DiffUtil

About DiffUtil in Kanmoba #17

Transcript

1. DiffUtil @takuji31
2. @takuji31 (Takuji Nishibayashi) Application Engineer at Hatena
3. Loves ! (AVG 160 ~ 170)
4. Loves Kotlin
5. Kansai.kt #2 ΍Γ·͢
6. 11݄ͷͲ͔͜ͷ౔༵೔ (༧ఆ)
7. ࠷ۙ͸Perlͱ TypeScriptॻ͍ͯ·͢
8. AGENDA • DiffUtilͱ͸ • ࢖ͬͯΈΔ • ੍ݶࣄ߲
9. DiffUtilͱ͸
10. 2ͭͷListͷࠩ෼Λܭࢉ͢ ΔϢʔςΟϦςΟʔɻ
11. recyclerview-v7 24.2.0 ~
12. ܭࢉͰ͖Δมߋ • ௥Ճ • ࡟আ • ߋ৽ • Ҡಈ • Φϓγϣϯࢦఆ • ܭࢉίετ͕௓Ͷ্͕Δ
13. 2ͭͷΫϥε • DiffUtil.Callback • DiffUtil.DiffResult
14. DiffUtil.Callback
15. มԽΛDiffUtilʹ఻͑Δ Callback
16. DiffUtil.Callback • getNewListSize() • getOldListSize() • areItemsTheSame(int, int) • areContentsTheSame(int, int) • getChangePayload(int, int)
17. DiffUtil.DiffResult
18. ܭࢉͨ͠diffͷ݁Ռ
19. DiffResult.dispatchUp datesTo(RecyclerView .Adapter| ListUpdateCallback)
20. ࢖ͬͯΈΔ
21. ※͍ͭ΋௨ΓKotlinͰ͢
22. build.gradle dependencies { compile 'com.android.support:recyclerview-v7:24.2.0' }
23. Model enum class Status { INTERESTED, LIKE, LOVE; } data class Artist(val name: String, val status: Status) { companion object { val list: List<Artist> = listOf( Artist(name = "খ૔།", status = LOVE), Artist(name = "Ӎٶఱ", status = LOVE), //... ) } }
24. DiffUtil.Callback class DiffCallback( val oldList: List<Artist>, val newList: List<Artist>) : DiffUtil.Callback() { override fun areItemsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean { return oldList[oldItemPosition].name == newList[newItemPosition].name } override fun getOldListSize(): Int { return oldList.size } override fun getNewListSize(): Int { return newList.size } override fun areContentsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean { return oldList[oldItemPosition] == newList[newItemPosition] } override fun getChangePayload( oldItemPosition: Int, newItemPosition: Int): Pair<Status, Status> { return Pair(oldList[oldItemPosition].status, newList[newItemPosition].status) } }
25. diffΛܭࢉ͢Δ fun updateItems(items : List<Artist>) { val oldItems = adapter.items val diffResult = DiffUtil.calculateDiff( DiffCallback( oldList = oldItems, newList = items ), true ) adapter.items = items diffResult.dispatchUpdatesTo(adapter) }
27. RecylerViewҎ֎ͱ૊ Έ߹Θ͍ͤͨ
28. Change payloadͷத਎ ΛݟͯԿ͔͍ͨ͠ɺͳͲ ͱ͍ͬͨ৔߹͸
29. ListUpdateCallbackΛ ࢖͏
30. ੍ݶࣄ߲ • ৽͍͠Listͱݹ͍ListΛൺֱ͢Δ • × MutableͳList • RealmCollection • × ཁૉͦͷ΋ͷ͕ߋ৽͞ΕΔ • RealmObject • Listͷཁૉ਺͸2^26(=67108864)·Ͱ
31. ·ͱΊ • DiffUtil Λ࢖͏͜ͱͰ RecylerView ΁ͷৄࡉͳߋ৽௨஌͕ ָʹͳΔ • RecylerView Ҏ֎ͱͷ૊Έ߹ΘͤͳͲڽͬͨ͜ͱΛ΍Γ͍ͨ ࣌͸ ListUpdateCallback Λ࢖͏
32. takuji31/ DiffUtilSample
33. enjoy diff life !