Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Flutter Hooks, sometimes Jetpack Compose
Search
Daichi Furiya (Wasabeef)
June 22, 2021
Programming
3
1.8k
Flutter Hooks, sometimes Jetpack Compose
Flutter Hooks, sometimes Jetpack Compose
Daichi Furiya (Wasabeef)
June 22, 2021
Tweet
Share
More Decks by Daichi Furiya (Wasabeef)
See All by Daichi Furiya (Wasabeef)
DevFest Tokyo 2025 - Flutter のアプリアーキテクチャ現在地点
wasabeef
5
1.4k
About Flutter Architecture
wasabeef
1
190
2023 Flutter/Dart Summary
wasabeef
0
56
I/O Extended 2023 - Dart と Flutter の新機能
wasabeef
0
160
I/O Extended 2023 - Flutter 活用事例
wasabeef
10
2.8k
What it Takes to be a Flutter Developer
wasabeef
0
180
FlutterKaigi 2022 Keynote
wasabeef
1
570
Flutter Hooks を使ったアプリ開発 / App Development with the Flutter Hooks
wasabeef
2
1.3k
Flutter 2021 の振り返りと今後のアプリ開発に向けて / Looking back on Flutter 2021 and for future app development.
wasabeef
4
2.1k
Other Decks in Programming
See All in Programming
クリーンアーキテクチャから見る依存の向きの大切さ
shimabox
4
900
コミュニティ駆動 AWS CDK ライブラリ「Open Constructs Library」 / community-cdk-library
gotok365
2
180
Introduction to kotlinx.rpc
arawn
0
750
1年目の私に伝えたい!テストコードを怖がらなくなるためのヒント/Tips for not being afraid of test code
push_gawa
1
480
『品質』という言葉が嫌いな理由
korimu
0
180
一休.com のログイン体験を支える技術 〜Web Components x Vue.js 活用事例と最適化について〜
atsumim
0
750
プログラミング言語学習のススメ / why-do-i-learn-programming-language
yashi8484
0
150
第3回関東Kaggler会_AtCoderはKaggleの役に立つ
chettub
3
1.1k
責務と認知負荷を整える! 抽象レベルを意識した関心の分離
yahiru
8
1.3k
データの整合性を保つ非同期処理アーキテクチャパターン / Async Architecture Patterns
mokuo
53
18k
Multi Step Form, Decentralized Autonomous Organization
pumpkiinbell
1
830
PHPのバージョンアップ時にも役立ったAST
matsuo_atsushi
0
210
Featured
See All Featured
Documentation Writing (for coders)
carmenintech
67
4.6k
Rebuilding a faster, lazier Slack
samanthasiow
80
8.8k
How GitHub (no longer) Works
holman
314
140k
Into the Great Unknown - MozCon
thekraken
35
1.6k
The Art of Delivering Value - GDevCon NA Keynote
reverentgeek
10
1.3k
"I'm Feeling Lucky" - Building Great Search Experiences for Today's Users (#IAC19)
danielanewman
226
22k
Dealing with People You Can't Stand - Big Design 2015
cassininazir
366
25k
StorybookのUI Testing Handbookを読んだ
zakiyama
28
5.5k
BBQ
matthewcrist
87
9.5k
Stop Working from a Prison Cell
hatefulcrawdad
267
20k
No one is an island. Learnings from fostering a developers community.
