Androidで使えるKotlinレシピ

"OESPJEͰ࢖͑Δ,PUMJOϨγϐ ,BNFEPO

ϓϩϑΟʔϧ • Χϝυϯ • Kotlin޷͖Ͱ͢ • AndroidͷΞϓϦ։ൃ΍ͬͯ·͢ • ϘʔυήʔϜ͕޷͖Ͱ͢
Akiba.BoardGameओ࠵

,PUMJO͕"OESPJEެࣜݴޠԽ㊗

Έͳ͞Μ  KotlinͰշదAndroidΞϓϦ։ൃͯ͠·͔͢ʁ

,PUMJO w+FUCSBJOT੡ϦϦʔε w+7.ݴޠɺ,PUMJO/BUJWF w#FUUFS+BWB+BWBޓ׵ੑ w੩తܕ෇͚ wΦϒδΣΫτࢦ޲ w/VMM҆શ ΑΓ/VMMѻ͍΍͘͢ͳΔʣ

ର৅ऀ w,PUMJOΛҰ౓͸৮ͬͨ͜ͱ͕͋Δਓ w,PUMJOͷػೳ͸ͳΜͱͳ͘Θ͔Δ͕ɺ  "OESPJEͰͲ͏׆͔͢೰ΜͰ͍Δਓ w,PUMJOΛ࣮ફతͳίʔυΛ஌Γ͍ͨํ KotlinͷྗΛ։์͍ͤͨ͞

"OESPJEͰ,PUMJOͷྗΛղ͖์ͭϨγϐ ,PUMJOͷྗΛղ͖์ͭΛΩʔϫʔυΛ٧ΊࠐΈ·ͨ͠  ݴޠ࢓༷ͷࡉ͍ͱ͜Ζ·Ͱࠓճ͸ѻ͍·ͤΜ w1SPQFSUJFTBOE'JFMET w%4- w%*

"OESPJEͰ,PUMJOͷྗΛղ͖์ͭϨγϐ Properties and Fields

,PUMJOͷ1SPQFSUJFTBOE'JFMET wLFZXPSEQSPQFSUZ/BNF<1SPQFSUZ5ZQF>< QSPQFSUZ@JOJUJBMJ[FS>  <HFUUFS><TFUUFS> wLFZXPSEWBM SFBEPOMZ WBS NVUBCMF
w1SPQFSUZ5ZQF<ʜ>  ͳ͠ /PU/VMM ɺ /VMMBCMF ɺ 1MBUGPSN5ZQF wWBMIPHF4USJOHl5FTUz wWBSGPP4USJOH OVMM

1SPQFSUJFTBOE'JFMETͷબͼํʹ͍ͭͯ WBSΑΓWBMɺ ΑΓ /PU/VMM ɺΑΓ ͷ΄͏͕ΑΓ҆શ wWBMͰࣄ଍ΓΔͷͰ͋Ε͹ɺWBMΛ࢖༻͠Α͏͢Δ  ্ॻ͖͠ͳ͍Α͏ʹؾΛ͚ͭΔͰ͸ͳ͘ɺ  ্ॻ͖Ͱ͖ͳ͍Α͏ʹ͢Δ
wΫϥε੹຿తʹ͸WBM͕ͩɺ"OESPJEͷ࢓্༷WBS΍ ʹͤ͟ Δ௥͑ͳ͍͕࣌ଟʑ͋Δ w͋Δఔ౓ճආ͢ΔςΫχοΫ͕ଘࡏ͢Δ

1SPQFSUJFTBOE'JFMETͷࢦ਑Λ࡞ͬͯΈͨ

ܕͷબͼํ

ॳظԽ࣌ʹΠϯελϯεԽͰ͖Δ ActivityͷϥΠϑαΠΫϧͳͲʹґଘ͠ͳ͍৔߹ class SampleActivity : AppCompatActivity() {    val
adapter = ItemAdapter()    override fun onCreate(savedInstanceState: Bundle?) {  super.onCreate(savedInstanceState)  setContentView(R.layout.activity_sample)  val listView = (findViewById(R.id.listView) as ListView)  listView.adapter = adapter  }  }

