Drawable.java revision 53a3ed7c46c12c2e578d1b1df8b039c6db690eaa
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 drawable will change its appearance based on 517 * state. Clients can use this to determine whether it is necessary to 518 * calculate their state and call setState. 519 * 520 * @return True if this drawable changes its appearance based on state, 521 * false otherwise. 522 * @see #setState(int[]) 523 */ 524 public boolean isStateful() { 525 return false; 526 } 527 528 /** 529 * Specify a set of states for the drawable. These are use-case specific, 530 * so see the relevant documentation. As an example, the background for 531 * widgets like Button understand the following states: 532 * [{@link android.R.attr#state_focused}, 533 * {@link android.R.attr#state_pressed}]. 534 * 535 * <p>If the new state you are supplying causes the appearance of the 536 * Drawable to change, then it is responsible for calling 537 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 538 * true will be returned from this function. 539 * 540 * <p>Note: The Drawable holds a reference on to <var>stateSet</var> 541 * until a new state array is given to it, so you must not modify this 542 * array during that time.</p> 543 * 544 * @param stateSet The new set of states to be displayed. 545 * 546 * @return Returns true if this change in state has caused the appearance 547 * of the Drawable to change (hence requiring an invalidate), otherwise 548 * returns false. 549 */ 550 public boolean setState(final int[] stateSet) { 551 if (!Arrays.equals(mStateSet, stateSet)) { 552 mStateSet = stateSet; 553 return onStateChange(stateSet); 554 } 555 return false; 556 } 557 558 /** 559 * Describes the current state, as a union of primitve states, such as 560 * {@link android.R.attr#state_focused}, 561 * {@link android.R.attr#state_selected}, etc. 562 * Some drawables may modify their imagery based on the selected state. 563 * @return An array of resource Ids describing the current state. 564 */ 565 public int[] getState() { 566 return mStateSet; 567 } 568 569 /** 570 * If this Drawable does transition animations between states, ask that 571 * it immediately jump to the current state and skip any active animations. 572 */ 573 public void jumpToCurrentState() { 574 } 575 576 /** 577 * @return The current drawable that will be used by this drawable. For simple drawables, this 578 * is just the drawable itself. For drawables that change state like 579 * {@link StateListDrawable} and {@link LevelListDrawable} this will be the child drawable 580 * currently in use. 581 */ 582 public Drawable getCurrent() { 583 return this; 584 } 585 586 /** 587 * Specify the level for the drawable. This allows a drawable to vary its 588 * imagery based on a continuous controller, for example to show progress 589 * or volume level. 590 * 591 * <p>If the new level you are supplying causes the appearance of the 592 * Drawable to change, then it is responsible for calling 593 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 594 * true will be returned from this function. 595 * 596 * @param level The new level, from 0 (minimum) to 10000 (maximum). 597 * 598 * @return Returns true if this change in level has caused the appearance 599 * of the Drawable to change (hence requiring an invalidate), otherwise 600 * returns false. 601 */ 602 public final boolean setLevel(int level) { 603 if (mLevel != level) { 604 mLevel = level; 605 return onLevelChange(level); 606 } 607 return false; 608 } 609 610 /** 611 * Retrieve the current level. 612 * 613 * @return int Current level, from 0 (minimum) to 10000 (maximum). 614 */ 615 public final int getLevel() { 616 return mLevel; 617 } 618 619 /** 620 * Set whether this Drawable is visible. This generally does not impact 621 * the Drawable's behavior, but is a hint that can be used by some 622 * Drawables, for example, to decide whether run animations. 623 * 624 * @param visible Set to true if visible, false if not. 625 * @param restart You can supply true here to force the drawable to behave 626 * as if it has just become visible, even if it had last 627 * been set visible. Used for example to force animations 628 * to restart. 629 * 630 * @return boolean Returns true if the new visibility is different than 631 * its previous state. 