Drawable.java revision 52b999f0721b53e9c6e18a4bd664e89aeb65b2d5
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 /** 125 * Hotspot identifier mask for tracking touch points. 126 * 127 * @hide until hotspot APIs are finalized 128 */ 129 public static final int HOTSPOT_TOUCH_MASK = 0xFF; 130 131 /** 132 * Hotspot identifier for tracking keyboard focus. 133 * 134 * @hide until hotspot APIs are finalized 135 */ 136 public static final int HOTSPOT_FOCUS = 0x100; 137 138 private static final Rect ZERO_BOUNDS_RECT = new Rect(); 139 140 private int[] mStateSet = StateSet.WILD_CARD; 141 private int mLevel = 0; 142 private int mChangingConfigurations = 0; 143 private Rect mBounds = ZERO_BOUNDS_RECT; // lazily becomes a new Rect() 144 private WeakReference<Callback> mCallback = null; 145 private boolean mVisible = true; 146 147 private int mLayoutDirection; 148 149 /** 150 * Draw in its bounds (set via setBounds) respecting optional effects such 151 * as alpha (set via setAlpha) and color filter (set via setColorFilter). 152 * 153 * @param canvas The canvas to draw into 154 */ 155 public abstract void draw(Canvas canvas); 156 157 /** 158 * Specify a bounding rectangle for the Drawable. This is where the drawable 159 * will draw when its draw() method is called. 160 */ 161 public void setBounds(int left, int top, int right, int bottom) { 162 Rect oldBounds = mBounds; 163 164 if (oldBounds == ZERO_BOUNDS_RECT) { 165 oldBounds = mBounds = new Rect(); 166 } 167 168 if (oldBounds.left != left || oldBounds.top != top || 169 oldBounds.right != right || oldBounds.bottom != bottom) { 170 if (!oldBounds.isEmpty()) { 171 // first invalidate the previous bounds 172 invalidateSelf(); 173 } 174 mBounds.set(left, top, right, bottom); 175 onBoundsChange(mBounds); 176 } 177 } 178 179 /** 180 * Specify a bounding rectangle for the Drawable. This is where the drawable 181 * will draw when its draw() method is called. 182 */ 183 public void setBounds(Rect bounds) { 184 setBounds(bounds.left, bounds.top, bounds.right, bounds.bottom); 185 } 186 187 /** 188 * Return a copy of the drawable's bounds in the specified Rect (allocated 189 * by the caller). The bounds specify where this will draw when its draw() 190 * method is called. 191 * 192 * @param bounds Rect to receive the drawable's bounds (allocated by the 193 * caller). 194 */ 195 public final void copyBounds(Rect bounds) { 196 bounds.set(mBounds); 197 } 198 199 /** 200 * Return a copy of the drawable's bounds in a new Rect. This returns the 201 * same values as getBounds(), but the returned object is guaranteed to not 202 * be changed later by the drawable (i.e. it retains no reference to this 203 * rect). If the caller already has a Rect allocated, call copyBounds(rect). 204 * 205 * @return A copy of the drawable's bounds 206 */ 207 public final Rect copyBounds() { 208 return new Rect(mBounds); 209 } 210 211 /** 212 * Return the drawable's bounds Rect. Note: for efficiency, the returned 213 * object may be the same object stored in the drawable (though this is not 214 * guaranteed), so if a persistent copy of the bounds is needed, call 215 * copyBounds(rect) instead. 216 * You should also not change the object returned by this method as it may 217 * be the same object stored in the drawable. 218 * 219 * @return The bounds of the drawable (which may change later, so caller 220 * beware). DO NOT ALTER the returned object as it may change the 221 * stored bounds of this drawable. 222 * 223 * @see #copyBounds() 224 * @see #copyBounds(android.graphics.Rect) 225 */ 226 public final Rect getBounds() { 227 if (mBounds == ZERO_BOUNDS_RECT) { 228 mBounds = new Rect(); 229 } 230 231 return mBounds; 232 } 233 234 /** 235 * Return the drawable's dirty bounds Rect. Note: for efficiency, the 236 * returned object may be the same object stored in the drawable (though 237 * this is not guaranteed). 238 * <p> 239 * By default, this returns the full drawable bounds. Custom drawables may 240 * override this method to perform more precise invalidation. 241 * 242 * @hide 243 */ 244 public Rect getDirtyBounds() { 245 return getBounds(); 246 } 247 248 /** 249 * Set a mask of the configuration parameters for which this drawable 250 * may change, requiring that it be re-created. 251 * 252 * @param configs A mask of the changing configuration parameters, as 253 * defined by {@link android.content.res.Configuration}. 254 * 255 * @see android.content.res.Configuration 256 */ 257 public void setChangingConfigurations(int configs) { 258 mChangingConfigurations = configs; 259 } 260 261 /** 262 * Return a mask of the configuration parameters for which this drawable 263 * may change, requiring that it be re-created. The default implementation 264 * returns whatever was provided through 265 * {@link #setChangingConfigurations(int)} or 0 by default. Subclasses 266 * may extend this to or in the changing configurations of any other 267 * drawables they hold. 268 * 269 * @return Returns a mask of the changing configuration parameters, as 270 * defined by {@link android.content.res.Configuration}. 