LinearLayoutManagerSnappingTest.java revision c587f7dba5a337169e854e235da59f595255d6cc
1/* 2 * Copyright (C) 2016 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package android.support.v7.widget; 18 19import org.junit.Test; 20import org.junit.runner.RunWith; 21import org.junit.runners.Parameterized; 22 23import android.support.annotation.Nullable; 24import android.test.suitebuilder.annotation.MediumTest; 25import android.view.View; 26 27import java.util.ArrayList; 28import java.util.Arrays; 29import java.util.List; 30import java.util.concurrent.atomic.AtomicBoolean; 31 32import static junit.framework.Assert.assertEquals; 33import static junit.framework.Assert.assertNotSame; 34import static junit.framework.Assert.assertSame; 35import static junit.framework.Assert.assertTrue; 36 37@RunWith(Parameterized.class) 38public class LinearLayoutManagerSnappingTest extends BaseLinearLayoutManagerTest { 39 40 final Config mConfig; 41 final boolean mReverseScroll; 42 43 public LinearLayoutManagerSnappingTest(Config config, boolean reverseScroll) { 44 mConfig = config; 45 mReverseScroll = reverseScroll; 46 } 47 48 @Parameterized.Parameters(name = "config:{0}, reverseScroll:{1}") 49 public static List<Object[]> getParams() { 50 List<Object[]> result = new ArrayList<>(); 51 List<Config> configs = createBaseVariations(); 52 for (Config config : configs) { 53 for (boolean reverseScroll : new boolean[] {true, false}) { 54 result.add(new Object[]{config, reverseScroll}); 55 } 56 } 57 return result; 58 } 59 60 @MediumTest 61 @Test 62 public void snapOnScrollSameView() throws Throwable { 63 final Config config = (Config) mConfig.clone(); 64 setupByConfig(config, true); 65 setupSnapHelper(); 66 67 // Record the current center view. 68 View view = findCenterView(mLayoutManager); 69 assertCenterAligned(view); 70 71 int scrollDistance = (getViewDimension(view) / 2) - 1; 72 int scrollDist = mReverseScroll ? -scrollDistance : scrollDistance; 73 mLayoutManager.expectIdleState(2); 74 smoothScrollBy(scrollDist); 75 mLayoutManager.waitForSnap(10); 76 77 // Views have not changed 78 View viewAfterFling = findCenterView(mLayoutManager); 79 assertSame("The view should have scrolled", view, viewAfterFling); 80 assertCenterAligned(viewAfterFling); 81 } 82 83 @MediumTest 84 @Test 85 public void snapOnScrollNextView() throws Throwable { 86 final Config config = (Config) mConfig.clone(); 87 setupByConfig(config, true); 88 setupSnapHelper(); 89 90 // Record the current center view. 91 View view = findCenterView(mLayoutManager); 92 assertCenterAligned(view); 93 94 int scrollDistance = (getViewDimension(view) / 2) + 1; 95 int scrollDist = mReverseScroll ? -scrollDistance : scrollDistance; 96 mLayoutManager.expectIdleState(2); 97 smoothScrollBy(scrollDist); 98 mLayoutManager.waitForSnap(10); 99 100 // Views have not changed 101 View viewAfterFling = findCenterView(mLayoutManager); 102 assertNotSame("The view should have scrolled", view, viewAfterFling); 103 assertCenterAligned(viewAfterFling); 104 } 105 106 @MediumTest 107 @Test 108 public void snapOnFlingSameView() throws Throwable { 109 final Config config = (Config) mConfig.clone(); 110 setupByConfig(config, true); 111 setupSnapHelper(); 112 113 // Record the current center view. 114 View view = findCenterView(mLayoutManager); 115 assertCenterAligned(view); 116 117 // Velocity small enough to not scroll to the next view. 118 int velocity = (int) (1.000001 * mRecyclerView.getMinFlingVelocity()); 