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stream-chat-flutter/lib/src/user_list_view.dart
T

553 lines
18 KiB
Dart

import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:stream_chat/stream_chat.dart';
import 'package:stream_chat_flutter/src/lazy_load_scroll_view.dart';
import 'package:stream_chat_flutter/src/users_bloc.dart';
import 'package:stream_chat_flutter/stream_chat_flutter.dart';
import 'user_item.dart';
/// Callback called when tapping on a user
typedef UserTapCallback = void Function(User, Widget);
/// Builder used to create a custom [ListUserItem] from a [User]
typedef UserItemBuilder = Widget Function(BuildContext, User, bool);
///
/// It shows the list of current users.
///
/// ```dart
/// class UsersListPage extends StatelessWidget {
/// @override
/// Widget build(BuildContext context) {
/// return Scaffold(
/// body: UsersListView(
/// filter: {
/// 'members': {
/// '\$in': [StreamChat.of(context).user.id],
/// }
/// },
/// sort: [SortOption('last_message_at')],
/// pagination: PaginationParams(
/// limit: 20,
/// ),
/// channelWidget: ChannelPage(),
/// ),
/// );
/// }
/// }
/// ```
///
///
/// Make sure to have a [UsersBloc] ancestor in order to provide the information about the users.
/// The widget uses a [ListView.separated], [GridView.builder] to render the list, grid of channels.
///
/// The widget components render the ui based on the first ancestor of type [StreamChatTheme].
/// Modify it to change the widget appearance.
class UserListView extends StatefulWidget {
/// Instantiate a new UserListView
const UserListView({
Key key,
this.errorBuilder,
this.emptyBuilder,
this.filter,
this.options,
this.sort,
this.pagination,
this.onUserTap,
this.onUserLongPress,
this.userWidget,
this.userItemBuilder,
this.separatorBuilder,
this.onImageTap,
this.selectedUsers,
this.pullToRefresh = true,
this.groupAlphabetically = false,
this.crossAxisCount = 1,
}) : assert(
crossAxisCount == 1 || groupAlphabetically == false,
'Cannot group alphabetically when crossAxisCount > 1',
),
super(key: key);
/// The builder that will be used in case of error
final Widget Function(Error error) errorBuilder;
/// The builder used when the channel list is empty.
final WidgetBuilder emptyBuilder;
/// The query filters to use.
/// You can query on any of the custom fields you've defined on the [Channel].
/// You can also filter other built-in channel fields.
final Map<String, dynamic> filter;
/// Query channels options.
///
/// state: if true returns the Channel state
/// watch: if true listen to changes to this Channel in real time.
final Map<String, dynamic> options;
/// The sorting used for the channels matching the filters.
/// Sorting is based on field and direction, multiple sorting options can be provided.
/// You can sort based on last_updated, last_message_at, updated_at, created_at or member_count.
/// Direction can be ascending or descending.
final List<SortOption> sort;
/// Pagination parameters
/// limit: the number of users to return (max is 30)
/// offset: the offset (max is 1000)
/// message_limit: how many messages should be included to each channel
final PaginationParams pagination;
/// Function called when tapping on a channel
/// By default it calls [Navigator.push] building a [MaterialPageRoute]
/// with the widget [userWidget] as child.
final UserTapCallback onUserTap;
/// Function called when long pressing on a channel
final Function(User) onUserLongPress;
/// Widget used when opening a channel
final Widget userWidget;
/// Builder used to create a custom user preview
final UserItemBuilder userItemBuilder;
/// Builder used to create a custom item separator
final Function(BuildContext, int) separatorBuilder;
/// The function called when the image is tapped
final Function(User) onImageTap;
/// Set it to false to disable the pull-to-refresh widget
final bool pullToRefresh;
/// Sets a blue trailing checkMark in [ListUserItem] for all the [selectedUsers]
final Set<User> selectedUsers;
/// Set it to true to group users by their first character
///
/// defaults to false
final bool groupAlphabetically;
/// The number of children in the cross axis.
