Drawable.java revision 7dc5b41e609d3ff55ca194682832d14a7236fa87
1/* 2 * Copyright (C) 2006 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.graphics.drawable; 18 19import android.annotation.NonNull; 20import android.graphics.Insets; 21import android.graphics.Xfermode; 22import android.os.Trace; 23 24import org.xmlpull.v1.XmlPullParser; 25import org.xmlpull.v1.XmlPullParserException; 26 27import android.content.res.Resources; 28import android.content.res.Resources.Theme; 29import android.content.res.TypedArray; 30import android.graphics.Bitmap; 31import android.graphics.BitmapFactory; 32import android.graphics.Canvas; 33import android.graphics.ColorFilter; 34import android.graphics.NinePatch; 35import android.graphics.Outline; 36import android.graphics.PixelFormat; 37import android.graphics.PorterDuff; 38import android.graphics.PorterDuffColorFilter; 39import android.graphics.Rect; 40import android.graphics.Region; 41import android.graphics.PorterDuff.Mode; 42import android.util.AttributeSet; 43import android.util.DisplayMetrics; 44import android.util.StateSet; 45import android.util.TypedValue; 46import android.util.Xml; 47import android.view.View; 48 49import java.io.IOException; 50import java.io.InputStream; 51import java.lang.ref.WeakReference; 52import java.util.Arrays; 53 54/** 55 * A Drawable is a general abstraction for "something that can be drawn." Most 56 * often you will deal with Drawable as the type of resource retrieved for 57 * drawing things to the screen; the Drawable class provides a generic API for 58 * dealing with an underlying visual resource that may take a variety of forms. 59 * Unlike a {@link android.view.View}, a Drawable does not have any facility to 60 * receive events or otherwise interact with the user. 61 * 62 * <p>In addition to simple drawing, Drawable provides a number of generic 63 * mechanisms for its client to interact with what is being drawn: 64 * 65 * <ul> 66 * <li> The {@link #setBounds} method <var>must</var> be called to tell the 67 * Drawable where it is drawn and how large it should be. All Drawables 68 * should respect the requested size, often simply by scaling their 69 * imagery. A client can find the preferred size for some Drawables with 70 * the {@link #getIntrinsicHeight} and {@link #getIntrinsicWidth} methods. 71 * 72 * <li> The {@link #getPadding} method can return from some Drawables 73 * information about how to frame content that is placed inside of them. 74 * For example, a Drawable that is intended to be the frame for a button 75 * widget would need to return padding that correctly places the label 76 * inside of itself. 77 * 78 * <li> The {@link #setState} method allows the client to tell the Drawable 79 * in which state it is to be drawn, such as "focused", "selected", etc. 80 * Some drawables may modify their imagery based on the selected state. 81 * 82 * <li> The {@link #setLevel} method allows the client to supply a single 83 * continuous controller that can modify the Drawable is displayed, such as 84 * a battery level or progress level. Some drawables may modify their 85 * imagery based on the current level. 86 * 87 * <li> A Drawable can perform animations by calling back to its client 88 * through the {@link Callback} interface. All clients should support this 89 * interface (via {@link #setCallback}) so that animations will work. A 90 * simple way to do this is through the system facilities such as 91 * {@link android.view.View#setBackground(Drawable)} and 92 * {@link android.widget.ImageView}. 93 * </ul> 94 * 95 * Though usually not visible to the application, Drawables may take a variety 96 * of forms: 97 * 98 * <ul> 99 * <li> <b>Bitmap</b>: the simplest Drawable, a PNG or JPEG image. 100 * <li> <b>Nine Patch</b>: an extension to the PNG format allows it to 101 * specify information about how to stretch it and place things inside of 102 * it. 103 * <li> <b>Shape</b>: contains simple drawing commands instead of a raw 104 * bitmap, allowing it to resize better in some cases. 105 * <li> <b>Layers</b>: a compound drawable, which draws multiple underlying 106 * drawables on top of each other. 107 * <li> <b>States</b>: a compound drawable that selects one of a set of 108 * drawables based on its state. 109 * <li> <b>Levels</b>: a compound drawable that selects one of a set of 110 * drawables based on its level. 111 * <li> <b>Scale</b>: a compound drawable with a single child drawable, 112 * whose overall size is modified based on the current level. 113 * </ul> 114 * 115 * <div class="special reference"> 116 * <h3>Developer Guides</h3> 117 * <p>For more information about how to use drawables, read the 118 * <a href="{@docRoot}guide/topics/graphics/2d-graphics.html">Canvas and Drawables</a> developer 119 * guide. For information and examples of creating drawable resources (XML or bitmap files that 120 * can be loaded in code), read the 121 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a> 122 * document.</p></div> 123 */ 124public abstract class Drawable { 125 private static final Rect ZERO_BOUNDS_RECT = new Rect(); 126 127 private int[] mStateSet = StateSet.WILD_CARD; 128 private int mLevel = 0; 129 private int mChangingConfigurations = 0; 130 private Rect mBounds = ZERO_BOUNDS_RECT; // lazily becomes a new Rect() 131 private WeakReference<Callback> mCallback = null; 132 private boolean mVisible = true; 133 134 private int mLayoutDirection; 135 136 /** 137 * Draw in its bounds (set via setBounds) respecting optional effects such 138 * as alpha (set via setAlpha) and color filter (set via setColorFilter). 