Tomato-Sandwich

Github repo: Link: https://github.com/Wesely/tomato-sandwich SSH: git@github.com:Wesely/tomato-sandwich.git

Thank you for taking your time to review this project :)

I uphold the spirit of "keeping it simple". When encountering complex logic, I skip it for the time being and jot it down in the Misc section at the end of this document. Sometimes, I opt for a more humorous approach. :)

Web version of this documentation? Check it out here.

I use a GitHub project to make my plans. They're not very detailed but I've included previews in each step. Check out the project here.

Setup

Example Image:

1. Match the Java version in AndroidStudio. Go to Settings and search for Gradle.
2. Under Gradle, set the Gradle JDK to Java 17 (example: jbr-17).
3. Currently can build with Android Studio > Build > Build APK

Basic Architecture

Example Image:

• This app contains only 1 Activity with 5 Fragment and managed by reservation_nav.xml
• Data are shared with ViewModels between all Fragment
• All ViewModels manipulates data through the same ReservationRepository instance, injected by Hilt
• All Views, or saying Fragments collects or access the immutable data exposed by ViewModels
• So when ever any data is modified, all Fragments can get the same result.

Thoughts When I'm making decision

Some of them might not used in the end.

• This time, I want to try Fragments with a navigation flow (Main, ViewDetails, SelectTime, PartySize, Details).
  • They could share the same viewModel or maybe a Reservation object.
  • I'm probably going to add/get reservation as two different viewModels later.
• The time slots need to be sorted.
  • I thought about writing them to RoomDB and querying them (sorted) as a flow.
  • But for simplicity, I'll use SortedSet<Reservation> here. Since it can't duplicate and needs to be sorted by time, it's an interesting choice.
• Reservations last for an hour:
  • We assume we don't need to clean the table.
  • Actually, I know I can just store them as String, and for each timeSlot is booked, mark the 3 slot ahead and 3 slot after as not available.
  • But I came up with a fun implementation, which is to store the time "03:30 PM" as "Integer(1530)". It would make calculating the time difference easy.
  • By doing this, I can use (time - other.time) >= 0 && (time - other.time) <= 85 to check if it's occupied by another reservation. This 85 stands for 1 hour minus 15 minutes => 100 -15 = 85.
  • It's tested in fun testIsOccupiedBy() and works fine.
  • The format converter is also simple: hour = time / 100 minutes = time % 100.
• I wrapped the Vertical LinearLayout of the detail inputs in a scrollView for smaller devices.
  • Because when the soft keyboard appears, the screen space becomes even smaller.
  • Sometimes when we're typing we'd like to scroll a bit, so I added trailing space at the bottom of the DetailInput page.
• The application handles configuration changes (like screen rotation).
• With lifecycleScope we don't need to worry about the recycle in the background. Or we can assign the active lifecycle like launchWhenResumed ...which I didn't do.

Misc

• I used a delegate for the viewModel private val reservationViewModel: ReservationViewModel by viewModels().
  • It's said that this delegate will bind your viewModel correctly with the Activity's lifecycle.
• There's no way to cancel the appointment, oh wait, users can close the app :rofl.
• I looked into attr and picked some colors as the theme. But I didn't check if it's working properly this time, haha.
• I should have used notifyItemRangeChanged() instead of notifyDataSetChanged().
• For the PartySize, there are only 5 buttons so I generated 5 buttons programmatically and put them into the ScrollView.
• I used Timber.d() to print logs only on debug builds.
• I could have used TextSpan to make the Reservation Details look better, but I didn't.
• I'm not setting all dimensions to dimens.xml.
• Wanted to import some viewBinding delegates so I don't have to clean them up.