Flutter Modal bottom sheet that supports full screen height

bottom_sheet_fix_status_bar.dart

//Flutter Modal Bottom Sheet
//Modified by Giorgio Bertolotti
//Based on https://gist.github.com/crimsonsuv/b25d5ebd04236f9be2aa66accba19446

import 'dart:async';
import 'package:flutter/material.dart';
import 'package:meta/meta.dart';

const Duration _kBottomSheetDuration = const Duration(milliseconds: 200);

class _ModalBottomSheetLayout extends SingleChildLayoutDelegate {
  _ModalBottomSheetLayout(
      this.progress, this.bottomInset, this.statusBarHeight);

  final double progress;
  final double bottomInset;
  final double statusBarHeight;

  @override
  BoxConstraints getConstraintsForChild(BoxConstraints constraints) {
    return new BoxConstraints(
        minWidth: constraints.maxWidth,
        maxWidth: constraints.maxWidth,
        minHeight: 0.0,
        maxHeight: constraints.maxHeight - statusBarHeight);
  }

  @override
  Offset getPositionForChild(Size size, Size childSize) {
    return new Offset(
        0.0, size.height - bottomInset - childSize.height * progress);
  }

  @override
  bool shouldRelayout(_ModalBottomSheetLayout oldDelegate) {
    return progress != oldDelegate.progress ||
        bottomInset != oldDelegate.bottomInset;
  }
}

class _ModalBottomSheet<T> extends StatefulWidget {
  const _ModalBottomSheet({Key key, this.route}) : super(key: key);

  final _ModalBottomSheetRoute<T> route;

  @override
  _ModalBottomSheetState<T> createState() => new _ModalBottomSheetState<T>();
}

class _ModalBottomSheetState<T> extends State<_ModalBottomSheet<T>> {
  @override
  Widget build(BuildContext context) {
    return new GestureDetector(
        onTap: widget.route.dismissOnTap ? () => Navigator.pop(context) : null,
        child: new AnimatedBuilder(
            animation: widget.route.animation,
            builder: (BuildContext context, Widget child) {
              double bottomInset = widget.route.resizeToAvoidBottomPadding
                  ? MediaQuery.of(context).viewInsets.bottom
                  : 0.0;
              return new ClipRect(
                  child: new CustomSingleChildLayout(
                      delegate: new _ModalBottomSheetLayout(
                          widget.route.animation.value,
                          bottomInset,
                          widget.route.statusBarHeight),
                      child: new BottomSheet(
                          animationController:
                              widget.route._animationController,
                          onClosing: () => Navigator.pop(context),
                          builder: widget.route.builder)));
            }));
  }
}

class _ModalBottomSheetRoute<T> extends PopupRoute<T> {
  _ModalBottomSheetRoute({
    this.builder,
    this.theme,
    this.barrierLabel,
    RouteSettings settings,
    this.resizeToAvoidBottomPadding,
    this.dismissOnTap,
    this.statusBarHeight,
  }) : super(settings: settings);

  final WidgetBuilder builder;
  final ThemeData theme;
  final bool resizeToAvoidBottomPadding;
  final bool dismissOnTap;
  final double statusBarHeight;

  @override
  Duration get transitionDuration => _kBottomSheetDuration;

  @override
  bool get barrierDismissible => false;

  @override
  final String barrierLabel;

  @override
  Color get barrierColor => Colors.black54;

  AnimationController _animationController;

  @override
  AnimationController createAnimationController() {
    assert(_animationController == null);
    _animationController =
        BottomSheet.createAnimationController(navigator.overlay);
    return _animationController;
  }

  @override
  Widget buildPage(BuildContext context, Animation<double> animation,
      Animation<double> secondaryAnimation) {
    Widget bottomSheet = new MediaQuery.removePadding(
      context: context,
      removeTop: true,
      child: new _ModalBottomSheet<T>(route: this),
    );
    if (theme != null) bottomSheet = new Theme(data: theme, child: bottomSheet);
    return bottomSheet;
  }
}

Future<T> showModalBottomSheetApp<T>({
  @required BuildContext context,
  @required WidgetBuilder builder,
  bool dismissOnTap: false,
  bool resizeToAvoidBottomPadding: true,
  double statusBarHeight: 0,
}) {
  assert(context != null);
  assert(builder != null);
  return Navigator.push(
      context,
      _ModalBottomSheetRoute<T>(
        builder: builder,
        theme: Theme.of(context, shadowThemeOnly: true),
        barrierLabel:
            MaterialLocalizations.of(context).modalBarrierDismissLabel,
        resizeToAvoidBottomPadding: resizeToAvoidBottomPadding,
        dismissOnTap: dismissOnTap,
        statusBarHeight: statusBarHeight,
      ));
}

NB: This code is based on this gist, I just added some lines for it to stay below the statusBar (in Android).

Just drag this file to your project and when calling Modal Bottom sheet use it as follows
showModalBottomSheetApp( context: context, builder: (builder) { return NewPage(); }, statusBarHeight: MediaQuery.of(context).padding.top, );