added launch in maps functionality

lib/pages/collection_page.dart

@@ -3,6 +3,7 @@ import 'package:flutter/material.dart';
 import '../model/bookmark.dart';
 import '../service/bookmarks_provider.dart';
 import '../service/storage.dart';
+import '../service/url_launcher.dart';
 import '../widgets/create_bookmark_dialog.dart';
 
 class CollectionPage extends StatefulWidget {
@@ -15,31 +16,6 @@ class CollectionPage extends StatefulWidget {
 }
 
 class _CollectionPageState extends State<CollectionPage> {
-  @override
-  Widget build(BuildContext context) {
-    if (BookmarksProvider.selectedCollectionId == null) {
-      Navigator.of(context).pop();
-    }
-    final bookmarks = Storage.loadBookmarksForCollection(
-      BookmarksProvider.selectedCollectionId!,
-    );
-
-    final collection = Storage.loadCollections().firstWhere(
-      (c) => c.id == BookmarksProvider.selectedCollectionId,
-    );
-
-    return Scaffold(
-      appBar: AppBar(title: Text(collection.name)),
-      body: ListView(
-        children: bookmarks.map((e) => ListTile(title: Text(e.name))).toList(),
-      ),
-      floatingActionButton: FloatingActionButton(
-        onPressed: onAddButtonPressed,
-        child: Icon(Icons.add),
-      ),
-    );
-  }
-
   void onAddButtonPressed() => showDialog(
     context: context,
     builder: (context) => CreateBookmarkDialog(
@@ -52,4 +28,37 @@ class _CollectionPageState extends State<CollectionPage> {
     Storage.addBookmark(bookmark);
     setState(() {});
   }
+
+  Widget bookmarkListBuilder(BuildContext context, Bookmark bookmark) {
+    return ListTile(
+      title: Text(bookmark.name),
+      onTap: () => launchUrlFromString(bookmark.link),
+    );
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    if (BookmarksProvider.selectedCollectionId == null) {
+      Navigator.of(context).pop();
+    }
+    final bookmarks = Storage.loadBookmarksForCollection(
+      BookmarksProvider.selectedCollectionId!,
+    );
+    final collection = Storage.loadCollections().firstWhere(
+      (c) => c.id == BookmarksProvider.selectedCollectionId,
+    );
+
+    return Scaffold(
+      appBar: AppBar(title: Text(collection.name)),
+      body: ListView.builder(
+        itemBuilder: (context, index) =>
+            bookmarkListBuilder(context, bookmarks.elementAt(index)),
+        itemCount: bookmarks.length,
+      ),
+      floatingActionButton: FloatingActionButton(
+        onPressed: onAddButtonPressed,
+        child: Icon(Icons.add),
+      ),
+    );
+  }
 }