LinearLayoutManagerSnappingTest.java revision 3911e1c2d38e301d5ffbdf11f808fdc593dd83e9
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 snapOnScrollSameViewEdge() throws Throwable { 63 final Config config = (Config) mConfig.clone(); 64 // Ensure that the views are big enough to reach the pathological case when the view closest 65 // to the center is an edge view, but it cannot scroll further in order to snap. 66 setupByConfig(config, true, new RecyclerView.LayoutParams(1000, 1000), 67 new RecyclerView.LayoutParams(1500, 1500)); 68 SnapHelper snapHelper = new LinearSnapHelper(); 69 mLayoutManager.expectIdleState(1); 70 snapHelper.attachToRecyclerView(mRecyclerView); 71 mLayoutManager.waitForSnap(10); 72 73 // Record the current center view. 74 View view = findCenterView(mLayoutManager); 75 76 int scrollDistance = (getViewDimension(view) / 2) - 1; 77 int scrollDist = config.mStackFromEnd == config.mReverseLayout 78 ? -scrollDistance : scrollDistance; 79 mLayoutManager.expectIdleState(1); 80 smoothScrollBy(scrollDist); 81 mLayoutManager.waitForSnap(10); 82 mLayoutManager.expectCallbacks(5); 83 mLayoutManager.assertNoCallbacks("There should be no callbacks after some time", 3); 84 } 85 86 @MediumTest 87 @Test 88 public void snapOnScrollSameView() throws Throwable { 89 final Config config = (Config) mConfig.clone(); 90 setupByConfig(config, true); 91 setupSnapHelper(); 92 93 // Record the current center view. 94 View view = findCenterView(mLayoutManager); 95 assertCenterAligned(view); 96 97 int scrollDistance = (getViewDimension(view) / 2) - 1; 98 int scrollDist = mReverseScroll ? -scrollDistance : scrollDistance; 99 mLayoutManager.expectIdleState(2); 100 smoothScrollBy(scrollDist); 101 mLayoutManager.waitForSnap(10); 102 103 // Views have not changed 104 View viewAfterFling = findCenterView(mLayoutManager); 105 assertSame("The view should NOT have scrolled", view, viewAfterFling); 106 assertCenterAligned(viewAfterFling); 107 } 108 109 @MediumTest 110 @Test 111 public void snapOnScrollNextView() throws Throwable { 112 final Config config = (Config) mConfig.clone(); 113 setupByConfig(config, true); 114 setupSnapHelper(); 115 116 // Record the current center view. 117 View view = findCenterView(mLayoutManager); 118 assertCenterAligned(view); 119 120 int scrollDistance = (getViewDimension(view) / 2) + 1; 121 int scrollDist = mReverseScroll ? -scrollDistance : scrollDistance; 122 mLayoutManager.expectIdleState(2); 123 smoothScrollBy(scrollDist); 124 mLayoutManager.waitForSnap(10); 125 126 // Views have not changed 127 View viewAfterFling = findCenterView(mLayoutManager); 128 assertNotSame("The view should have scrolled", view, viewAfterFling); 129 assertCenterAligned(viewAfterFling); 130 } 131 132 @MediumTest 133 @Test 134 public void snapOnFlingSameView() 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 small enough to not scroll to the next view. 144 int velocity = (int) (1.000001 * mRecyclerView.getMinFlingVelocity()); 145 int velocityDir = mReverseScroll ? -velocity : velocity; 146 mLayoutManager.expectIdleState(2); 147 assertTrue(fling(velocityDir, velocityDir)); 148 // Wait for two settling scrolls: the initial one and the corrective one. 149 waitForIdleScroll(mRecyclerView); 150 mLayoutManager.waitForSnap(100); 151 152 View viewAfterFling = findCenterView(mLayoutManager); 153 154 assertSame("The view should NOT have scrolled", view, viewAfterFling); 