Create pick user dialog

lib/ui/dialogs/pick_user_dialog.dart

@@ -0,0 +1,63 @@
+import 'package:comunic/models/user.dart';
+import 'package:comunic/ui/widgets/dialogs/cancel_dialog_button.dart';
+import 'package:comunic/ui/widgets/dialogs/confirm_dialog_button.dart';
+import 'package:comunic/ui/widgets/pick_user_widget.dart';
+import 'package:comunic/ui/widgets/safe_state.dart';
+import 'package:comunic/utils/intl_utils.dart';
+import 'package:flutter/cupertino.dart';
+import 'package:flutter/material.dart';
+
+/// Pick user dialog
+///
+/// @author Pierre HUBERT
+
+/// Ask the user to pick a user
+///
+/// Returns null if no user was selected
+Future<int> showPickUserDialog(BuildContext context) async {
+  return await showDialog(context: context, builder: (c) => _PickUserDialog());
+}
+
+class _PickUserDialog extends StatefulWidget {
+  @override
+  __PickUserDialogState createState() => __PickUserDialogState();
+}
+
+class __PickUserDialogState extends SafeState<_PickUserDialog> {
+  User _user;
+
+  bool get _isValid => _user != null;
+
+  @override
+  Widget build(BuildContext context) {
+    return AlertDialog(
+      title: Text(tr("Choose a user")),
+      content: _buildContent(),
+      actions: <Widget>[
+        CancelDialogButton(),
+        ConfirmDialogButton(
+          value: _isValid ? _user.id : null,
+          enabled: _isValid,
+        ),
+      ],
+    );
+  }
+
+  Widget _buildContent() {
+    final size = MediaQuery.of(context).size;
+    print(size);
+    return Container(
+      width: size.width,
+      height: size.height,
+      child: Column(
+        children: <Widget>[
+          PickUserWidget(
+            onSelectUser: (u) => setState(() => _user = u),
+            label: tr("Search user..."),
+            onValueChange: (u) => setState(() => _user = null),
+          ),
+        ],
+      ),
+    );
+  }
+}

lib/ui/screens/group_members_screen.dart

@@ -6,6 +6,7 @@ import 'package:comunic/models/group.dart';
 import 'package:comunic/models/group_membership.dart';
 import 'package:comunic/models/user.dart';
 import 'package:comunic/ui/dialogs/multi_choices_dialog.dart';
+import 'package:comunic/ui/dialogs/pick_user_dialog.dart';
 import 'package:comunic/ui/widgets/account_image_widget.dart';
 import 'package:comunic/ui/widgets/async_screen_widget.dart';
 import 'package:comunic/ui/widgets/comunic_back_button_widget.dart';
@@ -61,8 +62,11 @@ class _GroupMembersScreenState extends State<GroupMembersScreen> {
       );
 
   Widget _buildBodyContent() {
-    return ListView(
-      children: _members.map(_buildGroupMemberTile).toList(),
+    return Stack(
+      children: [
+        ListView(children: _members.map(_buildGroupMemberTile).toList()),
+        _buildInvitationFAB()
+      ],
     );
   }
 
@@ -75,6 +79,29 @@ class _GroupMembersScreenState extends State<GroupMembersScreen> {
       onUpdated: () => _key.currentState.refresh(),
     );
   }
+
+  Widget _buildInvitationFAB() {
+    return Positioned(
+      right: 20,
+      bottom: 20,
+      child: FloatingActionButton(
+        onPressed: _inviteMember,
+        child: Icon(Icons.add),
+      ),
+    );
+  }
+
+  void _inviteMember() async {
+    try {
+      final userID = await showPickUserDialog(context);
+      if (userID == null) return;
+
+      print("Invite user: $userID");
+    } catch (e, s) {
+      print("Could not invite a user! $e\n$s");
+      showSimpleSnack(context, tr("Could not invite a user!"));
+    }
+  }
 }
 
 List<MultiChoiceEntry<GroupMembershipLevel>> get _membershipLevels => [

lib/ui/widgets/dialogs/cancel_dialog_button.dart

@@ -0,0 +1,17 @@
+import 'package:comunic/utils/intl_utils.dart';
+import 'package:flutter/material.dart';
+
+/// Render a cancel button for an alert dialog
+///
+/// @author Pierre HUBERT
+
+class CancelDialogButton extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    return MaterialButton(
+      onPressed: () => Navigator.of(context).pop(),
+      child: Text(tr("Cancel").toUpperCase()),
+      textColor: Colors.red,
+    );
+  }
+}

lib/ui/widgets/dialogs/confirm_dialog_button.dart

@@ -0,0 +1,27 @@
+import 'package:comunic/utils/intl_utils.dart';
+import 'package:flutter/material.dart';
+
+/// Confirm dialog button
+///
+/// @author Pierre HUBERT
+
+class ConfirmDialogButton<T> extends StatelessWidget {
+  final bool enabled;
+  final T value;
+
+  const ConfirmDialogButton({
+    Key key,
+    this.enabled = true,
+    @required this.value,
+  })  : assert(enabled != null),
+        super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialButton(
+      onPressed: enabled ? () => Navigator.of(context).pop(value) : null,
+      child: Text(tr("Confirm").toUpperCase()),
+      textColor: Colors.green,
+    );
+  }
+}

lib/ui/widgets/pick_user_widget.dart

@@ -15,19 +15,21 @@ typedef OnSelectUserCallback = void Function(User);
 
 class PickUserWidget extends StatefulWidget {
   final OnSelectUserCallback onSelectUser;
+  final void Function(String) onValueChange;
   final String label;
   final bool resetOnChoose;
   final bool keepFocusOnChoose;
   final bool enabled;
 
-  const PickUserWidget(
-      {Key key,
-      @required this.onSelectUser,
-      @required this.label,
-      this.resetOnChoose = false,
-      this.keepFocusOnChoose = false,
-      this.enabled = true})
-      : assert(onSelectUser != null),
+  const PickUserWidget({
+    Key key,
+    @required this.onSelectUser,
+    @required this.label,
+    this.resetOnChoose = false,
+    this.keepFocusOnChoose = false,
+    this.onValueChange,
+    this.enabled = true,
+  })  : assert(onSelectUser != null),
         assert(label != null),
         assert(resetOnChoose != null),
         assert(keepFocusOnChoose != null),
@@ -93,9 +95,9 @@ class _PickUserWidgetState extends State<PickUserWidget> {
             shrinkWrap: true,
             itemCount: _suggestions == null ? 0 : _suggestions.length,
             itemBuilder: (c, i) => SimpleUserTile(
-                  user: _suggestions[i],
-                  onTap: _userTapped,
-                ),
+              user: _suggestions[i],
+              onTap: _userTapped,
+            ),
           ),
         ),
       );
@@ -116,9 +118,11 @@ class _PickUserWidgetState extends State<PickUserWidget> {
 
   /// This method get called each time the input value is updated
   Future<void> _updateSuggestions() async {
-    if (_controller.value.text.length == 0) return _removeOverlay();
+    if (widget.onValueChange != null) widget.onValueChange(_controller.text);
 
-    final results = await _searchHelper.searchUser(_controller.value.text);
+    if (_controller.text.length == 0) return _removeOverlay();
+
+    final results = await _searchHelper.searchUser(_controller.text);
 
     if (results == null) return;