139 * 140 * @param canvas The canvas to draw into 141 */ 142 public abstract void draw(Canvas canvas); 143 144 /** 145 * Specify a bounding rectangle for the Drawable. This is where the drawable 146 * will draw when its draw() method is called. 147 */ 148 public void setBounds(int left, int top, int right, int bottom) { 149 Rect oldBounds = mBounds; 150 151 if (oldBounds == ZERO_BOUNDS_RECT) { 152 oldBounds = mBounds = new Rect(); 153 } 154 155 if (oldBounds.left != left || oldBounds.top != top || 156 oldBounds.right != right || oldBounds.bottom != bottom) { 157 if (!oldBounds.isEmpty()) { 158 // first invalidate the previous bounds 159 invalidateSelf(); 160 } 161 mBounds.set(left, top, right, bottom); 162 onBoundsChange(mBounds); 163 } 164 } 165 166 /** 167 * Specify a bounding rectangle for the Drawable. This is where the drawable 168 * will draw when its draw() method is called. 169 */ 170 public void setBounds(Rect bounds) { 171 setBounds(bounds.left, bounds.top, bounds.right, bounds.bottom); 172 } 173 174 /** 175 * Return a copy of the drawable's bounds in the specified Rect (allocated 176 * by the caller). The bounds specify where this will draw when its draw() 177 * method is called. 178 * 179 * @param bounds Rect to receive the drawable's bounds (allocated by the 180 * caller). 181 */ 182 public final void copyBounds(Rect bounds) { 183 bounds.set(mBounds); 184 } 185 186 /** 187 * Return a copy of the drawable's bounds in a new Rect. This returns the 188 * same values as getBounds(), but the returned object is guaranteed to not 189 * be changed later by the drawable (i.e. it retains no reference to this 190 * rect). If the caller already has a Rect allocated, call copyBounds(rect). 191 * 192 * @return A copy of the drawable's bounds 193 */ 194 public final Rect copyBounds() { 195 return new Rect(mBounds); 196 } 197 198 /** 199 * Return the drawable's bounds Rect. Note: for efficiency, the returned 200 * object may be the same object stored in the drawable (though this is not 201 * guaranteed), so if a persistent copy of the bounds is needed, call 202 * copyBounds(rect) instead. 203 * You should also not change the object returned by this method as it may 204 * be the same object stored in the drawable. 205 * 206 * @return The bounds of the drawable (which may change later, so caller 207 * beware). DO NOT ALTER the returned object as it may change the 208 * stored bounds of this drawable. 209 * 210 * @see #copyBounds() 211 * @see #copyBounds(android.graphics.Rect) 212 */ 213 public final Rect getBounds() { 214 if (mBounds == ZERO_BOUNDS_RECT) { 215 mBounds = new Rect(); 216 } 217 218 return mBounds; 219 } 220 221 /** 222 * Return the drawable's dirty bounds Rect. Note: for efficiency, the 223 * returned object may be the same object stored in the drawable (though 224 * this is not guaranteed). 225 * <p> 226 * By default, this returns the full drawable bounds. Custom drawables may 227 * override this method to perform more precise invalidation. 228 * 229 * @hide 230 */ 231 public Rect getDirtyBounds() { 232 return getBounds(); 233 } 234 235 /** 236 * Set a mask of the configuration parameters for which this drawable 237 * may change, requiring that it be re-created. 238 * 239 * @param configs A mask of the changing configuration parameters, as 240 * defined by {@link android.content.res.Configuration}. 241 * 242 * @see android.content.res.Configuration 243 */ 244 public void setChangingConfigurations(int configs) { 245 mChangingConfigurations = configs; 246 } 247 248 /** 249 * Return a mask of the configuration parameters for which this drawable 250 * may change, requiring that it be re-created. The default implementation 251 * returns whatever was provided through 252 * {@link #setChangingConfigurations(int)} or 0 by default. Subclasses 253 * may extend this to or in the changing configurations of any other 254 * drawables they hold. 255 * 256 * @return Returns a mask of the changing configuration parameters, as 257 * defined by {@link android.content.res.Configuration}. 258 * 259 * @see android.content.res.Configuration 260 */ 261 public int getChangingConfigurations() { 262 return mChangingConfigurations; 263 } 264 265 /** 266 * Set to true to have the drawable dither its colors when drawn to a device 267 * with fewer than 8-bits per color component. This can improve the look on 268 * those devices, but can also slow down the drawing a little. 269 */ 270 public void setDither(boolean dither) {} 271 272 /** 273 * Set to true to have the drawable filter its bitmap when scaled or rotated 274 * (for drawables that use bitmaps). If the drawable does not use bitmaps, 275 * this call is ignored. This can improve the look when scaled or rotated, 276 * but also slows down the drawing. 277 */ 278 public void setFilterBitmap(boolean filter) {} 279 280 /** 281 * Implement this interface if you want to create an animated drawable that 282 * extends {@link android.graphics.drawable.Drawable Drawable}. 283 * Upon retrieving a drawable, use 284 * {@link Drawable#setCallback(android.graphics.drawable.Drawable.Callback)} 285 * to supply your implementation of the interface to the drawable; it uses 286 * this interface to schedule and execute animation changes. 287 */ 288 public static interface Callback { 289 /** 290 * Called when the drawable needs to be redrawn. A view at this point 291 * should invalidate itself (or at least the part of itself where the 292 * drawable appears). 