ܕͷબͼํ

"DUJWJUZ࢓༷ͷ͍ͤͰॳظԽͰ͖ͳ͍ ίϯύΠϧ͸௨Δ͕ɺNPEʹͳΔ setContentViewҎ߱Ͱͳ͍ͱﬁndViewById͸औಘͰ͖ͳ͍ class SampleActivity : AppCompatActivity() {   
val adapter = ItemAdapter()    val listView = (findViewById(R.id.listView) as ListView)    override fun onCreate(savedInstanceState: Bundle?) {  super.onCreate(savedInstanceState)  setContentView(R.layout.activity_sample)  listView.adapter = adapter  }  }

"DUJWJUZϥΠϑαΠΫϧͷ͍ͤͰॳظԽͰ͖ͳ͍ listViewΛࢀর͞ΕΔ·ͰॲཧΛ஗Ԇ͢Δ setContentViewҎ߱Ͱࢀর͞Ε͍ͯΔͨΊ໰୊ͳ͠ class SampleActivity : AppCompatActivity() {   
val adapter = ItemAdapter()    val listView by lazy {  (findViewById(R.id.listView) as ListView)  }    override fun onCreate(savedInstanceState: Bundle?) {  super.onCreate(savedInstanceState)  setContentView(R.layout.activity_sample)  listView.adapter = adapter  }  }

ܕͷબͼํ

֎෦͔Βґଘؔ܎Λղܾ͢Δඞཁ͋Γ class SampleActivity : AppCompatActivity() {  val binding by
lazy {  DataBindingUtil.setContentView<ActivitySampleBinding>(this, R.layout.activity_sample)  }  }  class SampleFragment : Fragment() {  lateinit var binding: FragmentSampleBinding   override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {  binding = DataBindingUtil.inflate<FragmentSampleBinding> (inflater, R.layout.fragment_sample, container, false)    }  }

֎෦͔Βґଘؔ܎Λղܾ͢Δඞཁ͋Γ class SampleFragment : Fragment() {  lateinit var binding:
FragmentSampleBinding  override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {  binding = DataBindingUtil.inflate<FragmentSampleBinding> (inflater, R.layout.fragment_sample, container, false)    }  } inﬂaterͱcontainer͸onCreateViewͰ ࢀরͰ͖ΔΑ͏ʹͳΔͨΊɺby lazyͰॻ͘͜ͱ͕Ͱ͖ͳ͍

ܕͷબͼํ

ϓϥοτϑΥʔϜܕͱઓ͏ +BWBͷϝιου͸ɺ ϓϥοτϑΥʔϜܕ ʹͳΔ wϓϥοτϑΥʔϜܕ͸ɺ/PU/VMMͰ΋/VMMBCMFͰ΋͋Δ w΋ͪΖΜ/PU/VMMͷͱ͖ʹ/VMM৔߹͸/1&ʹͳΔ

ϓϥοτϑΥʔϜܕͱઓ͏ val listView: View = findViewById(R.id.listView)  val listView: View?
= findViewById(R.id.listView) ϓϥοτϑΥʔϜܕ ͷ৔߹͸໌ࣔతʹܕΛॻ͘ wϓϥοτϑΥʔϜܕ͸ɺܕਪ࿦͠ͳ͍΄͏͕٢ w/PU/VMMͩͱࢥ͏ͷͰ͋Ε͹ɺ/PU/VMMʹ͢Δ w/VMMͷॠؒʹ/1&ͰམͪΔͷͰૣظʹόάΛൃݟͰ͖Δ w,PUMJO͸/1&Ͱམͱ͞ͳ͍ٕज़Ͱ͸ͳ͘ɺ/VMMΛద੾ʹѻ͍΍͘͢ ͯ͘͠ΕΔɻҙਤ͠ͳ͍ͷͰ͋Ε͹མͱ͢΂͖ɻ