thoeni
21
3.1k
Large-scale JavaScript Application Architecture
addyosmani
511
110k
Transcript
Flutter 1 Flutter Hooksɺ ɹɹɹ࣌ʑ Jetpack Compose Daichi Furiya @wasabeef_jp
Target audience Hooks ΛΒͳ͍ਓ React Hook ͬͯΔਓ 2 ͜ΕΛظʹ Hooks
ʹ৮Εͯɺ Flutter Hooks/React Hook ͱ Jetpack Compose ͷεςʔ τཧΛཧղͷҰาΛਐΉ Flutter Hooks ͱ React Hook ɺ΄΅ಉ͡ͳͷͰม ͭͭ͠ Jetpack Compose ͷ εςʔτཧʹ৮ΕΔ Jetpack Compose ͱ Flutter Hooks/React Hooks Λม Ͱ͖ΔΑ͏ʹ͢Δ Jetpack Compose ͬͯΔਓ
Target audience Hooks ΛΒͳ͍ਓ React Hook ͬͯΔਓ 3 ͜ΕΛظʹ Hooks
ʹ৮Εͯɺ Flutter Hooks/React Hook ͱ Jetpack Compose ͷεςʔ τཧΛཧղͷҰาΛਐΉ Flutter Hooks ͱ React Hook ɺ΄΅ಉ͡ͳͷͰม ͭͭ͠ Jetpack Compose ͷ εςʔτཧʹ৮ΕΔ Jetpack Compose ͱ Flutter Hooks/React Hooks Λม Ͱ͖ΔΑ͏ʹ͢Δ Jetpack Compose ͬͯΔਓ
Target audience Hooks ΛΒͳ͍ਓ React Hook ͬͯΔਓ 4 ͜ΕΛظʹ Hooks
ʹ৮Εͯɺ Flutter Hooks/React Hook ͱ Jetpack Compose ͷεςʔ τཧΛཧղͷҰาΛਐΉ Flutter Hooks ͱ React Hook ɺ΄΅ಉ͡ͳͷͰม ͭͭ͠ Jetpack Compose ͷ εςʔτཧʹ৮ΕΔ Jetpack Compose ͱ Flutter Hooks/React Hooks Λม Ͱ͖ΔΑ͏ʹ͢Δ Jetpack Compose ͬͯΔਓ
Target audience Hooks ΛΒͳ͍ਓ React Hook ͬͯΔਓ 5 ͜ΕΛظʹ Hooks
ʹ৮Εͯɺ Flutter Hooks/React Hook ͱ Jetpack Compose ͷεςʔ τཧΛཧղͷҰาΛਐΉ Flutter Hooks ͱ React Hook ɺ΄΅ಉ͡ͳͷͰม ͭͭ͠ Jetpack Compose ͷ εςʔτཧʹ৮ΕΔ Jetpack Compose ͱ Flutter Hooks/React Hooks Λม Ͱ͖ΔΑ͏ʹ͢Δ Jetpack Compose ͬͯΔਓ
6 02 StatelessWidget, StatefulWidget 01 Flutter Hooks 03 useXXX 04
Use Cases 05 Conclusion
Flutter Hooks Flutter Hooks ͱʁ ϝϦοτ 7 React Hooks ͷ
Flutter ൛Ͱจ ๏͍ํ΄΅Ұॹɻ εςʔτͷॳظԽʢinitStateʣഁغ (dispose) ΛΟδΣοτͱ͕Ͱ͖Δɻ ୯७ʹΫϥεͷఆٛΛݮΒ͢γϯλοΫεγϡ ΨʔతͳԸܙ͋Δɻ
Flutter Hooks Flutter Hooks ͱʁ ϝϦοτ 8 React Hooks ͷ
Flutter ൛Ͱจ ๏͍ํ΄΅Ұॹɻ εςʔτͷॳظԽʢinitStateʣഁغ (dispose) ΛΟδΣοτͱ͕Ͱ͖Δɻ ୯७ʹΫϥεͷఆٛΛݮΒ͢γϯλοΫεγϡ ΨʔతͳԸܙ͋Δɻ
Flutter Hooks Flutter Hooks ͱʁ ϝϦοτ 9 React Hooks ͷ
Flutter ൛Ͱจ ๏͍ํ΄΅Ұॹɻ εςʔτͷॳظԽʢinitStateʣഁغ (dispose) ΛΟδΣοτͱ͕Ͱ͖Δɻ ୯७ʹΫϥεͷఆٛΛݮΒ͢γϯλοΫεγϡ ΨʔతͳԸܙ͋Δɻ
10 02 StatelessWidget, StatefulWidget 01 Flutter Hooks 03 useXXX 04
Use Cases 05 Conclusion
11 StatelessWidget, StatefulWidget StatelessWidget StatefulWidget ΦϒδΣΫτੜ࣌ʹ༩͑ΒΕͨ ใͱ BuildContext Ҏ֎ʹґଘ͠ͳ ͍ΟδΣοτͰ͢ɻIconɺ
IconButton Text ͳͲ͕ StatelessWidget ͷαϒΫϥεͰ͢ɻ γεςϜͷঢ়ଶͳͲʹΑͬͯಈతʹ มԽΛ͢Δখ͞ͳϥΠϑαΠΫϧΛ ͬͨΟδΣοτͰ͢ɻImageɺ TextFormField Hero ͳͲ͕ StatefulWidget ͷαϒΫϥεͰ͢ɻ
12 StatelessWidget, StatefulWidget StatelessWidget StatefulWidget ΦϒδΣΫτੜ࣌ʹ༩͑ΒΕͨ ใͱ BuildContext Ҏ֎ʹґଘ͠ͳ ͍ΟδΣοτͰ͢ɻIconɺ
IconButton Text ͳͲ͕ StatelessWidget ͷαϒΫϥεͰ͢ɻ γεςϜͷঢ়ଶͳͲʹΑͬͯಈతʹ มԽΛ͢Δখ͞ͳϥΠϑαΠΫϧΛ ͬͨΟδΣοτͰ͢ɻImageɺ TextFormField Hero ͳͲ͕ StatefulWidget ͷαϒΫϥεͰ͢ɻ
13 StatelessWidget, StatefulWidget StatelessWidget StatefulWidget ΦϒδΣΫτੜ࣌ʹ༩͑ΒΕͨ ใͱ BuildContext Ҏ֎ʹґଘ͠ͳ ͍ΟδΣοτͰ͢ɻIconɺ
