RowPresenter.java revision 5358b0ca6ed795892bd097fdf15d41fb6b1a03d2
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. 41 * Subclasses of RowPresenter may override {@link #onRowViewSelected(ViewHolder, boolean)}. 42 * </li> 43 * <li> 44 * A Row is expanded to full width via {@link #setRowViewExpanded(Presenter.ViewHolder, boolean)}. 45 * The event is triggered immediately before the expand animation is started. 46 * Subclasses of RowPresenter may override {@link #onRowViewExpanded(ViewHolder, boolean)}. 47 * </li> 48 * </ul> 49 * 50 * <h3>User events</h3> 51 * RowPresenter provides {@link OnItemSelectedListener} and {@link OnItemClickedListener}. 52 * If a subclass wants to add its own {@link View.OnFocusChangeListener} or 53 * {@link View.OnClickListener}, it must do that in {@link #createRowViewHolder(ViewGroup)} 54 * to be properly chained by the library. Adding View listeners after 55 * {@link #createRowViewHolder(ViewGroup)} is undefined and may result in 56 * incorrect behavior by the library's listeners. 57 * 58 * <h3>Selection animation</h3> 59 * <p> 60 * When a user scrolls through rows, a fragment will initiate animation and call 61 * {@link #setSelectLevel(Presenter.ViewHolder, float)} with float value between 62 * 0 and 1. By default, the RowPresenter draws a dim overlay on top of the row 63 * view for views that are not selected. Subclasses may override this default effect 64 * by having {@link #isUsingDefaultSelectEffect()} return false and overriding 65 * {@link #onSelectLevelChanged(ViewHolder)} to apply a different selection effect. 66 * </p> 67 * <p> 68 * Call {@link #setSelectEffectEnabled(boolean)} to enable/disable the select effect, 69 * This will not only enable/disable the default dim effect but also subclasses must 70 * respect this flag as well. 71 * </p> 72 */ 73public abstract class RowPresenter extends Presenter { 74 75 static class ContainerViewHolder extends Presenter.ViewHolder { 76 /** 77 * wrapped row view holder 78 */ 79 final ViewHolder mRowViewHolder; 80 81 public ContainerViewHolder(RowContainerView containerView, ViewHolder rowViewHolder) { 82 super(containerView); 83 containerView.addRowView(rowViewHolder.view); 84 if (rowViewHolder.mHeaderViewHolder != null) { 85 containerView.addHeaderView(rowViewHolder.mHeaderViewHolder.view); 86 } 87 mRowViewHolder = rowViewHolder; 88 mRowViewHolder.mContainerViewHolder = this; 89 } 90 } 91 92 /** 93 * A view holder for a {@link Row}. 94 */ 95 public static class ViewHolder extends Presenter.ViewHolder { 96 ContainerViewHolder mContainerViewHolder; 97 RowHeaderPresenter.ViewHolder mHeaderViewHolder; 98 Row mRow; 99 boolean mSelected; 100 boolean mExpanded; 101 boolean mInitialzed; 102 float mSelectLevel = 0f; // initially unselected 103 protected final ColorOverlayDimmer mColorDimmer; 104 105 /** 106 * Constructor for ViewHolder. 107 * 108 * @param view The View bound to the Row. 109 */ 110 public ViewHolder(View view) { 111 super(view); 112 mColorDimmer = ColorOverlayDimmer.createDefault(view.getContext()); 113 } 114 115 /** 116 * Returns the Row bound to the View in this ViewHolder. 117 */ 118 public final Row getRow() { 119 return mRow; 120 } 121 122 /** 123 * Returns whether the Row is in its expanded state. 124 * 125 * @return true if the Row is expanded, false otherwise. 126 */ 127 public final boolean isExpanded() { 128 return mExpanded; 129 } 130 131 /** 132 * Returns whether the Row is selected. 133 * 134 * @return true if the Row is selected, false otherwise. 