271 * 272 * @see android.content.res.Configuration 273 */ 274 public int getChangingConfigurations() { 275 return mChangingConfigurations; 276 } 277 278 /** 279 * Set to true to have the drawable dither its colors when drawn to a device 280 * with fewer than 8-bits per color component. This can improve the look on 281 * those devices, but can also slow down the drawing a little. 282 */ 283 public void setDither(boolean dither) {} 284 285 /** 286 * Set to true to have the drawable filter its bitmap when scaled or rotated 287 * (for drawables that use bitmaps). If the drawable does not use bitmaps, 288 * this call is ignored. This can improve the look when scaled or rotated, 289 * but also slows down the drawing. 290 */ 291 public void setFilterBitmap(boolean filter) {} 292 293 /** 294 * Implement this interface if you want to create an animated drawable that 295 * extends {@link android.graphics.drawable.Drawable Drawable}. 296 * Upon retrieving a drawable, use 297 * {@link Drawable#setCallback(android.graphics.drawable.Drawable.Callback)} 298 * to supply your implementation of the interface to the drawable; it uses 299 * this interface to schedule and execute animation changes. 300 */ 301 public static interface Callback { 302 /** 303 * Called when the drawable needs to be redrawn. A view at this point 304 * should invalidate itself (or at least the part of itself where the 305 * drawable appears). 306 * 307 * @param who The drawable that is requesting the update. 308 */ 309 public void invalidateDrawable(Drawable who); 310 311 /** 312 * A Drawable can call this to schedule the next frame of its 313 * animation. An implementation can generally simply call 314 * {@link android.os.Handler#postAtTime(Runnable, Object, long)} with 315 * the parameters <var>(what, who, when)</var> to perform the 316 * scheduling. 317 * 318 * @param who The drawable being scheduled. 319 * @param what The action to execute. 320 * @param when The time (in milliseconds) to run. The timebase is 321 * {@link android.os.SystemClock#uptimeMillis} 322 */ 323 public void scheduleDrawable(Drawable who, Runnable what, long when); 324 325 /** 326 * A Drawable can call this to unschedule an action previously 327 * scheduled with {@link #scheduleDrawable}. An implementation can 328 * generally simply call 329 * {@link android.os.Handler#removeCallbacks(Runnable, Object)} with 330 * the parameters <var>(what, who)</var> to unschedule the drawable. 331 * 332 * @param who The drawable being unscheduled. 333 * @param what The action being unscheduled. 334 */ 335 public void unscheduleDrawable(Drawable who, Runnable what); 336 } 337 338 /** 339 * Bind a {@link Callback} object to this Drawable. Required for clients 340 * that want to support animated drawables. 341 * 342 * @param cb The client's Callback implementation. 343 * 344 * @see #getCallback() 345 */ 346 public final void setCallback(Callback cb) { 347 mCallback = new WeakReference<Callback>(cb); 348 } 349 350 /** 351 * Return the current {@link Callback} implementation attached to this 352 * Drawable. 353 * 354 * @return A {@link Callback} instance or null if no callback was set. 355 * 356 * @see #setCallback(android.graphics.drawable.Drawable.Callback) 357 */ 358 public Callback getCallback() { 359 if (mCallback != null) { 360 return mCallback.get(); 361 } 362 return null; 363 } 364 365 /** 366 * Use the current {@link Callback} implementation to have this Drawable 367 * redrawn. Does nothing if there is no Callback attached to the 368 * Drawable. 369 * 370 * @see Callback#invalidateDrawable 371 * @see #getCallback() 372 * @see #setCallback(android.graphics.drawable.Drawable.Callback) 373 */ 374 public void invalidateSelf() { 375 final Callback callback = getCallback(); 376 if (callback != null) { 377 callback.invalidateDrawable(this); 378 } 379 } 380 381 /** 382 * Use the current {@link Callback} implementation to have this Drawable 383 * scheduled. Does nothing if there is no Callback attached to the 384 * Drawable. 385 * 386 * @param what The action being scheduled. 387 * @param when The time (in milliseconds) to run. 388 * 389 * @see Callback#scheduleDrawable 390 */ 391 public void scheduleSelf(Runnable what, long when) { 392 final Callback callback = getCallback(); 393 if (callback != null) { 394 callback.scheduleDrawable(this, what, when); 395 } 396 } 397 398 /** 399 * Use the current {@link Callback} implementation to have this Drawable 400 * unscheduled. Does nothing if there is no Callback attached to the 401 * Drawable. 402 * 403 * @param what The runnable that you no longer want called. 404 * 405 * @see Callback#unscheduleDrawable 406 */ 407 public void unscheduleSelf(Runnable what) { 408 final Callback callback = getCallback(); 409 if (callback != null) { 410 callback.unscheduleDrawable(this, what); 411 } 412 } 413 414 /** 415 * Returns the resolved layout direction for this Drawable. 