Androidアプリで安定して動作させ継続的に開発するために設計の原則を利用して開発した話

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AndroidΞϓϦͰɺ
 
҆ఆͯ͠ಈ࡞ͤ͞

ܧଓతʹ։ൃ͢ΔͨΊʹɺ
 
ઃܭͷݪଇΛར༻ͯ͠ɺ
 
։ൃͨ͠࿩
2023 March 16th
גࣜձࣾαΠόʔΤʔδΣϯτ

takahirom(@new_runnable)

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ࣗݾ঺հ
2
ໟडਸ༸ (ΊΜ͡Ύ͔ͨͻΖ ͱಡΈ·͢)

takahiromͱ͍͏໊લͰΑ͘Qiitaॻ͍ͨΓOSS
࡞ͬͨΓ͍ͯ͠·͢ɻ

ABEMAɺAndroidΤϯδχΞ
 
CyberAgent Developer Expert

Google Developers Expert for Android

DroidKaigi Co-Organizer, App Leader

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ࠓճ঺հ͢Δ࣮૷Λಋೖͨ͠ը໘
3
ػೳ

● ์ૹͷࢹௌ

● ௥͔͚ͬ࠶ੜͷࢹௌ

● ݟಀ͠഑৴ࢹௌ

● ϚϧνΞϯάϧ

● ίϝϯτ

● ͳͲ

FIFA ϫʔϧυΧοϓ Χλʔϧ 2022 ޙ΋ɺ
 
ܧଓͯ͠ར༻͍ͯ͘͠ը໘
FIFA ϫʔϧυΧοϓ Χλʔϧ 2022 ʹ޲͚ͯ৽ن
Ͱ࡞੒ͨ͠ը໘
ABEMAͰFIFA ϫʔϧυΧοϓΛࢹௌ͢Δํ๏͸ʁϚϧνΞϯάϧɺݟಀ͠഑৴ɺ௥͔͚ͬ࠶ੜͳͲศརͳػೳΛ͝঺հ

https://times.abema.tv/fifaworldcup/articles/-/10036755

“ABEMAͰϫʔϧυΧοϓ2022Λࢹௌ͢Δํ๏ʂྉۚ͸͍͘Βʁ࿥ը͸Ͱ͖Δʁ”ΑΓ

https://times.abema.tv/fifaworldcup/articles/-/10048409

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ࠓճͷ“ઃܭͷݪଇ”ͱ͸
4
AndroidͷެࣜαΠτʹ
 
AndroidͷΞϓϦͷઃܭΨΠυ͕͋Γɺ

ͦͷதʹ͍͔ͭ͘ݪଇ͕ࡌ͍ͬͯͯɺ

ͦΕΛࢀߟʹ͠ͳ͕Β

ABEMAͰͲ͏࡞ͬͨͷ͔Λઆ໌͍͖ͯ͠·
͢ɻ

͢΂ͯͷΞϓϦͰ࢖͑Δ΋ͷͰ͸ͳ͘ɺ
 
վળ఺͕·ͩ·ͩ͋Δͱࢥ͏ͷͰɺ
 
͜͏͍͏΍Γํ΋͋Δͷ͔ͱ͍͏͙Β͍Ͱײ͡
Ͱݟ͍͚ͯͨͩΔͱΑ͍͔΋͠Ε·ͤΜɻ
Android DevelopersͷGuide to app architectureͳͲʹ
 
ܝࡌ͞Ε͍ͯΔ΋ͷ
Guide to app architecture

https://developer.android.com/topic/architecture

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Single Source of Truth
5

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ϝϦοτ
Android Developersʹ͋Δઃܭ֓೦Λ
ࢀর
Single Source of Truth(SSoT)ͱ͸
6
https://developer.android.com/topic/architecture#single-source-of-truth

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ϝϦοτ
ࢀর
6
● Guide to app architectureͷCommon architectural
principlesͷҰͭ

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ϝϦοτ
ࢀর
6
principlesͷҰͭ
● ϙΠϯτ

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ϝϦοτ
ࢀর
6
principlesͷҰͭ
● ϙΠϯτ
○ SSoT͸σʔλͷΦʔφʔ

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ϝϦοτ
ࢀর
6
principlesͷҰͭ
● ϙΠϯτ
○ SSoT͚͕ͩσʔλΛมߋͰ͖Δ

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ϝϦοτ
ࢀর
6
principlesͷҰͭ
● ϙΠϯτ
○ SSoT͸ImmutableͳσʔλΛެ։͢Δ

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ϝϦοτ
ࢀর
6
principlesͷҰͭ
● ϙΠϯτ
○ SSoT͸֎͔ΒσʔλΛมߋՄೳͳؔ਺͔
ΠϕϯτΛड͚औΔ

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ϝϦοτ
ࢀর
6
principlesͷҰͭ
● ϙΠϯτ
● σʔλͷूத؅ཧ

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ϝϦοτ
ࢀর
6
principlesͷҰͭ
● ϙΠϯτ
● ଞͷͱ͜Ζ͔Βσʔλ͕มߋ͞Εͳ
͍Α͏ʹอޢ͢Δ

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ϝϦοτ
ࢀর
6
principlesͷҰͭ
● ϙΠϯτ
● ଞͷͱ͜Ζ͔Βσʔλ͕มߋ͞Εͳ
͍Α͏ʹอޢ͢Δ
● σʔλ΁ͷมߋ͕௥੻ՄೳʹͳΔ

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΋ͱ΋ͱͷ࣮૷ͷ໰୊఺1
Single Source of Truth(SSoT)ΛͲ͏࢖͔ͬͨ
7
fun playIfNeeded() {

if(!isResumed) return

if(!player.isPlaying()) return

if(!viewModel.isAuthorized()) {

// Ͳ͔͜Ͱ·ͨplayIfNeededΛ

// ݺͿඞཁ͕͋Δ

requestAuthorize()

return

}

if(!viewModel.isUserPaused()) {

return

}

player.play()