293 * 294 * @param who The drawable that is requesting the update. 295 */ 296 public void invalidateDrawable(Drawable who); 297 298 /** 299 * A Drawable can call this to schedule the next frame of its 300 * animation. An implementation can generally simply call 301 * {@link android.os.Handler#postAtTime(Runnable, Object, long)} with 302 * the parameters <var>(what, who, when)</var> to perform the 303 * scheduling. 304 * 305 * @param who The drawable being scheduled. 306 * @param what The action to execute. 307 * @param when The time (in milliseconds) to run. The timebase is 308 * {@link android.os.SystemClock#uptimeMillis} 309 */ 310 public void scheduleDrawable(Drawable who, Runnable what, long when); 311 312 /** 313 * A Drawable can call this to unschedule an action previously 314 * scheduled with {@link #scheduleDrawable}. An implementation can 315 * generally simply call 316 * {@link android.os.Handler#removeCallbacks(Runnable, Object)} with 317 * the parameters <var>(what, who)</var> to unschedule the drawable. 318 * 319 * @param who The drawable being unscheduled. 320 * @param what The action being unscheduled. 321 */ 322 public void unscheduleDrawable(Drawable who, Runnable what); 323 } 324 325 /** 326 * Bind a {@link Callback} object to this Drawable. Required for clients 327 * that want to support animated drawables. 328 * 329 * @param cb The client's Callback implementation. 330 * 331 * @see #getCallback() 332 */ 333 public final void setCallback(Callback cb) { 334 mCallback = new WeakReference<Callback>(cb); 335 } 336 337 /** 338 * Return the current {@link Callback} implementation attached to this 339 * Drawable. 340 * 341 * @return A {@link Callback} instance or null if no callback was set. 342 * 343 * @see #setCallback(android.graphics.drawable.Drawable.Callback) 344 */ 345 public Callback getCallback() { 346 if (mCallback != null) { 347 return mCallback.get(); 348 } 349 return null; 350 } 351 352 /** 353 * Use the current {@link Callback} implementation to have this Drawable 354 * redrawn. Does nothing if there is no Callback attached to the 355 * Drawable. 356 * 357 * @see Callback#invalidateDrawable 358 * @see #getCallback() 359 * @see #setCallback(android.graphics.drawable.Drawable.Callback) 360 */ 361 public void invalidateSelf() { 362 final Callback callback = getCallback(); 363 if (callback != null) { 364 callback.invalidateDrawable(this); 365 } 366 } 367 368 /** 369 * Use the current {@link Callback} implementation to have this Drawable 370 * scheduled. Does nothing if there is no Callback attached to the 371 * Drawable. 372 * 373 * @param what The action being scheduled. 374 * @param when The time (in milliseconds) to run. 375 * 376 * @see Callback#scheduleDrawable 377 */ 378 public void scheduleSelf(Runnable what, long when) { 379 final Callback callback = getCallback(); 380 if (callback != null) { 381 callback.scheduleDrawable(this, what, when); 382 } 383 } 384 385 /** 386 * Use the current {@link Callback} implementation to have this Drawable 387 * unscheduled. Does nothing if there is no Callback attached to the 388 * Drawable. 389 * 390 * @param what The runnable that you no longer want called. 391 * 392 * @see Callback#unscheduleDrawable 393 */ 394 public void unscheduleSelf(Runnable what) { 395 final Callback callback = getCallback(); 396 if (callback != null) { 397 callback.unscheduleDrawable(this, what); 398 } 399 } 400 401 /** 402 * Returns the resolved layout direction for this Drawable. 403 * 404 * @return One of {@link android.view.View#LAYOUT_DIRECTION_LTR}, 405 * {@link android.view.View#LAYOUT_DIRECTION_RTL} 406 * 407 * @hide 408 */ 409 public int getLayoutDirection() { 410 return mLayoutDirection; 411 } 412 413 /** 414 * Set the layout direction for this drawable. Should be a resolved direction as the 415 * Drawable as no capacity to do the resolution on his own. 416 * 417 * @param layoutDirection One of {@link android.view.View#LAYOUT_DIRECTION_LTR}, 418 * {@link android.view.View#LAYOUT_DIRECTION_RTL} 419 * 420 * @hide 421 */ 422 public void setLayoutDirection(@View.ResolvedLayoutDir int layoutDirection) { 423 if (getLayoutDirection() != layoutDirection) { 424 mLayoutDirection = layoutDirection; 425 } 426 } 427 428 /** 429 * Specify an alpha value for the drawable. 0 means fully transparent, and 430 * 255 means fully opaque. 431 */ 432 public abstract void setAlpha(int alpha); 433 434 /** 435 * Gets the current alpha value for the drawable. 0 means fully transparent, 436 * 255 means fully opaque. This method is implemented by 437 * Drawable subclasses and the value returned is specific to how that class treats alpha. 438 * The default return value is 255 if the class does not override this method to return a value 439 * specific to its use of alpha. 440 */ 441 public int getAlpha() { 442 return 0xFF; 443 } 444 445 /** 446 * @hide Consider for future API inclusion 447 */ 448 public void setXfermode(Xfermode mode) { 449 // Base implementation drops it on the floor for compatibility. Whee! 450 // TODO: For this to be included in the API proper, all framework drawables need impls. 451 // For right now only BitmapDrawable has it. 452 } 453 454 /** 455 * Specify an optional color filter for the drawable. Pass {@code null} to 456 * remove any existing color filter. 457 * 458 * @param cf the color filter to apply, or {@code null} to remove the 459 * existing color filter 460 */ 461 public abstract void setColorFilter(ColorFilter cf); 462 463 /** 464 * Specify a color and Porter-Duff mode to be the color filter for this 465 * drawable. 