Jetpack Compose State Practices

記事版
https://qiita.com/takahirom/items/862f3c607850ce524744
English version
https://medium.com/@takahirom/inside-jetpack-compose-2e971675e55e

Transcript

1. Jetpack Compose State Practices takahirom
2. ࣗ෼ʹ͍ͭͯɹ takahirom • Takahiro Menju • Androidʹؔ͢Δٕज़͕޷͖ • DroidKaigi co-organizer • Google Developers Expert for Android • CyberAgent.Inc ABEMA • Twitter takahirom (@new_runnable) • GitHub takahirom
3. ࠓ೔ͷࢿྉʹ͍ͭͯ ҎԼͷURLͰ΋֬ೝͰ͖·͢ɻ https://qiita.com/takahirom/items/862f3c607850ce524744 (೔ຊޠ) https://medium.com/@takahirom/jetpack-compose-state-guideline-494d467b6e76 (ӳޠ൛) https://d.android.com/jetpack/compose?hl=ja
4. Jetpack Composeͱ͸ʁ “Jetpack Compose ͸ɺωΠςΟϒ UI ΛϏϧυ͢ΔͨΊͷ Android ͷ࠷৽πʔϧΩοτ Ͱ͢ɻAndroid ͷ UI ։ൃΛ؆ૉԽ͠ɺՃ଎͠·͢ɻগͳ͍ίʔυɺύϫϑϧͳπʔϧɺ ௚ײతͳ Kotlin API Λ࢖༻ͯ͠ΞϓϦΛ͙͢ʹಈ͔͢͜ͱ͕Ͱ͖·͢ɻ” https://d.android.com/jetpack/compose?hl=ja
5. Jetpack ComposeΛগ͠ݟͯΈΔ @Composable fun HelloWorld(){ Column { Text(text = "Hello") Text(text = "World") } }
6. ࣮ࡍͷΞϓϦέʔγϣϯ͸ɻɻʁ android/compose-samplesʹ͸ ࢀߟʹͳΔJetpack Composeͷαϯϓϧ͕ͨ͘͞Μ͋Γ·͢ https://github.com/android/compose-samples
7. ࣮ࡍͷΞϓϦέʔγϣϯ͸ɻɻʁ
8. ࣮ࡍͷΞϓϦέʔγϣϯ͸ɻɻʁ
9. ࣮ࡍͷΞϓϦέʔγϣϯ͸ɻɻʁ ViewModelͷStateΛݟΔ
10. ࣮ࡍͷΞϓϦέʔγϣϯ͸ɻɻʁ ViewModelͷStateΛݟΔ ComposableͷதͰStateΛอ࣋
11. ࣮ࡍͷΞϓϦέʔγϣϯ͸ɻɻʁ ViewModelͷStateΛݟΔ ComposableͷதͰStateΛอ࣋ State = ঢ়ଶͱ͸ʁ “࣌ؒͱͱ΋ʹมԽ͢ΔՄೳੑ͕͋Δ஋͢΂ͯ” ࣮ࡍͷΞϓϦέʔγϣϯͰ͸ComposeͰͳͯ͘΋ StateʹΑͬͯσʔλͷදࣔͳͲΛߦ͏ https://developer.android.com/jetpack/compose/state?hl=ja
12. Jetpack ComposeΛ࣮ࡍʹಋೖ͍ͯͨ͘͠Ίʹ جຊతͳJetpack Composeͷॻ͖ํ͸ͳΜͱͳ͘෼͔͕ͬͨɺ࣮ࡍJetpack ComposeͰͲ͏ॻ͍ ͍ͯͬͨΒ͍͍ͷ͔ʁ ԿΛ͢Δ΂͖ͰԿΛ͢Δ΂͖Ͱ͸ͳ͍ͷ͔ʁ
13. Jetpack ComposeΛ࣮ࡍʹಋೖ͍ͯͨ͘͠Ίʹ جຊతͳJetpack Composeͷॻ͖ํ͸ͳΜͱͳ͘෼͔͕ͬͨɺ࣮ࡍJetpack ComposeͰͲ͏ॻ͍ ͍ͯͬͨΒ͍͍ͷ͔ʁ ԿΛ͢Δ΂͖ͰԿΛ͢Δ΂͖Ͱ͸ͳ͍ͷ͔ʁ Stateͷѻ͍ํʹ͍ͭͯ͜ͷAndroid Dev SummitͷηογϣϯͰ
 ͔ͳΓ·ͱ·͍ͬͯ·͕͢
 DO DON’TͷܗࣜͰ͸ͳ͘ɺ
 ͋·Γ޿·͍ͬͯͳ͍ͷͰɻ
 ͦΕΛϦετԽͯ͠঺հ͍͖ͯ͠·͢ɻ https://www.youtube.com/watch?v=rmv2ug-wW4U
14. Jetpack ComposeͷStateͷجຊ
15. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ
16. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ❌ DON’T (μϝͳྫ)
17. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ❌ DON’T (μϝͳྫ)
18. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ❌ DON’T (μϝͳྫ) Kotlinͷม਺Λએݴ
19. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ❌ DON’T (μϝͳྫ) Kotlinͷม਺Λએݴ ͦͷม਺Λ࢖ͬͯSwitchΛදࣔ
20. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ❌ DON’T (μϝͳྫ) Kotlinͷม਺Λએݴ ͦͷม਺Λ࢖ͬͯSwitchΛදࣔ ม਺Λมߋ
21. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ❌ DON’T มߋ͕൓ө͞ΕͣɻεΠονͱͯ͠ಈ࡞͠ͳ͍ 😭
22. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ❌ DON’T มߋ͕൓ө͞ΕͣɻεΠονͱͯ͠ಈ࡞͠ͳ͍ 😭
23. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ❌ DON’T ⭕ DO
24. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ❌ DON’T ⭕ DO
25. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ❌ DON’T ⭕ DO MutableStateͰ஋Λอ͍࣋ͯ͠Δ
26. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ❌ DON’T ⭕ DO MutableStateͰ஋Λอ͍࣋ͯ͠Δ MutableStateͷvalueʹΞΫηε
27. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ❌ DON’T ⭕ DO MutableStateͰ஋Λอ͍࣋ͯ͠Δ MutableStateͷvalueʹΞΫηε MutableStateͷvalueΛมߋ
28. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ⭕ DO
29. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ⭕ DO
30. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ⭕ DO ͳͥ͏·͘ಈ͘ͷ͔ʁ
31. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ͳͥDOͷྫ͸͏·͘ಈ͘ͷ͔ʁ println()Λ௥Ճͯ֬͠ೝͯ͠ΈΔ ⭕ DO + println()
32. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ͳͥDOͷྫ͸͏·͘ಈ͘ͷ͔ʁ DOͷྫͰ͸MySwitch()͕΋͏Ұ౓ಈ͔͘Β൓ө͞Ε͍ͯΔɻ ⭕ DO + println()
33. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ͳͥDOͷྫ͸͏·͘ಈ͘ͷ͔ʁ DOͷྫͰ͸MySwitch()͕΋͏Ұ౓ಈ͔͘Β൓ө͞Ε͍ͯΔɻ ⭕ DO + println()
34. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ͳͥDOͷྫ͸͏·͘ಈ͘ͷ͔ʁ DOͷྫͰ͸MySwitch()͕΋͏Ұ౓ಈ͔͘Β൓ө͞Ε͍ͯΔɻ ͳͥMySwitch()͸΋͏Ұ౓ಈ͘ͷ͔ʁ ⭕ DO + println()
35. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ͳͥMySwitch()͸΋͏Ұ౓ಈ͘ͷ͔ʁ ΄Μͷগ͚ͩ͠ίʔυΛݟͯΈ·͠ΐ͏ MutableStateͷ࣮૷
36. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ͳͥMySwitch()͸΋͏Ұ౓ಈ͘ͷ͔ʁ ΄Μͷগ͚ͩ͠ίʔυΛݟͯΈ·͠ΐ͏ MutableStateͷ࣮૷ Ͳ͏΍ΒΧελϜήολʔ͕
 ࣮૷͞Ε͍ͯͦ͏ʁ🕵
37. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ͳͥMySwitch()͸΋͏Ұ౓ಈ͘ͷ͔ʁ ࣮͸Jetpack ComposeͰ͸StateͷಡΈࠐΈ͕ ؂ࢹ͞Ε͓ͯΓɺ
38. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ͳͥMySwitch()͸΋͏Ұ౓ಈ͘ͷ͔ʁ ࣮͸Jetpack ComposeͰ͸StateͷಡΈࠐΈ͕ ؂ࢹ͞Ε͓ͯΓɺ Jetpack Compose͸MutableStateʹ
 ରͯ͠ಡΈࠐΈͨ͠Composableؔ਺ Λอ͍࣋ͯ͠ΔͨΊɺ
39. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ͳͥMySwitch()͸΋͏Ұ౓ಈ͘ͷ͔ʁ ࣮͸Jetpack ComposeͰ͸StateͷಡΈࠐΈ͕ ؂ࢹ͞Ε͓ͯΓɺ Jetpack Compose͸MutableStateʹ
 ରͯ͠ಡΈࠐΈͨ͠Composableؔ਺ Λอ͍࣋ͯ͠ΔͨΊɺ Compose͸MutableState͕มߋ͞Εͨͱ͖ʹ StateΛಡΈࠐΜͰ͍ΔComposableؔ਺Λݺͼ ग़͠·͢ɻ(ྫ֎͕͋Γগ͠ਖ਼֬Ͱ͸ͳ͍ͷͰ͕͢େମͦ͏Ͱ͢)
40. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ͳͥMySwitch()͸΋͏Ұ౓ಈ͘ͷ͔ʁ ࣮͸Jetpack ComposeͰ͸StateͷಡΈࠐΈ͕ ؂ࢹ͞Ε͓ͯΓɺ Compose͸MySwitch()͕MutableState.valueΛಡΜͩ͜ͱΛ஌͍ͬͯΔਤ Jetpack Compose͸MutableStateʹ
 ରͯ͠ಡΈࠐΈͨ͠Composableؔ਺ Λอ͍࣋ͯ͠ΔͨΊɺ Compose͸MutableState͕มߋ͞Εͨͱ͖ʹ StateΛಡΈࠐΜͰ͍ΔComposableؔ਺Λݺͼ ग़͠·͢ɻ(ྫ֎͕͋Γগ͠ਖ਼֬Ͱ͸ͳ͍ͷͰ͕͢େମͦ͏Ͱ͢)
41. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ͭ·ΓͲ͏͢Ε͹͍͍ͷ͔ʁ ⭕ DO
42. Practice1: දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ ͞ΕΔΑ͏ʹ͢Δ ͭ·ΓͲ͏͢Ε͹͍͍ͷ͔ʁ ⭕ DO ComposeͰ͸MutableStateͳͲͷ ComposeͷStateΛ࢖͏͜ͱʹΑΓ ComposeʹΑͬͯStateͷมߋΛ
 ؍ଌͰ͖ΔΑ͏ʹ͠Α͏
43. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍
44. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ ❌ DON’T ⭕ DO
45. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ ❌ DON’T ⭕ DO remember{}Λ࢖͍ͬͯΔ
46. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ ❌ DON’T ⭕ DO remember{}Λ࢖͍ͬͯΔ remember{}Λ࢖͍ͬͯͳ͍
47. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ ❌ DON’T ⭕ DO DON’TͰ͸ಉ༷ʹMutableState࢖͍ͬͯΔͷʹಈ͔ͳ͍ʂͳͥʁʁ
48. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ ❌ DON’T ⭕ DO DON’TͰ͸ಉ༷ʹMutableState࢖͍ͬͯΔͷʹಈ͔ͳ͍ʂͳͥʁʁ
49. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ ❌ DON’T ಉ༷ʹprintln()Λ௥Ճͯ֬͠ೝΈΔ
50. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ ❌ DON’T ͪΌΜͱλοϓͷλΠϛϯάͰMySwitch()͕
 Ͳ͏΍Βಈ͍ͯ͸͍ͦ͏ʁʁͳͥಈ͔ͳ͍ʁʁ
51. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ ❌ DON’T ͪΌΜͱλοϓͷλΠϛϯάͰMySwitch()͕
 Ͳ͏΍Βಈ͍ͯ͸͍ͦ͏ʁʁͳͥಈ͔ͳ͍ʁʁ
52. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ ❌ DON’T Ͳ͏΍ΒMySwitch͕ݺͼग़͞Ε௚ͨ͢ͼʹ MutableStateͷΠϯελϯε͕࡞Γ௚͞Ε͍ͯͦ͏ʂ
53. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ Ͳ͏΍Βremember{}͢ΔͱͲ͔͜ʹอଘ͞ΕΔΒ͍͕͠Ͳ͜ʹอଘ͞ΕΔͷ͔ʁ
54. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ Ͳ͏΍Βremember{}͢ΔͱͲ͔͜ʹอଘ͞ΕΔΒ͍͕͠Ͳ͜ʹอଘ͞ΕΔͷ͔ʁ Compositionʹอ࣋͞ΕΔ
55. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ Ͳ͏΍Βremember{}͢ΔͱͲ͔͜ʹอଘ͞ΕΔΒ͍͕͠Ͳ͜ʹอଘ͞ΕΔͷ͔ʁ Compositionʹอ࣋͞ΕΔ Compositionͱ͸ͳʹ͔ʁʁ
56. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ Ͳ͏΍Βremember{}͢ΔͱͲ͔͜ʹอଘ͞ΕΔΒ͍͕͠Ͳ͜ʹอଘ͞ΕΔͷ͔ʁ “Composition”Λཧղ͠Α͏ Composableؔ਺ https://developer.android.com/jetpack/compose/lifecycle?hl=en#composition-anatomy
57. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ Ͳ͏΍Βremember{}͢ΔͱͲ͔͜ʹอଘ͞ΕΔΒ͍͕͠Ͳ͜ʹอଘ͞ΕΔͷ͔ʁ “Composition”Λཧղ͠Α͏ Composableؔ਺ https://developer.android.com/jetpack/compose/lifecycle?hl=en#composition-anatomy
58. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ Ͳ͏΍Βremember{}͢ΔͱͲ͔͜ʹอଘ͞ΕΔΒ͍͕͠Ͳ͜ʹอଘ͞ΕΔͷ͔ʁ “Composition”Λཧղ͠Α͏ Composition Composableؔ਺ https://developer.android.com/jetpack/compose/lifecycle?hl=en#composition-anatomy
59. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ Ͳ͏΍Βremember{}͢ΔͱͲ͔͜ʹอଘ͞ΕΔΒ͍͕͠Ͳ͜ʹอଘ͞ΕΔͷ͔ʁ “Composition”Λཧղ͠Α͏ Compose͸࣮ߦ࣌ʹComposableؔ਺Λ࣮ߦ͢Δ͜ͱʹΑͬͯɺ
 “Composition”Λߏ੒͢Δʂ Composition Composableؔ਺ https://developer.android.com/jetpack/compose/lifecycle?hl=en#composition-anatomy
60. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ Ͳ͏΍Βremember{}͢ΔͱͲ͔͜ʹอଘ͞ΕΔΒ͍͕͠Ͳ͜ʹอଘ͞ΕΔͷ͔ʁ “Composition”Λཧղ͠Α͏ ❌ DON’T
61. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ Ͳ͏΍Βremember{}͢ΔͱͲ͔͜ʹอଘ͞ΕΔΒ͍͕͠Ͳ͜ʹอଘ͞ΕΔͷ͔ʁ “Composition”Λཧղ͠Α͏ Composition ❌ DON’T remember͍ͯ͠ͳ͍ͷͰɺ CompositionͰMutableState͕อ࣋͞Ε͍ͯͳ͍
62. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ Ͳ͏΍Βremember{}͢ΔͱͲ͔͜ʹอଘ͞ΕΔΒ͍͕͠Ͳ͜ʹอଘ͞ΕΔͷ͔ʁ “Composition”Λཧղ͠Α͏ ⭕ DO
63. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ Ͳ͏΍Βremember{}͢ΔͱͲ͔͜ʹอଘ͞ΕΔΒ͍͕͠Ͳ͜ʹอଘ͞ΕΔͷ͔ʁ “Composition”Λཧղ͠Α͏ Composition CompositionͰMutableState͕อ࣋͞ΕΔ ⭕ DO
64. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ remember͸࣮ࡍԿΛߦ͏ͷ͔ʁ A value computed by remember is stored in the Composition during initial composition, and the stored value is returned during recomposition. https://d.android.com/jetpack/compose/state#state-in-composables remember{}ͷ஋͸Compositionʹอ࣋͞ΕɺͦΕ͕࣍ͷݺͼग़͠Ͱ࢖ΘΕΔ
65. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ ❌ DON’T ⭕ DO ͭ·ΓͲ͏͢Ε͹͍͍ͷ͔ʁ
