RowPresenter.java revision ad9af35ec6a808136478daf7bd57d564ac517e0e
1/* 2 * Copyright (C) 2014 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except 5 * in compliance with the License. You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software distributed under the License 10 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express 11 * or implied. See the License for the specific language governing permissions and limitations under 12 * the License. 13 */ 14package android.support.v17.leanback.widget; 15 16import android.support.v17.leanback.app.HeadersFragment; 17import android.support.v17.leanback.graphics.ColorOverlayDimmer; 18import android.view.View; 19import android.view.ViewGroup; 20 21/** 22 * An abstract {@link Presenter} that renders a {@link Row}. 23 * 24 * <h3>Customize UI widgets</h3> 25 * When a subclass of RowPresenter adds UI widgets, it should subclass 26 * {@link RowPresenter.ViewHolder} and override {@link #createRowViewHolder(ViewGroup)} 27 * and {@link #initializeRowViewHolder(ViewHolder)}. The subclass must use layout id 28 * "row_content" for the widget that will be aligned to the title of any {@link HeadersFragment} 29 * that may exist in the parent fragment. RowPresenter contains an optional and 30 * replaceable {@link RowHeaderPresenter} that renders the header. You can disable 31 * the default rendering or replace the Presenter with a new header presenter 32 * by calling {@link #setHeaderPresenter(RowHeaderPresenter)}. 33 * 34 * <h3>UI events from fragments</h3> 35 * RowPresenter receives calls from its parent (typically a Fragment) when: 36 * <ul> 37 * <li> 38 * A row is selected via {@link #setRowViewSelected(Presenter.ViewHolder, boolean)}. The event 39 * is triggered immediately when there is a row selection change before the selection 40 * animation is started. Selected status may control activated status of the row (see 41 * "Activated status" below). 42 * Subclasses of RowPresenter may override {@link #onRowViewSelected(ViewHolder, boolean)}. 43 * </li> 44 * <li> 45 * A row is expanded to full height via {@link #setRowViewExpanded(Presenter.ViewHolder, boolean)} 46 * when BrowseFragment hides fast lane on the left. 47 * The event is triggered immediately before the expand animation is started. 48 * Row title is shown when row is expanded. Expanded status may control activated status 49 * of the row (see "Activated status" below). 50 * Subclasses of RowPresenter may override {@link #onRowViewExpanded(ViewHolder, boolean)}. 51 * </li> 52 * </ul> 53 * 54 * <h3>Activated status</h3> 55 * The activated status of a row is applied to the row view and it's children via 56 * {@link View#setActivated(boolean)}. 57 * The activated status is typically used to control {@link BaseCardView} info region visibility. 58 * The row's activated status can be controlled by selected status and/or expanded status. 59 * Call {@link #setSyncActivatePolicy(int)} and choose one of the four policies: 60 * <ul> 61 * <li>{@link #SYNC_ACTIVATED_TO_EXPANDED} Activated status is synced with row expanded status</li> 62 * <li>{@link #SYNC_ACTIVATED_TO_SELECTED} Activated status is synced with row selected status</li> 63 * <li>{@link #SYNC_ACTIVATED_TO_EXPANDED_AND_SELECTED} Activated status is set to true 64 * when both expanded and selected status are true</li> 65 * <li>{@link #SYNC_ACTIVATED_CUSTOM} Activated status is not controlled by selected status 66 * or expanded status, application can control activated status by its own. 67 * Application should call {@link RowPresenter.ViewHolder#setActivated(boolean)} to change 68 * activated status of row view. 69 * </li> 70 * </ul> 71 * 72 * <h3>User events</h3> 73 * RowPresenter provides {@link OnItemSelectedListener} and {@link OnItemClickedListener}. 74 * If a subclass wants to add its own {@link View.OnFocusChangeListener} or 75 * {@link View.OnClickListener}, it must do that in {@link #createRowViewHolder(ViewGroup)} 76 * to be properly chained by the library. Adding View listeners after 77 * {@link #createRowViewHolder(ViewGroup)} is undefined and may result in 78 * incorrect behavior by the library's listeners. 