`Day30` - Finished Lesson 8 ◦ Actually got qui...

# 100daysofkotlin-2021

[JungIn Choi]

Day30
• Finished Lesson 8
◦ Actually got quite stuck with data binding & binding adapter part, so this part was a bottleneck. What goes around comes around^^.. I just hastily crammed it, and from some point I got puzzled, so I had to spend some time re-catching the flow.
◦ Parcel, Parcelables, Adding filter
• Start Lesson 9
◦ Network caching (Storing network results on disk, http caching, caching results per query etc.)
▪︎ Issue: Cache invalidation (outdated / modified ..)
▪︎ Solution : Using SQL&_Room_ db for caching!
• Other options: _SharedPreferences_(Only in key-value form, writing to disk only for small data, with no query support), _Files_(Flexible but too flexible..have to manage all those)
• (Getting data from server to app) Server --> DB --> app (Always showing data from the db!)
• (Updating data from app to server) app --> Server --> DB
◦ Room methods, DAO
▪︎ @ Query @ Insert @ Upsert
▪︎ conflict strategy should be specified (what to do if inserting data’s key already exists - ex. upsert)
◦ Data objects - 1) Domain object 2) Data transfer object 3) Database object (--> entirely for interacting with database)
Self-Comment
• Daytime was blew off - I still don’t understand why I have to wait hours at hospital in 21 century
• Thursday will be Day1 of my internship. Looking forward to it, there seems lot to do / lot to learn / lot to study.
• Didn’t sleep well yesterday. Was hard to focus at evening. To be honest, so I wasn’t in a good mood today. Hospital thing and many other things were quite troublesome, but just settled down and made the minimum progress.
Goals Tomorrow
• Finish lesson9
• Hopefully move into lesson10
• Look more into data binding

[JungIn Choi]

Memos
• (recap) RecyclerView adapter - Item, Viewholder, DiffUtil callback should be passed
• === (triple equal sign) compares the object references
• (recap)onCreateView in Fragment - inflate layout using data binding, set the lifecycle owner to itself to observe the live data in ViewModel, set up RecyclerView with adapter
• (recap) companion object become included to the namespace of the parent class
• (recap) Android Bundle - Parcelable object that contains key-value