| /* |
| * Copyright (C) 2018 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package androidx.viewpager2.widget.swipe; |
| |
| import static android.support.test.espresso.Espresso.onView; |
| import static android.support.test.espresso.matcher.ViewMatchers.isDisplayed; |
| import static android.support.test.espresso.matcher.ViewMatchers.withId; |
| |
| import static androidx.core.util.Preconditions.checkArgumentNonnegative; |
| import static androidx.recyclerview.widget.RecyclerView.SCROLL_STATE_IDLE; |
| |
| import static org.hamcrest.CoreMatchers.allOf; |
| |
| import android.support.test.espresso.ViewAction; |
| import android.support.test.espresso.action.ViewActions; |
| |
| import androidx.recyclerview.widget.RecyclerView; |
| import androidx.viewpager2.test.R; |
| |
| import java.util.concurrent.CountDownLatch; |
| import java.util.concurrent.TimeUnit; |
| |
| public class PageSwiper { |
| private CountDownLatch mStableAfterSwipe; |
| private final int mLastPageIx; |
| |
| public PageSwiper(int totalPages, RecyclerView recyclerView) { |
| mLastPageIx = checkArgumentNonnegative(totalPages - 1); |
| |
| recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() { |
| @Override |
| public void onScrollStateChanged(RecyclerView recyclerView, int newState) { |
| // coming to idle from another state (dragging or setting) means we're stable now |
| if (newState == SCROLL_STATE_IDLE) { |
| mStableAfterSwipe.countDown(); |
| } |
| } |
| }); |
| } |
| |
| public void swipe(int currentPageIx, int nextPageIx) throws InterruptedException { |
| if (nextPageIx > mLastPageIx) { |
| throw new IllegalArgumentException("Invalid next page: beyond last page."); |
| } |
| |
| if (currentPageIx == nextPageIx) { // dedicated for testing edge behaviour |
| if (nextPageIx == 0) { |
| swipeRight(); // bounce off the left edge |
| return; |
| } |
| if (nextPageIx == mLastPageIx) { // bounce off the right edge |
| swipeLeft(); |
| return; |
| } |
| throw new IllegalArgumentException( |
| "Invalid sequence. Not on an edge, and current page = next page."); |
| } |
| |
| if (Math.abs(nextPageIx - currentPageIx) > 1) { |
| throw new IllegalArgumentException( |
| "Specified next page not adjacent to the current page."); |
| } |
| |
| if (nextPageIx > currentPageIx) { |
| swipeLeft(); |
| } else { |
| swipeRight(); |
| } |
| } |
| |
| private void swipeLeft() throws InterruptedException { |
| swipe(ViewActions.swipeLeft()); |
| } |
| |
| private void swipeRight() throws InterruptedException { |
| swipe(ViewActions.swipeRight()); |
| } |
| |
| private void swipe(ViewAction swipeAction) throws InterruptedException { |
| mStableAfterSwipe = new CountDownLatch(1); |
| onView(allOf(isDisplayed(), withId(R.id.text_view))).perform(swipeAction); |
| mStableAfterSwipe.await(1, TimeUnit.SECONDS); |
| } |
| } |