Drawable.java revision f31512eb17b6327c5f81bfb8a69c3a6119a0dd66
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.graphics.Insets; 20import android.graphics.Xfermode; 21import android.os.Trace; 22 23import org.xmlpull.v1.XmlPullParser; 24import org.xmlpull.v1.XmlPullParserException; 25 26import android.content.res.Resources; 27import android.content.res.Resources.Theme; 28import android.content.res.TypedArray; 29import android.graphics.Bitmap; 30import android.graphics.BitmapFactory; 31import android.graphics.Canvas; 32import android.graphics.ColorFilter; 33import android.graphics.NinePatch; 34import android.graphics.Outline; 35import android.graphics.PixelFormat; 36import android.graphics.PorterDuff; 37import android.graphics.PorterDuffColorFilter; 38import android.graphics.Rect; 39import android.graphics.Region; 40import android.graphics.PorterDuff.Mode; 41import android.util.AttributeSet; 42import android.util.DisplayMetrics; 43import android.util.StateSet; 44import android.util.TypedValue; 45import android.util.Xml; 46import android.view.View; 47 48import java.io.IOException; 49import java.io.InputStream; 50import java.lang.ref.WeakReference; 51import java.util.Arrays; 52 53/** 54 * A Drawable is a general abstraction for "something that can be drawn." Most 55 * often you will deal with Drawable as the type of resource retrieved for 56 * drawing things to the screen; the Drawable class provides a generic API for 57 * dealing with an underlying visual resource that may take a variety of forms. 58 * Unlike a {@link android.view.View}, a Drawable does not have any facility to 59 * receive events or otherwise interact with the user. 60 * 61 * <p>In addition to simple drawing, Drawable provides a number of generic 62 * mechanisms for its client to interact with what is being drawn: 63 * 64 * <ul> 65 * <li> The {@link #setBounds} method <var>must</var> be called to tell the 66 * Drawable where it is drawn and how large it should be. All Drawables 67 * should respect the requested size, often simply by scaling their 68 * imagery. A client can find the preferred size for some Drawables with 69 * the {@link #getIntrinsicHeight} and {@link #getIntrinsicWidth} methods. 70 * 71 * <li> The {@link #getPadding} method can return from some Drawables 72 * information about how to frame content that is placed inside of them. 73 * For example, a Drawable that is intended to be the frame for a button 74 * widget would need to return padding that correctly places the label 75 * inside of itself. 76 * 77 * <li> The {@link #setState} method allows the client to tell the Drawable 78 * in which state it is to be drawn, such as "focused", "selected", etc. 79 * Some drawables may modify their imagery based on the selected state. 80 * 81 * <li> The {@link #setLevel} method allows the client to supply a single 82 * continuous controller that can modify the Drawable is displayed, such as 83 * a battery level or progress level. Some drawables may modify their 84 * imagery based on the current level. 85 * 86 * <li> A Drawable can perform animations by calling back to its client 87 * through the {@link Callback} interface. All clients should support this 88 * interface (via {@link #setCallback}) so that animations will work. A 89 * simple way to do this is through the system facilities such as 90 * {@link android.view.View#setBackground(Drawable)} and 91 * {@link android.widget.ImageView}. 92 * </ul> 93 * 94 * Though usually not visible to the application, Drawables may take a variety 95 * of forms: 96 * 97 * <ul> 98 * <li> <b>Bitmap</b>: the simplest Drawable, a PNG or JPEG image. 99 * <li> <b>Nine Patch</b>: an extension to the PNG format allows it to 100 * specify information about how to stretch it and place things inside of 101 * it. 102 * <li> <b>Shape</b>: contains simple drawing commands instead of a raw 103 * bitmap, allowing it to resize better in some cases. 104 * <li> <b>Layers</b>: a compound drawable, which draws multiple underlying 105 * drawables on top of each other. 106 * <li> <b>States</b>: a compound drawable that selects one of a set of 107 * drawables based on its state. 108 * <li> <b>Levels</b>: a compound drawable that selects one of a set of 109 * drawables based on its level. 