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Hamid Palo
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Add ViewObservables.listViewScroll(AbsListView).
1 parent aa1f2aa commit dd9f301

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6 files changed

+372
-19
lines changed

6 files changed

+372
-19
lines changed

‎library/src/main/java/rx/android/events/OnListViewScrollEvent.java‎

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/**
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package rx.android.events;
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import android.widget.AbsListView;
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public class OnListViewScrollEvent {
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public final AbsListView listView;
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public final int scrollState;
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public final int firstVisibleItem;
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public final int visibleItemCount;
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public final int totalItemCount;
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public OnListViewScrollEvent(
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AbsListView listView, int scrollState, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
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this.listView = listView;
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this.scrollState = scrollState;
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this.firstVisibleItem = firstVisibleItem;
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this.visibleItemCount = visibleItemCount;
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this.totalItemCount = totalItemCount;
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}
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@Override
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public boolean equals(Object o) {
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if (this == o) {
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return true;
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}
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if (o == null || getClass() != o.getClass()) {
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return false;
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}
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OnListViewScrollEvent that = (OnListViewScrollEvent) o;
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if (firstVisibleItem != that.firstVisibleItem) {
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return false;
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}
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if (scrollState != that.scrollState) {
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return false;
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}
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if (totalItemCount != that.totalItemCount) {
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return false;
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}
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if (visibleItemCount != that.visibleItemCount) {
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return false;
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}
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if (!listView.equals(that.listView)) {
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return false;
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}
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return true;
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}
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@Override
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public int hashCode() {
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int result = listView.hashCode();
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result = 31 * result + scrollState;
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result = 31 * result + firstVisibleItem;
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result = 31 * result + visibleItemCount;
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result = 31 * result + totalItemCount;
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return result;
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}
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@Override
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public String toString() {
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return "OnListViewScrollEvent{" +
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"listView=" + listView +
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", scrollState=" + scrollState +
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", firstVisibleItem=" + firstVisibleItem +
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", visibleItemCount=" + visibleItemCount +
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", totalItemCount=" + totalItemCount +
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'}';
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}
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}

‎library/src/main/java/rx/android/observables/ViewObservable.java‎

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package rx.android.observables;
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import android.view.View;
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import android.widget.AbsListView;
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import android.widget.AdapterView;
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import android.widget.CompoundButton;
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import android.widget.TextView;
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import rx.android.events.OnCheckedChangeEvent;
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import rx.android.events.OnClickEvent;
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import rx.android.events.OnItemClickEvent;
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import rx.android.events.OnListViewScrollEvent;
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import rx.android.events.OnTextChangeEvent;
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import rx.android.operators.OperatorAdapterViewOnItemClick;
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import rx.android.operators.OperatorCompoundButtonInput;
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import rx.android.operators.OnSubscribeListViewScroll;
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import rx.android.operators.OperatorTextViewInput;
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import rx.android.operators.OperatorViewClick;
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@@ -58,4 +61,13 @@ public static Observable<OnItemClickEvent> itemClicks(final AdapterView<?> adapt
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return Observable.create(new OperatorAdapterViewOnItemClick(adapterView));
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}
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/**
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* Returns an observable that emits all the scroll events from the provided ListView.
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* Note that this will replace any listeners previously set through
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* {@link android.widget.AbsListView#setOnScrollListener(android.widget.AbsListView.OnScrollListener)} unless those
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* were set by this method or {@link rx.android.operators.OnSubscribeListViewScroll}.
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*/
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public static Observable<OnListViewScrollEvent> listScrollEvents(final AbsListView listView) {
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return Observable.create(new OnSubscribeListViewScroll(listView));
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}
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}

‎library/src/main/java/rx/android/operators/OnSubscribeListViewScroll.java‎

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/**
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package rx.android.operators;
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import android.widget.AbsListView;
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import android.widget.AdapterView;
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import rx.Observable;
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import rx.Subscriber;
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import rx.android.events.OnListViewScrollEvent;
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import rx.android.observables.Assertions;
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import rx.android.subscriptions.AndroidSubscriptions;
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import rx.functions.Action0;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.Map;
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import java.util.WeakHashMap;
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public class OnSubscribeListViewScroll implements Observable.OnSubscribe<OnListViewScrollEvent> {
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private final AbsListView listView;
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public OnSubscribeListViewScroll(AbsListView listView) {
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this.listView = listView;
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}
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@Override
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public void call(final Subscriber<? super OnListViewScrollEvent> observer) {
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Assertions.assertUiThread();
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final CompositeOnScrollListener composite = CachedListeners.getFromViewOrCreate(listView);
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final AbsListView.OnScrollListener listener = new AbsListView.OnScrollListener() {
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int currentScrollState = SCROLL_STATE_IDLE;
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@Override
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public void onScrollStateChanged(AbsListView view, int scrollState) {
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this.currentScrollState = scrollState;
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}
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@Override
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public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
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OnListViewScrollEvent event = new OnListViewScrollEvent(view, this.currentScrollState, firstVisibleItem,
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visibleItemCount, totalItemCount);
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observer.onNext(event);
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}
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};
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composite.addOnScrollListener(listener);
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observer.add(AndroidSubscriptions.unsubscribeInUiThread(new Action0() {
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@Override
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public void call() {
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composite.removeOnScrollListener(listener);
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}
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}));
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}
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private static class CompositeOnScrollListener implements AbsListView.OnScrollListener {
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private final List<AbsListView.OnScrollListener> listeners = new ArrayList<AbsListView.OnScrollListener>();
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public boolean addOnScrollListener(final AbsListView.OnScrollListener listener) {
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return listeners.add(listener);
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}
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public boolean removeOnScrollListener(final AbsListView.OnScrollListener listener) {
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return listeners.remove(listener);
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}
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@Override
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public void onScrollStateChanged(AbsListView view, int scrollState) {
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for (AbsListView.OnScrollListener listener : listeners) {
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listener.onScrollStateChanged(view, scrollState);
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}
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}
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@Override
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public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
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for (AbsListView.OnScrollListener listener : listeners) {
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listener.onScroll(view, firstVisibleItem, visibleItemCount, totalItemCount);
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}
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}
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}
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private static class CachedListeners {
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private static final Map<AdapterView<?>, CompositeOnScrollListener> sCachedListeners =
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new WeakHashMap<AdapterView<?>, CompositeOnScrollListener>();
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public static CompositeOnScrollListener getFromViewOrCreate(final AbsListView view) {
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final CompositeOnScrollListener cached = sCachedListeners.get(view);
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if (cached != null) {
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return cached;
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}
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final CompositeOnScrollListener listener = new CompositeOnScrollListener();
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sCachedListeners.put(view, listener);
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view.setOnScrollListener(listener);
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return listener;
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}
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}
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}