"OESPJEͰ,PUMJOͷྗΛղ͖์ͭϨγϐ DSL (Domain Speciﬁc Language)

%4- w͋ΔಛఆͷྖҬʢυϝΠϯʣͷ໰୊Λղܾ͢ΔͨΊʹ࡞ΒΕɺ ͦΕҎ֎ͷྖҬͷ໰୊Λղ͘͜ͱ͸૝ఆ͍ͯ͠ͳ͍ɻ wࠓճ͸7BMJEBUJPOΛྫʹ͢Δ wྫ͑͹ςΩετϘοΫεͳͲͰ6TFSͷOBNF͕ೖྗ͞Εͨͱ͖ ʹɺ༗ޮͳ΋ͷ͔ߟ͑Δ wจࣈ਺͸ɺdจࣈ·Ͱ༗ޮ

࠷ॳ͸ྑ͔͕ͬͨʜ ػೳ௥Ճ͸͞Ε͍ͯ͘… • ৽ͨʹageΛ௥Ճ: 20ࡀҎ্ • name͕NGϫʔυΛؚ·ͳ͍ class User(val
name: String) {    fun vaildate(): Boolean {  return name.length in 1..16 }    }

ຊ౰ͷઓ͍͸͜Ε͔Βͩͥ • ԿͰΤϥʔʹͳ͔ͬͨɺΤϥʔϝοηʔδ͍ͩͨ͠  ɹɹɹɹɹɹɹɹɹʘ(^o^)ʗ class User(val name: String, val
age: Int) {    fun vaildate(): Boolean {  return name.length in 1..16 &&  name in listOf("hoge","foo") &&  age >= 20  }    }

7BMJEBUJPOͷ%4-Λ࡞ͬͯɺϦϑΝΫλϦϯά • Validation֤ཁૉͷ͋Δ΂͖࢟ɺͦ͏Ͱͳ͍࣌ͷϝοηʔδ • A ͸ B Ͱ͋Δɻͦ͏Ͱͳ͍࣌ɺ Error
Message class User(val name: String, val age: Int) {    fun vaildate(): Boolean {  return name.length in 1..16 &&  name in listOf("hoge","foo") &&  age >= 20  }    }

%4-Ͱཁ݅ wυϝΠϯΛఆٛ͢Δදݱྗ wຊ࣭ʹूதͰ͖ΔΑ͏ʹγϯλοΫεΛΘ͔Γ΍͘͢ w*%&ͷػೳΛ͍͔͑ΔΑ͏ʹܕͳͲอ؅Ͱ͖Δ͔ wυϝΠϯͷݴ༿Ͱ͔͚Δ w"͸#Ͱ͋Δɻͦ͏Ͱͳ͍࣌ɺ&SSPS.FTTBHF

͍͖ͳΓ࠷ऴܕΛͲʔΜ • User be {validation} not “error message” •
Validation͕૿͑ͯ΋໰୊ͳ͠ • υϝΠϯͷจ๏ͷ··ͰɺಡΈ΍͍͢ class User(val name: String, val age: Int) {  val validation = Validation<User> { be { age >= 20 } not "成人のみです"  be { name.length in 1..16 } not "1-16文字以下で"  be { name !in listOf("hoge", "foo") }   not "NGワード以外で"  }  fun vaildate() = validation.validate(this)  }

͞ΒʹಡΈ΍͘͢ • ΍Γա͗ײ͕͋Δ class User(val name: String, val age:
Int) {  val validation = Validation<User> { of(age) be { it >= 20 } not "成人のみです"  of(name) be { it.length in 1..16 } not "1-16文字以下で"  of(name) be { it !in listOf("hoge", "foo") }   not "NGワード以外で"  }  fun vaildate() = validation.validate(this)  }

%4-Λ࣮ݱ͢Δٕज़ wWBS͔ΒWBMʹ͢ΔͨΊʹ#VJMEFS wఆٛͬΆ͘͢ΔPQFSBUPSJOWPLF w୹͘͢ΔϨγʔόʔࢦఆMBNCEB w࠷ޙͷҾ਺ͷ৔߹͸ ΛলུՄೳ w୹͘͢Δ&YUFOTJPOT'VODUJPOTPS1SPQFSUJFT wӳޠͬΆ͍จ๏ʹJOpY