135 */ 136 public final boolean isSelected() { 137 return mSelected; 138 } 139 140 /** 141 * Returns the current selection level of the Row. 142 */ 143 public final float getSelectLevel() { 144 return mSelectLevel; 145 } 146 147 /** 148 * Returns the view holder for the Row header for this Row. 149 */ 150 public final RowHeaderPresenter.ViewHolder getHeaderViewHolder() { 151 return mHeaderViewHolder; 152 } 153 } 154 155 private RowHeaderPresenter mHeaderPresenter = new RowHeaderPresenter(); 156 private OnItemSelectedListener mOnItemSelectedListener; 157 private OnItemClickedListener mOnItemClickedListener; 158 private OnItemViewSelectedListener mOnItemViewSelectedListener; 159 private OnItemViewClickedListener mOnItemViewClickedListener; 160 161 boolean mSelectEffectEnabled = true; 162 163 @Override 164 public final Presenter.ViewHolder onCreateViewHolder(ViewGroup parent) { 165 ViewHolder vh = createRowViewHolder(parent); 166 vh.mInitialzed = false; 167 Presenter.ViewHolder result; 168 if (needsRowContainerView()) { 169 RowContainerView containerView = new RowContainerView(parent.getContext()); 170 if (mHeaderPresenter != null) { 171 vh.mHeaderViewHolder = (RowHeaderPresenter.ViewHolder) 172 mHeaderPresenter.onCreateViewHolder((ViewGroup) vh.view); 173 } 174 result = new ContainerViewHolder(containerView, vh); 175 } else { 176 result = vh; 177 } 178 initializeRowViewHolder(vh); 179 if (!vh.mInitialzed) { 180 throw new RuntimeException("super.initializeRowViewHolder() must be called"); 181 } 182 return result; 183 } 184 185 /** 186 * Called to create a ViewHolder object for a Row. Subclasses will override 187 * this method to return a different concrete ViewHolder object. 188 * 189 * @param parent The parent View for the Row's view holder. 190 * @return A ViewHolder for the Row's View. 191 */ 192 protected abstract ViewHolder createRowViewHolder(ViewGroup parent); 193 194 /** 195 * Called after a {@link RowPresenter.ViewHolder} is created for a Row. 196 * Subclasses may override this method and start by calling 197 * super.initializeRowViewHolder(ViewHolder). 198 * 199 * @param vh The ViewHolder to initialize for the Row. 200 */ 201 protected void initializeRowViewHolder(ViewHolder vh) { 202 vh.mInitialzed = true; 203 } 204 205 /** 206 * Set the Presenter used for rendering the header. Can be null to disable 207 * header rendering. The method must be called before creating any Row Views. 208 */ 209 public final void setHeaderPresenter(RowHeaderPresenter headerPresenter) { 210 mHeaderPresenter = headerPresenter; 211 } 212 213 /** 214 * Get the Presenter used for rendering the header, or null if none has been 215 * set. 216 */ 217 public final RowHeaderPresenter getHeaderPresenter() { 218 return mHeaderPresenter; 219 } 220 221 /** 222 * Get the {@link RowPresenter.ViewHolder} from the given Presenter 223 * ViewHolder. 224 */ 225 public final ViewHolder getRowViewHolder(Presenter.ViewHolder holder) { 226 if (holder instanceof ContainerViewHolder) { 227 return ((ContainerViewHolder) holder).mRowViewHolder; 228 } else { 229 return (ViewHolder) holder; 230 } 231 } 232 233 /** 234 * Set the expanded state of a Row view. 235 * 236 * @param holder The Row ViewHolder to set expanded state on. 237 * @param expanded True if the Row is expanded, false otherwise. 238 */ 239 public final void setRowViewExpanded(Presenter.ViewHolder holder, boolean expanded) { 240 ViewHolder rowViewHolder = getRowViewHolder(holder); 241 rowViewHolder.mExpanded = expanded; 242 onRowViewExpanded(rowViewHolder, expanded); 243 } 244 245 /** 246 * Set the selected state of a Row view. 247 * 248 * @param holder The Row ViewHolder to set expanded state on. 249 * @param selected True if the Row is expanded, false otherwise. 250 */ 251 public final void setRowViewSelected(Presenter.ViewHolder holder, boolean selected) { 252 ViewHolder rowViewHolder = getRowViewHolder(holder); 253 rowViewHolder.mSelected = selected; 254 onRowViewSelected(rowViewHolder, selected); 255 } 256 257 /** 258 * Subclass may override this to respond to expanded state changes of a Row. 259 * The default implementation will hide/show the header view. Subclasses may 260 * make visual changes to the Row View but must not create animation on the 261 * Row view. 262 */ 263 protected void onRowViewExpanded(ViewHolder vh, boolean expanded) { 264 updateHeaderViewVisibility(vh); 265 vh.view.setActivated(expanded); 266 } 267 268 /** 269 * Subclass may override this to respond to selected state