110 * <li> <b>Scale</b>: a compound drawable with a single child drawable, 111 * whose overall size is modified based on the current level. 112 * </ul> 113 * 114 * <div class="special reference"> 115 * <h3>Developer Guides</h3> 116 * <p>For more information about how to use drawables, read the 117 * <a href="{@docRoot}guide/topics/graphics/2d-graphics.html">Canvas and Drawables</a> developer 118 * guide. For information and examples of creating drawable resources (XML or bitmap files that 119 * can be loaded in code), read the 120 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a> 121 * document.</p></div> 122 */ 123public abstract class Drawable { 124 private static final Rect ZERO_BOUNDS_RECT = new Rect(); 125 126 private int[] mStateSet = StateSet.WILD_CARD; 127 private int mLevel = 0; 128 private int mChangingConfigurations = 0; 129 private Rect mBounds = ZERO_BOUNDS_RECT; // lazily becomes a new Rect() 130 private WeakReference<Callback> mCallback = null; 131 private boolean mVisible = true; 132 133 private int mLayoutDirection; 134 135 /** 136 * Draw in its bounds (set via setBounds) respecting optional effects such 137 * as alpha (set via setAlpha) and color filter (set via setColorFilter). 138 * 139 * @param canvas The canvas to draw into 140 */ 141 public abstract void draw(Canvas canvas); 142 143 /** 144 * Specify a bounding rectangle for the Drawable. This is where the drawable 145 * will draw when its draw() method is called. 146 */ 147 public void setBounds(int left, int top, int right, int bottom) { 148 Rect oldBounds = mBounds; 149 150 if (oldBounds == ZERO_BOUNDS_RECT) { 151 oldBounds = mBounds = new Rect(); 152 } 153 154 if (oldBounds.left != left || oldBounds.top != top || 155 oldBounds.right != right || oldBounds.bottom != bottom) { 156 if (!oldBounds.isEmpty()) { 157 // first invalidate the previous bounds 158 invalidateSelf(); 159 } 160 mBounds.set(left, top, right, bottom); 161 onBoundsChange(mBounds); 162 } 163 } 164 165 /** 166 * Specify a bounding rectangle for the Drawable. This is where the drawable 167 * will draw when its draw() method is called. 168 */ 169 public void setBounds(Rect bounds) { 170 setBounds(bounds.left, bounds.top, bounds.right, bounds.bottom); 171 } 172 173 /** 174 * Return a copy of the drawable's bounds in the specified Rect (allocated 175 * by the caller). The bounds specify where this will draw when its draw() 176 * method is called. 177 * 178 * @param bounds Rect to receive the drawable's bounds (allocated by the 179 * caller). 180 */ 181 public final void copyBounds(Rect bounds) { 182 bounds.set(mBounds); 183 } 184 185 /** 186 * Return a copy of the drawable's bounds in a new Rect. This returns the 187 * same values as getBounds(), but the returned object is guaranteed to not 188 * be changed later by the drawable (i.e. it retains no reference to this 189 * rect). If the caller already has a Rect allocated, call copyBounds(rect). 190 * 191 * @return A copy of the drawable's bounds 192 */ 193 public final Rect copyBounds() { 194 return new Rect(mBounds); 195 } 196 197 /** 198 * Return the drawable's bounds Rect. Note: for efficiency, the returned 199 * object may be the same object stored in the drawable (though this is not 200 * guaranteed), so if a persistent copy of the bounds is needed, call 201 * copyBounds(rect) instead. 202 * You should also not change the object returned by this method as it may 203 * be the same object stored in the drawable. 204 * 205 * @return The bounds of the drawable (which may change later, so caller 206 * beware). DO NOT ALTER the returned object as it may change the 207 * stored bounds of this drawable. 208 * 209 * @see #copyBounds() 210 * @see #copyBounds(android.graphics.Rect) 211 */ 212 public final Rect getBounds() { 213 if (mBounds == ZERO_BOUNDS_RECT) { 214 mBounds = new Rect(); 215 } 216 217 return mBounds; 218 } 219 220 /** 221 * Return the drawable's dirty bounds Rect. Note: for efficiency, the 222 * returned object may be the same object stored in the drawable (though 223 * this is not guaranteed). 224 * <p> 225 * By default, this returns the full drawable bounds. Custom drawables may 226 * override this method to perform more precise invalidation. 