416 * 417 * @return One of {@link android.view.View#LAYOUT_DIRECTION_LTR}, 418 * {@link android.view.View#LAYOUT_DIRECTION_RTL} 419 * 420 * @hide 421 */ 422 public int getLayoutDirection() { 423 return mLayoutDirection; 424 } 425 426 /** 427 * Set the layout direction for this drawable. Should be a resolved direction as the 428 * Drawable as no capacity to do the resolution on his own. 429 * 430 * @param layoutDirection One of {@link android.view.View#LAYOUT_DIRECTION_LTR}, 431 * {@link android.view.View#LAYOUT_DIRECTION_RTL} 432 * 433 * @hide 434 */ 435 public void setLayoutDirection(@View.ResolvedLayoutDir int layoutDirection) { 436 if (getLayoutDirection() != layoutDirection) { 437 mLayoutDirection = layoutDirection; 438 } 439 } 440 441 /** 442 * Specify an alpha value for the drawable. 0 means fully transparent, and 443 * 255 means fully opaque. 444 */ 445 public abstract void setAlpha(int alpha); 446 447 /** 448 * Gets the current alpha value for the drawable. 0 means fully transparent, 449 * 255 means fully opaque. This method is implemented by 450 * Drawable subclasses and the value returned is specific to how that class treats alpha. 451 * The default return value is 255 if the class does not override this method to return a value 452 * specific to its use of alpha. 453 */ 454 public int getAlpha() { 455 return 0xFF; 456 } 457 458 /** 459 * @hide Consider for future API inclusion 460 */ 461 public void setXfermode(Xfermode mode) { 462 // Base implementation drops it on the floor for compatibility. Whee! 463 // TODO: For this to be included in the API proper, all framework drawables need impls. 464 // For right now only BitmapDrawable has it. 465 } 466 467 /** 468 * Specify an optional color filter for the drawable. Pass {@code null} to 469 * remove any existing color filter. 470 * 471 * @param cf the color filter to apply, or {@code null} to remove the 472 * existing color filter 473 */ 474 public abstract void setColorFilter(ColorFilter cf); 475 476 /** 477 * Specify a color and Porter-Duff mode to be the color filter for this 478 * drawable. 479 */ 480 public void setColorFilter(int color, PorterDuff.Mode mode) { 481 setColorFilter(new PorterDuffColorFilter(color, mode)); 482 } 483 484 /** 485 * Returns the current color filter, or {@code null} if none set. 486 * 487 * @return the current color filter, or {@code null} if none set 488 */ 489 public ColorFilter getColorFilter() { 490 return null; 491 } 492 493 /** 494 * Removes the color filter for this drawable. 495 */ 496 public void clearColorFilter() { 497 setColorFilter(null); 498 } 499 500 /** 501 * Indicates whether the drawable supports hotspots. Hotspots are uniquely 502 * identifiable coordinates the may be added, updated and removed within the 503 * drawable. 504 * 505 * @return true if hotspots are supported 506 * @see #setHotspot(int, float, float) 507 * @see #removeHotspot(int) 508 * @see #clearHotspots() 509 * @hide until hotspot APIs are finalized 510 */ 511 public boolean supportsHotspots() { 512 return false; 513 } 514 515 /** 516 * Specifies a hotspot's location within the drawable. 517 * 518 * @param id unique identifier for the hotspot 519 * @param x x-coordinate 520 * @param y y-coordinate 521 * @hide until hotspot APIs are finalized 522 */ 523 public void setHotspot(int id, float x, float y) {} 524 525 /** 526 * Removes the specified hotspot from the drawable. 527 * 528 * @param id unique identifier for the hotspot 529 * @hide until hotspot APIs are finalized 530 */ 531 public void removeHotspot(int id) {} 532 533 /** 534 * Removes all hotspots from the drawable. 535 * 536 * @hide until hotspot APIs are finalized 537 */ 538 public void clearHotspots() {} 539 540 /** 541 * Whether this drawable requests projection. 542 * 543 * @hide 544 */ 545 public boolean isProjected() { 546 return false; 547 } 548 549 /** 550 * Indicates whether this view will change its appearance based on state. 551 * Clients can use this to determine whether it is necessary to calculate 552 * their state and call setState. 553 * 554 * @return True if this view changes its appearance based on state, false 555 * otherwise. 556 * 557 * @see #setState(int[]) 558 */ 559 public boolean isStateful() { 560 return false; 561 } 562 563 /** 564 * Specify a set of states for the drawable. These are use-case specific, 565 * so see the relevant documentation. As an example, the background for 566 * widgets like Button understand the following states: 567 * [{@link android.R.attr#state_focused}, 568 * {@link android.R.attr#state_pressed}]. 569 * 570 * <p>If the new state you are supplying causes the appearance of the 571 * Drawable to change, then it is responsible for calling 572 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 573 * true will be returned from this function. 574 * 575 * <p>Note: The Drawable holds a reference on to <var>stateSet</var> 576 * until a new state array is given to it, so you must not modify this 577 * array during that time.