final int crossAxisCount;
@override
_UserListViewState createState() => _UserListViewState();
}
class _UserListViewState extends State<UserListView>
with WidgetsBindingObserver {
bool get _isListView => widget.crossAxisCount == 1;
@override
void initState() {
super.initState();
final usersBloc = UsersBloc.of(context);
usersBloc.queryUsers(
filter: widget.filter,
sort: widget.sort,
pagination: widget.pagination,
options: widget.options,
);
}
@override
Widget build(BuildContext context) {
final usersBloc = UsersBloc.of(context);
if (!widget.pullToRefresh) {
return _buildListView(usersBloc);
}
return RefreshIndicator(
onRefresh: () async {
return usersBloc.queryUsers(
filter: widget.filter,
sort: widget.sort,
options: widget.options,
pagination: widget.pagination,
);
},
child: _buildListView(usersBloc),
);
}
bool get isListAlreadySorted =>
widget.sort?.any((e) => e.field == 'name' && e.direction == 1) ?? false;
Stream<List<ListItem>> _buildUserStream(
UsersBlocState usersBlocState,
) {
return usersBlocState.usersStream.map(
(users) {
if (widget.groupAlphabetically) {
var temp = users;
if (!isListAlreadySorted) {
temp = users..sort((curr, next) => curr.name.compareTo(next.name));
}
final groupedUsers = <String, List<User>>{};
for (var e in temp) {
final alphabet = e.name[0]?.toUpperCase();
groupedUsers[alphabet] = [...groupedUsers[alphabet] ?? [], e];
}
final items = <ListItem>[];
for (var key in groupedUsers.keys) {
items.add(ListHeaderItem(key));
items.addAll(groupedUsers[key].map((e) => ListUserItem(e)));
}
return items;
}
return users.map((e) => ListUserItem(e)).toList();
},
);
}
StreamBuilder<List<ListItem>> _buildListView(
UsersBlocState usersBlocState,
) {
return StreamBuilder(
stream: _buildUserStream(usersBlocState),
builder: (context, snapshot) {
if (snapshot.hasError) {
if (snapshot.error is Error) {
print((snapshot.error as Error).stackTrace);
}
if (widget.errorBuilder != null) {
return widget.errorBuilder(snapshot.error);
}
var message = snapshot.error.toString();
if (snapshot.error is DioError) {
final dioError = snapshot.error as DioError;
if (dioError.type == DioErrorType.RESPONSE) {
message = dioError.message;
} else {
message = 'Check your connection and retry';
}
}
return Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text.rich(
TextSpan(
children: [
WidgetSpan(
child: Padding(
padding: const EdgeInsets.only(
right: 2.0,
),
child: Icon(Icons.error_outline),
),
),
TextSpan(text: 'Error loading channels'),
],
),
style: Theme.of(context).textTheme.headline6,
),
Padding(
padding: const EdgeInsets.only(
top: 16.0,
),
child: Text(message),
),
FlatButton(
onPressed: () {
usersBlocState.queryUsers(
filter: widget.filter,
sort: widget.sort,
pagination: widget.pagination,
options: widget.options,
);
},
child: Text('Retry'),
),
],
),
);
}
if (!snapshot.hasData) {
return LayoutBuilder(
builder: (context, viewportConstraints) {
return SingleChildScrollView(
physics: AlwaysScrollableScrollPhysics(),
child: ConstrainedBox(
constraints: BoxConstraints(
minHeight: viewportConstraints.maxHeight,
),
child: Center(
child: CircularProgressIndicator(),
),
),
);
},
);
}
final items = snapshot.data;
if (items.isEmpty && widget.emptyBuilder != null) {
return widget.emptyBuilder(context);
}
if (items.isEmpty && widget.emptyBuilder == null) {
return LayoutBuilder(
builder: (context, viewportConstraints) {
return SingleChildScrollView(
physics: AlwaysScrollableScrollPhysics(),
child: ConstrainedBox(
constraints: BoxConstraints(
minHeight: viewportConstraints.maxHeight,
),
child: Center(
child: Text('There are no users currently'),
),
),
);
},
);
}
final child = _isListView
? ListView.separated(
physics: AlwaysScrollableScrollPhysics(),
itemCount: items.isNotEmpty ? items.length + 1 : items.length,
separatorBuilder: (_, index) {
if (widget.separatorBuilder != null) {
return widget.separatorBuilder(context, index);
}
return _separatorBuilder(context, index);
},
itemBuilder: (context, index) {
return _listItemBuilder(context, index, items);
},
)
: GridView.builder(
gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
crossAxisCount: widget.crossAxisCount,
),
itemCount: items.isNotEmpty ? items.length + 1 : items.length,
physics: AlwaysScrollableScrollPhysics(),
itemBuilder: (context, index) {
return _gridItemBuilder(context, index, items);
},
);
return LazyLoadScrollView(
onEndOfPage: () async {
return _listenUserPagination(usersBlocState);
},
child: child,
);
},
);
}
Widget _listItemBuilder(BuildContext context, int i, List<ListItem> items) {