changes of a Row. 270 * Subclass may make visual changes to Row view but must not create 271 * animation on the Row view. 272 */ 273 protected void onRowViewSelected(ViewHolder vh, boolean selected) { 274 if (selected) { 275 if (mOnItemViewSelectedListener != null) { 276 mOnItemViewSelectedListener.onItemSelected(null, null, vh, vh.getRow()); 277 } 278 if (mOnItemSelectedListener != null) { 279 mOnItemSelectedListener.onItemSelected(null, vh.getRow()); 280 } 281 } 282 updateHeaderViewVisibility(vh); 283 } 284 285 private void updateHeaderViewVisibility(ViewHolder vh) { 286 if (mHeaderPresenter != null && vh.mHeaderViewHolder != null) { 287 RowContainerView containerView = ((RowContainerView) vh.mContainerViewHolder.view); 288 containerView.showHeader(vh.isExpanded()); 289 } 290 } 291 292 /** 293 * Set the current select level to a value between 0 (unselected) and 1 (selected). 294 * Subclasses may override {@link #onSelectLevelChanged(ViewHolder)} to 295 * respond to changes in the selected level. 296 */ 297 public final void setSelectLevel(Presenter.ViewHolder vh, float level) { 298 ViewHolder rowViewHolder = getRowViewHolder(vh); 299 rowViewHolder.mSelectLevel = level; 300 onSelectLevelChanged(rowViewHolder); 301 } 302 303 /** 304 * Get the current select level. The value will be between 0 (unselected) 305 * and 1 (selected). 306 */ 307 public final float getSelectLevel(Presenter.ViewHolder vh) { 308 return getRowViewHolder(vh).mSelectLevel; 309 } 310 311 /** 312 * Callback when select level is changed. The default implementation applies 313 * the select level to {@link RowHeaderPresenter#setSelectLevel(RowHeaderPresenter.ViewHolder, float)} 314 * when {@link #getSelectEffectEnabled()} is true. Subclasses may override 315 * this function and implement a different select effect. In this case, you 316 * should also override {@link #isUsingDefaultSelectEffect()} to disable 317 * the default dimming effect applied by the library. 318 */ 319 protected void onSelectLevelChanged(ViewHolder vh) { 320 if (getSelectEffectEnabled()) { 321 vh.mColorDimmer.setActiveLevel(vh.mSelectLevel); 322 if (vh.mHeaderViewHolder != null) { 323 mHeaderPresenter.setSelectLevel(vh.mHeaderViewHolder, vh.mSelectLevel); 324 } 325 if (isUsingDefaultSelectEffect()) { 326 ((RowContainerView) vh.mContainerViewHolder.view).setForegroundColor( 327 vh.mColorDimmer.getPaint().getColor()); 328 } 329 } 330 } 331 332 /** 333 * Enables or disables the row selection effect. 334 * This will not only affect the default dim effect, but subclasses must 335 * respect this flag as well. 336 */ 337 public final void setSelectEffectEnabled(boolean applyDimOnSelect) { 338 mSelectEffectEnabled = applyDimOnSelect; 339 } 340 341 /** 342 * Returns true if the row selection effect is enabled. 343 * This value not only determines whether the default dim implementation is 344 * used, but subclasses must also respect this flag. 345 */ 346 public final boolean getSelectEffectEnabled() { 347 return mSelectEffectEnabled; 348 } 349 350 /** 351 * Return whether this RowPresenter is using the default dimming effect 352 * provided by the library. Subclasses may(most likely) return false and 353 * override {@link #onSelectLevelChanged(ViewHolder)}. 354 */ 355 public boolean isUsingDefaultSelectEffect() { 356 return true; 357 } 358 359 final boolean needsDefaultSelectEffect() { 360 return isUsingDefaultSelectEffect() && getSelectEffectEnabled(); 361 } 362 363 final boolean needsRowContainerView() { 364 return mHeaderPresenter != null || needsDefaultSelectEffect(); 365 } 366 367 /** 368 * Return true if the Row view can draw outside its bounds. 