ente/lib/ui/progress_dialog.dart

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter/painting.dart';

enum ProgressDialogType { Normal, Download }

String _dialogMessage = "Loading...";
double _progress = 0.0, _maxProgress = 100.0;

Widget _customBody;

TextAlign _textAlign = TextAlign.left;
Alignment _progressWidgetAlignment = Alignment.centerLeft;

TextDirection _direction = TextDirection.ltr;

bool _isShowing = false;
BuildContext _context, _dismissingContext;
ProgressDialogType _progressDialogType;
bool _barrierDismissible = true, _showLogs = false;
Color _barrierColor;

TextStyle _progressTextStyle = TextStyle(
      color: Colors.black,
      fontSize: 12.0,
      fontWeight: FontWeight.w400,
    ),
    _messageStyle = TextStyle(
      color: Colors.black,
      fontSize: 18.0,
      fontWeight: FontWeight.w600,
    );

double _dialogElevation = 8.0, _borderRadius = 8.0;
Color _backgroundColor = Colors.white;
Curve _insetAnimCurve = Curves.easeInOut;
EdgeInsets _dialogPadding = const EdgeInsets.all(8.0);

Widget _progressWidget = Image.asset(
  'assets/double_ring_loading_io.gif',
  package: 'progress_dialog',
);

class ProgressDialog {
  _Body _dialog;

  ProgressDialog(
    BuildContext context, {
    ProgressDialogType type,
    bool isDismissible,
    bool showLogs,
    TextDirection textDirection,
    Widget customBody,
    Color barrierColor,
  }) {
    _context = context;
    _progressDialogType = type ?? ProgressDialogType.Normal;
    _barrierDismissible = isDismissible ?? true;
    _showLogs = showLogs ?? false;
    _customBody = customBody ?? null;
    _direction = textDirection ?? TextDirection.ltr;
    _barrierColor = barrierColor ?? barrierColor;
  }

  void style({
    Widget child,
    double progress,
    double maxProgress,
    String message,
    Widget progressWidget,
    Color backgroundColor,
    TextStyle progressTextStyle,
    TextStyle messageTextStyle,
    double elevation,
    TextAlign textAlign,
    double borderRadius,
    Curve insetAnimCurve,
    EdgeInsets padding,
    Alignment progressWidgetAlignment,
  }) {
    if (_isShowing) return;
    if (_progressDialogType == ProgressDialogType.Download) {
      _progress = progress ?? _progress;
    }

    _dialogMessage = message ?? _dialogMessage;
    _maxProgress = maxProgress ?? _maxProgress;
    _progressWidget = progressWidget ?? _progressWidget;
    _backgroundColor = backgroundColor ?? _backgroundColor;
    _messageStyle = messageTextStyle ?? _messageStyle;
    _progressTextStyle = progressTextStyle ?? _progressTextStyle;
    _dialogElevation = elevation ?? _dialogElevation;
    _borderRadius = borderRadius ?? _borderRadius;
    _insetAnimCurve = insetAnimCurve ?? _insetAnimCurve;
    _textAlign = textAlign ?? _textAlign;
    _progressWidget = child ?? _progressWidget;
    _dialogPadding = padding ?? _dialogPadding;
    _progressWidgetAlignment =
        progressWidgetAlignment ?? _progressWidgetAlignment;
  }

  void update({
    double progress,
    double maxProgress,
    String message,
    Widget progressWidget,
    TextStyle progressTextStyle,
    TextStyle messageTextStyle,
  }) {
    if (_progressDialogType == ProgressDialogType.Download) {
      _progress = progress ?? _progress;
    }

