1 /* 2 * Copyright (C) 2014 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 17 package com.android.systemui.statusbar.stack; 18 19 import android.content.Context; 20 import android.util.Log; 21 import android.view.View; 22 import android.view.ViewGroup; 23 24 import com.android.systemui.R; 25 import com.android.systemui.statusbar.ExpandableNotificationRow; 26 import com.android.systemui.statusbar.ExpandableView; 27 import com.android.systemui.statusbar.notification.FakeShadowView; 28 import com.android.systemui.statusbar.notification.NotificationUtils; 29 30 import java.util.ArrayList; 31 import java.util.HashMap; 32 import java.util.List; 33 34 /** 35 * The Algorithm of the {@link com.android.systemui.statusbar.stack 36 * .NotificationStackScrollLayout} which can be queried for {@link com.android.systemui.statusbar 37 * .stack.StackScrollState} 38 */ 39 public class StackScrollAlgorithm { 40 41 private static final String LOG_TAG = "StackScrollAlgorithm"; 42 43 private static final int MAX_ITEMS_IN_BOTTOM_STACK = 3; 44 45 private int mPaddingBetweenElements; 46 private int mIncreasedPaddingBetweenElements; 47 private int mCollapsedSize; 48 private int mBottomStackPeekSize; 49 private int mZDistanceBetweenElements; 50 private int mZBasicHeight; 51 52 private StackIndentationFunctor mBottomStackIndentationFunctor; 53 54 private StackScrollAlgorithmState mTempAlgorithmState = new StackScrollAlgorithmState(); 55 private boolean mIsExpanded; 56 private int mBottomStackSlowDownLength; 57 StackScrollAlgorithm(Context context)58 public StackScrollAlgorithm(Context context) { 59 initView(context); 60 } 61 initView(Context context)62 public void initView(Context context) { 63 initConstants(context); 64 } 65 getBottomStackSlowDownLength()66 public int getBottomStackSlowDownLength() { 67 return mBottomStackSlowDownLength + mPaddingBetweenElements; 68 } 69 initConstants(Context context)70 private void initConstants(Context context) { 71 mPaddingBetweenElements = Math.max(1, context.getResources() 72 .getDimensionPixelSize(R.dimen.notification_divider_height)); 73 mIncreasedPaddingBetweenElements = context.getResources() 74 .getDimensionPixelSize(R.dimen.notification_divider_height_increased); 75 mCollapsedSize = context.getResources() 76 .getDimensionPixelSize(R.dimen.notification_min_height); 77 mBottomStackPeekSize = context.getResources() 78 .getDimensionPixelSize(R.dimen.bottom_stack_peek_amount); 79 mZDistanceBetweenElements = Math.max(1, context.getResources() 80 .getDimensionPixelSize(R.dimen.z_distance_between_notifications)); 81 mZBasicHeight = (MAX_ITEMS_IN_BOTTOM_STACK + 1) * mZDistanceBetweenElements; 82 mBottomStackSlowDownLength = context.getResources() 83 .getDimensionPixelSize(R.dimen.bottom_stack_slow_down_length); 84 mBottomStackIndentationFunctor = new PiecewiseLinearIndentationFunctor( 85 MAX_ITEMS_IN_BOTTOM_STACK, 86 mBottomStackPeekSize, 87 getBottomStackSlowDownLength(), 88 0.5f); 89 } 90 getStackScrollState(AmbientState ambientState, StackScrollState resultState)91 public void getStackScrollState(AmbientState ambientState, StackScrollState resultState) { 92 // The state of the local variables are saved in an algorithmState to easily subdivide it 93 // into multiple phases. 94 StackScrollAlgorithmState algorithmState = mTempAlgorithmState; 95 96 // First we reset the view states to their default values. 