IconButton Text ͳͲ͕ StatelessWidget ͷαϒΫϥεͰ͢ɻ γεςϜͷঢ়ଶͳͲʹΑͬͯಈతʹ มԽΛ͢Δখ͞ͳϥΠϑαΠΫϧΛ ͬͨΟδΣοτͰ͢ɻImageɺ TextFormField Hero ͳͲ͕ StatefulWidget ͷαϒΫϥεͰ͢ɻ
14 StatelessWidget, StatefulWidget class Counter extends StatefulWidget { @override State
createState() "=> _CountState(); } class _CountState extends State<CountPage> { int count = 0; void setCount(int value) { setState(() "=> count = value); } @override Widget build(BuildContext context) { return TextButton( child: Text("a is $count"), onPressed: () "=> setCount(count + 1), ); } } StatelessWidget class SimpleLabel extends StatelessWidget { const SimpleLabel({required this.label}); final String label; @override Widget build(BuildContext context) { return Text( label, style: const TextStyle( decoration: TextDecoration.underline, ), ); } } StatefulWidget ϘλϯΛԡ͢ຖʹ count ͕૿͑ɺςΩετ͕Մม͢ΔΟδΣοτˢ ↑ ༩͑ΒΕͨใͷΈͰෆมͳΟδΣοτ
15 StatelessWidget, StatefulWidget class Counter extends StatefulWidget { @override State
createState() "=> _CountState(); } class _CountState extends State<CountPage> { int count = 0; void setCount(int value) { setState(() "=> count = value); } @override Widget build(BuildContext context) { return TextButton( child: Text("a is $count"), onPressed: () "=> setCount(count + 1), ); } } StatelessWidget class SimpleLabel extends StatelessWidget { const SimpleLabel({required this.label}); final String label; @override Widget build(BuildContext context) { return Text( label, style: const TextStyle( decoration: TextDecoration.underline, ), ); } } StatefulWidget ϘλϯΛԡ͢ຖʹ count ͕૿͑ɺςΩετ͕Մม͢ΔΟδΣοτˢ ↑ ༩͑ΒΕͨใͷΈͰෆมͳΟδΣοτ
16 StatelessWidget, StatefulWidget class Counter extends StatefulWidget { @override State
createState() "=> _CountState(); } class _CountState extends State<CountPage> { int count = 0; void setCount(int value) { setState(() "=> count = value); } @override Widget build(BuildContext context) { return TextButton( child: Text("a is $count"), onPressed: () "=> setCount(count + 1), ); } } StatelessWidget class SimpleLabel extends StatelessWidget { const SimpleLabel({required this.label}); final String label; @override Widget build(BuildContext context) { return Text( label, style: const TextStyle( decoration: TextDecoration.underline, ), ); } } StatefulWidget ϘλϯΛԡ͢ຖʹ count ͕૿͑ɺςΩετ͕Մม͢ΔΟδΣοτˢ ↑ ༩͑ΒΕͨใͷΈͰෆมͳΟδΣοτ
17 class CountPage extends StatefulWidget { @override State createState() "=>