}

ΠϕϯτϕʔεͰಈ͘ίʔυͷྫ

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΋ͱ΋ͱͷ࣮૷ͷ໰୊఺1
7
● ΠϕϯτϕʔεͰίʔυ͕ಈ͘Α͏ʹͳ͍ͬͯͯSSoT͕ͳ͔ͬͨ





// ݺͿඞཁ͕͋Δ

requestAuthorize()

return

}


return

}

player.play()

}


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΋ͱ΋ͱͷ࣮૷ͷ໰୊఺1
7
○ ྫ͑͹ɺplayIfNeeded()ΛݺΜͩΒதͰ࠶ੜՄೳ͔Λ൑ఆͯ͠࠶
ੜ͢ΔͳͲɻ





// ݺͿඞཁ͕͋Δ

requestAuthorize()

return

}


return

}

player.play()

}


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΋ͱ΋ͱͷ࣮૷ͷ໰୊఺1
7
ੜ͢ΔͳͲɻ
○ ద੾ͳλΠϛϯάͰ͜ΕΛݺ͹ͳ͍ͱ࠶ੜ͞Εͳ͔ͬͨΓ͢
Δɻ





// ݺͿඞཁ͕͋Δ

requestAuthorize()

return

}


return

}

player.play()

}


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΋ͱ΋ͱͷ࣮૷ͷ໰୊఺1
7
ੜ͢ΔͳͲɻ
○ ద੾ͳλΠϛϯάͰ͜ΕΛݺ͹ͳ͍ͱ࠶ੜ͞Εͳ͔ͬͨΓ͢
Δɻ
○ ϓϨΠϠʔͷঢ়ଶͷSSoT͸Ͳ͜ͳͷ͔ෆ໌ͩͬͨɻViewʁ
PlayerʁViewModelʁ





// ݺͿඞཁ͕͋Δ

requestAuthorize()

return

}


return

}

player.play()

}


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΋ͱ΋ͱͷ࣮૷ͷ໰୊఺2
8
ViewModel಺Ͱ੔߹ੑΛऔΔͷ͕೉͍͠ྫ

class ViewModel {

val shouldPlay = MutableStateFlow(false)

val authorized = MutableStateFlow(false)

val isResumed = MutableStateFlow(false)

private fun authorized() {

authorized.value = true

if (isResumed.value) {

shouldPlay.value = true

}

}

fun onResume() {

isResumed.value = true

if (authorized.value) {


}

}

}

※UI states: single stream or multiple streams? https://developer.android.com/topic/architecture/ui-layer

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΋ͱ΋ͱͷ࣮૷ͷ໰୊఺2
8
● ੔߹ੑ

class ViewModel {








}

}

fun onResume() {




}

}

}


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΋ͱ΋ͱͷ࣮૷ͷ໰୊఺2
8
● ੔߹ੑ
○ ViewModelͷ͍ΖΜͳؔ਺͔Β͍Ζ͍Ζͳঢ়ଶΛ
͍͡ΔͷͰ੔߹ੑΛऔΔͷ͕೉͔ͬͨ͠ɻ

class ViewModel {








}

}

fun onResume() {




}

}

}


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΋ͱ΋ͱͷ࣮૷ͷ໰୊఺2
8
● ੔߹ੑ
○ ViewModelͷ͍ΖΜͳؔ਺͔Β͍Ζ͍Ζͳঢ়ଶΛ
͍͡ΔͷͰ੔߹ੑΛऔΔͷ͕೉͔ͬͨ͠ɻ
○ ύϑΥʔϚϯεͳͲͷӨڹ͕͋·Γͳͦ͞͏ͳͱ
͜ΖͰɺؔ࿈͋Δ΋ͷʹؔͯ͠͸੔߹ੑͷ؍఺͔
ΒUiModel͸Ͱ͖Δ͚ͩҰ͕͍͍ͭ (※)

class ViewModel {








}

}

fun onResume() {




}

}

}


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Ͳ͏͔ͨ͠
9

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Ͳ͏͔ͨ͠
9
● buildUiModel(stateFlow1, stateFlow2, block: (T1, T2) -> R): StateFlow ͱ͍͏
 
ؔ਺Λఆٛͨ͠ɻ

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Ͳ͏͔ͨ͠
9
 
ؔ਺Λఆٛͨ͠ɻ
○ StateFlowΛ࡞Δؔ਺ɻ

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Ͳ͏͔ͨ͠
9
 
ؔ਺Λఆٛͨ͠ɻ
○ ViewModelͷதͰ࢖͏ɻ

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Ͳ͏͔ͨ͠
9
 
ؔ਺Λఆٛͨ͠ɻ
○ ViewModelͷதͰ࢖͏ɻ
○ த਎͸جຊతʹ͸Flowͷcombine()͕ͩɺॳظ஋ΛଞͷStateFlow͔ΒblockΛݺͼ
ग़ͯ͠ɺܭࢉ͢Δ৔ॴΛҰͭʹͰ͖ΔΑ͏ʹͨ͠ɻ

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buildUiModel()ͷఆٛ
10
fun ViewModel.buildUiModel(

flow: StateFlow,

flow2: StateFlow,

flow3: StateFlow,

transform: (T1, T2, T3) -> R,

): StateFlow = combine(

flow = flow,

flow2 = flow2,

flow3 = flow3,

transform = transform

).stateIn(

scope = viewModelScope,

started = SharingStarted.WhileSubscribed(5_000),

initialValue = transform(

flow.value, flow2.value, flow3.value

)

)

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buildUiModel()ͷఆٛ
10
fun ViewModel.buildUiModel(

flow: StateFlow,

flow2: StateFlow,

flow3: StateFlow,

transform: (T1, T2, T3) -> R,

): StateFlow = combine(

flow = flow,

flow2 = flow2,

flow3 = flow3,

transform = transform

).stateIn(

scope = viewModelScope,

started = SharingStarted.WhileSubscribed(5_000),

initialValue = transform(

flow.value, flow2.value, flow3.value

)