79 * 80 * <h3>Selection animation</h3> 81 * <p> 82 * When a user scrolls through rows, a fragment will initiate animation and call 83 * {@link #setSelectLevel(Presenter.ViewHolder, float)} with float value between 84 * 0 and 1. By default, the RowPresenter draws a dim overlay on top of the row 85 * view for views that are not selected. Subclasses may override this default effect 86 * by having {@link #isUsingDefaultSelectEffect()} return false and overriding 87 * {@link #onSelectLevelChanged(ViewHolder)} to apply a different selection effect. 88 * </p> 89 * <p> 90 * Call {@link #setSelectEffectEnabled(boolean)} to enable/disable the select effect, 91 * This will not only enable/disable the default dim effect but also subclasses must 92 * respect this flag as well. 93 * </p> 94 */ 95public abstract class RowPresenter extends Presenter { 96 97 /** 98 * Don't synchronize row view activated status with selected status or expanded status, 99 * application will do its own through {@link RowPresenter.ViewHolder#setActivated(boolean)}. 100 */ 101 public static final int SYNC_ACTIVATED_CUSTOM = 0; 102 103 /** 104 * Synchronizes row view's activated status to expand status of the row view holder. 105 */ 106 public static final int SYNC_ACTIVATED_TO_EXPANDED = 1; 107 108 /** 109 * Synchronizes row view's activated status to selected status of the row view holder. 110 */ 111 public static final int SYNC_ACTIVATED_TO_SELECTED = 2; 112 113 /** 114 * Sets the row view's activated status to true when both expand and selected are true. 115 */ 116 public static final int SYNC_ACTIVATED_TO_EXPANDED_AND_SELECTED = 3; 117 118 static class ContainerViewHolder extends Presenter.ViewHolder { 119 /** 120 * wrapped row view holder 121 */ 122 final ViewHolder mRowViewHolder; 123 124 public ContainerViewHolder(RowContainerView containerView, ViewHolder rowViewHolder) { 125 super(containerView); 126 containerView.addRowView(rowViewHolder.view); 127 if (rowViewHolder.mHeaderViewHolder != null) { 128 containerView.addHeaderView(rowViewHolder.mHeaderViewHolder.view); 129 } 130 mRowViewHolder = rowViewHolder; 131 mRowViewHolder.mContainerViewHolder = this; 132 } 133 } 134 135 /** 136 * A view holder for a {@link Row}. 137 */ 138 public static class ViewHolder extends Presenter.ViewHolder { 139 private static final int ACTIVATED_NOT_ASSIGNED = 0; 140 private static final int ACTIVATED = 1; 141 private static final int NOT_ACTIVATED = 2; 142 143 ContainerViewHolder mContainerViewHolder; 144 RowHeaderPresenter.ViewHolder mHeaderViewHolder; 145 Row mRow; 146 int mActivated = ACTIVATED_NOT_ASSIGNED; 147 boolean mSelected; 148 boolean mExpanded; 149 boolean mInitialzed; 150 float mSelectLevel = 0f; // initially unselected 151 protected final ColorOverlayDimmer mColorDimmer; 152 153 /** 154 * Constructor for ViewHolder. 155 * 156 * @param view The View bound to the Row. 157 */ 158 public ViewHolder(View view) { 159 super(view); 160 mColorDimmer = ColorOverlayDimmer.createDefault(view.getContext()); 161 } 162 163 /** 164 * Returns the Row bound to the View in this ViewHolder. 165 */ 166 public final Row getRow() { 167 return mRow; 168 } 169 170 /** 171 * Returns whether the Row is in its expanded state. 172 * 173 * @return true if the Row is expanded, false otherwise. 174 */ 175 public final boolean isExpanded() { 176 return mExpanded; 177 } 178 179 /** 180 * Returns whether the Row is selected. 181 * 182 * @return true if the Row is selected, false otherwise. 