66. Practice2: ComposableͷதͰ࡞ΒΕͨState͸ remember͞Εͳ͚Ε͹ͳΒͳ͍ ❌ DON’T ⭕ DO MutableState͕CompositionͰอ࣋͞ΕΔΑ͏ʹrememberΛ࢖͓͏ ͭ·ΓͲ͏͢Ε͹͍͍ͷ͔ʁ
67. Practice3: State΁ͷΞΫηε͸KotlinͷDelegated PropertyΛ࢖͓͏
68. Practice3: State΁ͷΞΫηε͸KotlinͷDelegated PropertyΛ࢖͓͏ ❌ DON’T ⭕ DO
69. Practice3: State΁ͷΞΫηε͸KotlinͷDelegated PropertyΛ࢖͓͏ ❌ DON’T ⭕ DO KotlinͷDelegated Propertyͷ“by”Λ࢖͍ͬͯΔ
70. Practice3: State΁ͷΞΫηε͸KotlinͷDelegated PropertyΛ࢖͓͏ ❌ DON’T ⭕ DO KotlinͷDelegated Propertyͷ“by”Λ࢖͍ͬͯΔ valͰ͸ͳ͘มߋՄೳͳvarΛ࢖͍ͬͯΔ
71. Practice3: State΁ͷΞΫηε͸KotlinͷDelegated PropertyΛ࢖͓͏ ❌ DON’T ⭕ DO KotlinͷDelegated Propertyͷ“by”Λ࢖͍ͬͯΔ “.value”Λ࢖Θͣͱ΋valueʹΞΫηεͰ͖Δ valͰ͸ͳ͘มߋՄೳͳvarΛ࢖͍ͬͯΔ
72. Practice3: State΁ͷΞΫηε͸KotlinͷDelegated PropertyΛ࢖͓͏ ⭕ DO
73. Practice3: State΁ͷΞΫηε͸KotlinͷDelegated PropertyΛ࢖͓͏ ⭕ DO ͳͥʁ ୯७ʹStateͷvalue΁ͷΞΫηεΛ
 ҙࣝ͠ͳͯ͘ྑ͘ͳΔͨΊɻ
74. Practice3: State΁ͷΞΫηε͸KotlinͷDelegated PropertyΛ࢖͓͏ ⭕ DO ͳͥʁ ୯७ʹStateͷvalue΁ͷΞΫηεΛ
 ҙࣝ͠ͳͯ͘ྑ͘ͳΔͨΊɻ ஫ҙ఺⚠ ҎԼͷimport͕ͳ͍ͱಈ͔ͳ͍ͷͰ஫ҙʂ import androidx.compose.runtime.getValue import androidx.compose.runtime.setValue
75. Practice4: Stateͷมߋ͸Composableؔ਺ͷείʔϓ಺ Ͱߦͬͯ͸ͳΒͳ͍
76. Practice4: Stateͷมߋ͸Composableؔ਺ͷείʔϓ಺ Ͱߦͬͯ͸ͳΒͳ͍ ⭕ DO ❌ DON’T
77. Practice4: Stateͷมߋ͸Composableؔ਺ͷείʔϓ಺ Ͱߦͬͯ͸ͳΒͳ͍ ⭕ DO ❌ DON’T Composableؔ਺಺ͰMutableStateͷมߋʂ
78. Practice4: Stateͷมߋ͸Composableؔ਺ͷείʔϓ಺ Ͱߦͬͯ͸ͳΒͳ͍ ⭕ DO ❌ DON’T มߋ࣌ʹMySwitch()͕ݺͼग़͞ΕΔͷͰɺMySwitch()͕
 ແݶʹݺͼग़͠௚͞Εͯ͠·͏ɻ😂
79. Practice4: Stateͷมߋ͸Composableؔ਺ͷείʔϓ಺ Ͱߦͬͯ͸ͳΒͳ͍ ❌ DON’T ͭ·ΓͲ͏͢Ε͹͍͍ͷ͔ʁ https://d.android.com/jetpack/compose/side-effects
80. Practice4: Stateͷมߋ͸Composableؔ਺ͷείʔϓ಺ Ͱߦͬͯ͸ͳΒͳ͍ ❌ DON’T λΠτϧͷ··”Stateͷมߋ͸Composableؔ਺ͷείʔϓ ಺Ͱߦͬͯ͸ͳΒͳ͍” ͭ·ΓͲ͏͢Ε͹͍͍ͷ͔ʁ https://d.android.com/jetpack/compose/side-effects
81. Practice4: Stateͷมߋ͸Composableؔ਺ͷείʔϓ಺ Ͱߦͬͯ͸ͳΒͳ͍ ❌ DON’T λΠτϧͷ··”Stateͷมߋ͸Composableؔ਺ͷείʔϓ ಺Ͱߦͬͯ͸ͳΒͳ͍” `onCheckedChange`ʹ౉͍ͯ͠ΔϥϜμ͸Composableؔ ਺Ͱ͸ͳ͍ͷͰComposableؔ਺ͷείʔϓ֎ͷͨΊɺมߋ ͯ͠΋҆શͰ͢ɻ ͭ·ΓͲ͏͢Ε͹͍͍ͷ͔ʁ https://d.android.com/jetpack/compose/side-effects
82. Practice4: Stateͷมߋ͸Composableؔ਺ͷείʔϓ಺ Ͱߦͬͯ͸ͳΒͳ͍ ❌ DON’T λΠτϧͷ··”Stateͷมߋ͸Composableؔ਺ͷείʔϓ ಺Ͱߦͬͯ͸ͳΒͳ͍” `onCheckedChange`ʹ౉͍ͯ͠ΔϥϜμ͸Composableؔ ਺Ͱ͸ͳ͍ͷͰComposableؔ਺ͷείʔϓ֎ͷͨΊɺมߋ ͯ͠΋҆શͰ͢ɻ `MySwitch()`͕Compositionʹೖͬͨͱ͖΍ग़ͨͱ͖ʹState Λมߋ͍ͨ͠৔߹͸ɺLaunchedEffectͳͲͷSideEffectͷؔ ਺ͷར༻Λݕ౼͠·͠ΐ͏ɻ ͭ·ΓͲ͏͢Ε͹͍͍ͷ͔ʁ https://d.android.com/jetpack/compose/side-effects
83. Jetpack ComposeͷStateͷجຊ·ͱΊ දࣔ͢ΔStateͷมߋ͸ComposeʹΑͬͯ؍ଌ͞ΕΔΑ͏ʹ͢Δ ComposableͷதͰ࡞ΒΕͨState͸remember͞Εͳ͚Ε͹ͳΒͳ͍ State΁ͷΞΫηε͸KotlinͷDelegated PropertyΛ࢖͓͏ Stateͷมߋ͸Composableؔ਺ͷείʔϓ಺Ͱߦͬͯ͸ͳΒͳ͍ 01 02 03 04
84. Jetpack ComposeͷState؅ཧͷϓϥΫςΟε
85. Practice5: State hoistingͰComposableؔ਺Λ࠶ར༻Մ ೳͰςετՄೳʹ͠Α͏
86. Practice5: State hoistingͰComposableؔ਺Λ࠶ར༻Մ ೳͰςετՄೳʹ͠Α͏ ⭕ DO ❌ DON’T
87. Practice5: State hoistingͰComposableؔ਺Λ࠶ར༻Մ ೳͰςετՄೳʹ͠Α͏ ⭕ DO ❌ DON’T DON’T͸Ҿ਺ͳ͠
88. Practice5: State hoistingͰComposableؔ਺Λ࠶ར༻Մ ೳͰςετՄೳʹ͠Α͏ ⭕ DO ❌ DON’T DON’T͸Ҿ਺ͳ͠ ݺͼग़͠ઌͰ
 StateΛ͍࣋ͬͯΔ