</p> 578 * 579 * @param stateSet The new set of states to be displayed. 580 * 581 * @return Returns true if this change in state has caused the appearance 582 * of the Drawable to change (hence requiring an invalidate), otherwise 583 * returns false. 584 */ 585 public boolean setState(final int[] stateSet) { 586 if (!Arrays.equals(mStateSet, stateSet)) { 587 mStateSet = stateSet; 588 return onStateChange(stateSet); 589 } 590 return false; 591 } 592 593 /** 594 * Describes the current state, as a union of primitve states, such as 595 * {@link android.R.attr#state_focused}, 596 * {@link android.R.attr#state_selected}, etc. 597 * Some drawables may modify their imagery based on the selected state. 598 * @return An array of resource Ids describing the current state. 599 */ 600 public int[] getState() { 601 return mStateSet; 602 } 603 604 /** 605 * If this Drawable does transition animations between states, ask that 606 * it immediately jump to the current state and skip any active animations. 607 */ 608 public void jumpToCurrentState() { 609 } 610 611 /** 612 * @return The current drawable that will be used by this drawable. For simple drawables, this 613 * is just the drawable itself. For drawables that change state like 614 * {@link StateListDrawable} and {@link LevelListDrawable} this will be the child drawable 615 * currently in use. 616 */ 617 public Drawable getCurrent() { 618 return this; 619 } 620 621 /** 622 * Specify the level for the drawable. This allows a drawable to vary its 623 * imagery based on a continuous controller, for example to show progress 624 * or volume level. 625 * 626 * <p>If the new level you are supplying causes the appearance of the 627 * Drawable to change, then it is responsible for calling 628 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 629 * true will be returned from this function. 630 * 631 * @param level The new level, from 0 (minimum) to 10000 (maximum). 632 * 633 * @return Returns true if this change in level has caused the appearance 634 * of the Drawable to change (hence requiring an invalidate), otherwise 635 * returns false. 636 */ 637 public final boolean setLevel(int level) { 638 if (mLevel != level) { 639 mLevel = level; 640 return onLevelChange(level); 641 } 642 return false; 643 } 644 645 /** 646 * Retrieve the current level. 647 * 648 * @return int Current level, from 0 (minimum) to 10000 (maximum). 649 */ 650 public final int getLevel() { 651 return mLevel; 652 } 653 654 /** 655 * Set whether this Drawable is visible. This generally does not impact 656 * the Drawable's behavior, but is a hint that can be used by some 657 * Drawables, for example, to decide whether run animations. 658 * 659 * @param visible Set to true if visible, false if not. 660 * @param restart You can supply true here to force the drawable to behave 661 * as if it has just become visible, even if it had last 662 * been set visible. Used for example to force animations 663 * to restart. 664 * 665 * @return boolean Returns true if the new visibility is different than 666 * its previous state. 667 */ 668 public boolean setVisible(boolean visible, boolean restart) { 669 boolean changed = mVisible != visible; 670 if (changed) { 671 mVisible = visible; 672 invalidateSelf(); 673 } 674 return changed; 675 } 676 677 public final boolean isVisible() { 678 return mVisible; 679 } 680 681 /** 682 * Set whether this Drawable is automatically mirrored when its layout direction is RTL 683 * (right-to left). See {@link android.util.LayoutDirection}. 684 * 685 * @param mirrored Set to true if the Drawable should be mirrored, false if not. 686 */ 687 public void setAutoMirrored(boolean mirrored) { 688 } 689 690 /** 691 * Tells if this Drawable will be automatically mirrored when its layout direction is RTL 692 * right-to-left. See {@link android.util.LayoutDirection}. 693 * 694 * @return boolean Returns true if this Drawable will be automatically mirrored. 695 */ 696 public boolean isAutoMirrored() { 697 return false; 698 } 699 700 /** 701 * Applies the specified theme to this Drawable and its children. 702 */ 703 public void applyTheme(@SuppressWarnings("unused") Theme t) { 704 } 705 706 public boolean canApplyTheme() { 707 return false; 708 } 709 710 /** 711 * Return the opacity/transparency of this Drawable. The returned value is 712 * one of the abstract format constants in 713 * {@link android.graphics.PixelFormat}: 714 * {@link android.graphics.PixelFormat#UNKNOWN}, 715 * {@link android.graphics.PixelFormat#TRANSLUCENT}, 716 * {@link android.graphics.PixelFormat#TRANSPARENT}, or 717 * {@link android.graphics.PixelFormat#OPAQUE}. 718 * 719 * <p>Generally a Drawable should be as conservative as possible with the 720 * value it returns. For example, if it contains multiple child drawables 721 * and only shows one of them at a time, if only one of the children is 722 * TRANSLUCENT and the others are OPAQUE then TRANSLUCENT should be 723 * returned. You can use the method {@link #resolveOpacity} to perform a 724 * standard reduction of two opacities to the appropriate single output. 