RxBinding2源碼解析

RxBinding源碼解析

此處解析一個Click點擊事件，其他組件大同小異。

RxBinding/rxbinding/src/main/java/com/jakewharton/rxbinding3/view/ViewClickObservable.kt

源碼1：

@file:JvmName("RxView")
        @file:JvmMultifileClass

        @CheckResult    //clicks點擊事件是一個Unit類型Observable事件
        fun View.clicks():Observable<Unit> {
            //this（也就是當前被點擊View）
            return ViewClickObservable(this)
        }
        //整個方法是一個Unit類型Observable事件
        private class ViewClickObservable (private val view:View):Observable<Unit> () {
            //此方法在訂閱時被調用，這是一個Unit類型的訂閱者Observer
            override fun subscribeActual(observer:Observer<in Unit>){
                //不在主線程退出
                if (!checkMainThread(observer)) {
                    return
                }
                //以當前被點擊View和訂閱者observer創建監聽器
                val listener = Listener(view, observer)
                //產生一個Disposable，以便取消；Observer.onSubscribe(Disposable disposable)
                observer.onSubscribe(listener)
                //爲View設置點擊監聽
                view.setOnClickListener(listener)
            }
            //此監聽實現了主線程的onDispose和onClick
            private class Listener ( private val view:View,private val observer:Observer<in Unit>
            ) :MainThreadDisposable(), OnClickListener {
                //當Observable.onNext()發射了數據，Observer.onNext()會同步收到數據，這裏表現爲收到點擊事件
                override fun onClick(v:View){
                    if (!isDisposed) {
                        observer.onNext(Unit)
                    }
                }
                //取消監聽
                override fun onDispose() {
                    view.setOnClickListener(null)
                }
            }
        }

源碼2 . 帶xxxEvent的事件類型 由於RxJava只接收一個參數，所以將多參數封裝於xxxEvent

RxBinding/rxbinding/src/main/java/com/jakewharton/rxbinding3/view/ViewScrollChangeEventObservable.kt

 @file:JvmName("RxView")
        @file:JvmMultifileClass

        @RequiresApi(23)
        @CheckResult        //滾動事件
        fun View.scrollChangeEvents(): Observable<ViewScrollChangeEvent> {
            return ViewScrollChangeEventObservable(this)
        }
        //事件類型是ViewScrollChangeEvent
        @RequiresApi(23)
        private class ViewScrollChangeEventObservable( private val view: View
        ) : Observable<ViewScrollChangeEvent>() {

            override fun subscribeActual(observer: Observer<in ViewScrollChangeEvent>) {
                if (!checkMainThread(observer)) {
                    return
                }
                val listener = Listener(view, observer)
                observer.onSubscribe(listener)
                view.setOnScrollChangeListener(listener)
            }

            private class Listener(
            private val view: View,
            private val observer: Observer<in ViewScrollChangeEvent>
            ) : MainThreadDisposable(), OnScrollChangeListener {
                //滾動事件封裝的參數
                override fun onScrollChange(
                        v: View,
                        scrollX: Int,
                        scrollY: Int,
                        oldScrollX: Int,
                        oldScrollY: Int
            ) {
                    if (!isDisposed) {
                        observer.onNext(ViewScrollChangeEvent(v, scrollX, scrollY, oldScrollX, oldScrollY))
                    }
                }

                override fun onDispose() {
                    view.setOnScrollChangeListener(null)
                }
            }
        }