Ankoで触れるKotlin

Transcript

1. Anko Ͱ৮ΕΔKotlin 2017.07.05 Fukuoka.kt #1
2. ࣗݾ঺հ • ٢ాਗ਼྄ (twitter|github).com/seisuke • ݱࡏ੍࡞ͷΞϓϦͰ͸100%Kotlin Version͸1.1.x →ৄࡉ͸7/19ͷLINE Developer Meetup in Fukuoka #18Ͱ
3. • Ankoͱ͸ • ͳͥAnko͸͍͍ͷʁ • Tips ΞδΣϯμ
4. • Anko Layoutsͱ͍͏ViewΛ࡞ΔҝDSLͷϥΠϒϥϦ →XMLΛ࢖Θͳͯ͘ྑ͍ɻ௨ৗAnkoComponentͷαϒΫϥεΛ࡞Δ • https://github.com/Kotlin/anko 0.10.1 • https://twitter.com/yanex_ru https://github.com/yanex • dex.fm #17 #18 ޠݯ͸ᰩࢠ(Android + Kotlin) Ankoͱ͸
5. • Data Binding࢖͑·ͤΜ • ConstraintLayoutະରԠ • UI Preview͸ɺ”ࠓ͸”ಈ͔ͳ͍ ࠷ॳʹAnkoͷ൵͍͠ͱ͜Ζ
6. • ͸΍͍ → XML͕஗͍ • Anko Layouts DSL Ͱ Type Safety • CustomView ͳͥAnko͸͍͍ͷʁ
7. relativeLayout {
 lparams(width = matchParent, height = dimen(R.dimen.action_bar_size))
 leftButton = ankoView(::ToolbarButton, 0) {
 id = generateViewId()
 toolbarType = this@CustomToolbarUi.toolbarType
 }.lparams(height = matchParent) {
 centerVertically()
 } 
 rightButton = customView<ToolbarButton> {
 id = generateViewId()
 }.lparams(height = matchParent) {
 alignParentRight()
 centerVertically()
 } 
 centerLayout = linearLayout {
 gravity = Gravity.CENTER
 }.lparams(width = matchParent) {
 rightOf(leftButton)
 leftOf(rightButton)
 centerInParent()
 }
 }
 Anko Layouts DSL
8. • Ҿ਺࠷ޙͷLambdaʢϨγʔόࢦఆʣ • Extensions • @DslMarker →Anko͸DSLΛ࡞Δ࣌ͷ͍͍͓खຊʹͳΔ Kotlin ❤ DSL
9. • ࡞Δͷ؆୯ɺ ViewΛܧঝͯ͠ constructorʹContextΛ͚࣋ͭͩ • ࢖͏ͷ؆୯ val button = customView<ToolbarButton> { … } val button = ankoView(::ToolbarButton, 0) { … } • Define Custom Attributes ͸͍΍Ͱ͠ΐʁ https:// developer.android.com/training/custom-views/create-view.html Custom View
10. Custom View inline fun <T : View> ViewManager.ankoView(factory: (ctx: Context) -> T, theme: Int, init: T.() -> Unit): T {
 val ctx = AnkoInternals.wrapContextIfNeeded(AnkoInternals.getContext(this), theme)
 val view = factory(ctx)
 view.init()
 AnkoInternals.addView(this, view)
 return view
 } 
 inline fun <reified T : View> ViewManager.customView(theme: Int = 0, init: T.() -> Unit): T {
 return ankoView({ ctx -> AnkoInternals.initiateView(ctx, T::class.java) }, theme) { init() }
 } 

11. • ؾָʹCustom View͕࢖͑Δ → Type SafetyʹͳΔ → findById͕͍Βͳ͍ Custom View
12. Custom View class UserListAdapter : BaseAdapter<User>() {
 
 override fun onBindBasicItemView(holder: RecyclerView.ViewHolder, position: Int) {
 if (holder is UserViewHolder) {
 holder.bind(getBaseItem(position))
 }
 }
 
 override fun onCreateBasicItemViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
 return UserViewHolder(holderView(parent))
 }
 
 fun holderView(parent: ViewGroup): UserView = with(AnkoContext.create(parent.context, parent)) {
 customView { textView = textView { …
 } 
 }
 }
 
 class UserView(ctx: Context) : _LinearLayout(ctx) {
 lateinit var textView: TextView
 }
 
 inner class UserViewHolder(val view: UserView) : RecyclerView.ViewHolder(view) {
 fun bind(user: User) {
 view.textView.text = user.name
 }
 } }

13. • DelegationͰڞ௨ػೳ → ωοτϫʔΫॲཧͱ͔ • RelativeLayout • OnGlobalLayout Tips
14. • Anko͸Id࡞Δͷ͕େมʁ @+id/໰୊ • generateViewId͕͋ΔΑ fun View.generateViewId(): Int {
 return if (Build.VERSION.SDK_INT >= 17) {
 View.generateViewId()
 } else {
 this.hashCode()
 }
 } RelativeLayout
15. fun <T : View > T.onGlobalLayoutAction(once: Boolean = true, action: T.() -> Unit) {
 viewTreeObserver.addOnGlobalLayoutListener(object : ViewTreeObserver.OnGlobalLayoutListener {
 override fun onGlobalLayout() {
 action()
 if (once) {
 this@onGlobalLayoutAction .viewTreeObserver.removeOnGlobalLayoutListener(this)
 }
 }
 })
 } OnGlobalLayout
16. ͝੩ௌ ͋Γ͕ͱ͏͍͟͝·ͨ͠