466 */ 467 public void setColorFilter(int color, PorterDuff.Mode mode) { 468 setColorFilter(new PorterDuffColorFilter(color, mode)); 469 } 470 471 /** 472 * Returns the current color filter, or {@code null} if none set. 473 * 474 * @return the current color filter, or {@code null} if none set 475 */ 476 public ColorFilter getColorFilter() { 477 return null; 478 } 479 480 /** 481 * Removes the color filter for this drawable. 482 */ 483 public void clearColorFilter() { 484 setColorFilter(null); 485 } 486 487 /** 488 * Specifies the hotspot's location within the drawable. 489 * 490 * @param x The X coordinate of the center of the hotspot 491 * @param y The Y coordinate of the center of the hotspot 492 */ 493 public void setHotspot(float x, float y) {} 494 495 /** 496 * Sets the bounds to which the hotspot is constrained, if they should be 497 * different from the drawable bounds. 498 * 499 * @param left 500 * @param top 501 * @param right 502 * @param bottom 503 */ 504 public void setHotspotBounds(int left, int top, int right, int bottom) {} 505 506 /** 507 * Whether this drawable requests projection. 508 * 509 * @hide magic! 510 */ 511 public boolean isProjected() { 512 return false; 513 } 514 515 /** 516 * Indicates whether this view will change its appearance based on state. 517 * Clients can use this to determine whether it is necessary to calculate 518 * their state and call setState. 519 * 520 * @return True if this view changes its appearance based on state, false 521 * otherwise. 522 * 523 * @see #setState(int[]) 524 */ 525 public boolean isStateful() { 526 return false; 527 } 528 529 /** 530 * Specify a set of states for the drawable. These are use-case specific, 531 * so see the relevant documentation. As an example, the background for 532 * widgets like Button understand the following states: 533 * [{@link android.R.attr#state_focused}, 534 * {@link android.R.attr#state_pressed}]. 535 * 536 * <p>If the new state you are supplying causes the appearance of the 537 * Drawable to change, then it is responsible for calling 538 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 539 * true will be returned from this function. 540 * 541 * <p>Note: The Drawable holds a reference on to <var>stateSet</var> 542 * until a new state array is given to it, so you must not modify this 543 * array during that time.</p> 544 * 545 * @param stateSet The new set of states to be displayed. 546 * 547 * @return Returns true if this change in state has caused the appearance 548 * of the Drawable to change (hence requiring an invalidate), otherwise 549 * returns false. 550 */ 551 public boolean setState(final int[] stateSet) { 552 if (!Arrays.equals(mStateSet, stateSet)) { 553 mStateSet = stateSet; 554 return onStateChange(stateSet); 555 } 556 return false; 557 } 558 559 /** 560 * Describes the current state, as a union of primitve states, such as 561 * {@link android.R.attr#state_focused}, 562 * {@link android.R.attr#state_selected}, etc. 563 * Some drawables may modify their imagery based on the selected state. 564 * @return An array of resource Ids describing the current state. 565 */ 566 public int[] getState() { 567 return mStateSet; 568 } 569 570 /** 571 * If this Drawable does transition animations between states, ask that 572 * it immediately jump to the current state and skip any active animations. 573 */ 574 public void jumpToCurrentState() { 575 } 576 577 /** 578 * @return The current drawable that will be used by this drawable. For simple drawables, this 579 * is just the drawable itself. For drawables that change state like 580 * {@link StateListDrawable} and {@link LevelListDrawable} this will be the child drawable 581 * currently in use. 582 */ 583 public Drawable getCurrent() { 584 return this; 585 } 586 587 /** 588 * Specify the level for the drawable. This allows a drawable to vary its 589 * imagery based on a continuous controller, for example to show progress 590 * or volume level. 591 * 592 * <p>If the new level you are supplying causes the appearance of the 593 * Drawable to change, then it is responsible for calling 594 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 595 * true will be returned from this function. 596 * 597 * @param level The new level, from 0 (minimum) to 10000 (maximum). 598 * 599 * @return Returns true if this change in level has caused the appearance 600 * of the Drawable to change (hence requiring an invalidate), otherwise 601 * returns false. 602 */ 603 public final boolean setLevel(int level) { 604 if (mLevel != level) { 605 mLevel = level; 606 return onLevelChange(level); 607 } 608 return false; 609 } 610 611 /** 612 * Retrieve the current level. 613 * 614 * @return int Current level, from 0 (minimum) to 10000 (maximum). 615 */ 616 public final int getLevel() { 617 return mLevel; 618 } 619 620 /** 621 * Set whether this Drawable is visible. This generally does not impact 622 * the Drawable's behavior, but is a hint that can be used by some 623 * Drawables, for example, to decide whether run animations. 624 * 625 * @param visible Set to true if visible, false if not. 626 * @param restart You can supply true here to force the drawable to behave 627 * as if it has just become visible, even if it had last 628 * been set visible. Used for example to force animations 629 * to restart. 630 * 631 * @return boolean Returns true if the new visibility is different than 632 * its previous state. 