Flutter Google Maps Bottom Sheet

flutter_google_maps_bottom_sheet.dart

import 'package:flutter/material.dart';

class GoogleMapsClonePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Stack(
        children: <Widget>[
          CustomGoogleMap(),
          CustomHeader(),
          DraggableScrollableSheet(
            initialChildSize: 0.30,
            minChildSize: 0.15,
            builder: (BuildContext context, ScrollController scrollController) {
              return SingleChildScrollView(
                controller: scrollController,
                child: CustomScrollViewContent(),
              );
            },
          ),
        ],
      ),
    );
  }
}

/// Google Map in the background
class CustomGoogleMap extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      color: Colors.blue[50],
      child: Center(child: Text("Google Map here")),
    );
  }
}

/// Search text field plus the horizontally scrolling categories below the text field
class CustomHeader extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Column(
      children: <Widget>[
        CustomSearchContainer(),
        CustomSearchCategories(),
      ],
    );
  }
}

class CustomSearchContainer extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.fromLTRB(16, 40, 16, 8), //adjust "40" according to the status bar size
      child: Container(
        height: 50,
        decoration: BoxDecoration(color: Colors.white, borderRadius: BorderRadius.circular(6)),
        child: Row(
          children: <Widget>[
            CustomTextField(),
            Icon(Icons.mic),
            SizedBox(width: 16),
            CustomUserAvatar(),
            SizedBox(width: 16),
          ],
        ),
      ),
    );
  }
}

class CustomTextField extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Expanded(
      child: TextFormField(
        maxLines: 1,
        decoration: InputDecoration(
          contentPadding: const EdgeInsets.all(16),
          hintText: "Search here",
          border: InputBorder.none,
        ),
      ),
    );
  }
}

class CustomUserAvatar extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      height: 32,
      width: 32,
      decoration: BoxDecoration(color: Colors.grey[500], borderRadius: BorderRadius.circular(16)),
    );
  }
}

class CustomSearchCategories extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return SingleChildScrollView(
      scrollDirection: Axis.horizontal,
      child: Row(
        children: <Widget>[
          SizedBox(width: 16),
          CustomCategoryChip(Icons.fastfood, "Takeout"),
          SizedBox(width: 12),
          CustomCategoryChip(Icons.directions_bike, "Delivery"),
          SizedBox(width: 12),
          CustomCategoryChip(Icons.local_gas_station, "Gas"),
          SizedBox(width: 12),
          CustomCategoryChip(Icons.shopping_cart, "Groceries"),
          SizedBox(width: 12),
          CustomCategoryChip(Icons.local_pharmacy, "Pharmacies"),
          SizedBox(width: 12),
        ],
      ),
    );
  }
}

class CustomCategoryChip extends StatelessWidget {
  final IconData iconData;
  final String title;

  CustomCategoryChip(this.iconData, this.title);

  @override
  Widget build(BuildContext context) {
    return Chip(
      label: Row(
        children: <Widget>[Icon(iconData, size: 16), SizedBox(width: 8), Text(title)],
      ),
      backgroundColor: Colors.grey[50],
    );
  }
}

/// Content of the DraggableBottomSheet's child SingleChildScrollView
class CustomScrollViewContent extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Card(
      elevation: 12.0,
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(24)),
      margin: const EdgeInsets.all(0),
      child: Container(
        decoration: BoxDecoration(
          borderRadius: BorderRadius.circular(24),
        ),
        child: CustomInnerContent(),
      ),
    );
  }
}

class CustomInnerContent extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Column(
      children: <Widget>[
        SizedBox(height: 12),
        CustomDraggingHandle(),
        SizedBox(height: 16),
        CustomExploreBerlin(),
        SizedBox(height: 16),
        CustomHorizontallyScrollingRestaurants(),
        SizedBox(height: 24),
        CustomFeaturedListsText(),
        SizedBox(height: 16),
        CustomFeaturedItemsGrid(),
        SizedBox(height: 24),
        CustomRecentPhotosText(),
        SizedBox(height: 16),
        CustomRecentPhotoLarge(),
        SizedBox(height: 12),
        CustomRecentPhotosSmall(),
        SizedBox(height: 16),
      ],
    );
  }
}