_CountState(); } class _CountState extends State<CountPage> { int count = 0; @override void initState() { ""/** ॳظԽ **/ } @override void dispose() { ""/** ഁغ **/ } void setCount(int value) "=> setState(() "=> count = value); @override Widget build(BuildContext context) { return TextButton( child: Text("Count is $count"), onPressed: () "=> setCount(count + 1), ); } } StatefulWidget Λ͏ʹجຊతʹೋͭ ͷΫϥεΛ࡞Δඞཁ͕͋Γ·͢ɻ StatefulWidget Λܧঝͨ͠ CountPage ͱ State<T extends StatefulWidget> Λܧঝ ͨ͠ _CountState Ͱ͢ɻ initState ͰॳظԽɺdispose Ͱഁغͷॲ ཧΛॻ͘͜ͱ͕Ͱ͖·͢ɻ ·ͨ setState ΛݺͿ͜ͱͰঢ়ଶ͕มԽ͠ ͨ͜ͱΛ௨ͯ͠ϦϏϧυ͕Γ·͢ɻ StatelessWidget, StatefulWidget
18 class CountPage extends HookWidget { @override Widget build(BuildContext context)
{ final count = useState(0); return TextButton( child: Text("Count: ${count.value}"), onPressed: () "=> count.value"++, ); } } StatelessWidget, StatefulWidget γϯϓϧʹ useState Λ͏ͱॻ͘ͱ͜Ε ͘Β͍Ͱલͷϖʔδͱಉ͡ίʔυͷಈ࡞ Λ࣮ݱ͢Δ͜ͱ͕Ͱ͖·͢ɻuseState ͷ ׂͳͲޙड़͍͖ͯ͠·͢ɻ
19 class HomePage extends HookWidget { const HomePage({Key? key}) :
super(key: key); @override Widget build(BuildContext context) { final enabled = useState(false); return Column( children: [ TextFormField( onChanged: (value) "=> enabled.value = value.isNotEmpty, ), ElevatedButton( onPressed: enabled.value ? () { ""/** Submit **/ } : null, child: Text('Submit'), ), ], ); } } StatelessWidget, StatefulWidget Flutter Hooks ͷॳΊͯͷαϯϓϧΛ୳͠ ͯΈΔͱઌ΄ͲΑ͏ʹΧϯλʔͷίʔ υΛΑ͘ݟ͔͚·͕͢ɺ࣮ࡍʹॳݟͰ ͦΕ͚ͩΈͯϐϯͱ͜ͳ͔ͬͨͷͰɺ ͜͜ͰϑΥʔϜʹ͕͋Δ͔Ͳ͏͔Ͱ Ϙλϯͷ༗ޮແޮΛΓସ͍͑ͯ·͢ɻ
20 02 StatelessWidget, StatefulWidget 01 Flutter Hooks 03 useXXX 04
Use Cases 05 Conclusion
Flutter Hooks ͷϝιου HookWidget Λܧঝͨ͠ build ͷதͰ ݺͳ͍ͱ͍͚ͳ͍ useContext BuildContext
ΛऔಘͰ͖Δ 21
@Composable fun SampleName() { val context = LocalContext.current Text( text
= "${context.getString(R.string.name)}" ) } 22 useContext class SampleName extends HookWidget { @override Widget build(BuildContext context) { final l10n = useL10n(); return Text(l10n.name); } } L10n useL10n() { final context = useContext(); return L10n.of(context)!; } Flutter Hooks Jetpack Compose HookWidget Λܧঝ͢Δඞཁ͕͋Δɻ Hooks Λͬͨϝιουʹৗʹ use Ͱ࢝·Δ͜ͱ ͕ϧʔϧͱͳ͍ͬͯΔɻ
@Composable fun SampleName() { val context = LocalContext.current Text( text
= "${context.getString(R.string.name)}" ) } 23 useContext class SampleName extends HookWidget { @override Widget build(BuildContext context) { final l10n = useL10n(); return Text(l10n.name); } } L10n useL10n() { final context = useContext(); return L10n.of(context)!; } Flutter Hooks Jetpack Compose HookWidget Λܧঝ͢Δඞཁ͕͋Δɻ Hooks Λͬͨϝιουʹৗʹ use Ͱ࢝·Δ͜ͱ ͕ϧʔϧͱͳ͍ͬͯΔɻ