89. Practice5: State hoistingͰComposableؔ਺Λ࠶ར༻Մ ೳͰςετՄೳʹ͠Α͏ ⭕ DO ❌ DON’T DON’T͸Ҿ਺ͳ͠ DO͸Ҿ਺Λ౉ͯ͠ɺ ϥϜμ΋౉͢ ݺͼग़͠ઌͰ
 StateΛ͍࣋ͬͯΔ
90. Practice5: State hoistingͰComposableؔ਺Λ࠶ར༻Մ ೳͰςετՄೳʹ͠Α͏ ⭕ DO ❌ DON’T DON’T͸Ҿ਺ͳ͠ DO͸Ҿ਺Λ౉ͯ͠ɺ ϥϜμ΋౉͢ ݺͼग़͠ݩͰ
 StateΛ͍࣋ͬͯΔ ݺͼग़͠ઌͰ
 StateΛ͍࣋ͬͯΔ
91. Practice5: State hoistingͰComposableؔ਺Λ࠶ར༻Մ ೳͰςετՄೳʹ͠Α͏ ⭕ DO ❌ DON’T
92. Practice5: State hoistingͰComposableؔ਺Λ࠶ར༻Մ ೳͰςετՄೳʹ͠Α͏ ⭕ DO ❌ DON’T DON’TͰ΋ಈ͘͠ྑ͍ͷͰ͸ʁʁͦ΋ͦ΋State hoistingͱ͸ʁʁ
93. Practice5: State hoistingͰComposableؔ਺Λ࠶ར༻Մ ೳͰςετՄೳʹ͠Α͏ ⭕ DO State hoistingͱ͸ʁ StateΛ্ʹ্͛Δ͜ͱͰɺίϯϙʔωϯτ ΛStatelessʹ͢Δύλʔϯ

94. Practice5: State hoistingͰComposableؔ਺Λ࠶ར༻Մ ೳͰςετՄೳʹ͠Α͏ ⭕ DO State hoistingͱ͸ʁ StateΛ্ʹ্͛Δ͜ͱͰɺίϯϙʔωϯτ ΛStatelessʹ͢Δύλʔϯ
 Composableؔ਺ʹదԠ͢Δ৔߹͸͍͍ͩͨ ҎԼ2ͭͷҾ਺Λಋೖ͢Δ͜ͱΛҙຯ͢Δ value: T දࣔ͢Δσʔλ onValueChange: (T) -> Unit ஋ͷมߋΛཁ ٻ͢ΔΠϕϯτ
95. Practice5: State hoistingͰComposableؔ਺Λ࠶ར༻Մ ೳͰςετՄೳʹ͠Α͏ ⭕ DO State hoistingͱ͸ʁ StateΛ্ʹ্͛Δ͜ͱͰɺίϯϙʔωϯτ ΛStatelessʹ͢Δύλʔϯ
 DON’TͰ΋ಈ͘͠ྑ͍ͷͰ͸ʁʁ Composableؔ਺ʹదԠ͢Δ৔߹͸͍͍ͩͨ ҎԼ2ͭͷҾ਺Λಋೖ͢Δ͜ͱΛҙຯ͢Δ value: T දࣔ͢Δσʔλ onValueChange: (T) -> Unit ஋ͷมߋΛཁ ٻ͢ΔΠϕϯτ
96. Practice5: State hoistingͰComposableؔ਺Λ࠶ར༻Մ ೳͰςετՄೳʹ͠Α͏ ྫ͑͹ɺ͜Ε͕ઃఆը໘ͩͬͨΒɺ ࠓͷอଘ͞Ε͍ͯΔઃఆΛ౉ͤΔඞཁ͕͋ Γ·͕͢ɺ Ҿ਺͕ͳ͍ͱ౉ͤͳ͍Ͱ͢ΑͶʁʁ ಉ༷ʹ಺෦ʹঢ়ଶΛ࣋ͭͷͰɺ
 ςετ΋೉͘͠ͳΓ·͢ɻ DON’Tͷॻ͖ํͰ΋ಈ͘͠ྑ͍ͷͰ͸ʁʁ ❌ DON’T
97. Practice5: State hoistingͰComposableؔ਺Λ࠶ར༻Մ ೳͰςετՄೳʹ͠Α͏ ྫ͑͹ɺ͜Ε͕ઃఆը໘ͩͬͨΒɺ ࠓͷอଘ͞Ε͍ͯΔઃఆΛ౉ͤΔඞཁ͕͋ Γ·͕͢ɺ Ҿ਺͕ͳ͍ͱ౉ͤͳ͍Ͱ͢ΑͶʁʁ ಉ༷ʹ಺෦ʹঢ়ଶΛ࣋ͭͷͰɺ
 ςετ΋೉͘͠ͳΓ·͢ɻ DON’Tͷॻ͖ํͰ΋ಈ͘͠ྑ͍ͷͰ͸ʁʁ ❌ DON’T
98. Practice6: State hoistingͰSingle source of truthʹ͠Α͏ɻ·ͨState hoisting͸গͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ͷ਌ʹ͠Α͏ɻ
99. Practice6: State hoistingͰSingle source of truthʹ͠Α͏ɻ·ͨState hoisting͸গͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ͷ਌ʹ͠Α͏ɻ ӈʹ”on”ɺ”off”ͷTextΛ௥Ճ͢ΔྫͰઆ໌͠·͢ɻ
100. Practice6: State hoistingͰSingle source of truthʹ͠Α͏ɻ·ͨState hoisting͸গͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ͷ਌ʹ͠Α͏ɻ ӈʹ”on”ɺ”off”ͷTextΛ௥Ճ͢ΔྫͰઆ໌͠·͢ɻ
101. Practice6: State hoistingͰSingle source of truthʹ͠Α͏ɻ·ͨState hoisting͸গͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ͷ਌ʹ͠Α͏ɻ ⭕ DO ❌ DON’T
102. Practice6: State hoistingͰSingle source of truthʹ͠Α͏ɻ·ͨState hoisting͸গͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ͷ਌ʹ͠Α͏ɻ ⭕ DO ❌ DON’T
103. Practice6: State hoistingͰSingle source of truthʹ͠Α͏ɻ·ͨState hoisting͸গͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ͷ਌ʹ͠Α͏ɻ ⭕ DO ❌ DON’T DOͷྫͰ͸ઌఔͱಉ༷ʹ State hoistingͰ࣮૷͍ͯ͠ΔΈ͍ͨ
104. Practice6: State hoistingͰSingle source of truthʹ͠Α͏ɻ·ͨState hoisting͸গͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ͷ਌ʹ͠Α͏ɻ ⭕ DO ❌ DON’T DOͷྫͰ͸ઌఔͱಉ༷ʹ State hoistingͰ࣮૷͍ͯ͠ΔΈ͍ͨ ਌͚ͩͰStateΛ͍࣋ͬͯΔ🙆
105. Practice6: State hoistingͰSingle source of truthʹ͠Α͏ɻ·ͨState hoisting͸গͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ͷ਌ʹ͠Α͏ɻ ⭕ DO ❌ DON’T
106. Practice6: State hoistingͰSingle source of truthʹ͠Α͏ɻ·ͨState hoisting͸গͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ͷ਌ʹ͠Α͏ɻ ⭕ DO ❌ DON’T ॳظ஋ͷinitialCheckedΛ ౉͍ͯ͠Δ