633 */ 634 public boolean setVisible(boolean visible, boolean restart) { 635 boolean changed = mVisible != visible; 636 if (changed) { 637 mVisible = visible; 638 invalidateSelf(); 639 } 640 return changed; 641 } 642 643 public final boolean isVisible() { 644 return mVisible; 645 } 646 647 /** 648 * Set whether this Drawable is automatically mirrored when its layout direction is RTL 649 * (right-to left). See {@link android.util.LayoutDirection}. 650 * 651 * @param mirrored Set to true if the Drawable should be mirrored, false if not. 652 */ 653 public void setAutoMirrored(boolean mirrored) { 654 } 655 656 /** 657 * Tells if this Drawable will be automatically mirrored when its layout direction is RTL 658 * right-to-left. See {@link android.util.LayoutDirection}. 659 * 660 * @return boolean Returns true if this Drawable will be automatically mirrored. 661 */ 662 public boolean isAutoMirrored() { 663 return false; 664 } 665 666 /** 667 * Applies the specified theme to this Drawable and its children. 668 */ 669 public void applyTheme(@SuppressWarnings("unused") Theme t) { 670 } 671 672 public boolean canApplyTheme() { 673 return false; 674 } 675 676 /** 677 * Return the opacity/transparency of this Drawable. The returned value is 678 * one of the abstract format constants in 679 * {@link android.graphics.PixelFormat}: 680 * {@link android.graphics.PixelFormat#UNKNOWN}, 681 * {@link android.graphics.PixelFormat#TRANSLUCENT}, 682 * {@link android.graphics.PixelFormat#TRANSPARENT}, or 683 * {@link android.graphics.PixelFormat#OPAQUE}. 684 * 685 * <p>Generally a Drawable should be as conservative as possible with the 686 * value it returns. For example, if it contains multiple child drawables 687 * and only shows one of them at a time, if only one of the children is 688 * TRANSLUCENT and the others are OPAQUE then TRANSLUCENT should be 689 * returned. You can use the method {@link #resolveOpacity} to perform a 690 * standard reduction of two opacities to the appropriate single output. 691 * 692 * <p>Note that the returned value does <em>not</em> take into account a 693 * custom alpha or color filter that has been applied by the client through 694 * the {@link #setAlpha} or {@link #setColorFilter} methods. 695 * 696 * @return int The opacity class of the Drawable. 697 * 698 * @see android.graphics.PixelFormat 699 */ 700 public abstract int getOpacity(); 701 702 /** 703 * Return the appropriate opacity value for two source opacities. If 704 * either is UNKNOWN, that is returned; else, if either is TRANSLUCENT, 705 * that is returned; else, if either is TRANSPARENT, that is returned; 706 * else, OPAQUE is returned. 707 * 708 * <p>This is to help in implementing {@link #getOpacity}. 709 * 710 * @param op1 One opacity value. 711 * @param op2 Another opacity value. 712 * 713 * @return int The combined opacity value. 714 * 715 * @see #getOpacity 716 */ 717 public static int resolveOpacity(int op1, int op2) { 718 if (op1 == op2) { 719 return op1; 720 } 721 if (op1 == PixelFormat.UNKNOWN || op2 == PixelFormat.UNKNOWN) { 722 return PixelFormat.UNKNOWN; 723 } 724 if (op1 == PixelFormat.TRANSLUCENT || op2 == PixelFormat.TRANSLUCENT) { 725 return PixelFormat.TRANSLUCENT; 726 } 727 if (op1 == PixelFormat.TRANSPARENT || op2 == PixelFormat.TRANSPARENT) { 728 return PixelFormat.TRANSPARENT; 729 } 730 return PixelFormat.OPAQUE; 731 } 732 733 /** 734 * Returns a Region representing the part of the Drawable that is completely 735 * transparent. This can be used to perform drawing operations, identifying 736 * which parts of the target will not change when rendering the Drawable. 737 * The default implementation returns null, indicating no transparent 738 * region; subclasses can optionally override this to return an actual 739 * Region if they want to supply this optimization information, but it is 740 * not required that they do so. 741 * 742 * @return Returns null if the Drawables has no transparent region to 743 * report, else a Region holding the parts of the Drawable's bounds that 744 * are transparent. 745 */ 746 public Region getTransparentRegion() { 747 return null; 748 } 749 750 /** 751 * Override this in your subclass to change appearance if you recognize the 752 * specified state. 753 * 754 * @return Returns true if the state change has caused the appearance of 755 * the Drawable to change (that is, it needs to be drawn), else false 756 * if it looks the same and there is no need to redraw it since its 757 * last state. 758 */ 759 protected boolean onStateChange(int[] state) { return false; } 760 /** Override this in your subclass to change appearance if you vary based 761 * on level. 762 * @return Returns true if the level change has caused the appearance of 763 * the Drawable to change (that is, it needs to be drawn), else false 764 * if it looks the same and there is no need to redraw it since its 765 * last level. 766 */ 767 protected boolean onLevelChange(int level) { return false; } 768 /** 769 * Override this in your subclass to change appearance if you vary based on 770 * the bounds. 771 */ 772 protected void onBoundsChange(Rect bounds) {} 773 774 /** 775 * Return the intrinsic width of the underlying drawable object. Returns 776 * -1 if it has no intrinsic width, such as with a solid color. 777 */ 778 public int getIntrinsicWidth() { 779 return -1; 780 } 781 782 /** 783 * Return the intrinsic height of the underlying drawable object. Returns 784 * -1 if it has no intrinsic height, such as with a solid color. 