632 */ 633 public boolean setVisible(boolean visible, boolean restart) { 634 boolean changed = mVisible != visible; 635 if (changed) { 636 mVisible = visible; 637 invalidateSelf(); 638 } 639 return changed; 640 } 641 642 public final boolean isVisible() { 643 return mVisible; 644 } 645 646 /** 647 * Set whether this Drawable is automatically mirrored when its layout direction is RTL 648 * (right-to left). See {@link android.util.LayoutDirection}. 649 * 650 * @param mirrored Set to true if the Drawable should be mirrored, false if not. 651 */ 652 public void setAutoMirrored(boolean mirrored) { 653 } 654 655 /** 656 * Tells if this Drawable will be automatically mirrored when its layout direction is RTL 657 * right-to-left. See {@link android.util.LayoutDirection}. 658 * 659 * @return boolean Returns true if this Drawable will be automatically mirrored. 660 */ 661 public boolean isAutoMirrored() { 662 return false; 663 } 664 665 /** 666 * Applies the specified theme to this Drawable and its children. 667 */ 668 public void applyTheme(@SuppressWarnings("unused") Theme t) { 669 } 670 671 public boolean canApplyTheme() { 672 return false; 673 } 674 675 /** 676 * Return the opacity/transparency of this Drawable. The returned value is 677 * one of the abstract format constants in 678 * {@link android.graphics.PixelFormat}: 679 * {@link android.graphics.PixelFormat#UNKNOWN}, 680 * {@link android.graphics.PixelFormat#TRANSLUCENT}, 681 * {@link android.graphics.PixelFormat#TRANSPARENT}, or 682 * {@link android.graphics.PixelFormat#OPAQUE}. 683 * 684 * <p>Generally a Drawable should be as conservative as possible with the 685 * value it returns. For example, if it contains multiple child drawables 686 * and only shows one of them at a time, if only one of the children is 687 * TRANSLUCENT and the others are OPAQUE then TRANSLUCENT should be 688 * returned. You can use the method {@link #resolveOpacity} to perform a 689 * standard reduction of two opacities to the appropriate single output. 690 * 691 * <p>Note that the returned value does <em>not</em> take into account a 692 * custom alpha or color filter that has been applied by the client through 693 * the {@link #setAlpha} or {@link #setColorFilter} methods. 694 * 695 * @return int The opacity class of the Drawable. 696 * 697 * @see android.graphics.PixelFormat 698 */ 699 public abstract int getOpacity(); 700 701 /** 702 * Return the appropriate opacity value for two source opacities. If 703 * either is UNKNOWN, that is returned; else, if either is TRANSLUCENT, 704 * that is returned; else, if either is TRANSPARENT, that is returned; 705 * else, OPAQUE is returned. 706 * 707 * <p>This is to help in implementing {@link #getOpacity}. 708 * 709 * @param op1 One opacity value. 710 * @param op2 Another opacity value. 711 * 712 * @return int The combined opacity value. 713 * 714 * @see #getOpacity 715 */ 716 public static int resolveOpacity(int op1, int op2) { 717 if (op1 == op2) { 718 return op1; 719 } 720 if (op1 == PixelFormat.UNKNOWN || op2 == PixelFormat.UNKNOWN) { 721 return PixelFormat.UNKNOWN; 722 } 723 if (op1 == PixelFormat.TRANSLUCENT || op2 == PixelFormat.TRANSLUCENT) { 724 return PixelFormat.TRANSLUCENT; 725 } 726 if (op1 == PixelFormat.TRANSPARENT || op2 == PixelFormat.TRANSPARENT) { 727 return PixelFormat.TRANSPARENT; 728 } 729 return PixelFormat.OPAQUE; 730 } 731 732 /** 733 * Returns a Region representing the part of the Drawable that is completely 734 * transparent. This can be used to perform drawing operations, identifying 735 * which parts of the target will not change when rendering the Drawable. 736 * The default implementation returns null, indicating no transparent 737 * region; subclasses can optionally override this to return an actual 738 * Region if they want to supply this optimization information, but it is 739 * not required that they do so. 740 * 741 * @return Returns null if the Drawables has no transparent region to 742 * report, else a Region holding the parts of the Drawable's bounds that 743 * are transparent. 744 */ 745 public Region getTransparentRegion() { 746 return null; 747 } 748 749 /** 750 * Override this in your subclass to change appearance if you recognize the 751 * specified state. 752 * 753 * @return Returns true if the state change has caused the appearance of 754 * the Drawable to change (that is, it needs to be drawn), else false 755 * if it looks the same and there is no need to redraw it since its 756 * last state. 757 */ 758 protected boolean onStateChange(int[] state) { return false; } 759 /** Override this in your subclass to change appearance if you vary based 760 * on level. 