97 resultState.resetViewStates(); 98 99 initAlgorithmState(resultState, algorithmState, ambientState); 100 101 updatePositionsForState(resultState, algorithmState, ambientState); 102 103 updateZValuesForState(resultState, algorithmState, ambientState); 104 105 updateHeadsUpStates(resultState, algorithmState, ambientState); 106 107 handleDraggedViews(ambientState, resultState, algorithmState); 108 updateDimmedActivatedHideSensitive(ambientState, resultState, algorithmState); 109 updateClipping(resultState, algorithmState, ambientState); 110 updateSpeedBumpState(resultState, algorithmState, ambientState.getSpeedBumpIndex()); 111 getNotificationChildrenStates(resultState, algorithmState); 112 } 113 getNotificationChildrenStates(StackScrollState resultState, StackScrollAlgorithmState algorithmState)114 private void getNotificationChildrenStates(StackScrollState resultState, 115 StackScrollAlgorithmState algorithmState) { 116 int childCount = algorithmState.visibleChildren.size(); 117 for (int i = 0; i < childCount; i++) { 118 ExpandableView v = algorithmState.visibleChildren.get(i); 119 if (v instanceof ExpandableNotificationRow) { 120 ExpandableNotificationRow row = (ExpandableNotificationRow) v; 121 row.getChildrenStates(resultState); 122 } 123 } 124 } 125 updateSpeedBumpState(StackScrollState resultState, StackScrollAlgorithmState algorithmState, int speedBumpIndex)126 private void updateSpeedBumpState(StackScrollState resultState, 127 StackScrollAlgorithmState algorithmState, int speedBumpIndex) { 128 int childCount = algorithmState.visibleChildren.size(); 129 for (int i = 0; i < childCount; i++) { 130 View child = algorithmState.visibleChildren.get(i); 131 StackViewState childViewState = resultState.getViewStateForView(child); 132 133 // The speed bump can also be gone, so equality needs to be taken when comparing 134 // indices. 135 childViewState.belowSpeedBump = speedBumpIndex != -1 && i >= speedBumpIndex; 136 } 137 } 138 updateClipping(StackScrollState resultState, StackScrollAlgorithmState algorithmState, AmbientState ambientState)139 private void updateClipping(StackScrollState resultState, 140 StackScrollAlgorithmState algorithmState, AmbientState ambientState) { 141 float drawStart = ambientState.getTopPadding() + ambientState.getStackTranslation(); 142 float previousNotificationEnd = 0; 143 float previousNotificationStart = 0; 144 int childCount = algorithmState.visibleChildren.size(); 145 for (int i = 0; i < childCount; i++) { 146 ExpandableView child = algorithmState.visibleChildren.get(i); 147 StackViewState state = resultState.getViewStateForView(child); 148 if (!child.mustStayOnScreen()) { 149 previousNotificationEnd = Math.max(drawStart, previousNotificationEnd); 150 previousNotificationStart = Math.max(drawStart, previousNotificationStart); 151 } 152 float newYTranslation = state.yTranslation; 153 float newHeight = state.height; 154 float newNotificationEnd = newYTranslation + newHeight; 155 boolean isHeadsUp = (child instanceof ExpandableNotificationRow) 156 && ((ExpandableNotificationRow) child).isPinned(); 157 if (newYTranslation < previousNotificationEnd 158 && (!isHeadsUp || ambientState.isShadeExpanded())) { 159 // The previous view is overlapping on top, clip! 160 float overlapAmount = previousNotificationEnd - newYTranslation; 161 state.clipTopAmount = (int) overlapAmount; 162 } else { 163 state.clipTopAmount = 0; 164 } 165 166 if (!child.isTransparent()) { 167 // Only update the previous values if we are not transparent, 168 // otherwise we would clip to a transparent view. 169 previousNotificationEnd = newNotificationEnd; 170 previousNotificationStart = newYTranslation; 171 } 172 } 173 } 174 canChildBeDismissed(View v)175 public static boolean canChildBeDismissed(View v) { 176 if (!