183 */ 184 public final boolean isSelected() { 185 return mSelected; 186 } 187 188 /** 189 * Returns the current selection level of the Row. 190 */ 191 public final float getSelectLevel() { 192 return mSelectLevel; 193 } 194 195 /** 196 * Returns the view holder for the Row header for this Row. 197 */ 198 public final RowHeaderPresenter.ViewHolder getHeaderViewHolder() { 199 return mHeaderViewHolder; 200 } 201 202 /** 203 * Sets the row view's activated status. The status will be applied to children through 204 * {@link #syncActivatedStatus(View)}. Application should only call this function 205 * when {@link RowPresenter#getSyncActivatePolicy()} is 206 * {@link RowPresenter#SYNC_ACTIVATED_CUSTOM}; otherwise the value will 207 * be overwritten when expanded or selected status changes. 208 */ 209 public final void setActivated(boolean activated) { 210 mActivated = activated ? ACTIVATED : NOT_ACTIVATED; 211 } 212 213 /** 214 * Synchronizes the activated status of view to the last value passed through 215 * {@link RowPresenter.ViewHolder#setActivated(boolean)}. No operation if 216 * {@link RowPresenter.ViewHolder#setActivated(boolean)} is never called. Normally 217 * application does not need to call this method, {@link ListRowPresenter} automatically 218 * calls this method when a child is attached to list row. However if 219 * application writes its own custom RowPresenter, it should call this method 220 * when attaches a child to the row view. 221 */ 222 public final void syncActivatedStatus(View view) { 223 if (mActivated == ACTIVATED) { 224 view.setActivated(true); 225 } else if (mActivated == NOT_ACTIVATED) { 226 view.setActivated(false); 227 } 228 } 229 } 230 231 private RowHeaderPresenter mHeaderPresenter = new RowHeaderPresenter(); 232 private OnItemSelectedListener mOnItemSelectedListener; 233 private OnItemClickedListener mOnItemClickedListener; 234 private OnItemViewSelectedListener mOnItemViewSelectedListener; 235 private OnItemViewClickedListener mOnItemViewClickedListener; 236 237 boolean mSelectEffectEnabled = true; 238 int mSyncActivatePolicy = SYNC_ACTIVATED_TO_EXPANDED; 239 240 /** 241 * Constructs a RowPresenter. 242 */ 243 public RowPresenter() { 244 mHeaderPresenter.setNullItemVisibilityGone(true); 245 } 246 247 @Override 248 public final Presenter.ViewHolder onCreateViewHolder(ViewGroup parent) { 249 ViewHolder vh = createRowViewHolder(parent); 250 vh.mInitialzed = false; 251 Presenter.ViewHolder result; 252 if (needsRowContainerView()) { 253 RowContainerView containerView = new RowContainerView(parent.getContext()); 254 if (mHeaderPresenter != null) { 255 vh.mHeaderViewHolder = (RowHeaderPresenter.ViewHolder) 256 mHeaderPresenter.onCreateViewHolder((ViewGroup) vh.view); 257 } 258 result = new ContainerViewHolder(containerView, vh); 259 } else { 260 result = vh; 261 } 262 initializeRowViewHolder(vh); 263 if (!vh.mInitialzed) { 264 throw new RuntimeException("super.initializeRowViewHolder() must be called"); 265 } 266 return result; 267 } 268 269 /** 270 * Called to create a ViewHolder object for a Row. Subclasses will override 271 * this method to return a different concrete ViewHolder object. 272 * 273 * @param parent The parent View for the Row's view holder. 274 * @return A ViewHolder for the Row's View. 275 */ 276 protected abstract ViewHolder createRowViewHolder(ViewGroup parent); 277 278 /** 279 * Called after a {@link RowPresenter.ViewHolder} is created for a Row. 280 * Subclasses may override this method and start by calling 281 * super.initializeRowViewHolder(ViewHolder). 282 * 283 * @param vh The ViewHolder to initialize for the Row. 284 */ 285 protected void initializeRowViewHolder(ViewHolder vh) { 286 vh.mInitialzed = true; 287 // set clip children to false for slide transition 288 ((ViewGroup) vh.view).setClipChildren(false); 289 if (vh.mContainerViewHolder != null) { 290 ((ViewGroup) vh.mContainerViewHolder.view).setClipChildren(false); 291 } 292 } 293 294 /** 295 * Set the Presenter used for rendering the header. Can be null to disable 296 * header rendering. The method must be called before creating any Row Views. 297 */ 298 public final void setHeaderPresenter(RowHeaderPresenter headerPresenter) { 299 mHeaderPresenter = headerPresenter; 300 } 301 302 /** 303 * Get the Presenter used for rendering the header, or null if none has been 304 * set. 305 */ 306 public final RowHeaderPresenter getHeaderPresenter() { 307 return mHeaderPresenter; 308 } 309 310 /** 311 * Get the {@link RowPresenter.ViewHolder} from the given Presenter 312 * ViewHolder. 