725 * 726 * <p>Note that the returned value does <em>not</em> take into account a 727 * custom alpha or color filter that has been applied by the client through 728 * the {@link #setAlpha} or {@link #setColorFilter} methods. 729 * 730 * @return int The opacity class of the Drawable. 731 * 732 * @see android.graphics.PixelFormat 733 */ 734 public abstract int getOpacity(); 735 736 /** 737 * Return the appropriate opacity value for two source opacities. If 738 * either is UNKNOWN, that is returned; else, if either is TRANSLUCENT, 739 * that is returned; else, if either is TRANSPARENT, that is returned; 740 * else, OPAQUE is returned. 741 * 742 * <p>This is to help in implementing {@link #getOpacity}. 743 * 744 * @param op1 One opacity value. 745 * @param op2 Another opacity value. 746 * 747 * @return int The combined opacity value. 748 * 749 * @see #getOpacity 750 */ 751 public static int resolveOpacity(int op1, int op2) { 752 if (op1 == op2) { 753 return op1; 754 } 755 if (op1 == PixelFormat.UNKNOWN || op2 == PixelFormat.UNKNOWN) { 756 return PixelFormat.UNKNOWN; 757 } 758 if (op1 == PixelFormat.TRANSLUCENT || op2 == PixelFormat.TRANSLUCENT) { 759 return PixelFormat.TRANSLUCENT; 760 } 761 if (op1 == PixelFormat.TRANSPARENT || op2 == PixelFormat.TRANSPARENT) { 762 return PixelFormat.TRANSPARENT; 763 } 764 return PixelFormat.OPAQUE; 765 } 766 767 /** 768 * Returns a Region representing the part of the Drawable that is completely 769 * transparent. This can be used to perform drawing operations, identifying 770 * which parts of the target will not change when rendering the Drawable. 771 * The default implementation returns null, indicating no transparent 772 * region; subclasses can optionally override this to return an actual 773 * Region if they want to supply this optimization information, but it is 774 * not required that they do so. 775 * 776 * @return Returns null if the Drawables has no transparent region to 777 * report, else a Region holding the parts of the Drawable's bounds that 778 * are transparent. 779 */ 780 public Region getTransparentRegion() { 781 return null; 782 } 783 784 /** 785 * Override this in your subclass to change appearance if you recognize the 786 * specified state. 787 * 788 * @return Returns true if the state change has caused the appearance of 789 * the Drawable to change (that is, it needs to be drawn), else false 790 * if it looks the same and there is no need to redraw it since its 791 * last state. 792 */ 793 protected boolean onStateChange(int[] state) { return false; } 794 /** Override this in your subclass to change appearance if you vary based 795 * on level. 796 * @return Returns true if the level change has caused the appearance of 797 * the Drawable to change (that is, it needs to be drawn), else false 798 * if it looks the same and there is no need to redraw it since its 799 * last level. 800 */ 801 protected boolean onLevelChange(int level) { return false; } 802 /** 803 * Override this in your subclass to change appearance if you vary based on 804 * the bounds. 805 */ 806 protected void onBoundsChange(Rect bounds) {} 807 808 /** 809 * Return the intrinsic width of the underlying drawable object. Returns 810 * -1 if it has no intrinsic width, such as with a solid color. 811 */ 812 public int getIntrinsicWidth() { 813 return -1; 814 } 815 816 /** 817 * Return the intrinsic height of the underlying drawable object. Returns 818 * -1 if it has no intrinsic height, such as with a solid color. 819 */ 820 public int getIntrinsicHeight() { 821 return -1; 822 } 823 824 /** 825 * Returns the minimum width suggested by this Drawable. If a View uses this 826 * Drawable as a background, it is suggested that the View use at least this 827 * value for its width. (There will be some scenarios where this will not be 828 * possible.) This value should INCLUDE any padding. 829 * 830 * @return The minimum width suggested by this Drawable. If this Drawable 831 * doesn't have a suggested minimum width, 0 is returned. 832 */ 833 public int getMinimumWidth() { 834 final int intrinsicWidth = getIntrinsicWidth(); 835 return intrinsicWidth > 0 ? intrinsicWidth : 0; 836 } 837 838 /** 839 * Returns the minimum height suggested by this Drawable. If a View uses this 840 * Drawable as a background, it is suggested that the View use at least this 841 * value for its height. (There will be some scenarios where this will not be 842 * possible.) This value should INCLUDE any padding. 843 * 844 * @return The minimum height suggested by this Drawable. If this Drawable 845 * doesn't have a suggested minimum height, 0 is returned. 846 */ 847 public int getMinimumHeight() { 848 final int intrinsicHeight = getIntrinsicHeight(); 849 return intrinsicHeight > 0 ? intrinsicHeight : 0; 850 } 851 852 /** 853 * Return in padding the insets suggested by this Drawable for placing 854 * content inside the drawable's bounds. Positive values move toward the 855 * center of the Drawable (set Rect.inset). Returns true if this drawable 856 * actually has a padding, else false. When false is returned, the padding 857 * is always set to 0. 