ఆٛͬΆ͘͢ΔPQFSBUPSJOWPLF class Validation<in T>(val validations: List<Pair<T.() -> Boolean, String>>)
{    companion object {   operator fun <T> invoke(init: ValidationBuilder<T>.() -> Unit): Validation<T> {   val builder = ValidationBuilder<T>()  return builder.apply(init).build()  }  } Validation<User> { be { age >= 20 } not “成人のみです” } operator invokeͰinvokeΛলུɺValidation()Ͱ࣮ߦͰ͖Δ ࠷ޙ͕ϥϜμͳͷͰ()লུՄೳ͠ɺ{}ʹͳΔ

ఆٛͬΆ͘͢ΔPQFSBUPSJOWPLF class Validation<in T>(val validations: List<Pair<T.() -> Boolean, String>>)
{    companion object {   operator fun <T> invoke(init: ValidationBuilder<T>.() -> Unit): Validation<T> {   val builder = ValidationBuilder<T>()  return builder.apply(init).build()  }  } Validation<User>.invoke({…}) Validation<User>.invoke{…} Validation<User>{…} operator invokeͰinvokeΛলུɺValidation()Ͱ࣮ߦͰ͖Δ ࠷ޙ͕ϥϜμͳͷͰ()লུՄೳ͠ɺ{}ʹͳΔ

WBS͔ΒWBMʹ͢ΔͨΊʹ BuilderΛ࡞੒͠ɺ • ఆ͕ٛऴΘΔ·Ͱ͸mutableʹͯ͠Buildޙ͸immutableʹ͢Δ • Builder಺ʹఆٛ༻ͷγϯλοΫεΛด͡ΊΔ class Validation<in T>(val
validations: List<Pair<T.() -> Boolean, String>>) {  fun validate(value: T) = validations.filter { !it.first.invoke(value) }.map { it.second }  }  class ValidationBuilder<T> { var validations: MutableList<Pair<T.() -> Boolean, String>> = mutableListOf()    fun build(): Validation<T> {  return Validation(validations)  }  }

ϨγʔόʔࢦఆMBNCEB class ValidationBuilder<T> {  var validations: MutableList<Pair<T.() -> Boolean,
String>> = mutableListOf()   ɹɹfun be(validate: T.() -> Boolean) = validate } Validation<User> { be { age >= 20 } not “成人のみです” } TͷvalidateΛϥϜμͰ࡞੒͢Δɺ࠷ޙͷϥϜμ͸লུՄೳ T.() -> Boolean) = (T)->Boolean ͷҧ͍͸ʁ

5 #PPMFBO 5 #PPMFBOͷҧ͍͸ʁ Validation<User> { be { it.age
>= 20 } not “成人のみです” //fun be(validate: (T) -> Boolean) = validate be { this.age >= 20 } not “成人のみです” //fun be(validate: T.() -> Boolean) = validate } Ϩγʔόʔࢦఆͷ৔߹this͕TʹͳΔ

୹͘͢Δ&YUFOTJPOT'VODUJPOTPS1SPQFSUJFT class ValidationBuilder<T> {  var validations: MutableList<Pair<T.() -> Boolean,
String>> = mutableListOf()  fun be(validate: T.() -> Boolean) = validate infix fun (T.() -> Boolean).not(error: String) {  validations.add(this to error)  } } Validation<User> { be { age >= 20 } not “成人のみです” } validateͯ͠ແޮͳ஋ͩͬͨ৔߹Τϥʔϝοηʔδฦ͢Α͏ʹ͢Δ (T.() -> Boolean)ʹ֦ுؔ਺Λ࣮૷͠Pairʹͯ͠add͢Δ

