RecyclerViewBindings provides a wrapper class RecyclerViewScrollCallback which can be used to add Scroll to Bottom (Endless Scroll) and Pull to Refresh capability to your RecyclerView. You can make use of DataBinding to bind it via XML.
val callback = RecyclerViewScrollCallback
.Builder(visibleThreshold, recyclerView.layoutManager)
.resetLoadingState(resetLoadingState)
.onScrolledToBottom(onScrolledToBottom)
.build()
recyclerView.clearOnScrollListeners()
recyclerView.addOnScrollListener(callback)In your Gradle
dataBinding {
enabled = true
}In your BindingAdapter
/**
* @param recyclerView RecyclerView to bind to RecyclerViewScrollCallback
* @param visibleThreshold The minimum number of items to have below your current scroll position before loading more.
* @param resetLoadingState Reset endless scroll listener when performing a new search
* @param onScrolledToBottom OnScrolledListener for RecyclerView scrolled
*/
@BindingAdapter(value = *arrayOf("visibleThreshold", "resetLoadingState", "onScrolledToBottom"), requireAll = false)
fun setRecyclerViewScrollCallback(recyclerView: RecyclerView, visibleThreshold: Int, resetLoadingState: Boolean,
onScrolledToBottom: RecyclerViewScrollCallback.OnScrolledListener) {
... // add addOnScrollListener to RecyclerView using OnScrolledListener as above
}
/**
* @param swipeRefreshLayout Bind swipeRefreshLayout with OnRefreshListener
* @param onRefresh Listener for onRefresh when swiped
*/
@BindingAdapter("onPulledToRefresh")
fun setOnSwipeRefreshListener(swipeRefreshLayout: SwipeRefreshLayout, onPulledToRefresh: Runnable) {
swipeRefreshLayout.setOnRefreshListener { onPulledToRefresh.run() }
}In your XML file
<android.support.v4.widget.SwipeRefreshLayout
android:id="@+id/srl"
android:layout_width="match_parent"
android:layout_height="match_parent"
bind:onPulledToRefresh="@{() -> presenter.initialize()}">
<android.support.v7.widget.RecyclerView
android:id="@+id/rv"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/grey"
app:layoutManager="android.support.v7.widget.LinearLayoutManager"
bind:onScrolledToBottom="@{(page) -> presenter.onLoadMore(page)}"
bind:resetLoadingState="@{model.resetLoadingState}"
bind:spaceItemDecoration="@{@dimen/space_very_low}"
bind:visibleThreshold="@{model.visibleThreshold}"
tools:listitem="@layout/item_main" />
</android.support.v4.widget.SwipeRefreshLayout>/**
* initialize all resources
* set current page to 1
* create paginator and subscribe to events
*/
override fun initialize() {
currentPage = 1 // set page = 1
paginator = PublishProcessor.create() // create PublishProcessor
val d = paginator.onBackpressureDrop()
.filter { !loading } // return if it is still loading
.doOnNext { loading = view.showProgress() } // loading = true
.concatMap { contract.getUsersFromServer(it) } // API call
.observeOn(AndroidSchedulers.mainThread())
.subscribe({
loading = view.hideProgress() // loading = false
view.showItems(it) // show items
currentPage++ // increment page
}, {
loading = view.hideProgress() // loading = false
view.showError(it.localizedMessage) // show error
})
disposables.add(d)
onLoadMore(currentPage)
}
/**
* called when list is scrolled to its bottom
* @param page current page (not used)
*/
override fun onLoadMore(page: Int) {
paginator.onNext(currentPage) // increment page if not loading
}Add Android Support Design, RxJava and RxAndroid dependency to your gradle file.
dependencies {
compile 'com.android.support:design:{latest_version}'
compile 'io.reactivex.rxjava2:rxandroid:{latest_version}'
compile 'io.reactivex.rxjava2:rxjava:{latest_version}'
}