class CustomDraggingHandle extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      height: 5,
      width: 30,
      decoration: BoxDecoration(color: Colors.grey[200], borderRadius: BorderRadius.circular(16)),
    );
  }
}

class CustomExploreBerlin extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Row(
      mainAxisAlignment: MainAxisAlignment.center,
      children: <Widget>[
        Text("Explore Berlin", style: TextStyle(fontSize: 22, color: Colors.black45)),
        SizedBox(width: 8),
        Container(
          height: 24,
          width: 24,
          child: Icon(Icons.arrow_forward_ios, size: 12, color: Colors.black54),
          decoration: BoxDecoration(color: Colors.grey[200], borderRadius: BorderRadius.circular(16)),
        ),
      ],
    );
  }
}

class CustomHorizontallyScrollingRestaurants extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.only(left: 16),
      child: SingleChildScrollView(
        scrollDirection: Axis.horizontal,
        child: Row(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            CustomRestaurantCategory(),
            SizedBox(width: 12),
            CustomRestaurantCategory(),
            SizedBox(width: 12),
            CustomRestaurantCategory(),
            SizedBox(width: 12),
            CustomRestaurantCategory(),
            SizedBox(width: 12),
          ],
        ),
      ),
    );
  }
}

class CustomFeaturedListsText extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.only(left: 16),
      //only to left align the text
      child: Row(
        children: <Widget>[Text("Featured Lists", style: TextStyle(fontSize: 14))],
      ),
    );
  }
}

class CustomFeaturedItemsGrid extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 16),
      child: GridView.count(
        //to avoid scrolling conflict with the dragging sheet
        physics: NeverScrollableScrollPhysics(),
        padding: const EdgeInsets.all(0),
        crossAxisCount: 2,
        mainAxisSpacing: 12,
        crossAxisSpacing: 12,
        shrinkWrap: true,
        children: <Widget>[
          CustomFeaturedItem(),
          CustomFeaturedItem(),
          CustomFeaturedItem(),
          CustomFeaturedItem(),
        ],
      ),
    );
  }
}

class CustomRecentPhotosText extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.only(left: 16),
      child: Row(
        children: <Widget>[
          Text("Recent Photos", style: TextStyle(fontSize: 14)),
        ],
      ),
    );
  }
}

class CustomRecentPhotoLarge extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 16),
      child: CustomFeaturedItem(),
    );
  }
}

class CustomRecentPhotosSmall extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return CustomFeaturedItemsGrid();
  }
}

class CustomRestaurantCategory extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      height: 100,
      width: 100,
      decoration: BoxDecoration(
        color: Colors.grey[500],
        borderRadius: BorderRadius.circular(8),
      ),
    );
  }
}

class CustomFeaturedItem extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      height: 200,
      decoration: BoxDecoration(
        color: Colors.grey[500],
        borderRadius: BorderRadius.circular(8),
      ),
    );
  }
}

StackOverflow answer: https://stackoverflow.com/a/62077272/5066615

Hi thank you for your example, however I'm having trouble using it with a small widget as CustomScrollViewContent, the sheet can be scrolled all the way to the top while I'm trying to keep it at the bottom, do you have any solution ? Thank you again.

I found a solution but now my maps widget can't get reached:

LayoutBuilder(builder: (context, constraints) {
            return SingleChildScrollView(
              reverse: true,//to anchor it to the bottom so when my panel grow in size it expand from the drawer
              child: Column(children: [
                Container(
                  height: constraints.maxHeight - 67,//Create an empty box that stop the scroll at 67px of the drawer
                ),
                Container(//My drawer
                  decoration: BoxDecoration(
                      color: Coolors.background,
                      borderRadius:
                          BorderRadius.vertical(top: Radius.circular(30))),
                  padding: EdgeInsets.symmetric(horizontal: 30, vertical: 10),
                  child: Panel(),
                ),
              ]),
            );
          }),

The only problem I have with this is the inability to Ignore the pointer on the void container because its handled by SingleChildScrollView and thus my map below don't get any event. I tried using others widget but each one fail. Do you have an idea ?