761 * @return Returns true if the level change has caused the appearance of 762 * the Drawable to change (that is, it needs to be drawn), else false 763 * if it looks the same and there is no need to redraw it since its 764 * last level. 765 */ 766 protected boolean onLevelChange(int level) { return false; } 767 /** 768 * Override this in your subclass to change appearance if you vary based on 769 * the bounds. 770 */ 771 protected void onBoundsChange(Rect bounds) {} 772 773 /** 774 * Return the intrinsic width of the underlying drawable object. Returns 775 * -1 if it has no intrinsic width, such as with a solid color. 776 */ 777 public int getIntrinsicWidth() { 778 return -1; 779 } 780 781 /** 782 * Return the intrinsic height of the underlying drawable object. Returns 783 * -1 if it has no intrinsic height, such as with a solid color. 784 */ 785 public int getIntrinsicHeight() { 786 return -1; 787 } 788 789 /** 790 * Returns the minimum width suggested by this Drawable. If a View uses this 791 * Drawable as a background, it is suggested that the View use at least this 792 * value for its width. (There will be some scenarios where this will not be 793 * possible.) This value should INCLUDE any padding. 794 * 795 * @return The minimum width suggested by this Drawable. If this Drawable 796 * doesn't have a suggested minimum width, 0 is returned. 797 */ 798 public int getMinimumWidth() { 799 final int intrinsicWidth = getIntrinsicWidth(); 800 return intrinsicWidth > 0 ? intrinsicWidth : 0; 801 } 802 803 /** 804 * Returns the minimum height suggested by this Drawable. If a View uses this 805 * Drawable as a background, it is suggested that the View use at least this 806 * value for its height. (There will be some scenarios where this will not be 807 * possible.) This value should INCLUDE any padding. 808 * 809 * @return The minimum height suggested by this Drawable. If this Drawable 810 * doesn't have a suggested minimum height, 0 is returned. 811 */ 812 public int getMinimumHeight() { 813 final int intrinsicHeight = getIntrinsicHeight(); 814 return intrinsicHeight > 0 ? intrinsicHeight : 0; 815 } 816 817 /** 818 * Return in padding the insets suggested by this Drawable for placing 819 * content inside the drawable's bounds. Positive values move toward the 820 * center of the Drawable (set Rect.inset). 821 * 822 * @return true if this drawable actually has a padding, else false. When false is returned, 823 * the padding is always set to 0. 824 */ 825 public boolean getPadding(@NonNull Rect padding) { 826 padding.set(0, 0, 0, 0); 827 return false; 828 } 829 830 /** 831 * Return in insets the layout insets suggested by this Drawable for use with alignment 832 * operations during layout. 833 * 834 * @hide 835 */ 836 public Insets getOpticalInsets() { 837 return Insets.NONE; 838 } 839 840 /** 841 * Called to get the drawable to populate the Outline. 842 * <p> 843 * This method will be called by a View on its background Drawable after bounds change, or its 844 * Drawable is invalidated, if the View's Outline isn't set explicitly. This allows the 845 * background Drawable to define the shape of the shadow cast by the View. 846 * <p> 847 * The default behavior defines the outline to be the bounding rectangle. Subclasses that wish 848 * to convey a different shape must override this method. 849 * 850 * @return true if this drawable actually has an outline, else false. The outline must be 851 * populated by the drawable if true is returned. 852 * 853 * @see View#setOutline(android.graphics.Outline) 854 */ 855 public boolean getOutline(@NonNull Outline outline) { 856 outline.setRect(getBounds()); 857 return true; 858 } 859 860 /** 861 * Make this drawable mutable. This operation cannot be reversed. A mutable 862 * drawable is guaranteed to not share its state with any other drawable. 863 * This is especially useful when you need to modify properties of drawables 864 * loaded from resources. By default, all drawables instances loaded from 865 * the same resource share a common state; if you modify the state of one 866 * instance, all the other instances will receive the same modification. 867 * 868 * Calling this method on a mutable Drawable will have no effect. 869 * 870 * @return This drawable. 