@Composable fun SampleName() { val context = LocalContext.current Text( text
= "${context.getString(R.string.name)}" ) } 24 useContext class SampleName extends HookWidget { @override Widget build(BuildContext context) { final l10n = useL10n(); return Text(l10n.name); } } L10n useL10n() { final context = useContext(); return L10n.of(context)!; } Flutter Hooks Jetpack Compose HookWidget Λܧঝ͢Δඞཁ͕͋Δɻ Hooks Λͬͨϝιουʹৗʹ use Ͱ࢝·Δ͜ͱ ͕ϧʔϧͱͳ͍ͬͯΔɻ
StatelessWidget ͰԿ͔͠Βͷঢ়ଶ ཧ͕͍ͨ͠ͱࢥ͕ͬͨ࣌ useState Λ͏໘Ͱ͢ʢViewModel ૬Ͱ อ࣋͢Δ΄ͲͰͳ͍ͷͳͲʣ useState final count
= useState(0); count.value = 3; େମ֮͑Δͷ͜Ε͚ͩ StatefulWidget ΛΘͳ͍ ؆୯ 25
useState final count = useState(0); count.value = 3; େମ֮͑Δͷ͜Ε͚ͩ StatefulWidget
ΛΘͳ͍ ؆୯ 26 StatelessWidget ͰԿ͔͠Βͷঢ়ଶ ཧ͕͍ͨ͠ͱࢥ͕ͬͨ࣌ useState Λ͏໘Ͱ͢ʢViewModel ૬Ͱ อ࣋͢Δ΄ͲͰͳ͍ͷͳͲʣ
useState final count = useState(0); count.value = 3; େମ֮͑Δͷ͜Ε͚ͩ StatefulWidget
ΛΘͳ͍ ؆୯ 27 StatelessWidget ͰԿ͔͠Βͷঢ়ଶ ཧ͕͍ͨ͠ͱࢥ͕ͬͨ࣌ useState Λ͏໘Ͱ͢ʢViewModel ૬Ͱ อ࣋͢Δ΄ͲͰͳ͍ͷͳͲʣ
@Composable fun Count() { val count = remember { mutableStateOf(0)
} Button(onClick = { count.value"++ }) { Text("Count: ${count.value}") } } 28 useState class CountPage extends HookWidget { @override Widget build(BuildContext context) { final count = useState(0); return TextButton( onPressed: () { count.value"++; }, child: Text("Count: ${count.value}"), ); } } Flutter Hooks Jetpack Compose remember composable Λར༻ͯ͠ঢ়ଶͷอ ࣋Λߦ͏͜ͱ͕Ͱ͖Δ final state = useState(initialValue); state.value = newValue; ͜Ε͚ͩ
@Composable fun Count() { val count = remember { mutableStateOf(0)
} Button(onClick = { count.value"++ }) { Text("Count: ${count.value}") } } 29 useState class CountPage extends HookWidget { @override Widget build(BuildContext context) { final count = useState(0); return TextButton( onPressed: () { count.value"++; }, child: Text("Count: ${count.value}"), ); } } Flutter Hooks Jetpack Compose remember composable Λར༻ͯ͠ঢ়ଶͷอ ࣋Λߦ͏͜ͱ͕Ͱ͖Δ final state = useState(initialValue); state.value = newValue; ͜Ε͚ͩ
@Composable fun Count() { val (count, setCount) = remember {
mutableStateOf(0) } Button(onClick = { setCount(count + 1) }) { Text("Count: ${count}") } } 30 useState class CountPage extends HookWidget { @override Widget build(BuildContext context) { final count = useState(0); return TextButton( onPressed: () { count.value"++; }, child: Text("Count: ${count.value}"), ); } } Flutter Hooks Jetpack Compose Jetpack Compose value ͱ setter Λ࣋ͭ tuple Λੜ͢Δ͜ͱͰ͖·͢ʢReact Ά͍ʣ final state = useState(initialValue); state.value = newValue; ͜Ε͚ͩ
@Composable fun Count() { val (count, setCount) = remember {