)
͜͜Ͱॳظ஋Λܭࢉͯ͠͠·͏

Ҿ਺͕͢΂ͯStateFlowͳͷͰɺ͜Ε
͕ՄೳʹͳΔɻ

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private val productPlaybackStateFlow: StateFlow = buildUiModel(

isScreenVisibleStateFlow,

isUserPausedStateFlow,

isAuthorizedStateFlow

) { screenVisible, userPaused, authorized ->

if(!authorized) {

ProductPlaybackState.ShouldStop

}else if (userPaused || !screenVisible) {

ProductPlaybackState.ShouldPause

} else {

ProductPlaybackState.ShouldPlay

}

}

ྫ
11

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if(!authorized) {




} else {


}

}

ྫ
11
immutableͳσʔλΛ
 
࣋ͭStateFlow

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if(!authorized) {




} else {


}

}

ྫ
11
buildUiModel()
immutableͳσʔλΛ
 
࣋ͭStateFlow

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if(!authorized) {




} else {


}

}

ྫ
11
buildUiModel()
immutableͳσʔλΛ
 
࣋ͭStateFlow
ଞͷStateFlowΛҾ਺ʹऔΔͷͰ

ωετͯ͠ఆٛ΋Ͱ͖Δ

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if(!authorized) {




} else {


}

}

ྫ
11
buildUiModel()
ॳظ஋͕ϩδοΫʹΑͬͯܭࢉ͞
ΕΔͨΊɺࢦఆ͢Δඞཁ͕ͳ͘ɺ

͜ͷϩδοΫ͕஋Λ࡞ΔSSoTʹ
ͳ͍ͬͯΔ
immutableͳσʔλΛ
 
࣋ͭStateFlow
ଞͷStateFlowΛҾ਺ʹऔΔͷͰ

ωετͯ͠ఆٛ΋Ͱ͖Δ

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τϨʔυΦϑ͸ʁ୅ସखஈ͸ʁ
12

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12
● τϨʔυΦϑ

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12
● τϨʔυΦϑ
○ buildUiModel()ͷҾ਺͕ଟ͘ͳΓ͗͢Δɺͭ·Γ͏·͘෼཭Ͱ͖͍ͯͳ͍ύλʔϯ͕͋ͬͨɻ

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12
● τϨʔυΦϑ
■ 9ݸҎ্͸૿΍͞ͳ͍ͱ͍͏੍໿Λ͚ͭͯɺωετͯ͠͏·͘࡞ΕΔΑ͏ʹͨ͠ɻ

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12
● τϨʔυΦϑ
○ ͋Δσʔλʹର͢ΔҰ؏ੑ͸อͪ΍͍͕͢ɺྫ͑͹API͔ΒԿ͔Λऔಘͨ͋͠ͱʹԿΛॻ͖׵͑Δͷ͔ɺͲ͏Ξϓ
ϦέʔγϣϯʹӨڹΛ༩͑Δͷ͔ͷॲཧ͸ٯʹ௥͍ʹ͘͘ͳΔ͔΋͠Εͳ͍ɻ

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12
● τϨʔυΦϑ
■ ͜Ε͸τϨʔυΦϑͱͯ͠ड͚ೖΕ͍ͯΔɻ

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12
● τϨʔυΦϑ
● ୅ସखஈ

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12
● τϨʔυΦϑ
● ୅ସखஈ
○ Cash AppͷMoleculeͰ΋ྑ͔ͬͨɻ

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12
● τϨʔυΦϑ
● ୅ସखஈ
■ ͜ΕΛ࢖͏ͱJetpack ComposeΛ࢖ͬͯStateFlowΛ࡞ΕΔɻ

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12
● τϨʔυΦϑ
● ୅ସखஈ
■ ͜ΕΛ࢖͏ͱJetpack ComposeΛ࢖ͬͯStateFlowΛ࡞ΕΔɻ
■ ͦΕͧΕͷίϯϙʔωϯτͷUiModelͷ࡞੒ͳͲΛɺؔ਺ʹ੾Γग़͍͕ͨ͠ɺͦ͏ͯ͠େ͖͘ͳ͍ͬͯͬ
ͨͱ͖ʹύϑΥʔϚϯε͕Ͳ͏ͳͷ͔ͳͲɺݒ೦͕͋Γ࠾༻Ͱ͖ͳ͔ͬͨɻ(ѱ͍Θ͚Ͱ͸ͳ͘ଌΕ͍ͯ
ͳ͍͚ͩͰ͢ɻ)

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Unidirectional Data Flow
13

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ϝϦοτ
Android Developersʹ͋Δઃܭ֓೦
Λࢀর
Unidirectional Data Flow(UDF)ͱ͸
14
https://developer.android.com/topic/architecture#unidirectional-data-flow

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ϝϦοτ
Λࢀর
14
● Guide to App Architectureͷ
Common architectural principlesͷҰ
ͭ

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ϝϦοτ
Λࢀর
14
ͭ
● ϙΠϯτ

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ϝϦοτ
Λࢀর
14
ͭ
● ϙΠϯτ
○ State͕Ұํ޲ʹྲྀΕɺ
 
Event͕ٯଆʹྲྀΕΔɻ

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ϝϦοτ
Λࢀর
14
ͭ
● ϙΠϯτ
 
● SSoTʹΑͬͯಘΒΕΔརӹɻ

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ϝϦοτ
Λࢀর
14
ͭ
● ϙΠϯτ
 
● SSoTʹΑͬͯಘΒΕΔརӹɻ
● Ұ؏ੑɺޡΓΛݮΒ͢ɺσόοάΛָ
ʹ͢Δ

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΋ͱ΋ͱͷ࣮૷ͷ໰୊఺
Unidirectional Data Flow(UDF)ΛͲ͏࢖͔ͬͨ
15

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΋ͱ΋ͱͷ࣮૷ͷ໰୊఺
15
● Fragment΍RecyclerViewͷΞΠςϜ·Ͱɺ͞
·͟·ͳͱ͜Ζʹಉ͡ViewModel͕Ͱͯ͘Δ࣮
૷ʹͳ͍ͬͯͯσʔλͷྲྀΕ͕౷Ұ͞Ε͍ͯͳ
͔ͬͨɻ͜ΕʹΑΓɺσόοάͳͲ͕೉͘͠ͳ
ΔͳͲ͕ൃੜ͍ͯͨ͠ɻ