ӳޠͬΆ͍จ๏ʹJOpY class ValidationBuilder<T> {  var validations: MutableList<Pair<T.() -> Boolean,
String>> = mutableListOf()  fun be(validate: T.() -> Boolean) = validate infix fun (T.() -> Boolean).not(error: String) {  validations.add(this to error)  } } Validation<User> { be { age >= 20 } not “成人のみです” } inﬁx༗Γແ͠Ͳ͏ͳΔ͔ݟͯΈ·͠ΐ͏

ӳޠͬΆ͍จ๏ʹJOpY Validation<User> { be { it.age >= 20 }.not(“成人のみです”)
//fun (T.() -> Boolean).not(error: String)   be { this.age >= 20 } not “成人のみです” //infix fun (T.() -> Boolean).not(error: String) } inﬁxΛ࢖͏͜ͱͰ.() Λͳ͘͠ɺεϖʔε۠੾Γʹ ӳޠͬΆ͘Ͱ͖Δ

%4-Λ࣮ݱ͢Δٕज़ wWBS͔ΒWBMʹ͢ΔͨΊʹ#VJMEFS wఆٛͬΆ͘͢ΔPQFSBUPSJOWPLF w୹͘͢ΔϨγʔόʔࢦఆMBNCEB w࠷ޙͷҾ਺ͷ৔߹͸ ΛলུՄೳ w୹͘͢Δ&YUFOTJPOT'VODUJPOTPS1SPQFSUJFT wӳޠͬΆ͍จ๏ʹJOpY ͳΜͰ΋͍͍͔ΒɺDSLͷαϯϓϧΛ࡞ͬͯΈΑ͏
Kotlinྗ͕ඈ༂తʹΞοϓ͠·͢ʂ

"OESPJEͰ,PUMJOͷྗΛղ͖์ͭϨγϐ DI Container (Dependency Injection Container)

೔ຊޠ8JLJQFEJBͩͱʜ lґଘੑͷ஫ೖʢ͍ͦΜ͍ͤͷͪΎ͏ʹΎ͏ɺӳ %FQFOEFODZJOKFDUJPOʣͱ͸ɺίϯϙʔωϯτؒͷ ґଘؔ܎ΛϓϩάϥϜͷιʔείʔυ͔Βഉআ͠ɺ֎෦ ͷઃఆϑΝΠϧͳͲͰ஫ೖͰ͖ΔΑ͏ʹ͢Διϑτ΢Σ ΞύλʔϯͰ͋Δɻz 8JLJQFEJBґଘੑͷ஫ೖ

೔ຊޠ8JLJQFEJBͩͱʜ lґଘੑͷ஫ೖʢ͍ͦΜ͍ͤͷͪΎ͏ʹΎ͏ɺӳ %FQFOEFODZJOKFDUJPOʣͱ͸ɺίϯϙʔωϯτؒͷ ґଘؔ܎ΛϓϩάϥϜͷιʔείʔυ͔Βഉআ͠ɺ֎෦ ͷઃఆϑΝΠϧͳͲͰ஫ೖͰ͖ΔΑ͏ʹ͢Διϑτ΢Σ ΞύλʔϯͰ͋Δɻz 8JLJQFEJBґଘੑͷ஫ೖ ґଘੑͷ஫ೖʁ

ӳޠ൛8JLJQFEJBͩͱʜ l*OTPGUXBSFFOHJOFFSJOH EFQFOEFODZ JOKFDUJPOJTBUFDIOJRVFXIFSFCZPOFPCKFDU TVQQMJFTUIFEFQFOEFODJFTPGBOPUIFSPCKFDU "EFQFOEFODZJTBOPCKFDUUIBUDBOCFVTFE B TFSWJDF z
8JLJQFEJB%FQFOEFODZJOKFDUJPO

ӳޠ൛8JLJQFEJBͩͱʜ l*OTPGUXBSFFOHJOFFSJOH EFQFOEFODZ JOKFDUJPOJTBUFDIOJRVFXIFSFCZPOFPCKFDU TVQQMJFTUIFEFQFOEFODJFTPGBOPUIFSPCKFDU "EFQFOEFODZJTBOPCKFDUUIBUDBOCFVTFE B TFSWJDF z
8JLJQFEJB%FQFOEFODZJOKFDUJPO dependency͸ΦϒδΣΫτ ΦϒδΣΫτͷ஫ೖ