227 * 228 * @hide 229 */ 230 public Rect getDirtyBounds() { 231 return getBounds(); 232 } 233 234 /** 235 * Set a mask of the configuration parameters for which this drawable 236 * may change, requiring that it be re-created. 237 * 238 * @param configs A mask of the changing configuration parameters, as 239 * defined by {@link android.content.res.Configuration}. 240 * 241 * @see android.content.res.Configuration 242 */ 243 public void setChangingConfigurations(int configs) { 244 mChangingConfigurations = configs; 245 } 246 247 /** 248 * Return a mask of the configuration parameters for which this drawable 249 * may change, requiring that it be re-created. The default implementation 250 * returns whatever was provided through 251 * {@link #setChangingConfigurations(int)} or 0 by default. Subclasses 252 * may extend this to or in the changing configurations of any other 253 * drawables they hold. 254 * 255 * @return Returns a mask of the changing configuration parameters, as 256 * defined by {@link android.content.res.Configuration}. 257 * 258 * @see android.content.res.Configuration 259 */ 260 public int getChangingConfigurations() { 261 return mChangingConfigurations; 262 } 263 264 /** 265 * Set to true to have the drawable dither its colors when drawn to a device 266 * with fewer than 8-bits per color component. This can improve the look on 267 * those devices, but can also slow down the drawing a little. 268 */ 269 public void setDither(boolean dither) {} 270 271 /** 272 * Set to true to have the drawable filter its bitmap when scaled or rotated 273 * (for drawables that use bitmaps). If the drawable does not use bitmaps, 274 * this call is ignored. This can improve the look when scaled or rotated, 275 * but also slows down the drawing. 276 */ 277 public void setFilterBitmap(boolean filter) {} 278 279 /** 280 * Implement this interface if you want to create an animated drawable that 281 * extends {@link android.graphics.drawable.Drawable Drawable}. 282 * Upon retrieving a drawable, use 283 * {@link Drawable#setCallback(android.graphics.drawable.Drawable.Callback)} 284 * to supply your implementation of the interface to the drawable; it uses 285 * this interface to schedule and execute animation changes. 286 */ 287 public static interface Callback { 288 /** 289 * Called when the drawable needs to be redrawn. A view at this point 290 * should invalidate itself (or at least the part of itself where the 291 * drawable appears). 292 * 293 * @param who The drawable that is requesting the update. 294 */ 295 public void invalidateDrawable(Drawable who); 296 297 /** 298 * A Drawable can call this to schedule the next frame of its 299 * animation. An implementation can generally simply call 300 * {@link android.os.Handler#postAtTime(Runnable, Object, long)} with 301 * the parameters <var>(what, who, when)</var> to perform the 302 * scheduling. 303 * 304 * @param who The drawable being scheduled. 305 * @param what The action to execute. 306 * @param when The time (in milliseconds) to run. The timebase is 307 * {@link android.os.SystemClock#uptimeMillis} 308 */ 309 public void scheduleDrawable(Drawable who, Runnable what, long when); 310 311 /** 312 * A Drawable can call this to unschedule an action previously 313 * scheduled with {@link #scheduleDrawable}. An implementation can 314 * generally simply call 315 * {@link android.os.Handler#removeCallbacks(Runnable, Object)} with 316 * the parameters <var>(what, who)</var> to unschedule the drawable. 317 * 318 * @param who The drawable being unscheduled. 319 * @param what The action being unscheduled. 320 */ 321 public void unscheduleDrawable(Drawable who, Runnable what); 322 } 323 324 /** 325 * Bind a {@link Callback} object to this Drawable. Required for clients 326 * that want to support animated drawables. 327 * 328 * @param cb The client's Callback implementation. 329 * 330 * @see #getCallback() 331 */ 332 public final void setCallback(Callback cb) { 333 mCallback = new WeakReference<Callback>(cb); 334 } 335 336 /** 337 * Return the current {@link Callback} implementation attached to this 338 * Drawable. 