858 */ 859 public boolean getPadding(Rect padding) { 860 padding.set(0, 0, 0, 0); 861 return false; 862 } 863 864 /** 865 * Return in insets the layout insets suggested by this Drawable for use with alignment 866 * operations during layout. 867 * 868 * @hide 869 */ 870 public Insets getOpticalInsets() { 871 return Insets.NONE; 872 } 873 874 /** 875 * Returns the outline for this drawable if defined, null if not. 876 * <p> 877 * This method will be called by a View on its background Drawable after 878 * bounds change, if the View's Outline isn't set explicitly. This allows 879 * the background Drawable to provide the shape of the shadow casting 880 * portion of the View. It can also serve to clip the area of the View if 881 * if {@link View#setClipToOutline(boolean)} is set on the View. 882 * <p> 883 * The Outline queried by the View will not be modified, and is treated as 884 * a static shape that only needs to be requeried when the drawable's bounds 885 * change. 886 * 887 * @see View#setOutline(android.view.Outline) 888 * @see View#setClipToOutline(boolean) 889 */ 890 public Outline getOutline() { return null; } 891 892 /** 893 * Make this drawable mutable. This operation cannot be reversed. A mutable 894 * drawable is guaranteed to not share its state with any other drawable. 895 * This is especially useful when you need to modify properties of drawables 896 * loaded from resources. By default, all drawables instances loaded from 897 * the same resource share a common state; if you modify the state of one 898 * instance, all the other instances will receive the same modification. 899 * 900 * Calling this method on a mutable Drawable will have no effect. 901 * 902 * @return This drawable. 903 * @see ConstantState 904 * @see #getConstantState() 905 */ 906 public Drawable mutate() { 907 return this; 908 } 909 910 /** 911 * Create a drawable from an inputstream 912 */ 913 public static Drawable createFromStream(InputStream is, String srcName) { 914 return createFromStreamThemed(is, srcName, null); 915 } 916 917 public static Drawable createFromStreamThemed(InputStream is, String srcName, Theme theme) { 918 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, srcName != null ? srcName : "Unknown drawable"); 919 try { 920 return createFromResourceStreamThemed(null, null, is, srcName, theme); 921 } finally { 922 Trace.traceEnd(Trace.TRACE_TAG_RESOURCES); 923 } 924 } 925 926 /** 927 * Create a drawable from an inputstream, using the given resources and 928 * value to determine density information. 929 */ 930 public static Drawable createFromResourceStream(Resources res, TypedValue value, 931 InputStream is, String srcName) { 932 return createFromResourceStreamThemed(res, value, is, srcName, null); 933 } 934 935 public static Drawable createFromResourceStreamThemed(Resources res, TypedValue value, 936 InputStream is, String srcName, Theme theme) { 937 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, srcName != null ? srcName : "Unknown drawable"); 938 try { 939 return createFromResourceStreamThemed(res, value, is, srcName, null, theme); 940 } finally { 941 Trace.traceEnd(Trace.TRACE_TAG_RESOURCES); 942 } 943 } 944 945 /** 946 * Create a drawable from an inputstream, using the given resources and 947 * value to determine density information. 948 */ 949 public static Drawable createFromResourceStream(Resources res, TypedValue value, 950 InputStream is, String srcName, BitmapFactory.Options opts) { 951 return createFromResourceStreamThemed(res, value, is, srcName, opts, null); 952 } 953 954 public static Drawable createFromResourceStreamThemed(Resources res, TypedValue value, 955 InputStream is, String srcName, BitmapFactory.Options opts, Theme theme) { 956 if (is == null) { 957 return null; 958 } 959 960 /* ugh. The decodeStream contract is that we have already allocated 961 the pad rect, but if the bitmap does not had a ninepatch chunk, 962 then the pad will be ignored. If we could change this to lazily 963 alloc/assign the rect, we could avoid the GC churn of making new 964 Rects only to drop them on the floor. 965 */ 966 Rect pad = new Rect(); 967 968 // Special stuff for compatibility mode: if the target density is not 969 // the same as the display density, but the resource -is- the same as 970 // the display density, then don't scale it down to the target density. 971 // This allows us to load the system's density-correct resources into 972 // an application in compatibility mode, without scaling those down 973 // to the compatibility density only to have them scaled back up when 974 // drawn to the screen. 