Πϝʔδ͠Α͏ DIͬΆ͍ͷ͸Ͳͬͪʁ ۩ࡐɺຯΛௐ੔ɺม͑΍͍͢ͷ͸

ιʔείʔυͩͱ class FriedRice val friedRice = FriedRice() class BowlOFRice(val
rice: Rice, val topping: Topping) interface Topping interface Rice class JapaneseRice : Rice class BeefTopping : Topping //オブジェクトを入れる val beefBowl = BowlOFRice(JapaneseRice(), BeefTopping()) ※ઃܭ࣍ୈͰνϟʔϋϯ΋DIԽͰ͖·͢

%*ͷࢫຯɿมߋʹڧ͍ ஫ೖ͞ΕΔ΋ͷ͸ΦϒδΣΫτ͕ͩ  ΠϯλʔϑΣʔεʢ࢓༷ʣʹґଘͨ͠΄͏͕ΑΓॊೈ wڇက͡Όͳͯ͘ɺ;Γ͔͚ကͰ΋໰୊ͳ͠ wܧঝͰͳ͘ɺ࢓༷ʹґଘ͍ͯ͠ΔͨΊՄೳ wςετ ຯݟ ͷͱ͖ʹϥΠεΛϞοΫʹ͢Δ͜ͱͰɺ  ຯݟՄೳ

%* DI Container (Dependency Injection Container)

%*ͱ%*$POUBJOFS %*$POUBJOFS͸  %*Λ࣮ݱ͢ΔͨΊͷศརπʔϧͰ͔͠ͳ͍ wઌఔͷઆ໌Ͱ%BHHFSͳͲͰ͖ͯ·͔ͨ͠ʁ class BowlOFRice(val rice: Rice, val
topping: Topping) //オブジェクトを入れる val beefBowl = BowlOFRice(JapaneseRice(), BeefTopping())

%*$POUBJOFSͷࢫຯ ࠷େͷϞνϕʔγϣϯɿΊΜͲ͏͍͘͞ w͍͍ͪͪΦϒδΣΫτ࡞੒͢Δͷ͕໘౗ w౎౓OFX͢Δඞཁ͕ͳ͘࢖͍·Θ͍ͨ͠ w஫ೖ͢ΔΦϒδΣΫτΛมߋ͢Δ࣌ʹɺ  ͢΂ͯม͑Δͷ໘౗ ґଘؔ܎Λهड़ͨ͠Β উखʹੜ੒ɺ஫ೖͯ͘͠ΕͨΒ͍͍ͷʹ

%*$POUBJOFSͷࢫຯ ࠷େͷϞνϕʔγϣϯɿΊΜͲ͏͍͘͞ w͍͍ͪͪΦϒδΣΫτ࡞੒͢Δͷ͕໘౗ w౎౓OFX͢Δඞཁ͕ͳ͘࢖͍·Θ͍ͨ͠ w஫ೖ͢ΔΦϒδΣΫτΛมߋ͢Δ࣌ʹɺ  ͢΂ͯม͑Δͷ໘౗ ґଘؔ܎Λهड़ͨ͠Β উखʹੜ੒ɺ஫ೖͯ͘͠ΕͨΒ͍͍ͷʹ DI
Container͞Μ͓ئ͍͠·͢

Πϝʔδ͠Α͏ ڇက DIίϯςφ ΅͘Β͸ڇကΛఆٛ

%* DI Container? Service Locator?