mutableStateOf(0) } Button(onClick = { setCount(count + 1) }) { Text("Count: ${count}") } } 31 useState class CountPage extends HookWidget { @override Widget build(BuildContext context) { final count = useState(0); return TextButton( onPressed: () { count.value"++; }, child: Text("Count: ${count.value}"), ); } } Flutter Hooks Jetpack Compose remember composable Λར༻ͯ͠ঢ়ଶͷอ ࣋Λߦ͏͜ͱ͕Ͱ͖Δ final state = useState(initialValue); state.value = newValue; ͜Ε͚ͩ
؆୯ͳϥΠϑαΠΫϧॲཧ͕ඞཁ ͩͬͨ߹ʹ useEffect Λ͍· ͢ɻΟδΣοτੜ࣌ʹॳظԽ͠ ͍ͨ߹ͳͲɻ useEffect ॳظԽഁغͷॲཧ͕ඞཁͩͬͨΒ 32
DisposableEffect(id) { val subscription = source.subscribe(id) onDispose { "// ഁغ͞ΕΔ࣌ʹ࣮ߦ(ActivityഁغͳͲ)
subscription.unsubscribe(id) } } 33 useEffect useEffect(() "=> { final subscription = source.subscribe(id); return () "=> { "// ഁغ͞ΕΔ࣌ʹ࣮ߦ subscription.unsubscribe(id); }; }, [id]); Flutter Hooks Jetpack Compose
DisposableEffect(id) { val subscription = source.subscribe(id) onDispose { "// ഁغ͞ΕΔ࣌ʹ࣮ߦ(ActivityഁغͳͲ)
subscription.unsubscribe(id) } } 34 useEffect useEffect(() "=> { final subscription = source.subscribe(id); return () "=> { "// ഁغ͞ΕΔ࣌ʹ࣮ߦ subscription.unsubscribe(id); }; }, [id]); Flutter Hooks Jetpack Compose
DisposableEffect(id) { val subscription = source.subscribe(id) onDispose { "// ഁغ͞ΕΔ࣌ʹ࣮ߦ(ActivityഁغͳͲ)
subscription.unsubscribe(id) } } 35 useEffect useEffect(() "=> { final subscription = source.subscribe(id); return () "=> { "// ഁغ͞ΕΔ࣌ʹ࣮ߦ subscription.unsubscribe(id); }; }, [id]); Flutter Hooks Jetpack Compose
LaunchedEffect(id) { "// ID ͕มߋ͞ΕΔͨͼ } SideEffect { "// ຖճ
} LaunchedEffect(Unit) { "// ࠷ॳͷҰճ } 36 useEffect useEffect(() "=> { "// ID ͕มߋ͞ΕΔͨͼ }, [id]); useEffect(() "=> { "// ຖճ }); useEffect(() "=> { "// ࠷ॳͷҰճ }, []); Flutter Hooks Jetpack Compose
LaunchedEffect(id) { "// ID ͕มߋ͞ΕΔͨͼ } SideEffect { "// ຖճ
} LaunchedEffect(Unit) { "// ࠷ॳͷҰճ } 37 useEffect useEffect(() "=> { "// ID ͕มߋ͞ΕΔͨͼ }, [id]); useEffect(() "=> { "// ຖճ }); useEffect(() "=> { "// ࠷ॳͷҰճ }, []); Flutter Hooks Jetpack Compose
LaunchedEffect(id) { "// ID ͕มߋ͞ΕΔͨͼ } SideEffect { "// ຖճ
} LaunchedEffect(Unit) { "// ࠷ॳͷҰճ } 38 useEffect useEffect(() "=> { "// ID ͕มߋ͞ΕΔͨͼ }, [id]); useEffect(() "=> { "// ຖճ }); useEffect(() "=> { "// ࠷ॳͷҰճ }, const []); Flutter Hooks Jetpack Compose
39 useEffect Flutter Hooks @override Widget build(BuildContext context) { final