871 * @see ConstantState 872 * @see #getConstantState() 873 */ 874 public Drawable mutate() { 875 return this; 876 } 877 878 /** 879 * Create a drawable from an inputstream 880 */ 881 public static Drawable createFromStream(InputStream is, String srcName) { 882 return createFromStreamThemed(is, srcName, null); 883 } 884 885 public static Drawable createFromStreamThemed(InputStream is, String srcName, Theme theme) { 886 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, srcName != null ? srcName : "Unknown drawable"); 887 try { 888 return createFromResourceStreamThemed(null, null, is, srcName, theme); 889 } finally { 890 Trace.traceEnd(Trace.TRACE_TAG_RESOURCES); 891 } 892 } 893 894 /** 895 * Create a drawable from an inputstream, using the given resources and 896 * value to determine density information. 897 */ 898 public static Drawable createFromResourceStream(Resources res, TypedValue value, 899 InputStream is, String srcName) { 900 return createFromResourceStreamThemed(res, value, is, srcName, null); 901 } 902 903 public static Drawable createFromResourceStreamThemed(Resources res, TypedValue value, 904 InputStream is, String srcName, Theme theme) { 905 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, srcName != null ? srcName : "Unknown drawable"); 906 try { 907 return createFromResourceStreamThemed(res, value, is, srcName, null, theme); 908 } finally { 909 Trace.traceEnd(Trace.TRACE_TAG_RESOURCES); 910 } 911 } 912 913 /** 914 * Create a drawable from an inputstream, using the given resources and 915 * value to determine density information. 916 */ 917 public static Drawable createFromResourceStream(Resources res, TypedValue value, 918 InputStream is, String srcName, BitmapFactory.Options opts) { 919 return createFromResourceStreamThemed(res, value, is, srcName, opts, null); 920 } 921 922 public static Drawable createFromResourceStreamThemed(Resources res, TypedValue value, 923 InputStream is, String srcName, BitmapFactory.Options opts, Theme theme) { 924 if (is == null) { 925 return null; 926 } 927 928 /* ugh. The decodeStream contract is that we have already allocated 929 the pad rect, but if the bitmap does not had a ninepatch chunk, 930 then the pad will be ignored. If we could change this to lazily 931 alloc/assign the rect, we could avoid the GC churn of making new 932 Rects only to drop them on the floor. 933 */ 934 Rect pad = new Rect(); 935 936 // Special stuff for compatibility mode: if the target density is not 937 // the same as the display density, but the resource -is- the same as 938 // the display density, then don't scale it down to the target density. 939 // This allows us to load the system's density-correct resources into 940 // an application in compatibility mode, without scaling those down 941 // to the compatibility density only to have them scaled back up when 942 // drawn to the screen. 943 if (opts == null) opts = new BitmapFactory.Options(); 944 opts.inScreenDensity = res != null 945 ? res.getDisplayMetrics().noncompatDensityDpi : DisplayMetrics.DENSITY_DEVICE; 946 Bitmap bm = BitmapFactory.decodeResourceStream(res, value, is, pad, opts); 947 if (bm != null) { 948 byte[] np = bm.getNinePatchChunk(); 949 if (np == null || !NinePatch.isNinePatchChunk(np)) { 950 np = null; 951 pad = null; 952 } 953 int[] layoutBounds = bm.getLayoutBounds(); 954 Rect layoutBoundsRect = null; 955 if (layoutBounds != null) { 956 layoutBoundsRect = new Rect(layoutBounds[0], layoutBounds[1], 957 layoutBounds[2], layoutBounds[3]); 958 } 959 return drawableFromBitmap(res, bm, np, pad, layoutBoundsRect, srcName); 960 } 961 return null; 962 } 963 964 /** 965 * Create a drawable from an XML document. For more information on how to 966 * create resources in XML, see 967 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. 968 */ 969 public static Drawable createFromXml(Resources r, XmlPullParser parser) 970 throws XmlPullParserException, IOException { 971 return createFromXmlThemed(r, parser, null); 972 } 973 974 /** 975 * Create a themed drawable from an XML document. For more information on 976 * how to create resources in XML, see 977 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. 