785 */ 786 public int getIntrinsicHeight() { 787 return -1; 788 } 789 790 /** 791 * Returns the minimum width suggested by this Drawable. If a View uses this 792 * Drawable as a background, it is suggested that the View use at least this 793 * value for its width. (There will be some scenarios where this will not be 794 * possible.) This value should INCLUDE any padding. 795 * 796 * @return The minimum width suggested by this Drawable. If this Drawable 797 * doesn't have a suggested minimum width, 0 is returned. 798 */ 799 public int getMinimumWidth() { 800 final int intrinsicWidth = getIntrinsicWidth(); 801 return intrinsicWidth > 0 ? intrinsicWidth : 0; 802 } 803 804 /** 805 * Returns the minimum height suggested by this Drawable. If a View uses this 806 * Drawable as a background, it is suggested that the View use at least this 807 * value for its height. (There will be some scenarios where this will not be 808 * possible.) This value should INCLUDE any padding. 809 * 810 * @return The minimum height suggested by this Drawable. If this Drawable 811 * doesn't have a suggested minimum height, 0 is returned. 812 */ 813 public int getMinimumHeight() { 814 final int intrinsicHeight = getIntrinsicHeight(); 815 return intrinsicHeight > 0 ? intrinsicHeight : 0; 816 } 817 818 /** 819 * Return in padding the insets suggested by this Drawable for placing 820 * content inside the drawable's bounds. Positive values move toward the 821 * center of the Drawable (set Rect.inset). 822 * 823 * @return true if this drawable actually has a padding, else false. When false is returned, 824 * the padding is always set to 0. 825 */ 826 public boolean getPadding(@NonNull Rect padding) { 827 padding.set(0, 0, 0, 0); 828 return false; 829 } 830 831 /** 832 * Return in insets the layout insets suggested by this Drawable for use with alignment 833 * operations during layout. 834 * 835 * @hide 836 */ 837 public Insets getOpticalInsets() { 838 return Insets.NONE; 839 } 840 841 /** 842 * Called to get the drawable to populate the Outline. 843 * <p> 844 * This method will be called by a View on its background Drawable after bounds change, or its 845 * Drawable is invalidated, if the View's Outline isn't set explicitly. This allows the 846 * background Drawable to define the shape of the shadow cast by the View. 847 * <p> 848 * The default behavior defines the outline to be the bounding rectangle. Subclasses that wish 849 * to convey a different shape must override this method. 850 * 851 * @return true if this drawable actually has an outline, else false. The outline must be 852 * populated by the drawable if true is returned. 853 * 854 * @see View#setOutline(android.graphics.Outline) 855 */ 856 public boolean getOutline(@NonNull Outline outline) { 857 outline.setRect(getBounds()); 858 return true; 859 } 860 861 /** 862 * Make this drawable mutable. This operation cannot be reversed. A mutable 863 * drawable is guaranteed to not share its state with any other drawable. 864 * This is especially useful when you need to modify properties of drawables 865 * loaded from resources. By default, all drawables instances loaded from 866 * the same resource share a common state; if you modify the state of one 867 * instance, all the other instances will receive the same modification. 868 * 869 * Calling this method on a mutable Drawable will have no effect. 870 * 871 * @return This drawable. 872 * @see ConstantState 873 * @see #getConstantState() 874 */ 875 public Drawable mutate() { 876 return this; 877 } 878 879 /** 880 * Create a drawable from an inputstream 881 */ 882 public static Drawable createFromStream(InputStream is, String srcName) { 883 return createFromStreamThemed(is, srcName, null); 884 } 885 886 public static Drawable createFromStreamThemed(InputStream is, String srcName, Theme theme) { 887 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, srcName != null ? srcName : "Unknown drawable"); 888 try { 889 return createFromResourceStreamThemed(null, null, is, srcName, theme); 890 } finally { 891 Trace.traceEnd(Trace.TRACE_TAG_RESOURCES); 892 } 893 } 894 895 /** 896 * Create a drawable from an inputstream, using the given resources and 897 * value to determine density information. 898 */ 899 public static Drawable createFromResourceStream(Resources res, TypedValue value, 900 InputStream is, String srcName) { 901 return createFromResourceStreamThemed(res, value, is, srcName, null); 902 } 903 904 public static Drawable createFromResourceStreamThemed(Resources res, TypedValue value, 905 InputStream is, String srcName, Theme theme) { 906 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, srcName != null ? srcName : "Unknown drawable"); 907 try { 908 return createFromResourceStreamThemed(res, value, is, srcName, null, theme); 909 } finally { 910 Trace.traceEnd(Trace.TRACE_TAG_RESOURCES); 911 } 912 } 913 914 /** 915 * Create a drawable from an inputstream, using the given resources and 916 * value to determine density information. 917 */ 918 public static Drawable createFromResourceStream(Resources res, TypedValue value, 919 InputStream is, String srcName, BitmapFactory.Options opts) { 920 return createFromResourceStreamThemed(res, value, is, srcName, opts, null); 921 } 922 923 public static Drawable createFromResourceStreamThemed(Resources res, TypedValue value, 924 InputStream is, String srcName, BitmapFactory.Options opts, Theme theme) { 925 if (is == null) { 926 return null; 927 } 928 929 /* ugh. The decodeStream contract is that we have already allocated 930 the pad rect, but if the bitmap does not had a ninepatch chunk, 931 then the pad will be ignored. If we could change this to lazily 932 alloc/assign the rect, we could avoid the GC churn of making new 933 Rects only to drop them on the floor. 