119 int velocityDir = mReverseScroll ? -velocity : velocity; 120 mLayoutManager.expectIdleState(2); 121 assertTrue(fling(velocityDir, velocityDir)); 122 // Wait for two settling scrolls: the initial one and the corrective one. 123 waitForIdleScroll(mRecyclerView); 124 mLayoutManager.waitForSnap(100); 125 126 View viewAfterFling = findCenterView(mLayoutManager); 127 128 assertSame("The view should NOT have scrolled", view, viewAfterFling); 129 assertCenterAligned(viewAfterFling); 130 } 131 132 @MediumTest 133 @Test 134 public void snapOnFlingNextView() throws Throwable { 135 final Config config = (Config) mConfig.clone(); 136 setupByConfig(config, true); 137 setupSnapHelper(); 138 139 // Record the current center view. 140 View view = findCenterView(mLayoutManager); 141 assertCenterAligned(view); 142 143 // Velocity high enough to scroll beyond the current view. 144 int velocity = (int) (0.2 * mRecyclerView.getMaxFlingVelocity()); 145 int velocityDir = mReverseScroll ? -velocity : velocity; 146 mLayoutManager.expectIdleState(1); 147 assertTrue(fling(velocityDir, velocityDir)); 148 mLayoutManager.waitForSnap(100); 149 getInstrumentation().waitForIdleSync(); 150 151 View viewAfterFling = findCenterView(mLayoutManager); 152 153 assertNotSame("The view should have scrolled", view, viewAfterFling); 154 assertCenterAligned(viewAfterFling); 155 } 156 157 private void setupSnapHelper() throws Throwable { 158 SnapHelper snapHelper = new LinearSnapHelper(); 159 mLayoutManager.expectIdleState(1); 160 snapHelper.attachToRecyclerView(mRecyclerView); 161 mLayoutManager.waitForSnap(10); 162 163 mLayoutManager.expectLayouts(1); 164 scrollToPosition(mConfig.mItemCount / 2); 165 mLayoutManager.waitForLayout(2); 166 167 View view = findCenterView(mLayoutManager); 168 int scrollDistance = (getViewDimension(view) / 2) + 10; 169 int scrollDist = mReverseScroll ? -scrollDistance : scrollDistance; 170 171 mLayoutManager.expectIdleState(2); 172 smoothScrollBy(scrollDist); 173 mLayoutManager.waitForSnap(10); 174 } 175 176 @Nullable private View findCenterView(RecyclerView.LayoutManager layoutManager) { 177 if (layoutManager.canScrollHorizontally()) { 178 return mRecyclerView.findChildViewUnder(mRecyclerView.getWidth() / 2, 0); 179 } else { 180 return mRecyclerView.findChildViewUnder(0, mRecyclerView.getHeight() / 2); 181 } 182 } 183 184 private int getViewDimension(View view) { 185 OrientationHelper helper; 186 if (mLayoutManager.canScrollHorizontally()) { 187 helper = OrientationHelper.createHorizontalHelper(mLayoutManager); 188 } else { 189 helper = OrientationHelper.createVerticalHelper(mLayoutManager); 190 } 191 return helper.getDecoratedMeasurement(view); 192 } 193 194 private void assertCenterAligned(View view) { 195 if (mLayoutManager.canScrollHorizontally()) { 196 assertEquals(mRecyclerView.getWidth() / 2, 197 mLayoutManager.getViewBounds(view).centerX()); 198 } else { 199 assertEquals(mRecyclerView.getHeight() / 2, 200 mLayoutManager.getViewBounds(view).centerY()); 201 } 202 } 203 204 private boolean fling(final int velocityX, final int velocityY) throws Throwable { 205 final AtomicBoolean didStart = new AtomicBoolean(false); 206 runTestOnUiThread(new Runnable() { 207 @Override 208 public void run() { 209 boolean result = mRecyclerView.fling(velocityX, velocityY); 210 didStart.set(result); 211 } 212 }); 213 if (!didStart.get()) { 214 return false; 215 } 216 waitForIdleScroll(mRecyclerView); 217 return true; 218 } 219} 220