enabled = useState(false); useEffect(() { print("ॳճͷΈ"); }, const []); return Column( children: [ TextFormField( onChanged: (value) "=> enabled.value = value.isNotEmpty, ), ElevatedButton( onPressed: enabled.value ? () { ""/** Submit **/ } : null, child: Text('Submit'), ), ], ); } ςΩετ͕ೖྗ͞ΕͨΒϘλϯ͕༗ޮͱ ͳΔαϯϓϧͰ͕ͨ͠ɺ͜ͷ useEffect ͷ͍ํΛͨ͠߹ʹ࣮ߦ͞ΕΔͷ ࠷ॳͷҰճͱͳΓ·͢ɻ
State ͱ͍͍ͯͨ͠Θ͚Ͱͳ͘ຖ ճಉ͡σʔλΛऔಘ͢ΔͷͰͳ͘ Ωϟογϡ͓͖͍ͯͨ͠߹ͳͲʹ useMemoized ΛΩϟογϡ͍ͨ͠߹ 40
val now = remember(key) { LocalDateTime.now() } 41 useMemoized final
now = useMemoized(() { return DateTime.now(); }, [key]); Flutter Hooks Jetpack Compose remember ʹΩʔΛ͢͜ͱͰ͖ɺΩʔ͕ಉ͡ Ͱ͋ΕͦͷॲཧΩϟογϡ͞Ε·͢ useMemoized Λ͏͜ͱͰΩϟογϡ͕Ͱ ͖ɺΩʔ͕ಉ͡Ͱ͋ΕͦͷॲཧΩϟογϡ ͞Ε·͢
val now = remember(key) { LocalDateTime.now() } 42 useMemoized final
now = useMemoized(() { return DateTime.now(); }, [key]); Flutter Hooks Jetpack Compose remember ʹΩʔΛ͢͜ͱͰ͖ɺΩʔ͕ಉ͡ Ͱ͋ΕͦͷॲཧΩϟογϡ͞Ε·͢ useMemoized Λ͏͜ͱͰΩϟογϡ͕Ͱ ͖ɺΩʔ͕ಉ͡Ͱ͋ΕͦͷॲཧΩϟογϡ ͞Ε·͢
val now = remember(key) { LocalDateTime.now() } 43 useMemoized final
now = useMemoized(() { return DateTime.now(); }, [key]); Flutter Hooks Jetpack Compose remember ʹΩʔΛ͢͜ͱͰ͖ɺΩʔ͕ಉ͡ Ͱ͋ΕͦͷॲཧΩϟογϡ͞Ε·͢ useMemoized Λ͏͜ͱͰΩϟογϡ͕Ͱ ͖ɺΩʔ͕ಉ͡Ͱ͋ΕͦͷॲཧΩϟογϡ ͞Ε·͢
@Composable fun Greeting() { val (count, setCount) = remember {
mutableStateOf(0) } val now = remember(count) { LocalDateTime.now() } Column { Text(text = "Click Time: $now") Button(onClick = { setCount(count + 1) }) { Text("Count: ${count}") } } } 44 useMemoized @override Widget build(BuildContext context) { final count = useState(0); final now = useMemoized(() "=> DateTime.now(), [count.value]); return Column( children: [ Text("Click Time: $now"), TextButton( onPressed: () "=> count.value"++, child: Text("Count: ${count.value}"), ), ], ); } Flutter Hooks Jetpack Compose ͜ͷྫͰɺcount ͕૿͑ͨʢΫϦοΫͨ͠ʣλΠϛϯάͰݱࡏ࣌ؒ Λऔಘͯ͠Ωϟογϡ͍ͯ͠·͢
@Composable fun Greeting() { val (count, setCount) = remember {
mutableStateOf(0) } val now = remember(count) { LocalDateTime.now() } Column { Text(text = "Click Time: $now") Button(onClick = { setCount(count + 1) }) { Text("Count: ${count}") } } } 45 useMemoized @override Widget build(BuildContext context) { final count = useState(0); final now = useMemoized(() "=> DateTime.now(), [count.value]); return Column( children: [ Text("Click Time: $now"), TextButton( onPressed: () "=> count.value"++, child: Text("Count: ${count.value}"), ), ], ); } Flutter Hooks Jetpack Compose ͜ͷྫͰɺcount ͕૿͑ͨʢΫϦοΫͨ͠ʣλΠϛϯάͰݱࡏ࣌ؒ Λऔಘͯ͠Ωϟογϡ͍ͯ͠·͢
@Composable fun Greeting() { val (count, setCount) = remember {
