Flutter DialogController #flutter

dialog_controller.dart

import 'dart:async';

import 'package:flutter/material.dart' as material;
import 'package:flutter/material.dart' show BuildContext, Widget, Navigator;

class DialogController {
  final BuildContext context;
  final Widget Function(BuildContext) builder;

  Future<dynamic> value;
  BuildContext _innerContext;
  bool _isShowing = false;

  DialogController({this.context, this.builder});

  void close() {
    if (!_isShowing) return;
    Navigator.of(_innerContext).pop();
    _isShowing = false;
  }

  Future awaitDismissal() async {
    final result = await value;
    return result;
  }

  void showDialog() {
    _isShowing = true;
    value = material.showDialog(
      context: context,
      builder: (ctx) {
        _innerContext = ctx;
        final widget = builder(ctx);
        return widget;
      },
    );

    value.whenComplete(() => _isShowing = false);
  }
}

dialog_service.dart

import 'dart:async';

import 'package:meta/meta.dart';

import 'dialog_controller.dart';

class DialogService {
  static final DialogService _sharedInstance = DialogService._internal();
  Map<String, DialogController> dialogs = {};

  factory DialogService() {
    return _sharedInstance;
  }

  DialogService._internal();

  void registerDialogController(
      {@required DialogController controller, @required String key}) {
    dialogs[key] = controller;
  }

  DialogController controller(String key) {
    return dialogs[key];
  }

  void showDialog(String key) {
    final controller = dialogs[key];
    return controller.showDialog();
  }

  Future awaitDismissal(String key) {
    final controller = dialogs[key];
    return controller.awaitDismissal();
  }

  void close(String key) {
    final controller = dialogs[key];
    controller.close();
  }
}