934 */ 935 Rect pad = new Rect(); 936 937 // Special stuff for compatibility mode: if the target density is not 938 // the same as the display density, but the resource -is- the same as 939 // the display density, then don't scale it down to the target density. 940 // This allows us to load the system's density-correct resources into 941 // an application in compatibility mode, without scaling those down 942 // to the compatibility density only to have them scaled back up when 943 // drawn to the screen. 944 if (opts == null) opts = new BitmapFactory.Options(); 945 opts.inScreenDensity = res != null 946 ? res.getDisplayMetrics().noncompatDensityDpi : DisplayMetrics.DENSITY_DEVICE; 947 Bitmap bm = BitmapFactory.decodeResourceStream(res, value, is, pad, opts); 948 if (bm != null) { 949 byte[] np = bm.getNinePatchChunk(); 950 if (np == null || !NinePatch.isNinePatchChunk(np)) { 951 np = null; 952 pad = null; 953 } 954 int[] layoutBounds = bm.getLayoutBounds(); 955 Rect layoutBoundsRect = null; 956 if (layoutBounds != null) { 957 layoutBoundsRect = new Rect(layoutBounds[0], layoutBounds[1], 958 layoutBounds[2], layoutBounds[3]); 959 } 960 return drawableFromBitmap(res, bm, np, pad, layoutBoundsRect, srcName); 961 } 962 return null; 963 } 964 965 /** 966 * Create a drawable from an XML document. For more information on how to 967 * create resources in XML, see 968 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. 969 */ 970 public static Drawable createFromXml(Resources r, XmlPullParser parser) 971 throws XmlPullParserException, IOException { 972 return createFromXmlThemed(r, parser, null); 973 } 974 975 /** 976 * Create a themed drawable from an XML document. For more information on 977 * how to create resources in XML, see 978 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. 979 */ 980 public static Drawable createFromXmlThemed(Resources r, XmlPullParser parser, Theme theme) 981 throws XmlPullParserException, IOException { 982 AttributeSet attrs = Xml.asAttributeSet(parser); 983 984 int type; 985 while ((type=parser.next()) != XmlPullParser.START_TAG && 986 type != XmlPullParser.END_DOCUMENT) { 987 // Empty loop 988 } 989 990 if (type != XmlPullParser.START_TAG) { 991 throw new XmlPullParserException("No start tag found"); 992 } 993 994 Drawable drawable = createFromXmlInnerThemed(r, parser, attrs, theme); 995 996 if (drawable == null) { 997 throw new RuntimeException("Unknown initial tag: " + parser.getName()); 998 } 999 1000 return drawable; 1001 } 1002 1003 /** 1004 * Create from inside an XML document. Called on a parser positioned at 1005 * a tag in an XML document, tries to create a Drawable from that tag. 1006 * Returns null if the tag is not a valid drawable. 1007 */ 1008 public static Drawable createFromXmlInner(Resources r, XmlPullParser parser, AttributeSet attrs) 1009 throws XmlPullParserException, IOException { 1010 return createFromXmlInnerThemed(r, parser, attrs, null); 1011 } 1012 1013 public static Drawable createFromXmlInnerThemed(Resources r, XmlPullParser parser, 1014 AttributeSet attrs, Theme theme) throws XmlPullParserException, IOException { 1015 final Drawable drawable; 1016 1017 final String name = parser.getName(); 1018 if (name.equals("selector")) { 1019 drawable = new StateListDrawable(); 1020 } else if (name.equals("animated-selector")) { 1021 drawable = new AnimatedStateListDrawable(); 1022 } else if (name.equals("level-list")) { 1023 drawable = new LevelListDrawable(); 1024 } else if (name.equals("layer-list")) { 1025 drawable = new LayerDrawable(); 1026 } else if (name.equals("transition")) { 1027 drawable = new TransitionDrawable(); 1028 } else if (name.equals("ripple")) { 1029 drawable = new RippleDrawable(); 1030 } else if (name.equals("color")) { 1031 drawable = new ColorDrawable(); 1032 } else if (name.equals("shape")) { 1033 drawable = new GradientDrawable(); 1034 } else if (name.equals("vector")) { 1035 drawable = new VectorDrawable(); 1036 } else if (name.equals("scale")) { 1037 drawable = new ScaleDrawable(); 1038 } else if (name.equals("clip")) { 1039 drawable = new ClipDrawable(); 1040 } else if (name.equals("rotate")) { 1041 drawable = new RotateDrawable(); 1042 } else if (name.equals("animated-rotate")) { 1043 drawable = new AnimatedRotateDrawable(); 1044 } else if (name.equals("animation-list")) { 1045 drawable = new AnimationDrawable(); 1046 } else if (name.equals("inset")) { 1047 drawable = new InsetDrawable(); 1048 } else if (name.equals("bitmap")) { 1049 //noinspection deprecation 1050 drawable = new BitmapDrawable(r); 1051 if (r != null) { 1052 ((BitmapDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 1053 } 1054 } else if (name.equals("nine-patch")) { 1055 drawable = new NinePatchDrawable(); 1056 if (r != null) { 1057 ((NinePatchDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 1058 } 1059 } else { 1060 throw new XmlPullParserException(parser.getPositionDescription() + 1061 ": invalid drawable tag " + name); 1062 } 1063 1064 drawable.inflate(r, parser, attrs, theme); 1065 return drawable; 1066 } 1067 1068 1069 /** 1070 * Create a drawable from file path name. 1071 */ 1072 public static Drawable createFromPath(String pathName) { 1073 if (pathName == null) { 1074 return null; 1075 } 1076 1077 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, pathName); 1078 try { 1079 Bitmap bm = BitmapFactory.decodeFile(pathName); 1080 if (bm != null) { 1081 return drawableFromBitmap(null, bm, null, null, null, pathName); 1082 } 1083 } finally { 1084 Trace.traceEnd(Trace.TRACE_TAG_RESOURCES); 1085 } 1086 1087 return null; 1088 } 1089 1090 /** 1091 * Inflate this Drawable from an XML resource. Does not apply a theme. 