975 if (opts == null) opts = new BitmapFactory.Options(); 976 opts.inScreenDensity = res != null 977 ? res.getDisplayMetrics().noncompatDensityDpi : DisplayMetrics.DENSITY_DEVICE; 978 Bitmap bm = BitmapFactory.decodeResourceStream(res, value, is, pad, opts); 979 if (bm != null) { 980 byte[] np = bm.getNinePatchChunk(); 981 if (np == null || !NinePatch.isNinePatchChunk(np)) { 982 np = null; 983 pad = null; 984 } 985 int[] layoutBounds = bm.getLayoutBounds(); 986 Rect layoutBoundsRect = null; 987 if (layoutBounds != null) { 988 layoutBoundsRect = new Rect(layoutBounds[0], layoutBounds[1], 989 layoutBounds[2], layoutBounds[3]); 990 } 991 return drawableFromBitmap(res, bm, np, pad, layoutBoundsRect, srcName); 992 } 993 return null; 994 } 995 996 /** 997 * Create a drawable from an XML document. For more information on how to 998 * create resources in XML, see 999 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. 1000 */ 1001 public static Drawable createFromXml(Resources r, XmlPullParser parser) 1002 throws XmlPullParserException, IOException { 1003 return createFromXmlThemed(r, parser, null); 1004 } 1005 1006 /** 1007 * Create a themed drawable from an XML document. For more information on 1008 * how to create resources in XML, see 1009 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. 1010 */ 1011 public static Drawable createFromXmlThemed(Resources r, XmlPullParser parser, Theme theme) 1012 throws XmlPullParserException, IOException { 1013 AttributeSet attrs = Xml.asAttributeSet(parser); 1014 1015 int type; 1016 while ((type=parser.next()) != XmlPullParser.START_TAG && 1017 type != XmlPullParser.END_DOCUMENT) { 1018 // Empty loop 1019 } 1020 1021 if (type != XmlPullParser.START_TAG) { 1022 throw new XmlPullParserException("No start tag found"); 1023 } 1024 1025 Drawable drawable = createFromXmlInnerThemed(r, parser, attrs, theme); 1026 1027 if (drawable == null) { 1028 throw new RuntimeException("Unknown initial tag: " + parser.getName()); 1029 } 1030 1031 return drawable; 1032 } 1033 1034 /** 1035 * Create from inside an XML document. Called on a parser positioned at 1036 * a tag in an XML document, tries to create a Drawable from that tag. 1037 * Returns null if the tag is not a valid drawable. 1038 */ 1039 public static Drawable createFromXmlInner(Resources r, XmlPullParser parser, AttributeSet attrs) 1040 throws XmlPullParserException, IOException { 1041 return createFromXmlInnerThemed(r, parser, attrs, null); 1042 } 1043 1044 public static Drawable createFromXmlInnerThemed(Resources r, XmlPullParser parser, 1045 AttributeSet attrs, Theme theme) throws XmlPullParserException, IOException { 1046 final Drawable drawable; 1047 1048 final String name = parser.getName(); 1049 if (name.equals("selector")) { 1050 drawable = new StateListDrawable(); 1051 } else if (name.equals("level-list")) { 1052 drawable = new LevelListDrawable(); 1053 } else if (name.equals("layer-list")) { 1054 drawable = new LayerDrawable(); 1055 } else if (name.equals("transition")) { 1056 drawable = new TransitionDrawable(); 1057 } else if (name.equals("reveal")) { 1058 drawable = new RevealDrawable(); 1059 } else if (name.equals("touch-feedback")) { 1060 drawable = new TouchFeedbackDrawable(); 1061 } else if (name.equals("color")) { 1062 drawable = new ColorDrawable(); 1063 } else if (name.equals("shape")) { 1064 drawable = new GradientDrawable(); 1065 } else if (name.equals("scale")) { 1066 drawable = new ScaleDrawable(); 1067 } else if (name.equals("clip")) { 1068 drawable = new ClipDrawable(); 1069 } else if (name.equals("rotate")) { 1070 drawable = new RotateDrawable(); 1071 } else if (name.equals("animated-rotate")) { 1072 drawable = new AnimatedRotateDrawable(); 1073 } else if (name.equals("animation-list")) { 1074 drawable = new AnimationDrawable(); 1075 } else if (name.equals("inset")) { 1076 drawable = new InsetDrawable(); 1077 } else if (name.equals("bitmap")) { 1078 //noinspection deprecation 1079 drawable = new BitmapDrawable(r); 1080 if (r != null) { 1081 ((BitmapDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 1082 } 1083 } else if (name.equals("nine-patch")) { 1084 drawable = new NinePatchDrawable(); 1085 if (r != null) { 1086 ((NinePatchDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 1087 } 1088 } else { 1089 throw new XmlPullParserException(parser.getPositionDescription() + 1090 ": invalid drawable tag " + name); 1091 } 1092 1093 drawable.inflate(r, parser, attrs, theme); 1094 return drawable; 1095 } 1096 1097 1098 /** 1099 * Create a drawable from file path name. 1100 */ 1101 public static Drawable createFromPath(String pathName) { 1102 if (pathName == null) { 1103 return null; 1104 } 1105 1106 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, pathName); 1107 try { 1108 Bitmap bm = BitmapFactory.decodeFile(pathName); 1109 if (bm != null) { 1110 return drawableFromBitmap(null, bm, null, null, null, pathName); 1111 } 1112 } finally { 1113 Trace.traceEnd(Trace.TRACE_TAG_RESOURCES); 1114 } 1115 1116 return null; 1117 } 1118 1119 /** 1120 * Inflate this Drawable from an XML resource. Does not apply a theme. 