978 */ 979 public static Drawable createFromXmlThemed(Resources r, XmlPullParser parser, Theme theme) 980 throws XmlPullParserException, IOException { 981 AttributeSet attrs = Xml.asAttributeSet(parser); 982 983 int type; 984 while ((type=parser.next()) != XmlPullParser.START_TAG && 985 type != XmlPullParser.END_DOCUMENT) { 986 // Empty loop 987 } 988 989 if (type != XmlPullParser.START_TAG) { 990 throw new XmlPullParserException("No start tag found"); 991 } 992 993 Drawable drawable = createFromXmlInnerThemed(r, parser, attrs, theme); 994 995 if (drawable == null) { 996 throw new RuntimeException("Unknown initial tag: " + parser.getName()); 997 } 998 999 return drawable; 1000 } 1001 1002 /** 1003 * Create from inside an XML document. Called on a parser positioned at 1004 * a tag in an XML document, tries to create a Drawable from that tag. 1005 * Returns null if the tag is not a valid drawable. 1006 */ 1007 public static Drawable createFromXmlInner(Resources r, XmlPullParser parser, AttributeSet attrs) 1008 throws XmlPullParserException, IOException { 1009 return createFromXmlInnerThemed(r, parser, attrs, null); 1010 } 1011 1012 /** 1013 * Create a themed drawable from inside an XML document. Called on a parser 1014 * positioned at a tag in an XML document, tries to create a Drawable from 1015 * that tag. Returns null if the tag is not a valid drawable. 1016 */ 1017 public static Drawable createFromXmlInnerThemed(Resources r, XmlPullParser parser, 1018 AttributeSet attrs, Theme theme) throws XmlPullParserException, IOException { 1019 final Drawable drawable; 1020 1021 final String name = parser.getName(); 1022 if (name.equals("selector")) { 1023 drawable = new StateListDrawable(); 1024 } else if (name.equals("animated-selector")) { 1025 drawable = new AnimatedStateListDrawable(); 1026 } else if (name.equals("level-list")) { 1027 drawable = new LevelListDrawable(); 1028 } else if (name.equals("layer-list")) { 1029 drawable = new LayerDrawable(); 1030 } else if (name.equals("transition")) { 1031 drawable = new TransitionDrawable(); 1032 } else if (name.equals("ripple")) { 1033 drawable = new RippleDrawable(); 1034 } else if (name.equals("color")) { 1035 drawable = new ColorDrawable(); 1036 } else if (name.equals("shape")) { 1037 drawable = new GradientDrawable(); 1038 } else if (name.equals("vector")) { 1039 drawable = new VectorDrawable(); 1040 } else if (name.equals("scale")) { 1041 drawable = new ScaleDrawable(); 1042 } else if (name.equals("clip")) { 1043 drawable = new ClipDrawable(); 1044 } else if (name.equals("rotate")) { 1045 drawable = new RotateDrawable(); 1046 } else if (name.equals("animated-rotate")) { 1047 drawable = new AnimatedRotateDrawable(); 1048 } else if (name.equals("animation-list")) { 1049 drawable = new AnimationDrawable(); 1050 } else if (name.equals("inset")) { 1051 drawable = new InsetDrawable(); 1052 } else if (name.equals("bitmap")) { 1053 //noinspection deprecation 1054 drawable = new BitmapDrawable(r); 1055 if (r != null) { 1056 ((BitmapDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 1057 } 1058 } else if (name.equals("nine-patch")) { 1059 drawable = new NinePatchDrawable(); 1060 if (r != null) { 1061 ((NinePatchDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 1062 } 1063 } else { 1064 throw new XmlPullParserException(parser.getPositionDescription() + 1065 ": invalid drawable tag " + name); 1066 } 1067 1068 drawable.inflate(r, parser, attrs, theme); 1069 return drawable; 1070 } 1071 1072 1073 /** 1074 * Create a drawable from file path name. 1075 */ 1076 public static Drawable createFromPath(String pathName) { 1077 if (pathName == null) { 1078 return null; 1079 } 1080 1081 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, pathName); 1082 try { 1083 Bitmap bm = BitmapFactory.decodeFile(pathName); 1084 if (bm != null) { 1085 return drawableFromBitmap(null, bm, null, null, null, pathName); 1086 } 1087 } finally { 1088 Trace.traceEnd(Trace.TRACE_TAG_RESOURCES); 1089 } 1090 1091 return null; 1092 } 1093 1094 /** 1095 * Inflate this Drawable from an XML resource. Does not apply a theme. 1096 * 1097 * @see #inflate(Resources, XmlPullParser, AttributeSet, Theme) 1098 */ 1099 public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs) 1100 throws XmlPullParserException, IOException { 1101 inflate(r, parser, attrs, null); 1102 } 1103 1104 /** 1105 * Inflate this Drawable from an XML resource optionally styled by a theme. 