration.none)),
                  )
                ],
              ),
            ),
          ),
        ),
      );
    });

    Overlay.of(context).insert(_overlayEntry);
  }

  cancel() {
    _cancelToast();
  }

  // 移除Toast
  _cancelToast() {
    _overlayEntry?.remove();
    _overlayEntry = null;
  }
}