(v instanceof ExpandableNotificationRow)) { 177 return false; 178 } 179 ExpandableNotificationRow row = (ExpandableNotificationRow) v; 180 if (row.areGutsExposed()) { 181 return false; 182 } 183 return row.canViewBeDismissed(); 184 } 185 186 /** 187 * Updates the dimmed, activated and hiding sensitive states of the children. 188 */ updateDimmedActivatedHideSensitive(AmbientState ambientState, StackScrollState resultState, StackScrollAlgorithmState algorithmState)189 private void updateDimmedActivatedHideSensitive(AmbientState ambientState, 190 StackScrollState resultState, StackScrollAlgorithmState algorithmState) { 191 boolean dimmed = ambientState.isDimmed(); 192 boolean dark = ambientState.isDark(); 193 boolean hideSensitive = ambientState.isHideSensitive(); 194 View activatedChild = ambientState.getActivatedChild(); 195 int childCount = algorithmState.visibleChildren.size(); 196 for (int i = 0; i < childCount; i++) { 197 View child = algorithmState.visibleChildren.get(i); 198 StackViewState childViewState = resultState.getViewStateForView(child); 199 childViewState.dimmed = dimmed; 200 childViewState.dark = dark; 201 childViewState.hideSensitive = hideSensitive; 202 boolean isActivatedChild = activatedChild == child; 203 if (dimmed && isActivatedChild) { 204 childViewState.zTranslation += 2.0f * mZDistanceBetweenElements; 205 } 206 } 207 } 208 209 /** 210 * Handle the special state when views are being dragged 211 */ handleDraggedViews(AmbientState ambientState, StackScrollState resultState, StackScrollAlgorithmState algorithmState)212 private void handleDraggedViews(AmbientState ambientState, StackScrollState resultState, 213 StackScrollAlgorithmState algorithmState) { 214 ArrayList<View> draggedViews = ambientState.getDraggedViews(); 215 for (View draggedView : draggedViews) { 216 int childIndex = algorithmState.visibleChildren.indexOf(draggedView); 217 if (childIndex >= 0 && childIndex < algorithmState.visibleChildren.size() - 1) { 218 View nextChild = algorithmState.visibleChildren.get(childIndex + 1); 219 if (!draggedViews.contains(nextChild)) { 220 // only if the view is not dragged itself we modify its state to be fully 221 // visible 222 StackViewState viewState = resultState.getViewStateForView( 223 nextChild); 224 // The child below the dragged one must be fully visible 225 if (ambientState.isShadeExpanded()) { 226 viewState.shadowAlpha = 1; 227 viewState.hidden = false; 228 } 229 } 230 231 // Lets set the alpha to the one it currently has, as its currently being dragged 232 StackViewState viewState = resultState.getViewStateForView(draggedView); 233 // The dragged child should keep the set alpha 234 viewState.alpha = draggedView.getAlpha(); 235 } 236 } 237 } 238 239 /** 240 * Initialize the algorithm state like updating the visible children. 241 */ initAlgorithmState(StackScrollState resultState, StackScrollAlgorithmState state, AmbientState ambientState)242 private void initAlgorithmState(StackScrollState resultState, StackScrollAlgorithmState state, 243 AmbientState ambientState) { 244 state.itemsInBottomStack = 0.0f; 245 state.partialInBottom = 0.0f; 246 float bottomOverScroll = ambientState.getOverScrollAmount(false /* onTop */); 247 248 int scrollY = ambientState.getScrollY(); 249 250 // Due to the overScroller, the stackscroller can have negative scroll state. This is 251 // already accounted for by the top padding and doesn't need an additional adaption 252 scrollY = Math.max(0, scrollY); 253 state.scrollY = (int) (scrollY + bottomOverScroll); 254 255 //now init the visible children and update paddings 256 ViewGroup hostView = resultState.getHostView(); 257 int childCount = hostView.getChildCount(); 258 state.visibleChildren.clear(); 259 state.visibleChildren.ensureCapacity(childCount); 