    _dialogMessage = message ?? _dialogMessage;
    _maxProgress = maxProgress ?? _maxProgress;
    _progressWidget = progressWidget ?? _progressWidget;
    _messageStyle = messageTextStyle ?? _messageStyle;
    _progressTextStyle = progressTextStyle ?? _progressTextStyle;

    if (_isShowing) _dialog.update();
  }

  bool isShowing() {
    return _isShowing;
  }

  Future<bool> hide() async {
    try {
      if (_isShowing) {
        _isShowing = false;
        Navigator.of(_dismissingContext).pop();
        if (_showLogs) debugPrint('ProgressDialog dismissed');
        return Future.value(true);
      } else {
        if (_showLogs) debugPrint('ProgressDialog already dismissed');
        return Future.value(false);
      }
    } catch (err) {
      debugPrint('Seems there is an issue hiding dialog');
      debugPrint(err.toString());
      return Future.value(false);
    }
  }

  Future<bool> show() async {
    try {
      if (!_isShowing) {
        _dialog = new _Body();
        showDialog<dynamic>(
          context: _context,
          barrierDismissible: _barrierDismissible,
          barrierColor: _barrierColor,
          builder: (BuildContext context) {
            _dismissingContext = context;
            return WillPopScope(
              onWillPop: () async => _barrierDismissible,
              child: Dialog(
                backgroundColor: _backgroundColor,
                insetAnimationCurve: _insetAnimCurve,
                insetAnimationDuration: Duration(milliseconds: 100),
                elevation: _dialogElevation,
                shape: RoundedRectangleBorder(
                  borderRadius:
                      BorderRadius.all(Radius.circular(_borderRadius)),
                ),
                child: _dialog,
              ),
            );
          },
        );
        // Delaying the function for 200 milliseconds
        // [Default transitionDuration of DialogRoute]
        await Future.delayed(Duration(milliseconds: 200));
        if (_showLogs) debugPrint('ProgressDialog shown');
        _isShowing = true;
        return true;
      } else {
        if (_showLogs) debugPrint("ProgressDialog already shown/showing");
        return false;
      }
    } catch (err) {
      _isShowing = false;
      debugPrint('Exception while showing the dialog');
      debugPrint(err.toString());
      return false;
    }
  }
}

// ignore: must_be_immutable
class _Body extends StatefulWidget {
  final _BodyState _dialog = _BodyState();

  update() {
    _dialog.update();
  }

  @override
  State<StatefulWidget> createState() {
    return _dialog;
  }
}

class _BodyState extends State<_Body> {
  update() {
    setState(() {});
  }

  @override
  void dispose() {
    _isShowing = false;
    if (_showLogs) debugPrint('ProgressDialog dismissed by back button');
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final loader = Align(
      alignment: _progressWidgetAlignment,
      child: SizedBox(
        width: 60.0,
        height: 60.0,
        child: _progressWidget,
      ),
    );

    final text = Expanded(
      child: _progressDialogType == ProgressDialogType.Normal
          ? Text(
              _dialogMessage,
              textAlign: _textAlign,
              style: _messageStyle,
              textDirection: _direction,
            )
          : Padding(
              padding: const EdgeInsets.all(8.0),
              child: Column(
                mainAxisSize: MainAxisSize.min,
                children: <Widget>[
                  SizedBox(height: 8.0),
                  Row(
                    children: <Widget>[
                      Expanded(
                        child: Text(
                          _dialogMessage,
                          style: _messageStyle,
                          textDirection: _direction,
                        ),
                      ),
                    ],
                  ),
                  SizedBox(height: 4.0),
                  Align(
                    alignment: Alignment.bottomRight,
                    child: Text(
                      "$_progress/$_maxProgress",
                      style: _progressTextStyle,
                      textDirection: _direction,
                    ),
                  ),
                ],
              ),
            ),
    );

    return _customBody ??
        Container(
          padding: _dialogPadding,
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: <Widget>[
              // row body
              Row(
                mainAxisSize: MainAxisSize.min,
                children: <Widget>[
                  const SizedBox(width: 8.0),
                  _direction == TextDirection.ltr ? loader : text,
                  const SizedBox(width: 8.0),
                  _direction == TextDirection.rtl ? loader : text,
                  const SizedBox(width: 8.0)
                ],
              ),
            ],
          ),
        );
  }
}