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΋ͱ΋ͱͷ࣮૷ͷ໰୊఺
16

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΋ͱ΋ͱͷ࣮૷ͷ໰୊఺
16
● ৽͍͠Jetpack Compose ͔ ࣮੷ͷAndroid View ͔ɺͲͪΒΛ࢖͏͔ɻ

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΋ͱ΋ͱͷ࣮૷ͷ໰୊఺
16
○ ΋͠ऴ൫ʹக໋తͳ໰୊͕ݟ͔ͭΔͱऔΓฦ͕͔ͭ͠ͳ͔ͬͨͷͰɺ
 
දࣔͷج൫ͱͳΔ෦෼ʹ͸ΞϓϦ಺Ͱ࣮੷ͷ͋ΔAndroid ViewΛ࢖͍ͨ
͔ͬͨɻ

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΋ͱ΋ͱͷ࣮૷ͷ໰୊఺
16
○ ΋͠ऴ൫ʹக໋తͳ໰୊͕ݟ͔ͭΔͱऔΓฦ͕͔ͭ͠ͳ͔ͬͨͷͰɺ
 
දࣔͷج൫ͱͳΔ෦෼ʹ͸ΞϓϦ಺Ͱ࣮੷ͷ͋ΔAndroid ViewΛ࢖͍ͨ
͔ͬͨɻ
○ ࠓޙͷJetpack Composeͱͷޓ׵ੑΛͲ͏୲อ͢Δ͔ʁ

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Ͳ͏͔ͨ͠
17
class ViewBinder(

private val binding: PlayerBinding,

onUserPlayerPaused: () -> Unit

) {

fun apply(uiModel: PlayerUiModel) {

binding.title.text = uiModel.title

binding.pauseButton.setOnClickListener {

onUserPlayerPaused()

}

}

}

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Ͳ͏͔ͨ͠
17
● ViewBinderͱ͍͏ΫϥεΛఆٛͨ͠ɻ class ViewBinder(



) {





}

}

}

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Ͳ͏͔ͨ͠
17
● ViewBinderͱ͍͏ΫϥεΛఆٛͨ͠ɻ
○ ͜ͷΫϥεʹ͸Ҿ਺ʹViewModelͳͲ
Λ౉͞ͳ͍ͱ͍͏੍໿Λ͚ͭͯɺView
͸جຊతʹ͸͜ͷதͰมߋΛՃ͑Δɻ
class ViewBinder(



) {





}

}

}

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Ͳ͏͔ͨ͠
17
● ViewBinderͱ͍͏ΫϥεΛఆٛͨ͠ɻ
○ ͜ͷΫϥεʹ͸Ҿ਺ʹViewModelͳͲ
Λ౉͞ͳ͍ͱ͍͏੍໿Λ͚ͭͯɺView
͸جຊతʹ͸͜ͷதͰมߋΛՃ͑Δɻ
○ Jetpack ComposeʹҠߦ͠ऴΘΕ͹ফ
ͤΔΫϥεɻ
class ViewBinder(



) {





}

}

}

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Ͳ͏͔ͨ͠
18
class ViewBinder(



) {





}

}

}
ͨͩͷγϯϓϧͳΫϥε

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Ͳ͏͔ͨ͠
18
class ViewBinder(



) {





}

}

}
ݺͼݩ͔Βσʔλ͕౉͞ΕΔ
buildUiModel()ʹΑͬͯ౷߹͞Εͨ
UiModel͕౉ͬͯ͘ΔͷͰɺ

apply()ؔ਺͸ҰͭͷΈʹͳΓγϯϓϧ

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Ͳ͏͔ͨ͠
18
class ViewBinder(



) {





}

}

}
ݺͼݩ͔Βσʔλ͕౉͞ΕΔ
ݺͼݩʹΠϕϯτΛ౉͢
buildUiModel()ʹΑͬͯ౷߹͞Εͨ
UiModel͕౉ͬͯ͘ΔͷͰɺ

apply()ؔ਺͸ҰͭͷΈʹͳΓγϯϓϧ

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Ͳ͏͔ͨ͠
19

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Ͳ͏͔ͨ͠
19
→

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20
● τϨʔυΦϑ

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20
● τϨʔυΦϑ
○ ViewBinderͱ͍͏ଘࡏࣗମ͕ೃછΈ͕ͳ͍ͷͰֶशίετ্͕͕Δɻ

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20
● τϨʔυΦϑ
○ ViewBinderΫϥεͷҾ਺͕Πϕϯτͷ਺͚ͩͰ͖ΔͷͰଟ͘ͳΓ͕ͪ

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20
● τϨʔυΦϑ
■ → ໊લ෇͖Ҿ਺ʹͳΓɺ௥͍΍͍͢ͷͰɺͦ͜·Ͱͷ໰୊ʹ͸ͳΒͳ͍͸ͣɻ

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20
● τϨʔυΦϑ
○ ViewBinderͷதʹ͸View͚ͩͰͳ͘Compose΋ೖ͍ͬͯͨͷͰɺComposeͰ͸஋Λ౉͢ͱ͖ʹStateFlowΛ౉͢ඞཁ͕͋ͬ
͕ͨStateFlow΋ViewBinderʹ౉͢ඞཁ͕͋ͬͨͷͰɺͦΕʹΑͬͯదԠํ๏͕෼ࢄͯ͠͠·͍ͬͯͨɻ

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20
● τϨʔυΦϑ
■ → ͏·͘StateFlowͷΈͰಈ͔͢Α͏ʹ͢ΔͳͲͷ࢓૊Έ͕ඞཁɻ

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20
● τϨʔυΦϑ
○ ࡉ͔͍஋ͷมԽͰ͢΂ͯΛViewBinder.apply()ͰViewʹదԠ͠௚͢ͷͰύϑΥʔϚϯεతʹ·ͣͦ͏Ͱ͸ʁ

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20
● τϨʔυΦϑ
○ ࡉ͔͍஋ͷมԽͰ͢΂ͯΛViewBinder.apply()ͰViewʹదԠ͠௚͢ͷͰύϑΥʔϚϯεతʹ·ͣͦ͏Ͱ͸ʁ
■ → (࣍ϖʔδ)