260 state.increasedPaddingMap.clear(); 261 int notGoneIndex = 0; 262 ExpandableView lastView = null; 263 for (int i = 0; i < childCount; i++) { 264 ExpandableView v = (ExpandableView) hostView.getChildAt(i); 265 if (v.getVisibility() != View.GONE) { 266 notGoneIndex = updateNotGoneIndex(resultState, state, notGoneIndex, v); 267 float increasedPadding = v.getIncreasedPaddingAmount(); 268 if (increasedPadding != 0.0f) { 269 state.increasedPaddingMap.put(v, increasedPadding); 270 if (lastView != null) { 271 Float prevValue = state.increasedPaddingMap.get(lastView); 272 float newValue = prevValue != null 273 ? Math.max(prevValue, increasedPadding) 274 : increasedPadding; 275 state.increasedPaddingMap.put(lastView, newValue); 276 } 277 } 278 if (v instanceof ExpandableNotificationRow) { 279 ExpandableNotificationRow row = (ExpandableNotificationRow) v; 280 281 // handle the notgoneIndex for the children as well 282 List<ExpandableNotificationRow> children = 283 row.getNotificationChildren(); 284 if (row.isSummaryWithChildren() && children != null) { 285 for (ExpandableNotificationRow childRow : children) { 286 if (childRow.getVisibility() != View.GONE) { 287 StackViewState childState 288 = resultState.getViewStateForView(childRow); 289 childState.notGoneIndex = notGoneIndex; 290 notGoneIndex++; 291 } 292 } 293 } 294 } 295 lastView = v; 296 } 297 } 298 } 299 updateNotGoneIndex(StackScrollState resultState, StackScrollAlgorithmState state, int notGoneIndex, ExpandableView v)300 private int updateNotGoneIndex(StackScrollState resultState, 301 StackScrollAlgorithmState state, int notGoneIndex, 302 ExpandableView v) { 303 StackViewState viewState = resultState.getViewStateForView(v); 304 viewState.notGoneIndex = notGoneIndex; 305 state.visibleChildren.add(v); 306 notGoneIndex++; 307 return notGoneIndex; 308 } 309 310 /** 311 * Determine the positions for the views. This is the main part of the algorithm. 312 * 313 * @param resultState The result state to update if a change to the properties of a child occurs 314 * @param algorithmState The state in which the current pass of the algorithm is currently in 315 * @param ambientState The current ambient state 316 */ updatePositionsForState(StackScrollState resultState, StackScrollAlgorithmState algorithmState, AmbientState ambientState)317 private void updatePositionsForState(StackScrollState resultState, 318 StackScrollAlgorithmState algorithmState, AmbientState ambientState) { 319 320 // The starting position of the bottom stack peek 321 float bottomPeekStart = ambientState.getInnerHeight() - mBottomStackPeekSize; 322 323 // The position where the bottom stack starts. 324 float bottomStackStart = bottomPeekStart - mBottomStackSlowDownLength; 325 326 // The y coordinate of the current child. 327 float currentYPosition = -algorithmState.scrollY; 328 329 int childCount = algorithmState.visibleChildren.size(); 330 int paddingAfterChild; 331 for (int i = 0; i < childCount; i++) { 332 ExpandableView child = algorithmState.visibleChildren.get(i); 333 StackViewState childViewState = resultState.getViewStateForView(child); 334 childViewState.location = StackViewState.LOCATION_UNKNOWN; 335 paddingAfterChild = getPaddingAfterChild(algorithmState, child); 336 int childHeight = getMaxAllowedChildHeight(child); 337 int collapsedHeight = child.getCollapsedHeight(); 338 childViewState.yTranslation = currentYPosition; 339 if (i == 0) { 340 updateFirstChildHeight(child, childViewState, childHeight, ambientState); 341 } 342 343 // The y position after this element 344 float nextYPosition = currentYPosition + childHeight + 345 paddingAfterChild; 346 if (nextYPosition >= bottomStackStart) { 347 // Case 1: 348 // We are in the bottom stack. 