1121 * 1122 * @see #inflate(Resources, XmlPullParser, AttributeSet, Theme) 1123 */ 1124 public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs) 1125 throws XmlPullParserException, IOException { 1126 inflate(r, parser, attrs, null); 1127 } 1128 1129 /** 1130 * Inflate this Drawable from an XML resource optionally styled by a theme. 1131 * 1132 * @param r Resources used to resolve attribute values 1133 * @param parser XML parser from which to inflate this Drawable 1134 * @param attrs Base set of attribute values 1135 * @param theme Theme to apply, may be null 1136 * @throws XmlPullParserException 1137 * @throws IOException 1138 */ 1139 public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs, Theme theme) 1140 throws XmlPullParserException, IOException { 1141 final TypedArray a; 1142 if (theme != null) { 1143 a = theme.obtainStyledAttributes( 1144 attrs, com.android.internal.R.styleable.Drawable, 0, 0); 1145 } else { 1146 a = r.obtainAttributes(attrs, com.android.internal.R.styleable.Drawable); 1147 } 1148 1149 inflateWithAttributes(r, parser, a, com.android.internal.R.styleable.Drawable_visible); 1150 a.recycle(); 1151 } 1152 1153 /** 1154 * Inflate a Drawable from an XML resource. 1155 * 1156 * @throws XmlPullParserException 1157 * @throws IOException 1158 */ 1159 void inflateWithAttributes(Resources r, XmlPullParser parser, TypedArray attrs, int visibleAttr) 1160 throws XmlPullParserException, IOException { 1161 mVisible = attrs.getBoolean(visibleAttr, mVisible); 1162 } 1163 1164 /** 1165 * This abstract class is used by {@link Drawable}s to store shared constant state and data 1166 * between Drawables. {@link BitmapDrawable}s created from the same resource will for instance 1167 * share a unique bitmap stored in their ConstantState. 1168 * 1169 * <p> 1170 * {@link #newDrawable(Resources)} can be used as a factory to create new Drawable instances 1171 * from this ConstantState. 1172 * </p> 1173 * 1174 * Use {@link Drawable#getConstantState()} to retrieve the ConstantState of a Drawable. Calling 1175 * {@link Drawable#mutate()} on a Drawable should typically create a new ConstantState for that 1176 * Drawable. 1177 */ 1178 public static abstract class ConstantState { 1179 /** 1180 * Create a new drawable without supplying resources the caller 1181 * is running in. Note that using this means the density-dependent 1182 * drawables (like bitmaps) will not be able to update their target 1183 * density correctly. One should use {@link #newDrawable(Resources)} 1184 * instead to provide a resource. 1185 */ 1186 public abstract Drawable newDrawable(); 1187 1188 /** 1189 * Create a new Drawable instance from its constant state. This 1190 * must be implemented for drawables that change based on the target 1191 * density of their caller (that is depending on whether it is 1192 * in compatibility mode). 1193 */ 1194 public Drawable newDrawable(Resources res) { 1195 return newDrawable(); 1196 } 1197 1198 /** 1199 * Create a new Drawable instance from its constant state. This must be 1200 * implemented for drawables that can have a theme applied. 1201 */ 1202 public Drawable newDrawable(Resources res, Theme theme) { 1203 return newDrawable(); 1204 } 1205 1206 /** 1207 * Return a bit mask of configuration changes that will impact 1208 * this drawable (and thus require completely reloading it). 1209 */ 1210 public abstract int getChangingConfigurations(); 1211 1212 /** 1213 * @hide 1214 */ 1215 public Bitmap getBitmap() { 1216 return null; 1217 } 1218 1219 /** 1220 * Return whether this constant state can have a theme applied. 1221 */ 1222 public boolean canApplyTheme() { 1223 return false; 1224 } 1225 } 1226 1227 /** 1228 * Return a {@link ConstantState} instance that holds the shared state of this Drawable. 1229 * 1230 * @return The ConstantState associated to that Drawable. 1231 * @see ConstantState 1232 * @see Drawable#mutate() 1233 */ 1234 public ConstantState getConstantState() { 1235 return null; 1236 } 1237 1238 private static Drawable drawableFromBitmap(Resources res, Bitmap bm, byte[] np, 1239 Rect pad, Rect layoutBounds, String srcName) { 1240 1241 if (np != null) { 1242 return new NinePatchDrawable(res, bm, np, pad, layoutBounds, srcName); 1243 } 1244 1245 return new BitmapDrawable(res, bm); 1246 } 1247 1248 /** 1249 * Obtains styled attributes from the theme, if available, or unstyled 1250 * resources if the theme is null. 1251 */ 1252 static TypedArray obtainAttributes( 1253 Resources res, Theme theme, AttributeSet set, int[] attrs) { 1254 if (theme == null) { 1255 return res.obtainAttributes(set, attrs); 1256 } 1257 return theme.obtainStyledAttributes(set, attrs, 0, 0); 1258 } 1259 1260 /** 1261 * Parses a {@link android.graphics.PorterDuff.Mode} from a tintMode 1262 * attribute's enum value. 1263 */ 1264 static PorterDuff.Mode parseTintMode(int value, Mode defaultMode) { 1265 switch (value) { 1266 case 0: 1267 return Mode.SRC_IN; 1268 case 1: 1269 return Mode.SRC_ATOP; 1270 case 2: 1271 return Mode.MULTIPLY; 1272 case 3: 1273 return Mode.SCREEN; 1274 } 1275 return defaultMode; 1276 } 1277} 1278 1279