Updated sample catalog templates and app summaries (#11052)

examples/catalog/bin/entry.md.template

@@ -8,5 +8,11 @@
       <p>
         @(summary)
       </p>
+      <p>
+        This app features the following classes: @(classes).
+      </p>
+      <p>
+        <a href="/catalog/samples/@(link)/">Learn more</a>.
+      </p>
     </div>
   </div>

examples/catalog/bin/index.md.template

@@ -4,7 +4,9 @@ title: "Sample App Catalog"
 permalink: /catalog/samples/
 ---
 
-Complete applications that demonstrate how to get things done with Flutter. Each sample app features a few classes or an animation, a layout, or other feature of Flutter. The samples are short, just one file and usually only one or two pages of code. They should easy to try out with your favorite IDE.
+This catalog lists applications that demonstrate how to implement common mobile design patterns with Flutter. Each sample demonstrates how a few Flutter widgets can be put together to implement a meaningful user interface. The samples are short - just one Dart file - but they're complete applications. They should be easy to try out and tweak with your favorite IDE/code editor.
+
+If there are other sample apps that you'd like to see we'd appreciate hearing from you on our [Gitter channel](https://gitter.im/flutter/flutter) or [mailing list](https://groups.google.com/d/forum/flutter-dev).
 
 <div class="container-fluid">
 @(entries)

examples/catalog/lib/animated_list.dart

@@ -205,7 +205,7 @@ Sample Catalog
 
 Title: AnimatedList
 
-Summary: An AnimatedList that displays a list of cards which stay
+Summary: An AnimatedList for displaying a list of cards that stay
 in sync with an app-specific ListModel. When an item is added to or removed
 from the model, the corresponding card animates in or out of view.
 

examples/catalog/lib/app_bar_bottom.dart

@@ -123,6 +123,9 @@ Sample Catalog
 
 Title: AppBar with a custom bottom widget.
 
+Summary: An AppBar that includes a bottom widget. Any widget
+with a PreferredSize can appear at the bottom of an AppBar.
+
 Summary: Any widget with a PreferredSize can appear at the bottom of an AppBar.
 
 Description:

examples/catalog/lib/basic_app_bar.dart

@@ -104,7 +104,7 @@ Sample Catalog
 
 Title: AppBar Basics
 
-Summary: A typcial AppBar with a title, actions, and an overflow dropdown menu.
+Summary: A basic AppBar with a title, actions, and an overflow dropdown menu.
 
 Description:
 An app that displays one of a half dozen choices with an icon and a title.

examples/catalog/lib/expansion_tile_sample.dart

@@ -97,7 +97,7 @@ Sample Catalog
 
 Title: ExpansionTile
 
-Summary: ExpansionTiles can used to produce two-level or multi-level lists.
+Summary: An ExpansionTile for building nested lists, with two or more levels.
 
 Description:
 This app displays hierarchical data with ExpansionTiles. Tapping a tile

examples/catalog/lib/tabbed_app_bar.dart

@@ -85,7 +85,7 @@ Sample Catalog
 
 Title: Tabbed AppBar
 
-Summary: An AppBar with a TabBar as its bottom widget.
+Summary: An AppBar with a TabBar for navigating pages just below it.
 
 Description:
 A TabBar can be used to navigate among the pages displayed in a TabBarView.