[Crane] Adds README

Change-Id: Id7e26646e842b76410c86fd80350fb141f720bec

Crane/README.md

@@ -1 +1,71 @@
-Steps to run this sample in go/compose-samples-howto
+# Crane sample
+
+[Crane](https://material.io/design/material-studies/crane.html) is a travel app part of the Material
+Studies built with [Jetpack Compose](https://developer.android.com/jetpack/compose).
+The goal of the sample is to showcase Material components, draggable UI elements, Android Views
+inside Compose, and UI state handling.
+
+## Screenshots
+
+<img src="screenshots/crane.gif"/>
+
+## Features
+
+This sample contains 4 screens:
+- __Landing__ [screen][landing] that fades out after 2 seconds then slides the main content in from
+the bottom of the screen.
+- __Home__ [screen][home] where you can explore flights, hotels, and restaurants specifying
+the number of people.
+ - Clicking on the number of people refreshes the destinations.
+ - The [backdrop](https://material.io/components/backdrop) is draggable and can pin to the top of
+ the screen, just under the search criteria, and to the bottom. Implemented [here][backdrop].
+ - Destination's images are retrieved using the [coil-accompanist][coil-accompanist] library.
+- __Calendar__ [screen][calendar]. Tapping on __Select Dates__ takes you to a calendar built
+completely from scratch. It makes a heavy usage of Compose's state APIs.
+- Destination's __Details__ [screen][details]. When tapping on a destination, a new screen
+implemented using a different Activity will be displayed. In there, you can see the a `MapView`
+embedded in Compose and Compose buttons updating the Android View. Notice how you can also
+interact with the `MapView` seamlessly.
+
+## Google Maps SDK
+
+To get the MapView working, you need to get an API key as
+the [documentation says](https://developers.google.com/maps/documentation/android-sdk/get-api-key),
+and include it in the `local.properties` file as follows:
+
+```
+google.maps.key={insert_your_api_key_here}
+```
+
+## Data
+
+The data is hardcoded in the _CraneData_ [file][data] and exposed to the UI using the
+[MainViewModel][mainViewModel]. Image resources are retrieved from
+[Unsplash](https://unsplash.com/).
+
+## License
+
+```
+Copyright 2020 Google LLC
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    https://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+```
+
+[landing]: app/src/main/java/androidx/compose/samples/crane/home/LandingScreen.kt
+[home]: app/src/main/java/androidx/compose/samples/crane/home/CraneHome.kt
+[backdrop]: app/src/main/java/androidx/compose/samples/crane/ui/BackdropFrontLayer.kt
+[calendar]: app/src/main/java/androidx/compose/samples/crane/calendar/Calendar.kt
+[details]: app/src/main/java/androidx/compose/samples/crane/details/DetailsActivity.kt
+[data]: app/src/main/java/androidx/compose/samples/crane/data/CraneData.kt
+[mainViewModel]: app/src/main/java/androidx/compose/samples/crane/home/MainViewModel.kt
+[coil-accompanist]: https://github.com/chrisbanes/accompanist