Flutter 自定义带加载状态的按钮--LoadingButton

LoadingButton

import 'package:flutter/material.dart';

enum LoadingState {
  init,
  loading,
  success,
  failed,
}

class LoadingButton extends StatefulWidget {

  final double indicatorSize;
  final Future<void> Function() onPressed;
  final EdgeInsetsGeometry padding;
  final Widget child;
  final Function doSuccess;
  final Function(dynamic) doError;
  final bool disable;

  LoadingButton({
    Key key,
    @required this.onPressed,
    this.indicatorSize = 24.0,
    this.padding = EdgeInsets.zero,
    this.child,
    this.doSuccess,
    this.doError,
    this.disable = false
  }) : super(key: key);

  @override
  State<StatefulWidget> createState() => _LoadingButtonState();
}

class _LoadingButtonState extends State<LoadingButton> {

  LoadingState _state = LoadingState.init;

  @override
  Widget build(BuildContext context) {

    return FlatButton(
        padding: widget.padding,
        onPressed: () async {
          if (_state != LoadingState.init || widget.disable == true) return;
          
          setState(() {
            _state = LoadingState.loading;
          });

          LoadingResults results = await LoadingHelper.run(widget.onPressed);
          await delay(1000);

          if (results.isSuccess) {
            _state = LoadingState.success;
            if(widget.doSuccess != null) widget.doSuccess();
          } else {
            _state = LoadingState.failed;
            if(widget.doError != null) widget.doError(results.error);
          }

          setState(() { });
          await delay(1000);

          _state = LoadingState.init;
          setState(() { });
        },
        child: stateView()
    );
  }

  Widget stateView() {
    switch(_state) {
      case LoadingState.init : return widget.child;
      case LoadingState.loading : return SizedBox(child: CircularProgressIndicator(strokeWidth: 2,), width: widget.indicatorSize, height: widget.indicatorSize,);
      case LoadingState.success : return Icon(Icons.check, size: widget.indicatorSize, color: Colors.green,);
      case LoadingState.failed : return Icon(Icons.clear, size: widget.indicatorSize, color: Colors.red,);
      default : return Container();
    }
  }

}

class LoadingResults {
  bool isSuccess;
  dynamic error;

  LoadingResults(this.isSuccess, this.error);
}

class LoadingHelper {
  static Future<LoadingResults> run(Function run, {int timeout}) async {

    bool isLoading = false;

    if ((timeout ?? 1) > 0) {
      delay(timeout ?? 60 * 1000).then((_) async {
        if (isLoading)
          return LoadingResults(false, "Timeout error");
      });
    }

    try {
      await run();
      return LoadingResults(true, null);
    } catch (e) {
      return LoadingResults(false, e);
    }

  }
}