1106 * 1107 * @param r Resources used to resolve attribute values 1108 * @param parser XML parser from which to inflate this Drawable 1109 * @param attrs Base set of attribute values 1110 * @param theme Theme to apply, may be null 1111 * @throws XmlPullParserException 1112 * @throws IOException 1113 */ 1114 public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs, Theme theme) 1115 throws XmlPullParserException, IOException { 1116 final TypedArray a; 1117 if (theme != null) { 1118 a = theme.obtainStyledAttributes( 1119 attrs, com.android.internal.R.styleable.Drawable, 0, 0); 1120 } else { 1121 a = r.obtainAttributes(attrs, com.android.internal.R.styleable.Drawable); 1122 } 1123 1124 inflateWithAttributes(r, parser, a, com.android.internal.R.styleable.Drawable_visible); 1125 a.recycle(); 1126 } 1127 1128 /** 1129 * Inflate a Drawable from an XML resource. 1130 * 1131 * @throws XmlPullParserException 1132 * @throws IOException 1133 */ 1134 void inflateWithAttributes(Resources r, XmlPullParser parser, TypedArray attrs, int visibleAttr) 1135 throws XmlPullParserException, IOException { 1136 mVisible = attrs.getBoolean(visibleAttr, mVisible); 1137 } 1138 1139 /** 1140 * This abstract class is used by {@link Drawable}s to store shared constant state and data 1141 * between Drawables. {@link BitmapDrawable}s created from the same resource will for instance 1142 * share a unique bitmap stored in their ConstantState. 1143 * 1144 * <p> 1145 * {@link #newDrawable(Resources)} can be used as a factory to create new Drawable instances 1146 * from this ConstantState. 1147 * </p> 1148 * 1149 * Use {@link Drawable#getConstantState()} to retrieve the ConstantState of a Drawable. Calling 1150 * {@link Drawable#mutate()} on a Drawable should typically create a new ConstantState for that 1151 * Drawable. 1152 */ 1153 public static abstract class ConstantState { 1154 /** 1155 * Create a new drawable without supplying resources the caller 1156 * is running in. Note that using this means the density-dependent 1157 * drawables (like bitmaps) will not be able to update their target 1158 * density correctly. One should use {@link #newDrawable(Resources)} 1159 * instead to provide a resource. 1160 */ 1161 public abstract Drawable newDrawable(); 1162 1163 /** 1164 * Create a new Drawable instance from its constant state. This 1165 * must be implemented for drawables that change based on the target 1166 * density of their caller (that is depending on whether it is 1167 * in compatibility mode). 1168 */ 1169 public Drawable newDrawable(Resources res) { 1170 return newDrawable(); 1171 } 1172 1173 /** 1174 * Create a new Drawable instance from its constant state. This must be 1175 * implemented for drawables that can have a theme applied. 1176 */ 1177 public Drawable newDrawable(Resources res, Theme theme) { 1178 return newDrawable(); 1179 } 1180 1181 /** 1182 * Return a bit mask of configuration changes that will impact 1183 * this drawable (and thus require completely reloading it). 1184 */ 1185 public abstract int getChangingConfigurations(); 1186 1187 /** 1188 * @hide 1189 */ 1190 public Bitmap getBitmap() { 1191 return null; 1192 } 1193 1194 /** 1195 * Return whether this constant state can have a theme applied. 1196 */ 1197 public boolean canApplyTheme() { 1198 return false; 1199 } 1200 } 1201 1202 /** 1203 * Return a {@link ConstantState} instance that holds the shared state of this Drawable. 1204 * 1205 * @return The ConstantState associated to that Drawable. 1206 * @see ConstantState 1207 * @see Drawable#mutate() 1208 */ 1209 public ConstantState getConstantState() { 1210 return null; 1211 } 1212 1213 private static Drawable drawableFromBitmap(Resources res, Bitmap bm, byte[] np, 1214 Rect pad, Rect layoutBounds, String srcName) { 1215 1216 if (np != null) { 1217 return new NinePatchDrawable(res, bm, np, pad, layoutBounds, srcName); 1218 } 1219 1220 return new BitmapDrawable(res, bm); 1221 } 1222 1223 /** 1224 * Obtains styled attributes from the theme, if available, or unstyled 1225 * resources if the theme is null. 1226 */ 1227 static TypedArray obtainAttributes( 1228 Resources res, Theme theme, AttributeSet set, int[] attrs) { 1229 if (theme == null) { 1230 return res.obtainAttributes(set, attrs); 1231 } 1232 return theme.obtainStyledAttributes(set, attrs, 0, 0); 1233 } 1234 1235 /** 1236 * Parses a {@link android.graphics.PorterDuff.Mode} from a tintMode 1237 * attribute's enum value. 1238 */ 1239 static PorterDuff.Mode parseTintMode(int value, Mode defaultMode) { 1240 switch (value) { 1241 case 3: return Mode.SRC_OVER; 1242 case 5: return Mode.SRC_IN; 1243 case 9: return Mode.SRC_ATOP; 1244 case 14: return Mode.MULTIPLY; 1245 case 15: return Mode.SCREEN; 1246 case 16: return Mode.ADD; 1247 default: return defaultMode; 1248 } 1249 } 1250} 1251 1252