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ύϑΥʔϚϯεతʹ·ͣͦ͏ͱ͍͏࿩
21
ViewBinder.apply()Λେ͖ͳ୯ҐͰ૸ΒͤΔͱɺ
 
ྫ͑͹TextView͕தʹ͋Δͱɺ
 
wrap_contentͷ৔߹͸ಉ͡ςΩετͰ΋
requestLayout()͕૸ΓશମΛϨΠΞ΢τ͠௚͢

→ ԿΒ͔ͷࠩ෼ߋ৽͕ඞཁͦ͏


…

}

textView.setText()͔ΒrequestLayout()͕ݺ͹Ε͍ͯΔྫ

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ύϑΥʔϚϯεʹؔͯ͠ɺJetpack Compose͕಺෦తʹߦ͍ͬͯΔΞϓϩʔν
22

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22
● Jetpack ComposeͰ͸ঢ়ଶΛComposableؔ਺ຖʹ͍࣋ͬͯͯ(SlotTable)ɺؔ਺ͷҾ਺͕มΘͬͨ࣌ͷΈؔ਺தͷॲཧΛ
ߦ͏ɻ(͍ΘΏΔdonut-hole skipping)

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22
inline fun View.updateTag(

@IdRes tagId: Int,

value: T,

onUpdate: (old: T?, new: T) -> Unit

) {

val old: T? = getTag(tagId) as? T

if (old != value) {

setTag(tagId, value)

onUpdate(old, value)

}

}

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22

@IdRes tagId: Int,

value: T,


) {


if (old != value) {



}

}

● ͜ΕΛٖࣅతʹViewͰ΋Ͱ͖ͳ͍͔ʁ

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22

@IdRes tagId: Int,

value: T,


) {


if (old != value) {



}

}

○ View.updateTag { }ͱ͍͏ؔ਺Λ࡞੒

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22

@IdRes tagId: Int,

value: T,


) {


if (old != value) {



}

}

■ Viewͷอ࣋͢ΔtagΛར༻ͯ͠
 
ࠩ෼͕͋Ε͹౉͞Εͨؔ਺ΛݺͿ

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22

@IdRes tagId: Int,

value: T,


) {


if (old != value) {



}

}

■ Viewͷอ࣋͢ΔtagΛར༻ͯ͠
 
ࠩ෼͕͋Ε͹౉͞Εͨؔ਺ΛݺͿ
■ ͜ΕΛViewBinder.apply()ͷதͰɺ
 
ར༻͍ͯ͘͜͠ͱͰղܾɻ

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ViewModel͔ΒUIʹΠϕϯτΛૹΒͳ͍
23

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ϝϦοτ
Android Developersͷ
Recommendations for Android
architectureΑΓ
“ViewModel͔ΒUIʹΠϕϯτΛૹΒͳ͍”ͱ͸
24
https://developer.android.com/topic/architecture/
recommendations?hl=en

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ϝϦοτ
architectureΑΓ
24
● UI layerʹ͋Δ߲໨ͰɺStrongly
recommended

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ϝϦοτ
architectureΑΓ
24
recommended
● ϙΠϯτ

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ϝϦοτ
architectureΑΓ
24
recommended
● ϙΠϯτ
○ UIͷΞΫγϣϯ͸ΠϕϯτͰ͸ͳ
͘ɺUI StateͷΞοϓσʔτʹ
ΑͬͯߦΘΕΔ΂͖ɻ

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ϝϦοτ
architectureΑΓ
24
recommended
● ϙΠϯτ
● Πϕϯτ͕࠶ݱՄೳʹͳΔɻ

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ϝϦοτ
architectureΑΓ
24
recommended
● ϙΠϯτ
● Πϕϯτ͕࠶ݱՄೳʹͳΔɻ
● UIΞΫγϣϯ͕ࣦΘΕͳ͍͜ͱ͕อূ
͞ΕΔɻ

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΋ͱ΋ͱͷ࣮૷ͷ໰୊఺

“ViewModel͔ΒUIʹΠϕϯτΛૹΒͳ͍”ΛͲ͏࢖͔ͬͨ
25

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΋ͱ΋ͱͷ࣮૷ͷ໰୊఺

25
● collect{}ͷλΠϛϯάͳͲͰɺSharedFlowΛ࢖͏ίʔυͰόά͕ى͖Δ͜ͱ͕
͋ͬͨɻ

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΋ͱ΋ͱͷ࣮૷ͷ໰୊఺

25
͋ͬͨɻ
○ ྫ͑͹ɺreplay=0ͷ৔߹ɺrepeatOnLifecycle(Lifecycle.State.STARTED)ͳ
ͲΛ࢖͍ͬͯͯɺΠϕϯτ͕STARTEDҎલʹૹΒΕΔͱফ͑ΔͳͲ

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΋ͱ΋ͱͷ࣮૷ͷ໰୊఺

25
͋ͬͨɻ
○ ྫ͑͹ɺreplay=0ͷ৔߹ɺrepeatOnLifecycle(Lifecycle.State.STARTED)ͳ
ͲΛ࢖͍ͬͯͯɺΠϕϯτ͕STARTEDҎલʹૹΒΕΔͱফ͑ΔͳͲ
● ·ͨɺςετͩͱFake͕ૣ͘σʔλΛฦ͢ӨڹͰɺࢠͷFragmentͰσʔλΛड
͚औΔલʹSharedFlow͕ൃՐ͢ΔͳͲςετ΋೉͍͠ύλʔϯ͕͋Δ

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Ͳ͏͔ͨ͠
26
RequestStateͱ͍͏ΦϒδΣΫτΛ࡞ΔΑ͏ʹͯ͠ɺ͜ΕΛStateFlowͱ͠
ͯViewModelͰ࣋ͬͯॻ͖׵͑ΔΑ͏ʹͨ͠ɻ࠷ऴతʹ͸buildUiModel()ʹ
Αͬͯ͜Ε΋UiModelͷҰͭͷཁૉͱͯ͠ೖΔɻ

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Ͳ͏͔ͨ͠
27
// ViewBinder.apply()ͷத

if (alertRequestStates.showPlaybackErrorAlertRequestState.isRequested()) {

onShowPlaybackErrorAlert()

showSnackbar(message)

}
// ViewModel

val showPlaybackErrorAlertRequestState =
MutableStateFlow(RequestState.NotRequested)

fun hoge() {

try {

...