Succes !
Below is my code

class PanelDraggable extends StatefulWidget {
  @override
  _PanelDraggableState createState() => _PanelDraggableState();
}

class _PanelDraggableState extends State<PanelDraggable> {
  ScrollController scrollController = ScrollController();
  double containerSize =
      67; //my px value of the panel that need to be shown when closed
  double margin;
  double unlockScroll = 0;
  double previousOffset;
  bool lock = false;

  @override
  void initState() {
    super.initState();
    margin = containerSize;
    WidgetsBinding.instance.addPostFrameCallback((_) => scrollController.jumpTo(
        scrollController
            .position.maxScrollExtent)); //put the panel in closed position
  }

  Future<void> waitAndUpdate() async {
    //Wait for the ScrollPhysics to stop before updating the scrollarea
    //(I maybe need to change the scrollphysics's speed if some users play around quickly)
    if (lock) return;
    lock = true;
    Future.doWhile(() async {
      if (previousOffset == scrollController.offset) {
        updateScrollArea(null);
        lock = false;
        return false;
      }
      previousOffset = scrollController.offset;
      await Future.delayed(Duration(milliseconds: 40));
      return true;
    });
  }

  void updateScrollArea(double dimension) {
    if (dimension != null) {
      //print("child's dimension augmented");
      setState(() {
        containerSize = dimension - 1;
        unlockScroll = 1;
      });
    } else {
      //Lower the view port
      setState(() => containerSize = margin);
      //callback after the frame built
      WidgetsBinding.instance.addPostFrameCallback((_) => setState(() {
            containerSize = scrollController.position.maxScrollExtent -
                scrollController.offset +
                margin;

            //If it reached max (can't be scrolled since its useless), add 1px and update
            if (containerSize ==
                scrollController.position.maxScrollExtent + margin) {
              unlockScroll = 1;
              containerSize =
                  scrollController.position.maxScrollExtent + margin - 1;
            }
            print("container size = $containerSize");
          }));
    }
  }

  void notified() {
    //Called by the "pause" button
    //print("viewport $scrollController.position.viewportDimension");
    //print("capacuty to scroll $scrollController.position.maxScrollExtent");
    updateScrollArea((scrollController.position.maxScrollExtent > 0)
        ? scrollController.position.maxScrollExtent +
            scrollController.position.viewportDimension
        : null);
  }

  @override
  Widget build(BuildContext context) {
    return LayoutBuilder(builder: (context, constraints) {
      return Listener(
        onPointerUp: (_) => waitAndUpdate(),
        onPointerDown: (_) => setState(() => containerSize = margin),
        child: Container(
          height: containerSize,
          child: SingleChildScrollView(
            physics: NoVelocityScrollPhysics(),
            controller: scrollController,
            clipBehavior: Clip.none,
            reverse: true,
            child: Column(
              children: [
                Container(height: unlockScroll),
                Container(
                  //My drawer
                  decoration: BoxDecoration(
                      color: Coolors.background,
                      borderRadius:
                          BorderRadius.vertical(top: Radius.circular(30))),
                  padding: EdgeInsets.symmetric(horizontal: 30, vertical: 10),
                  child: Panel(notifySize: notified),
                ),
              ],
            ),
          ),
        ),
      );
    });
  }
}

This class sit in a stack with the alignment settings set to bottomCenter

Dear Sir

if i use Stack+Positioned (or Stack+? )

i want resize Google map area like attach image

the top & bottom widget is fix Positioned

other empty area i want put re-size Google map

how to do ?

THX