339 * 340 * @return A {@link Callback} instance or null if no callback was set. 341 * 342 * @see #setCallback(android.graphics.drawable.Drawable.Callback) 343 */ 344 public Callback getCallback() { 345 if (mCallback != null) { 346 return mCallback.get(); 347 } 348 return null; 349 } 350 351 /** 352 * Use the current {@link Callback} implementation to have this Drawable 353 * redrawn. Does nothing if there is no Callback attached to the 354 * Drawable. 355 * 356 * @see Callback#invalidateDrawable 357 * @see #getCallback() 358 * @see #setCallback(android.graphics.drawable.Drawable.Callback) 359 */ 360 public void invalidateSelf() { 361 final Callback callback = getCallback(); 362 if (callback != null) { 363 callback.invalidateDrawable(this); 364 } 365 } 366 367 /** 368 * Use the current {@link Callback} implementation to have this Drawable 369 * scheduled. Does nothing if there is no Callback attached to the 370 * Drawable. 371 * 372 * @param what The action being scheduled. 373 * @param when The time (in milliseconds) to run. 374 * 375 * @see Callback#scheduleDrawable 376 */ 377 public void scheduleSelf(Runnable what, long when) { 378 final Callback callback = getCallback(); 379 if (callback != null) { 380 callback.scheduleDrawable(this, what, when); 381 } 382 } 383 384 /** 385 * Use the current {@link Callback} implementation to have this Drawable 386 * unscheduled. Does nothing if there is no Callback attached to the 387 * Drawable. 388 * 389 * @param what The runnable that you no longer want called. 390 * 391 * @see Callback#unscheduleDrawable 392 */ 393 public void unscheduleSelf(Runnable what) { 394 final Callback callback = getCallback(); 395 if (callback != null) { 396 callback.unscheduleDrawable(this, what); 397 } 398 } 399 400 /** 401 * Returns the resolved layout direction for this Drawable. 402 * 403 * @return One of {@link android.view.View#LAYOUT_DIRECTION_LTR}, 404 * {@link android.view.View#LAYOUT_DIRECTION_RTL} 405 * 406 * @hide 407 */ 408 public int getLayoutDirection() { 409 return mLayoutDirection; 410 } 411 412 /** 413 * Set the layout direction for this drawable. Should be a resolved direction as the 414 * Drawable as no capacity to do the resolution on his own. 415 * 416 * @param layoutDirection One of {@link android.view.View#LAYOUT_DIRECTION_LTR}, 417 * {@link android.view.View#LAYOUT_DIRECTION_RTL} 418 * 419 * @hide 420 */ 421 public void setLayoutDirection(@View.ResolvedLayoutDir int layoutDirection) { 422 if (getLayoutDirection() != layoutDirection) { 423 mLayoutDirection = layoutDirection; 424 } 425 } 426 427 /** 428 * Specify an alpha value for the drawable. 0 means fully transparent, and 429 * 255 means fully opaque. 430 */ 431 public abstract void setAlpha(int alpha); 432 433 /** 434 * Gets the current alpha value for the drawable. 0 means fully transparent, 435 * 255 means fully opaque. This method is implemented by 436 * Drawable subclasses and the value returned is specific to how that class treats alpha. 437 * The default return value is 255 if the class does not override this method to return a value 438 * specific to its use of alpha. 439 */ 440 public int getAlpha() { 441 return 0xFF; 442 } 443 444 /** 445 * @hide Consider for future API inclusion 446 */ 447 public void setXfermode(Xfermode mode) { 448 // Base implementation drops it on the floor for compatibility. Whee! 449 // TODO: For this to be included in the API proper, all framework drawables need impls. 450 // For right now only BitmapDrawable has it. 451 } 452 453 /** 454 * Specify an optional color filter for the drawable. Pass {@code null} to 455 * remove any existing color filter. 456 * 457 * @param cf the color filter to apply, or {@code null} to remove the 458 * existing color filter 459 */ 460 public abstract void setColorFilter(ColorFilter cf); 461 462 /** 463 * Specify a color and Porter-Duff mode to be the color filter for this 464 * drawable. 465 */ 466 public void setColorFilter(int color, PorterDuff.Mode mode) { 467 setColorFilter(new PorterDuffColorFilter(color, mode)); 468 } 469 470 /** 471 * Returns the current color filter, or {@code null} if none set. 472 * 473 * @return the current color filter, or {@code null} if none set 474 */ 475 public ColorFilter getColorFilter() { 476 return null; 477 } 478 479 /** 480 * Removes the color filter for this drawable. 