107. Practice6: State hoistingͰSingle source of truthʹ͠Α͏ɻ·ͨState hoisting͸গͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ͷ਌ʹ͠Α͏ɻ ⭕ DO ❌ DON’T ॳظ஋ͷinitialCheckedΛ ౉͍ͯ͠Δ ਌Ͱ΋ࣗ෼Ͱ΋StateΛ ؅ཧ͍ͯ͠Δɻ
108. Practice6: State hoistingͰSingle source of truthʹ͠Α͏ɻ·ͨState hoisting͸গͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ͷ਌ʹ͠Α͏ɻ ⭕ DO ❌ DON’T ॳظ஋ͷinitialCheckedΛ ౉͍ͯ͠Δ ਌Ͱ΋ࣗ෼Ͱ΋StateΛ ؅ཧ͍ͯ͠Δɻ ͜ΕͳΒ࠶ར༻Ͱ͖ͯ
 ςετͰ͖ͦ͏͡Όͳ͍ʁʁ🤔
109. Practice6: State hoistingͰSingle source of truthʹ͠Α͏ɻ·ͨState hoisting͸গͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ͷ਌ʹ͠Α͏ɻ ❌ DON’T ࣮͸DON’Tͷྫ͸όά͍ͬͯΔ ϥϕϧΛԡͯ͠΋εΠονͷঢ়ଶ͕ ੾Γସ͑Βͳ͍όά͕͋Δ ͜͏͍͏όάΛ๷͍͗ͨ😂
110. Practice6: State hoistingͰSingle source of truthʹ͠Α͏ɻ·ͨState hoisting͸গͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ͷ਌ʹ͠Α͏ɻ ❌ DON’T ࣮͸DON’Tͷྫ͸όά͍ͬͯΔ ϥϕϧΛԡͯ͠΋εΠονͷঢ়ଶ͕ ੾Γସ͑Βͳ͍όά͕͋Δ ͜͏͍͏όάΛ๷͍͗ͨ😂
111. Practice6: State hoistingͰSingle source of truthʹ͠Α͏ɻ·ͨState hoisting͸গͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ͷ਌ʹ͠Α͏ɻ ͳͥState hoisting͢Δͷ͔ʁ λΠτϧʹ΋ॻ͍ͯ͋Δͱ͓ΓSingle source of truthʹͰ͖Δͨ ΊͰ͢ɻ
 ࠓճͷྫ΋ؤுΕ͹όάΛͳͤ͘Δͱࢥ͍·͕͢ࠓճͷΑ͏ͳ όάΛ๷͙ͨΊʹ͸ 
 ⭕ DO
112. Practice6: State hoistingͰSingle source of truthʹ͠Α͏ɻ·ͨState hoisting͸গͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ͷ਌ʹ͠Α͏ɻ ͳͥState hoisting͢Δͷ͔ʁ λΠτϧʹ΋ॻ͍ͯ͋Δͱ͓ΓSingle source of truthʹͰ͖Δͨ ΊͰ͢ɻ
 ࠓճͷྫ΋ؤுΕ͹όάΛͳͤ͘Δͱࢥ͍·͕͢ࠓճͷΑ͏ͳ όάΛ๷͙ͨΊʹ͸ 
 ⭕ DO Stateͷෳ੡Λ๷͗ɺStateͷมߋՕॴΛ1ͭʹ͢Δ
113. Practice6: State hoistingͰSingle source of truthʹ͠Α͏ɻ·ͨState hoisting͸গͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ͷ਌ʹ͠Α͏ɻ ͳͥState hoisting͢Δͷ͔ʁ λΠτϧʹ΋ॻ͍ͯ͋Δͱ͓ΓSingle source of truthʹͰ͖Δͨ ΊͰ͢ɻ
 ࠓճͷྫ΋ؤுΕ͹όάΛͳͤ͘Δͱࢥ͍·͕͢ࠓճͷΑ͏ͳ όάΛ๷͙ͨΊʹ͸ 
 ⭕ DO Stateͷෳ੡Λ๷͗ɺStateͷมߋՕॴΛ1ͭʹ͢Δ มߋෆՄೳ(immutable)ͳStateΛྲྀ͍ͯ͘͠
114. Practice6: State hoistingͰSingle source of truthʹ͠Α͏ɻ·ͨState hoisting͸গͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ͷ਌ʹ͠Α͏ɻ ͳͥState hoisting͢Δͷ͔ʁ λΠτϧʹ΋ॻ͍ͯ͋Δͱ͓ΓSingle source of truthʹͰ͖Δͨ ΊͰ͢ɻ
 ࠓճͷྫ΋ؤுΕ͹όάΛͳͤ͘Δͱࢥ͍·͕͢ࠓճͷΑ͏ͳ όάΛ๷͙ͨΊʹ͸ 
 ⭕ DO ͦΕ͕Single source of truthͱݺ͹ΕΔߏ଄Խͷํ๏Ͱ͢ɻ
 ͜ΕΛState hoisting͸Մೳʹ͠·͢ɻ Stateͷෳ੡Λ๷͗ɺStateͷมߋՕॴΛ1ͭʹ͢Δ มߋෆՄೳ(immutable)ͳStateΛྲྀ͍ͯ͘͠
115. Practice6: State hoistingͰSingle source of truthʹ͠Α͏ɻ·ͨState hoisting͸গͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ͷ਌ʹ͠Α͏ɻ “গͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ ͷ਌”ͱ͸Կ͔ʁ ⭕ DO
116. Practice6: State hoistingͰSingle source of truthʹ͠Α͏ɻ·ͨState hoisting͸গͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ͷ਌ʹ͠Α͏ɻ “গͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ ͷ਌”ͱ͸Կ͔ʁ ⭕ DO ͳͥ“গͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ͷ਌”ʁ Single source of truth͕೉͔ͬͨ͠ΓɺͰ͖ͳ͔ͬͨΓ͢ΔͨΊ
117. Practice7: ඞཁͳҾ਺͚ͩΛComposableؔ਺ʹ౉ͦ͏
118. Practice7: ඞཁͳҾ਺͚ͩΛComposableؔ਺ʹ౉ͦ͏ ❌ DON’T
119. Practice7: ඞཁͳҾ਺͚ͩΛComposableؔ਺ʹ౉ͦ͏ ❌ DON’T ViewModelͷ஋ΛcllectAsStateΛ࢖ͬͯݟ͍ͯΔ (ͭ·ΓComposeͷStateΛ࢖͍ͬͯΔ)