‎library/src/test/java/rx/android/operators/OnSubscribeListViewScrollTest.java‎

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package rx.android.operators;
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import android.widget.AbsListView;
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import android.widget.ListView;
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import org.junit.Before;
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import org.junit.Test;
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import org.junit.runner.RunWith;
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import org.mockito.ArgumentCaptor;
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import org.mockito.Captor;
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import org.mockito.InOrder;
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import org.mockito.Mock;
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import org.mockito.MockitoAnnotations;
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import org.robolectric.RobolectricTestRunner;
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import rx.Observer;
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import rx.Subscription;
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import rx.android.events.OnListViewScrollEvent;
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import rx.android.observables.ViewObservable;
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import rx.observers.TestObserver;
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import java.util.ArrayList;
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import java.util.List;
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import static org.mockito.Mockito.*;
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@RunWith(RobolectricTestRunner.class)
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public class OnSubscribeListViewScrollTest {
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@Mock
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private ListView listView;
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@Captor
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private ArgumentCaptor<AbsListView.OnScrollListener> captor;
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private List<OnListViewScrollEvent> events;
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@Before
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public void setup() {
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MockitoAnnotations.initMocks(this);
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events = new ArrayList<OnListViewScrollEvent>();
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for (int i = 0; i < 10; i++) {
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events.add(
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new OnListViewScrollEvent(listView, AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL, i, 2, 10));
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}
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}
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@Test
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@SuppressWarnings("unchecked")
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public void testEventsEmitted() {
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Observer<OnListViewScrollEvent> observer = mock(Observer.class);
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Subscription subscription =
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ViewObservable.listScrollEvents(listView).subscribe(new TestObserver<OnListViewScrollEvent>(observer));
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verify(observer, never()).onNext(any(OnListViewScrollEvent.class));
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verify(listView, times(1)).setOnScrollListener(captor.capture());
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captor.getValue().onScrollStateChanged(listView, AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL);
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InOrder inOrder = inOrder(observer);
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verifyObserversGetEvents(inOrder, observer);
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subscription.unsubscribe();
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verifyNoInteractionsOnEventEmit(inOrder);
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}
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@SuppressWarnings("unchecked")
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public void testMultipleObservablesOnSameViewGetCorrectEvents() {
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Observer<OnListViewScrollEvent> observerA = mock(Observer.class);
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Subscription subscriptionA = ViewObservable.listScrollEvents(listView)
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.subscribe(new TestObserver<OnListViewScrollEvent>(observerA));
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Observer<OnListViewScrollEvent> observerB = mock(Observer.class);
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Subscription subscriptionB = ViewObservable.listScrollEvents(listView)
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.subscribe(new TestObserver<OnListViewScrollEvent>(observerB));
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verify(listView, times(2)).setOnScrollListener(captor.capture());
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InOrder inOrder = inOrder(observerA, observerB);
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verifyObserversGetEvents(inOrder, observerA, observerB);
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subscriptionA.unsubscribe();
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verifyObserversGetEvents(inOrder, observerB);
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subscriptionB.unsubscribe();
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verifyNoInteractionsOnEventEmit(inOrder);
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}
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private void verifyNoInteractionsOnEventEmit(InOrder inOrder) {
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OnListViewScrollEvent lastEvent = events.get(0);
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captor.getValue().onScroll(listView,
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lastEvent.firstVisibleItem,
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lastEvent.visibleItemCount,
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lastEvent.totalItemCount);
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inOrder.verifyNoMoreInteractions();
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}
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private void verifyObserversGetEvents(InOrder inOrder, Observer<OnListViewScrollEvent>... observers) {
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for (OnListViewScrollEvent event : events) {
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captor.getValue().onScroll(event.listView,
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event.firstVisibleItem,
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event.visibleItemCount,
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event.totalItemCount);
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for (Observer<OnListViewScrollEvent> observer : observers) {
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inOrder.verify(observer, times(1)).onNext(event);
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}
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}
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inOrder.verifyNoMoreInteractions();
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}
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}

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