} catch(e: PlaybackError) {

showPlaybackErrorAlertRequestState.value =
RequestState.Requested(PlaybackErrorAlert)

}

}

fun onShowPlaybackErrorAlert() {

RequestState.NotRequested

}

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Ͳ͏͔ͨ͠
27




}
// ViewModel


fun hoge() {

try {

...



}

}



}

ᶃ StateFlowΛఆٛ

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Ͳ͏͔ͨ͠
27




}
// ViewModel


fun hoge() {

try {

...



}

}



}

ᶄ RequestedΛηοτ

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Ͳ͏͔ͨ͠
27




}
// ViewModel


fun hoge() {

try {

...



}

}



}

ᶅ Requestedʹͳͬͨ΋ͷΛ

ফඅ͢Δ

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Ͳ͏͔ͨ͠
27




}
// ViewModel


fun hoge() {

try {

...



}

}



}

ᶅ Requestedʹͳͬͨ΋ͷΛ

ফඅ͢Δ
ᶆ NotRequestedʹ໭͢

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28

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28
● τϨʔυΦϑ

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28
● τϨʔυΦϑ
○ ίʔυ͕૿͑Δมߋɻ

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28
● τϨʔυΦϑ
■ ϘΠϥʔϓϨʔτͬΆ͍ײ͡͸͋ΔͷͰɺͲͷStateΛม͍͑ͯΔ͔ͳͲҙਤͨ͠มߋͳͷ͔Ͳ͏͔͸Ϩ
Ϗϡʔ͢Δඞཁ͕͋Δɻ

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28
● τϨʔυΦϑ
■ ୅ΘΓʹϓϨΠϠʔͷStateͳͲͰ͸໌֬ʹSingle Source of Truth͕࡞ΒΕͨͨΊɺ໌Β͔ʹ؅ཧ͠΍͘͢
ͳͬͨײ͕͋͡Δɻ

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28
● τϨʔυΦϑ
ͳͬͨײ͕͋͡Δɻ
■ ίʔυͷ౷Ұײ͸Ͱ͖ͨɻComposeͷLaunchedEffect()ͳͲʹ΋ޓ׵ੑ͕͋Δ͸ͣɻ

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28
● τϨʔυΦϑ
ͳͬͨײ͕͋͡Δɻ
● ୅ସखஈ

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28
● τϨʔυΦϑ
ͳͬͨײ͕͋͡Δɻ
● ୅ସखஈ
○ UiModelʹมߋ͢ΔͨΊͷϥϜμΛ౉͢Α͏ͳ΍Γํ΋ࢼͯ͠Έͯ΋ྑ͍͔΋͠Εͳ͍ɻ˞

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28
● τϨʔυΦϑ
ͳͬͨײ͕͋͡Δɻ
● ୅ସखஈ
○ UiModelʹมߋ͢ΔͨΊͷϥϜμΛ౉͢Α͏ͳ΍Γํ΋ࢼͯ͠Έͯ΋ྑ͍͔΋͠Εͳ͍ɻ˞
※ https://developer.android.com/topic/architecture/ui-layer/events#recyclerview-events

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ςετͰ͸Ͱ͖Δ͚ͩ

ຊ෺ͷΦϒδΣΫτΛ࢖͏
29

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GoogleͷDIϥΠϒϥϦ Dagger Hiltͷ
υΩϡϝϯτͷHilt Testing
PhilosophyΑΓ
ςετͰ͸Ͱ͖Δ͚ͩຊ෺ͷΦϒδΣΫτΛ࢖͏
30
ϝϦοτ
https://dagger.dev/hilt/testing-philosophy.html ΑΓ

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PhilosophyΑΓ
30
● ҎԼͷॱ൪Ͱ࢖͏
ϝϦοτ

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PhilosophyΑΓ
30
○ ຊ෺ͷΦϒδΣΫτ
ϝϦοτ

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PhilosophyΑΓ
30
○ ϥΠϒϥϦ͕ఏڙ͢ΔFake
ϝϦοτ

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PhilosophyΑΓ
30
○ Mock
ϝϦοτ

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PhilosophyΑΓ
30
○ Mock
● (ύϑΥʔϚϯεͳͲͷཁ݅ʹΑΓม
ΘΔɻ)
ϝϦοτ

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PhilosophyΑΓ
30
○ Mock
ΘΔɻ)
ϝϦοτ
● ຊ෺ͷΦϒδΣΫτ͸ຊ౰ͷ໰୊ΛΩϟον͢Δ

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PhilosophyΑΓ
30
○ Mock
ΘΔɻ)
ϝϦοτ
● ಉ͡ΧόϨοδʹରͯ͠ɺগͳ͍ςετίʔυͰྑ͘ͳ
Δ

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PhilosophyΑΓ
30
○ Mock
ΘΔɻ)
ϝϦοτ
Δ
● ςετ͕ࣦഊ͢Δͱ͖͸ຊ౰ͷ໰୊Λर͍ͬͯΔՄೳੑ
͕ߴ͘ͳΔ

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PhilosophyΑΓ
30
○ Mock
ΘΔɻ)
ϝϦοτ
Δ
● ςετ͕ࣦഊ͢Δͱ͖͸ຊ౰ͷ໰୊Λर͍ͬͯΔՄೳੑ
͕ߴ͘ͳΔ
● Ϣʔβʔ͔Βͷ؍఺Ͱςετ͠΍͍͢