120. Practice7: ඞཁͳҾ਺͚ͩΛComposableؔ਺ʹ౉ͦ͏ ⭕ DO ❌ DON’T
121. Practice7: ඞཁͳҾ਺͚ͩΛComposableؔ਺ʹ౉ͦ͏ ⭕ DO ❌ DON’T
122. Practice7: ඞཁͳҾ਺͚ͩΛComposableؔ਺ʹ౉ͦ͏ ⭕ DO ❌ DON’T StatefulͱStatelessͰ SettingScreenΛ෼͚͍ͯΔɻ
123. Practice7: ඞཁͳҾ਺͚ͩΛComposableؔ਺ʹ౉ͦ͏ ⭕ DO ❌ DON’T StatefulͱStatelessͰ SettingScreenΛ෼͚͍ͯΔɻ ͳͥʁ
124. Practice7: ඞཁͳҾ਺͚ͩΛComposableؔ਺ʹ౉ͦ͏ ⭕ DO
125. Practice7: ඞཁͳҾ਺͚ͩΛComposableؔ਺ʹ౉ͦ͏ ⭕ DO ͳͥʁ
126. Practice7: ඞཁͳҾ਺͚ͩΛComposableؔ਺ʹ౉ͦ͏ ⭕ DO ɾStatelessͷComposableʹ ରͯ͠ϓϨϏϡʔ΍ςετ Λ͔ΜͨΜʹͰ͖Δ ͳͥʁ
127. Practice7: ඞཁͳҾ਺͚ͩΛComposableؔ਺ʹ౉ͦ͏ ⭕ DO ɾStatelessͷComposableʹ ରͯ͠ϓϨϏϡʔ΍ςετ Λ͔ΜͨΜʹͰ͖Δ ɾ࠶ར༻ʹ͢Δඞཁ͕͋Δ ͱ͖ʹ࠶ར༻͢Δ͜ͱ͕Ͱ ͖Δ ͳͥʁ
128. Practice7: ඞཁͳҾ਺͚ͩΛComposableؔ਺ʹ౉ͦ͏ ⭕ DO ɾStatelessͷComposableʹ ରͯ͠ϓϨϏϡʔ΍ςετ Λ͔ΜͨΜʹͰ͖Δ ɾ࠶ར༻ʹ͢Δඞཁ͕͋Δ ͱ͖ʹ࠶ར༻͢Δ͜ͱ͕Ͱ ͖Δ ͳͥʁ
129. Practice8: Architecture ComponentͷViewModelʹ CompositionͰอ࣋͞Ε͍ͯΔঢ়ଶΛ౉͞ͳ͍Α͏ʹ͠Α͏
130. Practice8: Architecture ComponentͷViewModelʹ CompositionͰอ࣋͞Ε͍ͯΔঢ়ଶΛ౉͞ͳ͍Α͏ʹ͠Α͏ ❌ DON’T
131. Practice8: Architecture ComponentͷViewModelʹ CompositionͰอ࣋͞Ε͍ͯΔঢ়ଶΛ౉͞ͳ͍Α͏ʹ͠Α͏ ❌ DON’T Composition಺Ͱอ࣋
132. Practice8: Architecture ComponentͷViewModelʹ CompositionͰอ࣋͞Ε͍ͯΔঢ়ଶΛ౉͞ͳ͍Α͏ʹ͠Α͏ ❌ DON’T Composition಺Ͱอ࣋ ViewModel಺Ͱอ࣋
133. Practice8: Architecture ComponentͷViewModelʹ CompositionͰอ࣋͞Ε͍ͯΔঢ়ଶΛ౉͞ͳ͍Α͏ʹ͠Α͏ ͳͥʁ ViewModelͱCompotionͰϥΠϑαΠΫϧ͕ҧ͍ɺViewModelͷ΄͏͕௕ੜ͖͢Δ ͷͨΊɻࠓճͰ͸scaffoldStateΛViewModelͰ͍࣋ͬͯΔͱݹ͍scaffoldStateΛ ViewModel͕࣋ͪଓ͚ͯϦʔΫ͢ΔͨΊɻ ❌ DON’T Composition಺Ͱอ࣋ ViewModel಺Ͱอ࣋
134. Practice8: Architecture ComponentͷViewModelʹ CompositionͰอ࣋͞Ε͍ͯΔঢ়ଶΛ౉͞ͳ͍Α͏ʹ͠Α͏ ❌ DON’T ViewModelʹॻ͚ͳ͍ͱɺComposableؔ਺ʹ
 scaffoldStateͱ͔͕ͨ͘͞Μग़͖ͯͯ
 UI(Composableؔ਺)ʹͨ͘͞ΜϩδοΫ͕ॻ͔ΕͪΌ͏ͷͰ͸ʁʁ🤔 → ͦ͜Ͱ࣍ͷϓϥΫςΟε
135. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏
136. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ νΣοΫΛม͑ͨΒSnackbar(Լͷࠇ͍όʔ)Λ
 දࣔ͢ΔΑ͏ʹͯ͠Έͨͱ͠·͠ΐ͏ɻ ৄ͘͠͸ࠓճઆ໌͠·ͤΜ͕ɺ CoroutinesScope͕ग़͖ͯͨΓɺଟগෳࡶʹͳΓ·͢
137. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ νΣοΫΛม͑ͨΒSnackbar(Լͷࠇ͍όʔ)Λ
 දࣔ͢ΔΑ͏ʹͯ͠Έͨͱ͠·͠ΐ͏ɻ ৄ͘͠͸ࠓճઆ໌͠·ͤΜ͕ɺ CoroutinesScope͕ग़͖ͯͨΓɺଟগෳࡶʹͳΓ·͢
138. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ rememberScaffoldState()ɺ rememberCoroutineScope()ɺ settingViewModel.isDarkMode.collectAs State() ͳͲ͕ Composableؔ਺ʹೖΓগ͠ෳࡶԽͯ͠ ͖·ͨ͠ɻɻͲ͏෼͚͍ͯ͜͏ʁ ❌ DON’T
139. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ ͲͷΑ͏ͳ੹຿Ͱ෼͚͍ͯ͘΂͖ͳͷ͔ʁ ࢀߟ: https://d.android.com/jetpack/compose/state#state-in-composables
140. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ State holder͸ҎԼͷΑ͏ʹґଘΛ࣋ͭ͜ͱ͕Ͱ͖·͢ɻ ͭ·ΓComosable͔Βར༻͞ΕΔΑ͏ʹͯ͠ɺViewModel΁ͷґଘΛ࣋ͬͯ΋ྑ͍
 ΋ͷͰ͢ɻ State holder https://developer.android.com/jetpack/compose/state#managing-state
141. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ ⭕ DO State holderΛ࢖͏ଆͷίʔυ
142. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ ⭕ DO ͜͜Ͱ
 SettingScreenState
 ( = State holder)Λ࡞ͬͯ Composition಺Ͱอ࣋͢Δ State holderΛ࢖͏ଆͷίʔυ
143. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ ⭕ DO ͜͜Ͱ
 SettingScreenState
 ( = State holder)Λ࡞ͬͯ Composition಺Ͱอ࣋͢Δ SettingScreenStateͰอ͍࣋ͯ͠Δ ஋Λ࢖͏͚ͩ State holderΛ࢖͏ଆͷίʔυ
144. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ ⭕ DO ❌ DON’T
145. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ ⭕ DO State holderΛ࢖͏ଆ͸͜Ε͚ͩɻ͔ͳΓγϯϓϧʹɻ ❌ DON’T
146. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ ⭕ DO State holderΛ࢖͏ଆ͸͜Ε͚ͩɻ͔ͳΓγϯϓϧʹɻ ❌ DON’T SettingScreenStateͷதΛݟ͍ͯ͜͏
147. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ ⭕ DO SettingScreenState͕State holderͰ͢ ૣ଎ݟͯΈ·͠ΐ͏
148. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ ⭕ DO
149. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ ⭕ DO SettingScreenState͸ Կ΋ܧঝ͠ͳ͍ͨͩͷΫϥεɻ Compose֎ͷϥΠϑαΠΫϧʹ റΒΕͳ͍Α͏ʹ͍ͯ͠Δ
150. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ ⭕ DO
151. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ ⭕ DO ଞͷComposeͷStateΛ
 ࣋ͭ͜ͱ͕Ͱ͖Δ
152. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ ⭕ DO
153. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ ⭕ DO ϏδωεϩδοΫ΍ը໘ͷঢ়ଶʹ ΞΫηε͢ΔͨΊʹViewModelʹ ΋ґଘͰ͖Δ
154. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ ⭕ DO
155. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ ⭕ DO Composeͷঢ়ଶΛݟΔͨΊʹ
 ม਺ͳͲΛComposableؔ਺ʹ͢ Δ͜ͱ͕Ͱ͖Δ
156. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ ⭕ DO
157. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ ⭕ DO remember{}Λ࢖ͬͯ Composition ಺ͰState holderΛอ࣋͢Δ
158. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ ͦ΋ͦ΋Composeͷ։ൃͰViewModelͳ͠ͰɺState holder͚ͩͰྑ͍ͷͰ͸ʁʁ ݱঢ়ͰͷAndroidͷ։ൃͰ͸ඞཁ ը໘ճసͳͲͷConfiguration changeΛ௨ͯ͠ੜ͖࢒Δ Navigationͱͷ౷߹ʹΑͬͯόοΫελοΫͷը໘ͷ৘ใΛอ͓͚࣋ͯ͠Δ HiltͳͲͱ͍ͬͨJetpackϥΠϒϥϦͷ౷߹ ࢀߟ: https://developer.android.com/jetpack/compose/state#viewmodel-state
159. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ ͳͥComposableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ʹ͢Δ΂͖ͳͷ͔ʁ ؔ৺ࣄͷ෼཭ͯ͠ɺ ςετ΍ϓϨϏϡʔΛՄೳʹ͢ΔͨΊ ࢀߟ: https://developer.android.com/jetpack/compose/state#viewmodel-state
160. Practice9: Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ ʹ͠Α͏ Ͳ͏͍ͯ͘͠΂͖ͳͷ͔ʁ State holder͸ෳࡶͳUIͷཁૉͷState؅ཧ͢Δ΋ͷɻ
 ෳࡶʹͳΕ͹ͳΔ΄ͲState holderͷඞཁੑ͕૿͍͑ͯ͘ͷͰɺ
 ෳࡶʹͳΕ͹ݕ౼ͯ͠ΈΑ͏ɻ ࢀߟ: https://d.android.com/jetpack/compose/state#state-in-composables
161. Jetpack ComposeͷState؅ཧͷϓϥΫςΟε·ͱΊ State hoistingͰComposableؔ਺Λ࠶ར༻ՄೳͰςετՄೳʹ͠Α͏ State hoistingͰSingle source of truthʹ͠Α͏ɻ·ͨState hoisting͸গ ͳ͘ͱ΋Ұ൪௿͍StateΛফඅ͍ͯ͠Δڞ௨ͷ਌ʹ͠Α͏ɻ ඞཁͳҾ਺͚ͩΛComposableؔ਺ʹ౉ͦ͏ Architecture ComponentͷViewModelʹCompositionͰอ࣋͞Ε͍ͯΔ ঢ়ଶΛ౉͞ͳ͍Α͏ʹ͠Α͏ Composableؔ਺ʹϩδοΫ͕ॻ͔Εͳ͍Α͏ʹ͠Α͏ 05 06
 07 08
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162. ·ͱΊ ɾState = ঢ়ଶͱ͸ʁ “࣌ؒͱͱ΋ʹมԽ͢ΔՄೳੑ͕͋Δ஋͢΂ͯ”ɻ ɾJetpack ComposeͰStateΛ؅ཧ͍ͯͨ͘͠Ίͷ9ݸͷϓϥΫςΟεΛ ঺հ͠·ͨ͠ɻ ɾͪΌΜͱಈ͔͢ʹ͸Jetpack Compose΁ͷཧղ͕ඞཁɻ ɾߟ͑ํͷجຊͱͳΔ෦෼͸Single source of truth΍ؔ৺ࣄ ͷ෼཭ͳͲɻ஌͓ͬͯ͘ͱComposeҎ֎Ͱ΋໾ʹཱ͔ͭ΋͠ Ε·ͤΜɻ