313 */ 314 public final ViewHolder getRowViewHolder(Presenter.ViewHolder holder) { 315 if (holder instanceof ContainerViewHolder) { 316 return ((ContainerViewHolder) holder).mRowViewHolder; 317 } else { 318 return (ViewHolder) holder; 319 } 320 } 321 322 /** 323 * Set the expanded state of a Row view. 324 * 325 * @param holder The Row ViewHolder to set expanded state on. 326 * @param expanded True if the Row is expanded, false otherwise. 327 */ 328 public final void setRowViewExpanded(Presenter.ViewHolder holder, boolean expanded) { 329 ViewHolder rowViewHolder = getRowViewHolder(holder); 330 rowViewHolder.mExpanded = expanded; 331 onRowViewExpanded(rowViewHolder, expanded); 332 } 333 334 /** 335 * Set the selected state of a Row view. 336 * 337 * @param holder The Row ViewHolder to set expanded state on. 338 * @param selected True if the Row is expanded, false otherwise. 339 */ 340 public final void setRowViewSelected(Presenter.ViewHolder holder, boolean selected) { 341 ViewHolder rowViewHolder = getRowViewHolder(holder); 342 rowViewHolder.mSelected = selected; 343 onRowViewSelected(rowViewHolder, selected); 344 } 345 346 /** 347 * Subclass may override this to respond to expanded state changes of a Row. 348 * The default implementation will hide/show the header view. Subclasses may 349 * make visual changes to the Row View but must not create animation on the 350 * Row view. 351 */ 352 protected void onRowViewExpanded(ViewHolder vh, boolean expanded) { 353 updateHeaderViewVisibility(vh); 354 updateActivateStatus(vh, vh.view); 355 } 356 357 /** 358 * Update view's activate status according to {@link #getSyncActivatePolicy()} and the 359 * selected status and expanded status of the RowPresenter ViewHolder. 360 */ 361 private void updateActivateStatus(ViewHolder vh, View view) { 362 switch (mSyncActivatePolicy) { 363 case SYNC_ACTIVATED_TO_EXPANDED: 364 vh.setActivated(vh.isExpanded()); 365 break; 366 case SYNC_ACTIVATED_TO_SELECTED: 367 vh.setActivated(vh.isSelected()); 368 break; 369 case SYNC_ACTIVATED_TO_EXPANDED_AND_SELECTED: 370 vh.setActivated(vh.isExpanded() && vh.isSelected()); 371 break; 372 } 373 vh.syncActivatedStatus(view); 374 } 375 376 /** 377 * Sets policy of updating row view activated status. Can be one of: 378 * <li> Default value {@link #SYNC_ACTIVATED_TO_EXPANDED} 379 * <li> {@link #SYNC_ACTIVATED_TO_SELECTED} 380 * <li> {@link #SYNC_ACTIVATED_TO_EXPANDED_AND_SELECTED} 381 * <li> {@link #SYNC_ACTIVATED_CUSTOM} 382 */ 383 public final void setSyncActivatePolicy(int syncActivatePolicy) { 384 mSyncActivatePolicy = syncActivatePolicy; 385 } 386 387 /** 388 * Returns policy of updating row view activated status. Can be one of: 389 * <li> Default value {@link #SYNC_ACTIVATED_TO_EXPANDED} 390 * <li> {@link #SYNC_ACTIVATED_TO_SELECTED} 391 * <li> {@link #SYNC_ACTIVATED_TO_EXPANDED_AND_SELECTED} 392 * <li> {@link #SYNC_ACTIVATED_CUSTOM} 393 */ 394 public final int getSyncActivatePolicy() { 395 return mSyncActivatePolicy; 396 } 397 398 /** 399 * Subclass may override this to respond to selected state changes of a Row. 400 * Subclass may make visual changes to Row view but must not create 401 * animation on the Row view. 402 */ 403 protected void onRowViewSelected(ViewHolder vh, boolean selected) { 404 if (selected) { 405 if (mOnItemViewSelectedListener != null) { 406 mOnItemViewSelectedListener.onItemSelected(null, null, vh, vh.getRow()); 407 } 408 if (mOnItemSelectedListener != null) { 409 mOnItemSelectedListener.onItemSelected(null, vh.getRow()); 410 } 411 } 412 updateHeaderViewVisibility(vh); 413 updateActivateStatus(vh, vh.view); 414 } 415 416 private void updateHeaderViewVisibility(ViewHolder vh) { 417 if (mHeaderPresenter != null && vh.mHeaderViewHolder != null) { 418 RowContainerView containerView = ((RowContainerView) vh.mContainerViewHolder.view); 419 containerView.showHeader(vh.isExpanded()); 420 } 421 } 422 423 /** 424 * Set the current select level to a value between 0 (unselected) and 1 (selected). 