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΋ͱ΋ͱͷ࣮૷ͷ໰୊఺
“ςετͰ͸Ͱ͖Δ͚ͩຊ෺ͷΦϒδΣΫτΛ࢖͏”ΛͲ͏࢖͔ͬͨ
31
※ʮFIFA ϫʔϧυΧοϓ Χλʔϧ 2022ʯΛશ64ࢼ߹ແྉੜதܧ͢ΔʮABEMAʯ͕αοΧʔͷ
৽͍͠ࢹௌମݧΛଅਐ͢Δ৽ػೳΛൃදɺແྉͷʮݟಀ͠ϑϧϚον഑৴ʯ΍ʮϋΠϥΠτө૾ʯ
ͳͲɺ11݄20೔ʢ೔ʣ։ນͱಉ࣌ʹఏڙ։࢝

https://www.cyberagent.co.jp/news/detail/id=28189

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΋ͱ΋ͱͷ࣮૷ͷ໰୊఺
31
● ࠓճͷ࣮૷Ͱ͸ը໘ͷঢ়ଶ͚ͩͰ΋ɺ์ૹͷ଴ػɺ์ૹͷ
ࢹௌɺ௥͔͚ͬ࠶ੜͷࢹௌɺݟಀ͠഑৴ͷࢹௌ˞͕͋Γɺ
์ૹͷऴྃɺ։࢝ΛखಈͰςετ͢Δʹ͸ࣗ෼Ͱ൪૊Λฤ
੒ͯ͠ɺ์ૹ࣌ؒ·Ͱ଴ͬͨΓɺ์ૹऴྃΛ଴ͬͨΓ͢Δ
ඞཁ͕͋Δɻ
※ʮFIFA ϫʔϧυΧοϓ Χλʔϧ 2022ʯΛશ64ࢼ߹ແྉੜதܧ͢ΔʮABEMAʯ͕αοΧʔͷ


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΋ͱ΋ͱͷ࣮૷ͷ໰୊఺
31
● ࠓճͷ࣮૷Ͱ͸ը໘ͷঢ়ଶ͚ͩͰ΋ɺ์ૹͷ଴ػɺ์ૹͷ
ࢹௌɺ௥͔͚ͬ࠶ੜͷࢹௌɺݟಀ͠഑৴ͷࢹௌ˞͕͋Γɺ
์ૹͷऴྃɺ։࢝ΛखಈͰςετ͢Δʹ͸ࣗ෼Ͱ൪૊Λฤ
੒ͯ͠ɺ์ૹ࣌ؒ·Ͱ଴ͬͨΓɺ์ૹऴྃΛ଴ͬͨΓ͢Δ
ඞཁ͕͋Δɻ
● ViewModelɺUseCaseͳͲݸผʹࡉ͔͘ςετΛॻ͍͍ͯ
ͯɺ࣮ࡍͷ໰୊ΛΩϟον͠ʹ͘͘ɺࡉ͔͍ϓϩύςΟ͕
૿͑ΔͳͲͰςετ͕յΕͨΓվमΛೖΕΔࣄ͕ଟ͔ͬ
ͨɻ ※ʮFIFA ϫʔϧυΧοϓ Χλʔϧ 2022ʯΛશ64ࢼ߹ແྉੜதܧ͢ΔʮABEMAʯ͕αοΧʔͷ


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Ͳ͏͔ͨ͠
32

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Ͳ͏͔ͨ͠
32
Robolectric + Dagger HiltͰςετΛ࣮૷͢Δ

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Ͳ͏͔ͨ͠
32
● Robolectric

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Ͳ͏͔ͨ͠
32
● Robolectric
○ ͭ·Γ࣮ߦ؀ڥ͸࣮ػͰ͸ͳ͘JVM্Ͱಈ͔͢ςε
τɻEspressoͱಉ͡ςετίʔυͰςετΛॻ͚Δɻ

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Ͳ͏͔ͨ͠
32
● Robolectric
○ UIʹؔͯ͠ຊ෺ͷΦϒδΣΫτͰ͸ͳ͘ͳΔ͕ɺςε
τͷ҆ఆੑΛ֬อ͢ΔͨΊ

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Ͳ͏͔ͨ͠
32
● Robolectric
● Hilt

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Ͳ͏͔ͨ͠
32
● Robolectric
● Hilt
○ ΞϓϦ಺ͰAPI͚ͩFakeʹஔ͖׵͑Λߦ͏

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Ͳ͏͔ͨ͠
32
● Robolectric
● Hilt
■ Dagger HiltͷTestInstallIn()Λ࢖ͬͯAPI͚ͩஔ
͖׵͑Δɻ

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Ͳ͏͔ͨ͠
32
● Robolectric
● Hilt
■ Dagger HiltͷTestInstallIn()Λ࢖ͬͯAPI͚ͩஔ
͖׵͑Δɻ
■ ͜ΕʹΑΓ΄ͱΜͲͷ࣮૷͕ຊ෺ͷΦϒδΣΫ
τͱͳΔ

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Ͳ͏͔ͨ͠
33

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Ͳ͏͔ͨ͠
33
௚઀View΍APIͷϨεϙϯεͳͲʹґଘ͢Δςε
τΛॻ͘ͱมߋʹऑ͘ͳΔͷͰ͸ʁ
 
ྫ͑͹λΠτϧͷViewͷIDॻ͖׵͑ͨΒશ෦ͷς
ετॻ͖௚͢ͷʁ

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Ͳ͏͔ͨ͠
33
 
ετॻ͖௚͢ͷʁ
● → Robot PatternΛ࢖͏ɻ͜Ε͸ςετ
ͷ”what”ͱ”how”Λ෼཭͢Δ˞

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Ͳ͏͔ͨ͠
33
 
ετॻ͖௚͢ͷʁ
● → Robot PatternΛ࢖͏ɻ͜Ε͸ςετ
ͷ”what”ͱ”how”Λ෼཭͢Δ˞
※ https://jakewharton.com/testing-robots/ΑΓ

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Ͳ͏͔ͨ͠
34
@Test

fun shouldPlayButtonVisibleWhenFinishingProgram() {

robot {

setupServer(NotProgramStartedPattern)

launchScreen()

// ൪૊ऴྃ·Ͱ଴ͭ(TestCoroutineSchedulerΛ͍͡Δ)

waitForFinishingProgram()

checkPlayButtonVisible()

