Created inline user picker

lib/ui/tiles/simple_user_tile.dart

@@ -0,0 +1,31 @@
+import 'package:comunic/models/user.dart';
+import 'package:comunic/ui/widgets/account_image_widget.dart';
+import 'package:flutter/material.dart';
+
+/// Simple user tile
+///
+/// Basically this only shows the name of the user + its account image
+///
+/// @author Pierre HUBERT
+
+typedef OnUserTap = void Function(User);
+
+class SimpleUserTile extends StatelessWidget {
+  final User user;
+  final OnUserTap onTap;
+
+  const SimpleUserTile({Key key, this.user, this.onTap})
+      : assert(user != null),
+        super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return ListTile(
+      onTap: onTap == null ? null : () => onTap(user),
+      leading: AccountImageWidget(
+        user: user,
+      ),
+      title: Text(user.fullName),
+    );
+  }
+}

lib/ui/widgets/pick_user_widget.dart

@@ -0,0 +1,117 @@
+import 'package:comunic/helpers/search_helper.dart';
+import 'package:comunic/lists/users_list.dart';
+import 'package:comunic/models/user.dart';
+import 'package:comunic/ui/tiles/simple_user_tile.dart';
+import 'package:comunic/utils/intl_utils.dart';
+import 'package:flutter/material.dart';
+
+/// Pick user widget
+///
+/// Allows to choose a user by starting to type his name and tapping on it
+/// when his name appear
+///
+/// @author Pierre HUBERT
+
+typedef OnSelectUserCallback = void Function(User);
+
+class PickUserWidget extends StatefulWidget {
+  final OnSelectUserCallback onSelectUser;
+
+  const PickUserWidget({Key key, @required this.onSelectUser})
+      : assert(onSelectUser != null),
+        super(key: key);
+
+  @override
+  State<StatefulWidget> createState() => _PickUserWidgetState();
+}
+
+class _PickUserWidgetState extends State<PickUserWidget> {
+  // Helper
+  final SearchHelper _searchHelper = SearchHelper();
+
+  // Widget properties
+  final FocusNode _focusNode = FocusNode();
+  final TextEditingController _controller = TextEditingController();
+  OverlayEntry _overlayEntry;
+  UsersList _suggestions;
+
+  @override
+  void initState() {
+    super.initState();
+
+    _focusNode.addListener(() {
+      if (_focusNode.hasFocus) {
+        //Check for focus
+        _overlayEntry = _createOverlayEntry();
+        Overlay.of(context).insert(_overlayEntry);
+      } else {
+        //Remove overlay
+        _removeOverlay();
+      }
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return TextField(
+      focusNode: _focusNode,
+      onChanged: (s) => _updateSuggestions(),
+      controller: _controller,
+      decoration: InputDecoration(labelText: tr("Select user")),
+    );
+  }
+
+  OverlayEntry _createOverlayEntry() {
+    RenderBox renderBox = context.findRenderObject();
+    final size = renderBox.size;
+    final offset = renderBox.localToGlobal(Offset.zero);
+
+    return OverlayEntry(builder: (c) {
+      return Positioned(
+        left: offset.dx,
+        top: offset.dy + size.height + 5.0,
+        width: size.width,
+        child: Material(
+          elevation: 4.0,
+          child: ListView.builder(
+            padding: EdgeInsets.zero,
+            shrinkWrap: true,
+            itemCount: _suggestions == null ? 0 : _suggestions.length,
+            itemBuilder: (c, i) => SimpleUserTile(
+                  user: _suggestions[i],
+                  onTap: _userTapped,
+                ),
+          ),
+        ),
+      );
+    });
+  }
+
+  void _removeOverlay() {
+    if (_overlayEntry != null) {
+      _overlayEntry.remove();
+      _overlayEntry = null;
+    }
+  }
+
+  /// This method get called each time the input value is updated
+  Future<void> _updateSuggestions() async {
+    if (_controller.value.text.length == 0) return;
+
+    final results = await _searchHelper.searchUser(_controller.value.text);
+
+    if (results == null) return;
+
+    _suggestions = results;
+    if (_overlayEntry != null) _overlayEntry.markNeedsBuild();
+  }
+
+  /// Method called each time a user is tapped (selected)
+  void _userTapped(User user) {
+    _controller.text = user.fullName;
+    _removeOverlay();
+    _focusNode.unfocus();
+
+    widget.onSelectUser(user);
+  }
+}