mutableStateOf(0) } val now = remember(count) { LocalDateTime.now() } Column { Text(text = "Click Time: $now") Button(onClick = { setCount(count + 1) }) { Text("Count: ${count}") } } } 46 useMemoized @override Widget build(BuildContext context) { final count = useState(0); final now = useMemoized(() "=> DateTime.now(), [count.value]); return Column( children: [ Text("Click Time: $now"), TextButton( onPressed: () "=> count.value"++, child: Text("Count: ${count.value}"), ), ], ); } Flutter Hooks Jetpack Compose ͜ͷྫͰɺcount ͕૿͑ͨʢΫϦοΫͨ͠ʣλΠϛϯάͰݱࡏ࣌ؒ Λऔಘͯ͠Ωϟογϡ͍ͯ͠·͢
47 02 StatelessWidget, StatefulWidget 01 Flutter Hooks 03 useXXX 04
Use Cases 05 Conclusion
48 Use Cases VideoPlayerController useAssetVideoController({ required String asset, bool autoPlay
= false, bool looping = false, }) { final controller = useMemoized( () "=> VideoPlayerController.asset(asset), [asset], ); useEffect(() { controller "..initialize() "..setLooping(looping); if (autoPlay) { controller.play(); } return () "=> controller.dispose(); }, [asset, autoPlay, looping]); return controller; } Flutter Hooks class VideoPage extends HookWidget { @override Widget build(BuildContext context) { final videoController = useAssetVideoController( asset: Assets.videos.bigbuckbunny, autoPlay: true, looping: true, ); return Scaffold( appBar: AppBar(), body: Center( child: AspectRatio( aspectRatio: 16 / 9, child: VideoPlayer(videoController), ), ), ); } } video_player ΛͬͨྫɻVideoPlayerController ͷॳظԽɾഁغΛΟδΣοτͱ͓ͯ͘͜͠ͱͰɺผͷΟδΣοτͰ͍ճ͕͠Ͱ͖Δ
49 Use Cases @Composable public fun BackHandler(enabled: Boolean = true,
onBack: () "-> Unit) { val currentOnBack by rememberUpdatedState(onBack) val backCallback = remember { object : OnBackPressedCallback(enabled) { override fun handleOnBackPressed() { currentOnBack() } } } SideEffect { backCallback.isEnabled = enabled } val backDispatcher = checkNotNull(LocalOnBackPressedDispatcherOwner.current) { "No OnBackPressedDispatcherOwner" }.onBackPressedDispatcher val lifecycleOwner = LocalLifecycleOwner.current DisposableEffect(lifecycleOwner, backDispatcher) { backDispatcher.addCallback(lifecycleOwner, backCallback) onDispose { backCallback.remove() } } } Jetpack Compose class MainActivity : ComponentActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContent { MaterialTheme { Surface() { BackHandler(onBack = { "// Back pressed }) } } } } } Back key ͷϋϯυϦϯάΛ Composable Խͨ͠ྫɻ͜Εଞͷը໘Ͱ͍ճ͕͠Ͱ͖ΔΑ͏ʹͳΔ
50 02 StatelessWidget, StatefulWidget 01 Flutter Hooks 03 useXXX 04
Use Cases 05 Conclusion
Thank you! https://wasabeef.jp http://github.com/wasabeef https://twitter.com/wasabeef_jp Resources 51 Daichi Furiya @wasabeef_jp