425 * Subclasses may override {@link #onSelectLevelChanged(ViewHolder)} to 426 * respond to changes in the selected level. 427 */ 428 public final void setSelectLevel(Presenter.ViewHolder vh, float level) { 429 ViewHolder rowViewHolder = getRowViewHolder(vh); 430 rowViewHolder.mSelectLevel = level; 431 onSelectLevelChanged(rowViewHolder); 432 } 433 434 /** 435 * Get the current select level. The value will be between 0 (unselected) 436 * and 1 (selected). 437 */ 438 public final float getSelectLevel(Presenter.ViewHolder vh) { 439 return getRowViewHolder(vh).mSelectLevel; 440 } 441 442 /** 443 * Callback when select level is changed. The default implementation applies 444 * the select level to {@link RowHeaderPresenter#setSelectLevel(RowHeaderPresenter.ViewHolder, float)} 445 * when {@link #getSelectEffectEnabled()} is true. Subclasses may override 446 * this function and implement a different select effect. In this case, you 447 * should also override {@link #isUsingDefaultSelectEffect()} to disable 448 * the default dimming effect applied by the library. 449 */ 450 protected void onSelectLevelChanged(ViewHolder vh) { 451 if (getSelectEffectEnabled()) { 452 vh.mColorDimmer.setActiveLevel(vh.mSelectLevel); 453 if (vh.mHeaderViewHolder != null) { 454 mHeaderPresenter.setSelectLevel(vh.mHeaderViewHolder, vh.mSelectLevel); 455 } 456 if (isUsingDefaultSelectEffect()) { 457 ((RowContainerView) vh.mContainerViewHolder.view).setForegroundColor( 458 vh.mColorDimmer.getPaint().getColor()); 459 } 460 } 461 } 462 463 /** 464 * Enables or disables the row selection effect. 465 * This will not only affect the default dim effect, but subclasses must 466 * respect this flag as well. 467 */ 468 public final void setSelectEffectEnabled(boolean applyDimOnSelect) { 469 mSelectEffectEnabled = applyDimOnSelect; 470 } 471 472 /** 473 * Returns true if the row selection effect is enabled. 474 * This value not only determines whether the default dim implementation is 475 * used, but subclasses must also respect this flag. 476 */ 477 public final boolean getSelectEffectEnabled() { 478 return mSelectEffectEnabled; 479 } 480 481 /** 482 * Return whether this RowPresenter is using the default dimming effect 483 * provided by the library. Subclasses may(most likely) return false and 484 * override {@link #onSelectLevelChanged(ViewHolder)}. 485 */ 486 public boolean isUsingDefaultSelectEffect() { 487 return true; 488 } 489 490 final boolean needsDefaultSelectEffect() { 491 return isUsingDefaultSelectEffect() && getSelectEffectEnabled(); 492 } 493 494 final boolean needsRowContainerView() { 495 return mHeaderPresenter != null || needsDefaultSelectEffect(); 496 } 497 498 /** 499 * Return true if the Row view can draw outside its bounds. 500 */ 501 public boolean canDrawOutOfBounds() { 502 return false; 503 } 504 505 @Override 506 public final void onBindViewHolder(Presenter.ViewHolder viewHolder, Object item) { 507 onBindRowViewHolder(getRowViewHolder(viewHolder), item); 508 } 509 510 protected void onBindRowViewHolder(ViewHolder vh, Object item) { 511 vh.mRow = (Row) item; 512 if (vh.mHeaderViewHolder != null) { 513 mHeaderPresenter.onBindViewHolder(vh.mHeaderViewHolder, item); 514 } 515 } 516 517 @Override 518 public final void onUnbindViewHolder(Presenter.ViewHolder viewHolder) { 519 onUnbindRowViewHolder(getRowViewHolder(viewHolder)); 520 } 521 522 protected void onUnbindRowViewHolder(ViewHolder vh) { 523 if (vh.mHeaderViewHolder != null) { 524 mHeaderPresenter.onUnbindViewHolder(vh.mHeaderViewHolder); 525 } 526 vh.mRow = null; 527 } 528 529 @Override 530 public final void onViewAttachedToWindow(Presenter.ViewHolder holder) { 531 onRowViewAttachedToWindow(getRowViewHolder(holder)); 532 } 533 534 protected void onRowViewAttachedToWindow(ViewHolder vh) { 535 if (vh.mHeaderViewHolder != null) { 536 mHeaderPresenter.onViewAttachedToWindow(vh.mHeaderViewHolder); 537 } 538 } 539 540 @Override 541 public final void onViewDetachedFromWindow(Presenter.ViewHolder holder) { 542 onRowViewDetachedFromWindow(getRowViewHolder(holder)); 543 } 544 545 protected void onRowViewDetachedFromWindow(ViewHolder vh) { 546 if (vh.mHeaderViewHolder != null) { 547 mHeaderPresenter.onViewDetachedFromWindow(vh.mHeaderViewHolder); 548 } 549 cancelAnimationsRecursive(vh.view); 550 } 551 552 /** 553 * Set the listener for item or row selection. A RowPresenter fires a row 554 * selection event with a null item. Subclasses (e.g. {@link ListRowPresenter}) 555 * can fire a selection event with the selected item. 556 */ 557 public final void setOnItemSelectedListener(OnItemSelectedListener listener) { 558 mOnItemSelectedListener = listener; 559 } 560 561 /** 562 * Get the listener for item or row selection. 563 */ 564 public final OnItemSelectedListener getOnItemSelectedListener() { 565 return mOnItemSelectedListener; 566 } 567 568 /** 569 * Set the listener for item click events. A RowPresenter does not use this 570 * listener, but a subclass may fire an item click event if it has the concept 571 * of an item. The {@link OnItemClickedListener} will override any 572 * {@link View.OnClickListener} that an item's Presenter sets during 573 * {@link Presenter#onCreateViewHolder(ViewGroup)}. So in general, you 574 * should choose to use an OnItemClickedListener or a {@link 575 * View.OnClickListener}, but not both. 576 */ 577 public final void setOnItemClickedListener(OnItemClickedListener listener) { 578 mOnItemClickedListener = listener; 579 } 580 581 /** 582 * Get the listener for item click events. 583 */ 584 public final OnItemClickedListener getOnItemClickedListener() { 585 return mOnItemClickedListener; 586 } 587 588 /** 589 * Set listener for item or row selection. RowPresenter fires row selection 590 * event with null item, subclass of RowPresenter e.g. {@link ListRowPresenter} can 591 * fire a selection event with selected item. 592 */ 593 public final void setOnItemViewSelectedListener(OnItemViewSelectedListener listener) { 594 mOnItemViewSelectedListener = listener; 595 } 596 597 /** 598 * Get listener for item or row selection. 599 */ 600 public final OnItemViewSelectedListener getOnItemViewSelectedListener() { 601 return mOnItemViewSelectedListener; 602 } 603 604 /** 605 * Set listener for item click event. RowPresenter does nothing but subclass of 606 * RowPresenter may fire item click event if it does have a concept of item. 607 * OnItemViewClickedListener will override {@link View.OnClickListener} that 608 * item presenter sets during {@link Presenter#onCreateViewHolder(ViewGroup)}. 609 * So in general, developer should choose one of the listeners but not both. 610 */ 611 public final void setOnItemViewClickedListener(OnItemViewClickedListener listener) { 612 mOnItemViewClickedListener = listener; 613 } 614 615 /** 616 * Set listener for item click event. 617 */ 618 public final OnItemViewClickedListener getOnItemViewClickedListener() { 619 return mOnItemViewClickedListener; 620 } 621 622 /** 623 * Freeze/Unfreeze the row, typically used when transition starts/ends. 624 * This method is called by fragment, app should not call it directly. 625 */ 626 public void freeze(ViewHolder holder, boolean freeze) { 627 } 628 629 /** 630 * Change visibility of views, entrance transition will be run against the views that 631 * change visibilities. Subclass may override and begin with calling 632 * super.setEntranceTransitionState(). This method is called by fragment, 633 * app should not call it directly. 634 */ 635 public void setEntranceTransitionState(ViewHolder holder, boolean afterTransition) { 636 if (holder.mHeaderViewHolder != null && 637 holder.mHeaderViewHolder.view.getVisibility() != View.GONE) { 638 holder.mHeaderViewHolder.view.setVisibility(afterTransition ? 639 View.VISIBLE : View.INVISIBLE); 640 } 641 } 642} 643