349 if (currentYPosition >= bottomStackStart) { 350 // According to the regular scroll view we are fully translated out of the 351 // bottom of the screen so we are fully in the bottom stack 352 updateStateForChildFullyInBottomStack(algorithmState, 353 bottomStackStart, childViewState, collapsedHeight, ambientState, child); 354 } else { 355 // According to the regular scroll view we are currently translating out of / 356 // into the bottom of the screen 357 updateStateForChildTransitioningInBottom(algorithmState, 358 bottomStackStart, child, currentYPosition, 359 childViewState, childHeight); 360 } 361 } else { 362 // Case 2: 363 // We are in the regular scroll area. 364 childViewState.location = StackViewState.LOCATION_MAIN_AREA; 365 clampPositionToBottomStackStart(childViewState, childViewState.height, childHeight, 366 ambientState); 367 } 368 369 if (i == 0 && ambientState.getScrollY() <= 0) { 370 // The first card can get into the bottom stack if it's the only one 371 // on the lockscreen which pushes it up. Let's make sure that doesn't happen and 372 // it stays at the top 373 childViewState.yTranslation = Math.max(0, childViewState.yTranslation); 374 } 375 currentYPosition = childViewState.yTranslation + childHeight + paddingAfterChild; 376 if (currentYPosition <= 0) { 377 childViewState.location = StackViewState.LOCATION_HIDDEN_TOP; 378 } 379 if (childViewState.location == StackViewState.LOCATION_UNKNOWN) { 380 Log.wtf(LOG_TAG, "Failed to assign location for child " + i); 381 } 382 383 childViewState.yTranslation += ambientState.getTopPadding() 384 + ambientState.getStackTranslation(); 385 } 386 } 387 getPaddingAfterChild(StackScrollAlgorithmState algorithmState, ExpandableView child)388 private int getPaddingAfterChild(StackScrollAlgorithmState algorithmState, 389 ExpandableView child) { 390 Float paddingValue = algorithmState.increasedPaddingMap.get(child); 391 return paddingValue == null 392 ? mPaddingBetweenElements 393 : (int) NotificationUtils.interpolate(mPaddingBetweenElements, 394 mIncreasedPaddingBetweenElements, 395 paddingValue); 396 } 397 updateHeadsUpStates(StackScrollState resultState, StackScrollAlgorithmState algorithmState, AmbientState ambientState)398 private void updateHeadsUpStates(StackScrollState resultState, 399 StackScrollAlgorithmState algorithmState, AmbientState ambientState) { 400 int childCount = algorithmState.visibleChildren.size(); 401 ExpandableNotificationRow topHeadsUpEntry = null; 402 for (int i = 0; i < childCount; i++) { 403 View child = algorithmState.visibleChildren.get(i); 404 if (!(child instanceof ExpandableNotificationRow)) { 405 break; 406 } 407 ExpandableNotificationRow row = (ExpandableNotificationRow) child; 408 if (!row.isHeadsUp()) { 409 break; 410 } 411 StackViewState childState = resultState.getViewStateForView(row); 412 if (topHeadsUpEntry == null) { 413 topHeadsUpEntry = row; 414 childState.location = StackViewState.LOCATION_FIRST_HUN; 415 } 416 boolean isTopEntry = topHeadsUpEntry == row; 417 float unmodifiedEndLocation = childState.yTranslation + childState.height; 418 if (mIsExpanded) { 419 // Ensure that the heads up is always visible even when scrolled off 420 clampHunToTop(ambientState, row, childState); 421 clampHunToMaxTranslation(ambientState, row, childState); 422 } 423 if (row.isPinned()) { 424 childState.yTranslation = Math.max(childState.yTranslation, 0); 425 childState.height = Math.max(row.getIntrinsicHeight(), childState.height); 426 StackViewState topState = resultState.getViewStateForView(topHeadsUpEntry); 427 if (!isTopEntry && (!mIsExpanded 428 || unmodifiedEndLocation < topState.yTranslation + topState.height)) { 429 // Ensure that a headsUp doesn't vertically extend further than the heads-up at 430 // the top most z-position 431 childState.height = row.getIntrinsicHeight(); 432 childState.yTranslation = topState.yTranslation + topState.height 433 - childState.height; 434 } 435 } 436 } 437 } 438 clampHunToTop(AmbientState ambientState, ExpandableNotificationRow row, StackViewState childState)439 private void clampHunToTop(AmbientState ambientState, ExpandableNotificationRow row, 440 StackViewState childState) { 441 float newTranslation = Math.max(ambientState.getTopPadding() 442 + ambientState.getStackTranslation(), childState.yTranslation); 443 childState.height = (int) Math.max(childState.height - (newTranslation 444 - childState.yTranslation), row.getCollapsedHeight()); 445 childState.yTranslation = newTranslation; 446 } 447 clampHunToMaxTranslation(AmbientState ambientState, ExpandableNotificationRow row, StackViewState childState)448 private void clampHunToMaxTranslation(AmbientState ambientState, ExpandableNotificationRow row, 449 StackViewState childState) { 450 float newTranslation; 451 float bottomPosition = ambientState.getMaxHeadsUpTranslation() - row.getCollapsedHeight(); 452 newTranslation = Math.min(childState.yTranslation, bottomPosition); 453 childState.height = (int) Math.max(childState.height 454 - (childState.yTranslation - newTranslation), row.getCollapsedHeight()); 455 childState.yTranslation = newTranslation; 456 } 457 458 /** 459 * Clamp the yTranslation of the child down such that its end is at most on the beginning of 460 * the bottom stack. 461 * 462 * @param childViewState the view state of the child 463 * @param childHeight the height of this child 464 * @param minHeight the minumum Height of the View 465 */ clampPositionToBottomStackStart(StackViewState childViewState, int childHeight, int minHeight, AmbientState ambientState)466 private void clampPositionToBottomStackStart(StackViewState childViewState, 467 int childHeight, int minHeight, AmbientState ambientState) { 468 469 int bottomStackStart = ambientState.getInnerHeight() 470 - mBottomStackPeekSize - mBottomStackSlowDownLength; 471 int childStart = bottomStackStart - childHeight; 472 if (childStart < childViewState.yTranslation) { 473 float newHeight = bottomStackStart - childViewState.yTranslation; 474 if (newHeight < minHeight) { 475 newHeight = minHeight; 476 childViewState.yTranslation = bottomStackStart - minHeight; 477 } 478 childViewState.height = (int) newHeight; 479 } 480 } 481 getMaxAllowedChildHeight(View child)482 private int getMaxAllowedChildHeight(View child) { 483 if (child instanceof ExpandableView) { 484 ExpandableView expandableView = (ExpandableView) child; 485 return expandableView.getIntrinsicHeight(); 486 } 487 return child == null? mCollapsedSize : child.getHeight(); 488 } 489 updateStateForChildTransitioningInBottom(StackScrollAlgorithmState algorithmState, float transitioningPositionStart, ExpandableView child, float currentYPosition, StackViewState childViewState, int childHeight)490 private void updateStateForChildTransitioningInBottom(StackScrollAlgorithmState algorithmState, 491 float transitioningPositionStart, ExpandableView child, float currentYPosition, 492 StackViewState childViewState, int childHeight) { 493 494 // This is the transitioning element on top of bottom stack, calculate how far we are in. 495 algorithmState.partialInBottom = 1.0f - ( 496 (transitioningPositionStart - currentYPosition) / (childHeight + 497 getPaddingAfterChild(algorithmState, child))); 