1092 * 1093 * @see #inflate(Resources, XmlPullParser, AttributeSet, Theme) 1094 */ 1095 public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs) 1096 throws XmlPullParserException, IOException { 1097 inflate(r, parser, attrs, null); 1098 } 1099 1100 /** 1101 * Inflate this Drawable from an XML resource optionally styled by a theme. 1102 * 1103 * @param r Resources used to resolve attribute values 1104 * @param parser XML parser from which to inflate this Drawable 1105 * @param attrs Base set of attribute values 1106 * @param theme Theme to apply, may be null 1107 * @throws XmlPullParserException 1108 * @throws IOException 1109 */ 1110 public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs, Theme theme) 1111 throws XmlPullParserException, IOException { 1112 final TypedArray a; 1113 if (theme != null) { 1114 a = theme.obtainStyledAttributes( 1115 attrs, com.android.internal.R.styleable.Drawable, 0, 0); 1116 } else { 1117 a = r.obtainAttributes(attrs, com.android.internal.R.styleable.Drawable); 1118 } 1119 1120 inflateWithAttributes(r, parser, a, com.android.internal.R.styleable.Drawable_visible); 1121 a.recycle(); 1122 } 1123 1124 /** 1125 * Inflate a Drawable from an XML resource. 1126 * 1127 * @throws XmlPullParserException 1128 * @throws IOException 1129 */ 1130 void inflateWithAttributes(Resources r, XmlPullParser parser, TypedArray attrs, int visibleAttr) 1131 throws XmlPullParserException, IOException { 1132 mVisible = attrs.getBoolean(visibleAttr, mVisible); 1133 } 1134 1135 /** 1136 * This abstract class is used by {@link Drawable}s to store shared constant state and data 1137 * between Drawables. {@link BitmapDrawable}s created from the same resource will for instance 1138 * share a unique bitmap stored in their ConstantState. 1139 * 1140 * <p> 1141 * {@link #newDrawable(Resources)} can be used as a factory to create new Drawable instances 1142 * from this ConstantState. 1143 * </p> 1144 * 1145 * Use {@link Drawable#getConstantState()} to retrieve the ConstantState of a Drawable. Calling 1146 * {@link Drawable#mutate()} on a Drawable should typically create a new ConstantState for that 1147 * Drawable. 1148 */ 1149 public static abstract class ConstantState { 1150 /** 1151 * Create a new drawable without supplying resources the caller 1152 * is running in. Note that using this means the density-dependent 1153 * drawables (like bitmaps) will not be able to update their target 1154 * density correctly. One should use {@link #newDrawable(Resources)} 1155 * instead to provide a resource. 1156 */ 1157 public abstract Drawable newDrawable(); 1158 1159 /** 1160 * Create a new Drawable instance from its constant state. This 1161 * must be implemented for drawables that change based on the target 1162 * density of their caller (that is depending on whether it is 1163 * in compatibility mode). 1164 */ 1165 public Drawable newDrawable(Resources res) { 1166 return newDrawable(); 1167 } 1168 1169 /** 1170 * Create a new Drawable instance from its constant state. This must be 1171 * implemented for drawables that can have a theme applied. 1172 */ 1173 public Drawable newDrawable(Resources res, Theme theme) { 1174 return newDrawable(); 1175 } 1176 1177 /** 1178 * Return a bit mask of configuration changes that will impact 1179 * this drawable (and thus require completely reloading it). 1180 */ 1181 public abstract int getChangingConfigurations(); 1182 1183 /** 1184 * @hide 1185 */ 1186 public Bitmap getBitmap() { 1187 return null; 1188 } 1189 1190 /** 1191 * Return whether this constant state can have a theme applied. 1192 */ 1193 public boolean canApplyTheme() { 1194 return false; 1195 } 1196 } 1197 1198 /** 1199 * Return a {@link ConstantState} instance that holds the shared state of this Drawable. 1200 * 1201 * @return The ConstantState associated to that Drawable. 1202 * @see ConstantState 1203 * @see Drawable#mutate() 1204 */ 1205 public ConstantState getConstantState() { 1206 return null; 1207 } 1208 1209 private static Drawable drawableFromBitmap(Resources res, Bitmap bm, byte[] np, 1210 Rect pad, Rect layoutBounds, String srcName) { 1211 1212 if (np != null) { 1213 return new NinePatchDrawable(res, bm, np, pad, layoutBounds, srcName); 1214 } 1215 1216 return new BitmapDrawable(res, bm); 1217 } 1218 1219 /** 1220 * Obtains styled attributes from the theme, if available, or unstyled 1221 * resources if the theme is null. 1222 */ 1223 static TypedArray obtainAttributes( 1224 Resources res, Theme theme, AttributeSet set, int[] attrs) { 1225 if (theme == null) { 1226 return res.obtainAttributes(set, attrs); 1227 } 1228 return theme.obtainStyledAttributes(set, attrs, 0, 0); 1229 } 1230 1231 /** 1232 * Parses a {@link android.graphics.PorterDuff.Mode} from a tintMode 1233 * attribute's enum value. 1234 */ 1235 static PorterDuff.Mode parseTintMode(int value, Mode defaultMode) { 1236 switch (value) { 1237 case 3: return Mode.SRC_OVER; 1238 case 5: return Mode.SRC_IN; 1239 case 9: return Mode.SRC_ATOP; 1240 case 14: return Mode.MULTIPLY; 1241 case 15: return Mode.SCREEN; 1242 case 16: return Mode.ADD; 1243 default: return defaultMode; 1244 } 1245 } 1246} 1247 1248