155 assertCenterAligned(viewAfterFling); 156 } 157 158 @MediumTest 159 @Test 160 public void snapOnFlingNextView() throws Throwable { 161 final Config config = (Config) mConfig.clone(); 162 setupByConfig(config, true); 163 setupSnapHelper(); 164 165 // Record the current center view. 166 View view = findCenterView(mLayoutManager); 167 assertCenterAligned(view); 168 169 // Velocity high enough to scroll beyond the current view. 170 int velocity = (int) (0.2 * mRecyclerView.getMaxFlingVelocity()); 171 int velocityDir = mReverseScroll ? -velocity : velocity; 172 mLayoutManager.expectIdleState(1); 173 assertTrue(fling(velocityDir, velocityDir)); 174 mLayoutManager.waitForSnap(100); 175 getInstrumentation().waitForIdleSync(); 176 177 View viewAfterFling = findCenterView(mLayoutManager); 178 179 assertNotSame("The view should have scrolled", view, viewAfterFling); 180 assertCenterAligned(viewAfterFling); 181 } 182 183 private void setupSnapHelper() throws Throwable { 184 SnapHelper snapHelper = new LinearSnapHelper(); 185 mLayoutManager.expectIdleState(1); 186 snapHelper.attachToRecyclerView(mRecyclerView); 187 mLayoutManager.waitForSnap(10); 188 189 mLayoutManager.expectLayouts(1); 190 scrollToPosition(mConfig.mItemCount / 2); 191 mLayoutManager.waitForLayout(2); 192 193 View view = findCenterView(mLayoutManager); 194 int scrollDistance = distFromCenter(view) / 2; 195 if (scrollDistance == 0) { 196 return; 197 } 198 199 int scrollDist = mReverseScroll ? -scrollDistance : scrollDistance; 200 201 mLayoutManager.expectIdleState(2); 202 smoothScrollBy(scrollDist); 203 mLayoutManager.waitForSnap(10); 204 } 205 206 @Nullable private View findCenterView(RecyclerView.LayoutManager layoutManager) { 207 if (layoutManager.canScrollHorizontally()) { 208 return mRecyclerView.findChildViewUnder(mRecyclerView.getWidth() / 2, 0); 209 } else { 210 return mRecyclerView.findChildViewUnder(0, mRecyclerView.getHeight() / 2); 211 } 212 } 213 214 private int getViewDimension(View view) { 215 OrientationHelper helper; 216 if (mLayoutManager.canScrollHorizontally()) { 217 helper = OrientationHelper.createHorizontalHelper(mLayoutManager); 218 } else { 219 helper = OrientationHelper.createVerticalHelper(mLayoutManager); 220 } 221 return helper.getDecoratedMeasurement(view); 222 } 223 224 private void assertCenterAligned(View view) { 225 if (mLayoutManager.canScrollHorizontally()) { 226 assertEquals(mRecyclerView.getWidth() / 2, 227 mLayoutManager.getViewBounds(view).centerX()); 228 } else { 229 assertEquals(mRecyclerView.getHeight() / 2, 230 mLayoutManager.getViewBounds(view).centerY()); 231 } 232 } 233 234 private int distFromCenter(View view) { 235 if (mLayoutManager.canScrollHorizontally()) { 236 return Math.abs(mRecyclerView.getWidth() / 2 - 237 mLayoutManager.getViewBounds(view).centerX()); 238 } else { 239 return Math.abs(mRecyclerView.getHeight() / 2 - 240 mLayoutManager.getViewBounds(view).centerY()); 241 } 242 } 243 244 private boolean fling(final int velocityX, final int velocityY) throws Throwable { 245 final AtomicBoolean didStart = new AtomicBoolean(false); 246 runTestOnUiThread(new Runnable() { 247 @Override 248 public void run() { 249 boolean result = mRecyclerView.fling(velocityX, velocityY); 250 didStart.set(result); 251 } 252 }); 253 if (!didStart.get()) { 254 return false; 255 } 256 waitForIdleScroll(mRecyclerView); 257 return true; 258 } 259} 260