}

}

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Ͳ͏͔ͨ͠
34
@Test


robot {


launchScreen()




}

}
robot{}Ͱғͬͯɺςετͷ”how”͸
robotʹ΍ͬͯ΋Β͏

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Ͳ͏͔ͨ͠
34
@Test


robot {


launchScreen()




}

}
APIηοτΞοϓ͸͋Δ͕ɺ௚઀Ϩε
ϙϯεΛࢦఆͨ͠Γ͠ͳ͍

(Robotʹ΍ͬͯ΋Β͏)
robotʹ΍ͬͯ΋Β͏

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Ͳ͏͔ͨ͠
34
@Test


robot {


launchScreen()




}

}
APIηοτΞοϓ͸͋Δ͕ɺ௚઀Ϩε
ϙϯεΛࢦఆͨ͠Γ͠ͳ͍

ViewͷνΣοΫ͸͋Δ͕௚઀IDΛݟͨ
Γ͠ͳ͍

robotʹ΍ͬͯ΋Β͏

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Robotͷ࣮૷͸ʁ
35
@Inject lateinit val robot: Robot
@Test
fun test() {
robot {
hoge()
}
}
class Robot {
operator fun invoke(block: Robot.() -> Unit) {
runTest{ block() }
}
fun hoge() {...}
}

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Ͳ͏͔ͨ͠
36
@Test


robot {


launchScreen()

// ൪૊ऴྃ·Ͱ଴ͭ



}

}
ςετͷ
 
”What = ԿΛ͢Δ͔”ͱ”How = Ͳ͏΍ͬͯ΍Δ͔”
Λ෼཭͢Δͷ͕Robot Patternɻ

ςετ΋ΞϓϦͱಉ͡Α͏ʹઃܭ͢Δɻ

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37

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37
● τϨʔυΦϑ

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37
● τϨʔυΦϑ
○ ςετͰ໰୊͕͋Δͱ͖ʹݪҼ͕෼͔Δ·Ͱʹ͕͔͔࣌ؒΔɻ

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37
● τϨʔυΦϑ
■ → ׂͱࡉ͔Ίʹϝιουͷݺͼग़͠ͱ͔ͷϩάΛೖΕΔɻ

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37
● τϨʔυΦϑ
● → ςετͰ͸ϩάϥΠϒϥϦ͕println()ʹϩάΛग़͢Α͏ʹTest RuleΛ࡞ͬͯͦΕΛ࢖͏

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37
● τϨʔυΦϑ
● → ύϑΥʔϚϯε؍఺ͰTimberCompat.d{} ͷΑ͏ͳܗͷؔ਺Λ༻ҙͯ͠ɺຊ൪Ͱ͸ϥϜμ಺Λ࣮ߦ͠ͳ͍͜ͱͰɺ
toString()Λຊ൪Ͱ࣮ߦ͠ͳ͍Α͏ʹ͢Δɻ

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37
● τϨʔυΦϑ
○ Robolectricͩͱɺը໘ݟΕͳ͍ͷͰɺ΋͠ςετಈ͍ͯ΋ɺݟ͑ͳ͍ͷͰಈ͍͍ͯΔͷ͔Α͘෼͔Βͳ͍ɻෆ҆ɻ

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37
● τϨʔυΦϑ
■ → Roborazziͱ͍͏ՄࢹԽϥΠϒϥϦΛ࠷ۙ࡞ͬͨͷͰ࢖ͬͯݟ͍ͯͩ͘͞

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37
● τϨʔυΦϑ
○ Robolectric͸ActivityؒͷҠಈ͸ςετͰ͖ͳ͍ɻ

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37
● τϨʔυΦϑ
■ FragmentͳΒOK

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37
● τϨʔυΦϑ
■ FragmentͳΒOK
● ୅ସखஈ

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37
● τϨʔυΦϑ
■ FragmentͳΒOK
● ୅ସखஈ
○ ࠓճ͸ΞϓϦ಺ΛͳΔ΂͘౷߹ͨ͠ςετΛߦ͍ͬͯͨɻཧ૝తʹ͸E2E΋΍͍ͬͯ͘΂͖Ͱ͸͋Δ͕Ͳ͏͍͔ͯ͘͠ɻ

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·ͱΊ
38

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·ͱΊ
38
● ҎԼͷݪଇΛར༻ͯ͠վળ͠ɺৼΓฦΓΛ͍͖ͯ͠·ͨ͠ɻ

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·ͱΊ
38
○ Single Source of Truth

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·ͱΊ
38
○ Unidirectional Data Flow

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·ͱΊ
38
○ ViewModel͔ΒUIʹΠϕϯτΛૹΒͳ͍

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·ͱΊ
38
○ ςετͰ͸Ͱ͖Δ͚ͩຊ෺ͷΦϒδΣΫτΛ࢖͏

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·ͱΊ
38
○ ςετͰ͸Ͱ͖Δ͚ͩຊ෺ͷΦϒδΣΫτΛ࢖͏
● ͜ͷΑ͏ͳ͞·͟·ͳऔΓ૊Έʹ͸ɺਖ਼ղ͸ͳ͍औΓ૊Έͩͱࢥ͍ͬͯΔΜͰ͕͢ɺΞ΢τ
ϓοτͯ͠ɺؒҧ͍ͬͯͨΓɺࢹ఺ͱͯ͠ൈ͚͍ͯΔͱ͜ΖͳͲ͕͋Ε͹ɺϑΟʔυόοΫͳ
Ͳ͔Βؾ͖ͮΛಘͨΓ͠ͳ͕Βվળ͍͚ͯ͠Δͱ͍͍ͳͱࢥ͍ͬͯ·͢ɻ

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Special thanks
39
● ։ൃɾϨϏϡʔΛҰॹʹͯ͘͠Εͨ

○ @fuji_kinaga ͞Μ

○ ଞABEMA NativeνʔϜͷօ͞Μ

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Androidアプリで安定して動作させ継続的に開発するために設計の原則を利用して開発した話

Androidアプリで安定して動作させ継続的に開発するために設計の原則を利用して開発した話

takahirom

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