481 */ 482 public void clearColorFilter() { 483 setColorFilter(null); 484 } 485 486 /** 487 * Specifies the hotspot's location within the drawable. 488 * 489 * @param x The X coordinate of the center of the hotspot 490 * @param y The Y coordinate of the center of the hotspot 491 */ 492 public void setHotspot(float x, float y) {} 493 494 /** 495 * Sets the bounds to which the hotspot is constrained, if they should be 496 * different from the drawable bounds. 497 * 498 * @param left 499 * @param top 500 * @param right 501 * @param bottom 502 */ 503 public void setHotspotBounds(int left, int top, int right, int bottom) {} 504 505 /** 506 * Whether this drawable requests projection. 507 * 508 * @hide magic! 509 */ 510 public boolean isProjected() { 511 return false; 512 } 513 514 /** 515 * Indicates whether this view will change its appearance based on state. 516 * Clients can use this to determine whether it is necessary to calculate 517 * their state and call setState. 518 * 519 * @return True if this view changes its appearance based on state, false 520 * otherwise. 521 * 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). Returns true if this drawable 821 * actually has a padding, else false. When false is returned, the padding 822 * is always set to 0. 823 */ 824 public boolean getPadding(Rect padding) { 825 padding.set(0, 0, 0, 0); 826 return false; 827 } 828 829 /** 830 * Return in insets the layout insets suggested by this Drawable for use with alignment 831 * operations during layout. 832 * 833 * @hide 834 */ 835 public Insets getOpticalInsets() { 836 return Insets.NONE; 837 } 838 839 /** 840 * Called to get the drawable to populate the Outline. 841 * <p> 842 * This method will be called by a View on its background Drawable after bounds change, or its 843 * Drawable is invalidated, if the View's Outline isn't set explicitly. This allows the 844 * background Drawable to define the shape of the shadow cast by the View. 845 * 846 * The default behavior defines the outline to be the bounding rectangle. Subclasses that wish 847 * to convey a different shape must override this method. 848 * 849 * @see View#setOutline(android.graphics.Outline) 850 */ 851 public boolean getOutline(Outline outline) { 852 outline.setRect(getBounds()); 853 return true; 854 } 855 856 /** 857 * Make this drawable mutable. This operation cannot be reversed. A mutable 858 * drawable is guaranteed to not share its state with any other drawable. 859 * This is especially useful when you need to modify properties of drawables 860 * loaded from resources. By default, all drawables instances loaded from 861 * the same resource share a common state; if you modify the state of one 862 * instance, all the other instances will receive the same modification. 863 * 864 * Calling this method on a mutable Drawable will have no effect. 865 * 866 * @return This drawable. 867 * @see ConstantState 868 * @see #getConstantState() 869 */ 870 public Drawable mutate() { 871 return this; 872 } 873 874 /** 875 * Create a drawable from an inputstream 876 */ 877 public static Drawable createFromStream(InputStream is, String srcName) { 878 return createFromStreamThemed(is, srcName, null); 879 } 880 881 public static Drawable createFromStreamThemed(InputStream is, String srcName, Theme theme) { 882 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, srcName != null ? srcName : "Unknown drawable"); 883 try { 884 return createFromResourceStreamThemed(null, null, is, srcName, theme); 885 } finally { 886 Trace.traceEnd(Trace.TRACE_TAG_RESOURCES); 887 } 888 } 889 890 /** 891 * Create a drawable from an inputstream, using the given resources and 892 * value to determine density information. 893 */ 894 public static Drawable createFromResourceStream(Resources res, TypedValue value, 895 InputStream is, String srcName) { 896 return createFromResourceStreamThemed(res, value, is, srcName, null); 897 } 898 899 public static Drawable createFromResourceStreamThemed(Resources res, TypedValue value, 900 InputStream is, String srcName, Theme theme) { 901 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, srcName != null ? srcName : "Unknown drawable"); 902 try { 903 return createFromResourceStreamThemed(res, value, is, srcName, null, theme); 904 } finally { 905 Trace.traceEnd(Trace.TRACE_TAG_RESOURCES); 906 } 907 } 908 909 /** 910 * Create a drawable from an inputstream, using the given resources and 911 * value to determine density information. 