4FSWJDF-PDBUPS class FriedRice val friedRice = FriedRice() class BowlOFRice(val
di: DIContainer){ @Inject lateinit var rice: Rice @Inject lateinit var topping: Topping init{ di.inject() } } //オブジェクトを入れる val beefBowl = BowlOFRice(di) ※ઃܭ࣍ୈͰνϟʔϋϯ΋DIԽͰ͖·͢

4FSWJDF-PDBUPS ґଘؔ܎ͷهड़͕ΊΜͲ͘ͳͬͯ4FSWJDF-PDBUPSʹ  ͯ͠͠·͏ w͋ΕʁͦͷΦϒδΣΫτͬͯ  %*$POUBJOFSͬͯؔ܎͋Γ·͚ͨͬ͠ʁ wςετ͢Δͱ͖ʹ%*$POUBJOFS͕ͳ͍ͱςετͰ͖ͳ͍ w୯७ʹ%*$POUBJOFS෼ͷґଘؔ܎͕૿͑ͯ͠·ͬͨ w͜Ε͔Β঺հ͢Δ%*$POUBJOFS͸  4FSWJDF-PDBUPSͱͯ͠ѻ͍΍͍͢ͷͰ஫ҙ͕ඞཁ

%* Android DI: Dagger2?

%*ͷ֓೦ͷΘΓʹෳࡶ wίϯϙʔωϯτɺαϒίϯϙʔωϯτɺϞδϡʔϧɺείʔ ϓΛద੾ʹఆٛ͢Δͷେม w%*ͷྖҬ͔Β"OESPJEྖҬʹ౿ΈࠐΜͰ͖͍ͯΔ w"DUJWJUZ 'SBHNFOU͕ੜ੒͞ΕͨޙɺͰ͔ࠩ͠͠ࠐΊͳ͍΋ ͷఆ͕ٛ໘౗ wLBQUͱ%BHHFSͱͷ૬ੑ͕ѱ͍ wLWTTDIFNBͳͲͰ࡞ΒΕΔΫϥεΛ1SPWJEFSͰ͖ͳ͍ɻʢ)PMEFS
࡞Ε͹Մೳʣ

,PUMJOͳΒҧ͏ํ๏͕͋Δ͔΋ %FMFHBUJPOɺ%FMFHBUFE1SPQFSUJFTΛ࢖͑͹΋ͬ ͱ͏·͘Ͱ͖Δ͔΋ class Delegate {  operator fun getValue(thisRef:
Any?, property: KProperty<*>): String {  return "$thisRef, thank you for delegating '${property.name}' to me!"  }    operator fun setValue(thisRef: Any?, property: KProperty<*>, value: String) {  println("$value has been assigned to '${property.name} in $thisRef.'")  }  }   class Example {  var hoge: String by Delegate()  }

%* Kotlin + Android DI: Kodein

,PEFJO w,PUMJO੡ wLBQUΛ࢖Θͳ͍ͷͰɺϏϧυ஗͘ͳΒͳ͍ w,PUMJOͷػೳΛ͏·͘࢖ͬͯΔ w%FMFHBUJPOΛ࢖ͬͯɺ͏·͘஫ೖ͍ͯ͠Δ w௚ײతͳจ๏ SalomonBrys/KodeinͷREADME.mdΑΓ

,PEFJO͕Ͱ͖Δ͜ͱ w -B[JMZJOTUBOUJBUFZPVSEFQFOEFODJFTXIFOOFFEFE w 4UPQDBSJOHBCPVUEFQFOEFODZJOJUJBMJ[BUJPOPSEFS w &BTJMZCJOEDMBTTFTPSJOUFSGBDFTUPUIFJSJOTUBODFPS QSPWJEFS w
&BTJMZEFCVHZPVSEFQFOEFODZCJOEJOHTBOE SFDVSTJPOT SalomonBrys/KodeinͷREADME.mdΑΓ

,PEFJO͕Ͱ͖Δ͜ͱ w -B[JMZJOTUBOUJBUFZPVSEFQFOEFODJFTXIFOOFFEFE w 4UPQDBSJOHBCPVUEFQFOEFODZJOJUJBMJ[BUJPOPSEFS w &BTJMZCJOEDMBTTFTPSJOUFSGBDFTUPUIFJSJOTUBODFPS QSPWJEFS w
&BTJMZEFCVHZPVSEFQFOEFODZCJOEJOHTBOE SFDVSTJPOT SalomonBrys/KodeinͷREADME.mdΑΓ •ඞཁͳ࣌ʹΠϯελϯεԽ •providerʹ  ΫϥεɺΠϯλʔϑΣʔεɺΠϯελϯεΛઃఆͰ͖ΔΑ