498 499 // the offset starting at the transitionPosition of the bottom stack 500 float offset = mBottomStackIndentationFunctor.getValue(algorithmState.partialInBottom); 501 algorithmState.itemsInBottomStack += algorithmState.partialInBottom; 502 int newHeight = childHeight; 503 if (childHeight > child.getCollapsedHeight()) { 504 newHeight = (int) Math.max(Math.min(transitioningPositionStart + offset - 505 getPaddingAfterChild(algorithmState, child) - currentYPosition, childHeight), 506 child.getCollapsedHeight()); 507 childViewState.height = newHeight; 508 } 509 childViewState.yTranslation = transitioningPositionStart + offset - newHeight 510 - getPaddingAfterChild(algorithmState, child); 511 childViewState.location = StackViewState.LOCATION_MAIN_AREA; 512 } 513 updateStateForChildFullyInBottomStack(StackScrollAlgorithmState algorithmState, float transitioningPositionStart, StackViewState childViewState, int collapsedHeight, AmbientState ambientState, ExpandableView child)514 private void updateStateForChildFullyInBottomStack(StackScrollAlgorithmState algorithmState, 515 float transitioningPositionStart, StackViewState childViewState, 516 int collapsedHeight, AmbientState ambientState, ExpandableView child) { 517 float currentYPosition; 518 algorithmState.itemsInBottomStack += 1.0f; 519 if (algorithmState.itemsInBottomStack < MAX_ITEMS_IN_BOTTOM_STACK) { 520 // We are visually entering the bottom stack 521 currentYPosition = transitioningPositionStart 522 + mBottomStackIndentationFunctor.getValue(algorithmState.itemsInBottomStack) 523 - getPaddingAfterChild(algorithmState, child); 524 childViewState.location = StackViewState.LOCATION_BOTTOM_STACK_PEEKING; 525 } else { 526 // we are fully inside the stack 527 if (algorithmState.itemsInBottomStack > MAX_ITEMS_IN_BOTTOM_STACK + 2) { 528 childViewState.hidden = true; 529 childViewState.shadowAlpha = 0.0f; 530 } else if (algorithmState.itemsInBottomStack 531 > MAX_ITEMS_IN_BOTTOM_STACK + 1) { 532 childViewState.shadowAlpha = 1.0f - algorithmState.partialInBottom; 533 } 534 childViewState.location = StackViewState.LOCATION_BOTTOM_STACK_HIDDEN; 535 currentYPosition = ambientState.getInnerHeight(); 536 } 537 childViewState.height = collapsedHeight; 538 childViewState.yTranslation = currentYPosition - collapsedHeight; 539 } 540 541 542 /** 543 * Update the height of the first child i.e clamp it to the bottom stack 544 * 545 * @param child the child to update 546 * @param childViewState the viewstate of the child 547 * @param childHeight the height of the child 548 * @param ambientState The ambient state of the algorithm 549 */ updateFirstChildHeight(ExpandableView child, StackViewState childViewState, int childHeight, AmbientState ambientState)550 private void updateFirstChildHeight(ExpandableView child, StackViewState childViewState, 551 int childHeight, AmbientState ambientState) { 552 553 // The starting position of the bottom stack peek 554 int bottomPeekStart = ambientState.getInnerHeight() - mBottomStackPeekSize - 555 mBottomStackSlowDownLength + ambientState.getScrollY(); 556 // Collapse and expand the first child while the shade is being expanded 557 childViewState.height = (int) Math.max(Math.min(bottomPeekStart, (float) childHeight), 558 child.getCollapsedHeight()); 559 } 560 561 /** 562 * Calculate the Z positions for all children based on the number of items in both stacks and 563 * save it in the resultState 564 * @param resultState The result state to update the zTranslation values 565 * @param algorithmState The state in which the current pass of the algorithm is currently in 566 * @param ambientState The ambient state