912 */ 913 public static Drawable createFromResourceStream(Resources res, TypedValue value, 914 InputStream is, String srcName, BitmapFactory.Options opts) { 915 return createFromResourceStreamThemed(res, value, is, srcName, opts, null); 916 } 917 918 public static Drawable createFromResourceStreamThemed(Resources res, TypedValue value, 919 InputStream is, String srcName, BitmapFactory.Options opts, Theme theme) { 920 if (is == null) { 921 return null; 922 } 923 924 /* ugh. The decodeStream contract is that we have already allocated 925 the pad rect, but if the bitmap does not had a ninepatch chunk, 926 then the pad will be ignored. If we could change this to lazily 927 alloc/assign the rect, we could avoid the GC churn of making new 928 Rects only to drop them on the floor. 929 */ 930 Rect pad = new Rect(); 931 932 // Special stuff for compatibility mode: if the target density is not 933 // the same as the display density, but the resource -is- the same as 934 // the display density, then don't scale it down to the target density. 935 // This allows us to load the system's density-correct resources into 936 // an application in compatibility mode, without scaling those down 937 // to the compatibility density only to have them scaled back up when 938 // drawn to the screen. 939 if (opts == null) opts = new BitmapFactory.Options(); 940 opts.inScreenDensity = res != null 941 ? res.getDisplayMetrics().noncompatDensityDpi : DisplayMetrics.DENSITY_DEVICE; 942 Bitmap bm = BitmapFactory.decodeResourceStream(res, value, is, pad, opts); 943 if (bm != null) { 944 byte[] np = bm.getNinePatchChunk(); 945 if (np == null || !NinePatch.isNinePatchChunk(np)) { 946 np = null; 947 pad = null; 948 } 949 int[] layoutBounds = bm.getLayoutBounds(); 950 Rect layoutBoundsRect = null; 951 if (layoutBounds != null) { 952 layoutBoundsRect = new Rect(layoutBounds[0], layoutBounds[1], 953 layoutBounds[2], layoutBounds[3]); 954 } 955 return drawableFromBitmap(res, bm, np, pad, layoutBoundsRect, srcName); 956 } 957 return null; 958 } 959 960 /** 961 * Create a drawable from an XML document. For more information on how to 962 * create resources in XML, see 963 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. 964 */ 965 public static Drawable createFromXml(Resources r, XmlPullParser parser) 966 throws XmlPullParserException, IOException { 967 return createFromXmlThemed(r, parser, null); 968 } 969 970 /** 971 * Create a themed drawable from an XML document. For more information on 972 * how to create resources in XML, see 973 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. 974 */ 975 public static Drawable createFromXmlThemed(Resources r, XmlPullParser parser, Theme theme) 976 throws XmlPullParserException, IOException { 977 AttributeSet attrs = Xml.asAttributeSet(parser); 978 979 int type; 980 while ((type=parser.next()) != XmlPullParser.START_TAG && 981 type != XmlPullParser.END_DOCUMENT) { 982 // Empty loop 983 } 984 985 if (type != XmlPullParser.START_TAG) { 986 throw new XmlPullParserException("No start tag found"); 987 } 988 989 Drawable drawable = createFromXmlInnerThemed(r, parser, attrs, theme); 990 991 if (drawable == null) { 992 throw new RuntimeException("Unknown initial tag: " + parser.getName()); 993 } 994 995 return drawable; 996 } 997 998 /** 999 * Create from inside an XML document. Called on a parser positioned at 1000 * a tag in an XML document, tries to create a Drawable from that tag. 1001 * Returns null if the tag is not a valid drawable. 1002 */ 1003 public static Drawable createFromXmlInner(Resources r, XmlPullParser parser, AttributeSet attrs) 1004 throws XmlPullParserException, IOException { 1005 return createFromXmlInnerThemed(r, parser, attrs, null); 1006 } 1007 1008 /** 1009 * Create a themed drawable from inside an XML document. Called on a parser 1010 * positioned at a tag in an XML document, tries to create a Drawable from 1011 * that tag. Returns null if the tag is not a valid drawable. 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