.PEVMFఆٛ Kodein.Module { bind<型>(Qualifier) with singleton { … }
bind<型>(Qualifier) with provider { … } bind<型>(Qualifier) with instance ( … ) } • Dagger2ͷModuleͱಉ͡ • KotlinͷػೳΛϑϧʹ࢖͍ͬͯͯจ๏ͰಡΈ΍͍͢ • inﬁxɺϥϜμলུɺϨγʔόʔࢦఆϥϜμ

.PEVMFྫ object NetworkModule { val module = Kodein.Module {
bind<OkHttpClient>() with singleton { OkHttpClient.Builder().build() } bind<Converter.Factory>() with singleton { GsonConverterFactory.create() } bind<Retrofit>() with singleton { Retrofit.Builder() .baseUrl(BuildConfig.GITHUB_ENDOPOINT) .addConverterFactory(instance()) .client(instance()).build() } } }

,PEFJOͷఆٛ • Dagger2ͷComponentͱಉ͡ • ࢖༻͢ΔϞδϡʔϧΛఆٛ͢Δ class App : Application(),
KodeinAware { override val kodein: Kodein = Kodein { bind<Context>() with instance(this@App) import(NetworkModule.module) import(PresentationModule.module) } }

*OKFDU class MVPActivity : AppCompatActivity(), GithubView { val binding
by lazy { DataBindingUtil.setContentView<…>(this, R.layout…) } val injector: KodeinInjector = KodeinInjector() val presenter: GithubPresenter by injector.instance() override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) injector.inject(Kodein { extend(kodein) bind<GithubView>() with instance(this@MVPActivity) }) binding.searchBtn.setOnClickListener { presenter.search(binding.userEdit.text.toString()) } } }

%* Dagger2 ͱ Kodein ൺֱ

%BHHFSͱ,PEFJO ,PEFJO %BHHFS ґଘؔ܎Λ LBQUͰੜ੒ ෆཁ ඞཁ BQUͰੜ੒͞Εͨ΋ͷ JOKFDU
̋ ˚ )PMEFSΛ࡞ΔͳͲ޻෉͕ඞཁ ґଘؔ܎ͷ Τϥʔ ࣮ߦ࣌ ίϯύΠϧ࣌ είʔϓ ̋ ̋ /BNFE 2VBMJpFS ̋ ̋

ґଘؔ܎͕͓͔͍࣌͠ͷΤϥʔ w%BHHFSͷ৔߹͸ɺίϯύΠϧ࣌ʹΤϥʔ wBQUͰੜ੒͢ΔͷͰɺґଘؔ܎͕͓͔͍͠৔߹ʹ͸ίϯύΠϧͰ͖ ·ͤΜ w,PEFJOͷ৔߹͸ɺ࣮ߦ࣌ʹΤϥʔ w.BQΈ͍ͨͳ΋ͷʹɺΦϒδΣΫτΛಥͬࠐΜͰऔΓग़ͯ͠Δ͚ͩ ͳͷͰɺJOKFDU͢Δͱ͖ʹͭͬ͜·Ε͍ͯΔͷ͔Ͳ͏͔͸ɺ࣮ߦ͞ ΕΔ·ͰΘ͔Βͳ͍ͨΊͰ͢

%*·ͱΊ w%*πʔϧΛ%BHHFSҎ֎ͷબ୒΋͋Δ͔΋ w%FMFHBUJPOΛ࢖ͬͯ%*Λ࣮ݱͰ͖ͦ͏ w,PUMJO͕"OESPJE։ൃݴޠͱͯ͠ೖͬͨ͜ͱͰఆ൪ϥΠϒϥ Ϧͷมಈ͕͋Δ͔΋͠Εͳ͍ʜ

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