Add in UI Explorer example for showing annotation callouts by default in <MapView>

Reviewed By: martinbigio

Differential Revision: D4253281

fbshipit-source-id: b4bd9fedf7042d3d43d2a50bdb7474caa875781f

Examples/UIExplorer/js/MapViewExample.js

@@ -242,6 +242,7 @@ class AnnotationExample extends React.Component {
 
     return (
       <MapView
+        showsAnnotationCallouts={this.props.showsAnnotationCallouts}
         style={styles.map}
         onRegionChangeComplete={onRegionChangeComplete}
         region={this.state.mapRegion}
@@ -366,6 +367,29 @@ exports.examples = [
       }}/>;
     }
   },
+  {
+    title: 'Show callouts by default example',
+    render() {
+      return <AnnotationExample
+        style={styles.map}
+        annotation={{
+          title: 'More Info...',
+          rightCalloutView: (
+            <TouchableOpacity
+              onPress={() => {
+                alert('You Are Here');
+              }}>
+              <Image
+                style={{width:30, height:30}}
+                source={require('./uie_thumb_selected.png')}
+              />
+            </TouchableOpacity>
+          ),
+        }}
+        showsAnnotationCallouts={true}
+      />;
+    }
+  },
   {
     title: 'Annotation focus example',
     render() {