final usersProvider = UsersBloc.of(context);
if (i < items.length) {
final item = items[i];
return item.when(
headerItem: (header) {
return Container(
key: ValueKey<String>('HEADER-$header'),
color:
StreamChatTheme.of(context).colorTheme.black.withOpacity(0.05),
child: Padding(
padding: const EdgeInsets.symmetric(horizontal: 8.0, vertical: 6),
child: Text(
header,
style: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 14.5,
color: StreamChatTheme.of(context)
.colorTheme
.black
.withOpacity(0.3)),
),
),
);
},
userItem: (user) {
final selected = widget.selectedUsers?.contains(user) ?? false;
return Container(
key: ValueKey<String>('USER-${user.id}'),
child: widget.userItemBuilder != null
? widget.userItemBuilder(context, user, selected)
: UserItem(
user: user,
onTap: (user) => widget.onUserTap(user, widget.userWidget),
onLongPress: widget.onUserLongPress,
onImageTap: widget.onImageTap,
selected: selected,
),
);
},
);
} else {
return _buildQueryProgressIndicator(context, usersProvider);
}
}
Widget _gridItemBuilder(BuildContext context, int i, List<ListItem> items) {
final usersProvider = UsersBloc.of(context);
if (i < items.length) {
final item = items[i];
return item.when(
headerItem: (_) => Offstage(),
userItem: (user) {
final selected = widget.selectedUsers?.contains(user) ?? false;
return Container(
key: ValueKey<String>('USER-${user.id}'),
child: widget.userItemBuilder != null
? widget.userItemBuilder(context, user, selected)
: Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
UserAvatar(
user: user,
borderRadius: BorderRadius.circular(32),
selected: selected,
constraints: BoxConstraints.tightFor(
height: 64,
width: 64,
),
onTap: (user) =>
widget.onUserTap(user, widget.userWidget),
onLongPress: widget.onUserLongPress,
),
SizedBox(height: 4),
Padding(
padding: const EdgeInsets.symmetric(horizontal: 8),
child: Text(
user.name,
textAlign: TextAlign.center,
maxLines: 2,
overflow: TextOverflow.ellipsis,
style: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 12,
),
),
),
],
),
);
},
);
} else {
return _buildQueryProgressIndicator(context, usersProvider);
}
}
Widget _buildQueryProgressIndicator(context, UsersBlocState usersProvider) {
return StreamBuilder<bool>(
stream: usersProvider.queryUsersLoading,
initialData: false,
builder: (context, snapshot) {
if (snapshot.hasError) {
return Container(
color: StreamChatTheme.of(context)
.colorTheme
.accentRed
.withOpacity(.2),
child: Padding(
padding: const EdgeInsets.symmetric(vertical: 16.0),
child: Center(
child: Text('Error loading users'),
),
),
);
}
return Container(
height: 100,
padding: EdgeInsets.all(32),
child: Center(
child: snapshot.data ? CircularProgressIndicator() : Container(),
),
);
});
}
Widget _separatorBuilder(context, i) {
return Container(
height: 1,
color: Theme.of(context).brightness == Brightness.dark
? StreamChatTheme.of(context).colorTheme.white.withOpacity(0.1)
: StreamChatTheme.of(context).colorTheme.black.withOpacity(0.1),
);
}
void _listenUserPagination(UsersBlocState usersProvider) {
usersProvider.queryUsers(
filter: widget.filter,
sort: widget.sort,
pagination: widget.pagination.copyWith(
offset: usersProvider.users?.length ?? 0,
),
options: widget.options,
);
}
@override
void didUpdateWidget(UserListView oldWidget) {
super.didUpdateWidget(oldWidget);
if (widget.filter?.toString() != oldWidget.filter?.toString() ||
jsonEncode(widget.sort) != jsonEncode(oldWidget.sort) ||
widget.pagination?.toJson()?.toString() !=
oldWidget.pagination?.toJson()?.toString() ||
widget.options?.toString() != oldWidget.options?.toString()) {
final usersBloc = UsersBloc.of(context);
usersBloc.queryUsers(
filter: widget.filter,
sort: widget.sort,
pagination: widget.pagination,
options: widget.options,
);
}
}
}
abstract class ListItem {
String get key {
if (this is ListHeaderItem) {
final header = (this as ListHeaderItem).heading;
return 'HEADER-$header';
}
if (this is ListUserItem) {
final user = (this as ListUserItem).user;
return 'USER-${user.id}';
}
}
Widget when({
@required Widget Function(String heading) headerItem,
@required Widget Function(User user) userItem,
}) {
if (this is ListHeaderItem) {
return headerItem((this as ListHeaderItem).heading);
}
if (this is ListUserItem) {
return userItem((this as ListUserItem).user);
}
}
}
class ListHeaderItem extends ListItem {
final String heading;
ListHeaderItem(this.heading);
}
class ListUserItem extends ListItem {
final User user;
ListUserItem(this.user);
}