of the algorithm 567 */ updateZValuesForState(StackScrollState resultState, StackScrollAlgorithmState algorithmState, AmbientState ambientState)568 private void updateZValuesForState(StackScrollState resultState, 569 StackScrollAlgorithmState algorithmState, AmbientState ambientState) { 570 int childCount = algorithmState.visibleChildren.size(); 571 float childrenOnTop = 0.0f; 572 for (int i = childCount - 1; i >= 0; i--) { 573 ExpandableView child = algorithmState.visibleChildren.get(i); 574 StackViewState childViewState = resultState.getViewStateForView(child); 575 if (i > (childCount - 1 - algorithmState.itemsInBottomStack)) { 576 // We are in the bottom stack 577 float numItemsAbove = i - (childCount - 1 - algorithmState.itemsInBottomStack); 578 float zSubtraction; 579 if (numItemsAbove <= 1.0f) { 580 float factor = 0.2f; 581 // Lets fade in slower to the threshold to make the shadow fade in look nicer 582 if (numItemsAbove <= factor) { 583 zSubtraction = FakeShadowView.SHADOW_SIBLING_TRESHOLD 584 * numItemsAbove * (1.0f / factor); 585 } else { 586 zSubtraction = FakeShadowView.SHADOW_SIBLING_TRESHOLD 587 + (numItemsAbove - factor) * (1.0f / (1.0f - factor)) 588 * (mZDistanceBetweenElements 589 - FakeShadowView.SHADOW_SIBLING_TRESHOLD); 590 } 591 } else { 592 zSubtraction = numItemsAbove * mZDistanceBetweenElements; 593 } 594 childViewState.zTranslation = mZBasicHeight - zSubtraction; 595 } else if (child.mustStayOnScreen() 596 && childViewState.yTranslation < ambientState.getTopPadding() 597 + ambientState.getStackTranslation()) { 598 if (childrenOnTop != 0.0f) { 599 childrenOnTop++; 600 } else { 601 float overlap = ambientState.getTopPadding() 602 + ambientState.getStackTranslation() - childViewState.yTranslation; 603 childrenOnTop += Math.min(1.0f, overlap / childViewState.height); 604 } 605 childViewState.zTranslation = mZBasicHeight 606 + childrenOnTop * mZDistanceBetweenElements; 607 } else { 608 childViewState.zTranslation = mZBasicHeight; 609 } 610 } 611 } 612 isMaxSizeInitialized(ExpandableView child)613 private boolean isMaxSizeInitialized(ExpandableView child) { 614 if (child instanceof ExpandableNotificationRow) { 615 ExpandableNotificationRow row = (ExpandableNotificationRow) child; 616 return row.isMaxExpandHeightInitialized(); 617 } 618 return child == null || child.getWidth() != 0; 619 } 620 findFirstVisibleChild(ViewGroup container)621 private View findFirstVisibleChild(ViewGroup container) { 622 int childCount = container.getChildCount(); 623 for (int i = 0; i < childCount; i++) { 624 View child = container.getChildAt(i); 625 if (child.getVisibility() != View.GONE) { 626 return child; 627 } 628 } 629 return null; 630 } 631 setIsExpanded(boolean isExpanded)632 public void setIsExpanded(boolean isExpanded) { 633 this.mIsExpanded = isExpanded; 634 } 635 636 class StackScrollAlgorithmState { 637 638 /** 639 * The scroll position of the algorithm 640 */ 641 public int scrollY; 642 643 /** 644 * The quantity of items which are in the bottom stack. 645 */ 646 public float itemsInBottomStack; 647 648 /** 649 * how far in is the element currently transitioning into the bottom stack 650 */ 651 public float partialInBottom; 652 653 /** 654 * The children from the host view which are not gone. 655 */ 656 public final ArrayList<ExpandableView> visibleChildren = new ArrayList<ExpandableView>(); 657 658 /** 659 * The children from the host that need an increased padding after them. A value of 0 means 660 * no increased padding, a value of 1 means full padding. 661 */ 662 public final HashMap<ExpandableView, Float> increasedPaddingMap = new HashMap<>(); 663 } 664 665 } 666