ralphhm / gygreviews

Review Browser

Sample Android Application written in Kotlin to browse reviews of a popular Berlin tour. Architecture Components ViewModel is used to implement MVVM and support orientation change without losing UI state.

Dependencies

• Retrofit 2
• RxJava 2
• Groupie
• Dagger 2
• Android Architecture Components (ViewModel)

###Open steps

• Add endless scrolling to the review list by fetching the next page when reaching the end of the list to allow users to browse all reviews
• Add caching to provide extended offline functionality

####Caching implementation The following approach would be taken if caching is a requirement.

• Use a database to store the paged results as review entities with the absolute result position for each review
• On database read sort the reviews by result position
• Use database entries an App start first, eventually try to fetch a fresh version of reviews
• Allow the user to refresh the (stale) content and replace stale database content on success
• Differentiate between initial fetch, next page fetch and refresh fetch

###Submit review POST request structure To be symmetric to the GET request the submit call could go to the same url but with POST method

curl -X POST \
  http://www.getyourguide.com/berlin-l17/tempelhof-2-hour-airport-history-tour-berlin-airlift-more-t23776/reviews.json

As the referencing tour is already path encoded the payload only needs to consist of the attributes of the review.

• 'rating' as float value
• 'title' as String
• 'message' as String
• 'reviewerName' as String

If the user needs to be logged in or authenticated to write a review one could use the 'reviewerName', 'languageCode', 'traveler_type' from the profile. Otherwise language code could be set by analyzing the language of the title/message and the country could be determined by the ip address or by using the location of the phone. The 'author' attribute is a concatenation of 'reviewerName' and 'reviewerCountry'. The date attribute can be determined based on the server time.

###Improvements

• Create view model for SubmitReviewActivity
• Create UI states for SubmitReviewActivity like Submitting, Success, Failure
• Separate api model from app model by creating higher level models (e.g. don't use api Review model in UI)
• Add (remote) logging of error cases
• Parse dates and show them according to the local date format
• Add input validation for review submission

###Challenge improvements

• Test whether API call works in Android environment (Cloudflare dosn't seem to accept slashes "/" in the User-Agent and returns a 403 html page)
• Define what offline functionality means