369 */ 370 public boolean canDrawOutOfBounds() { 371 return false; 372 } 373 374 @Override 375 public final void onBindViewHolder(Presenter.ViewHolder viewHolder, Object item) { 376 onBindRowViewHolder(getRowViewHolder(viewHolder), item); 377 } 378 379 protected void onBindRowViewHolder(ViewHolder vh, Object item) { 380 vh.mRow = (Row) item; 381 if (vh.mHeaderViewHolder != null) { 382 mHeaderPresenter.onBindViewHolder(vh.mHeaderViewHolder, item); 383 } 384 } 385 386 @Override 387 public final void onUnbindViewHolder(Presenter.ViewHolder viewHolder) { 388 onUnbindRowViewHolder(getRowViewHolder(viewHolder)); 389 } 390 391 protected void onUnbindRowViewHolder(ViewHolder vh) { 392 if (vh.mHeaderViewHolder != null) { 393 mHeaderPresenter.onUnbindViewHolder(vh.mHeaderViewHolder); 394 } 395 vh.mRow = null; 396 } 397 398 @Override 399 public final void onViewAttachedToWindow(Presenter.ViewHolder holder) { 400 onRowViewAttachedToWindow(getRowViewHolder(holder)); 401 } 402 403 protected void onRowViewAttachedToWindow(ViewHolder vh) { 404 if (vh.mHeaderViewHolder != null) { 405 mHeaderPresenter.onViewAttachedToWindow(vh.mHeaderViewHolder); 406 } 407 } 408 409 @Override 410 public final void onViewDetachedFromWindow(Presenter.ViewHolder holder) { 411 onRowViewDetachedFromWindow(getRowViewHolder(holder)); 412 } 413 414 protected void onRowViewDetachedFromWindow(ViewHolder vh) { 415 if (vh.mHeaderViewHolder != null) { 416 mHeaderPresenter.onViewDetachedFromWindow(vh.mHeaderViewHolder); 417 } 418 cancelAnimationsRecursive(vh.view); 419 } 420 421 /** 422 * Set the listener for item or row selection. A RowPresenter fires a row 423 * selection event with a null item. Subclasses (e.g. {@link ListRowPresenter}) 424 * can fire a selection event with the selected item. 425 */ 426 public final void setOnItemSelectedListener(OnItemSelectedListener listener) { 427 mOnItemSelectedListener = listener; 428 } 429 430 /** 431 * Get the listener for item or row selection. 432 */ 433 public final OnItemSelectedListener getOnItemSelectedListener() { 434 return mOnItemSelectedListener; 435 } 436 437 /** 438 * Set the listener for item click events. A RowPresenter does not use this 439 * listener, but a subclass may fire an item click event if it has the concept 440 * of an item. The {@link OnItemClickedListener} will override any 441 * {@link View.OnClickListener} that an item's Presenter sets during 442 * {@link Presenter#onCreateViewHolder(ViewGroup)}. So in general, you 443 * should choose to use an OnItemClickedListener or a {@link 444 * View.OnClickListener}, but not both. 445 */ 446 public final void setOnItemClickedListener(OnItemClickedListener listener) { 447 mOnItemClickedListener = listener; 448 } 449 450 /** 451 * Get the listener for item click events. 452 */ 453 public final OnItemClickedListener getOnItemClickedListener() { 454 return mOnItemClickedListener; 455 } 456 457 /** 458 * Set listener for item or row selection. RowPresenter fires row selection 459 * event with null item, subclass of RowPresenter e.g. {@link ListRowPresenter} can 460 * fire a selection event with selected item. 461 */ 462 public final void setOnItemViewSelectedListener(OnItemViewSelectedListener listener) { 463 mOnItemViewSelectedListener = listener; 464 } 465 466 /** 467 * Get listener for item or row selection. 468 */ 469 public final OnItemViewSelectedListener getOnItemViewSelectedListener() { 470 return mOnItemViewSelectedListener; 471 } 472 473 /** 474 * Set listener for item click event. RowPresenter does nothing but subclass of 475 * RowPresenter may fire item click event if it does have a concept of item. 476 * OnItemViewClickedListener will override {@link View.OnClickListener} that 477 * item presenter sets during {@link Presenter#onCreateViewHolder(ViewGroup)}. 478 * So in general, developer should choose one of the listeners but not both. 479 */ 480 public final void setOnItemViewClickedListener(OnItemViewClickedListener listener) { 481 mOnItemViewClickedListener = listener; 482 } 483 484 /** 485 * Set listener for item click event. 486 */ 487 public final OnItemViewClickedListener getOnItemViewClickedListener() { 488 return mOnItemViewClickedListener; 489 } 490 491 /** 492 * Freeze/Unfreeze the row, typically used when transition starts/ends. 493 */ 494 public void freeze(ViewHolder holder, boolean freeze) { 495 } 496 497} 498