Drawable.java revision 12b97f5d2b15194ed6673c9838b13c8312157709
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.TypedArray; 28import android.graphics.Bitmap; 29import android.graphics.BitmapFactory; 30import android.graphics.Canvas; 31import android.graphics.ColorFilter; 32import android.graphics.NinePatch; 33import android.graphics.PixelFormat; 34import android.graphics.PorterDuff; 35import android.graphics.PorterDuffColorFilter; 36import android.graphics.Rect; 37import android.graphics.Region; 38import android.graphics.PorterDuff.Mode; 39import android.util.AttributeSet; 40import android.util.DisplayMetrics; 41import android.util.StateSet; 42import android.util.TypedValue; 43import android.util.Xml; 44import android.view.View; 45 46import java.io.IOException; 47import java.io.InputStream; 48import java.lang.ref.WeakReference; 49import java.util.Arrays; 50 51/** 52 * A Drawable is a general abstraction for "something that can be drawn." Most 53 * often you will deal with Drawable as the type of resource retrieved for 54 * drawing things to the screen; the Drawable class provides a generic API for 55 * dealing with an underlying visual resource that may take a variety of forms. 56 * Unlike a {@link android.view.View}, a Drawable does not have any facility to 57 * receive events or otherwise interact with the user. 58 * 59 * <p>In addition to simple drawing, Drawable provides a number of generic 60 * mechanisms for its client to interact with what is being drawn: 61 * 62 * <ul> 63 * <li> The {@link #setBounds} method <var>must</var> be called to tell the 64 * Drawable where it is drawn and how large it should be. All Drawables 65 * should respect the requested size, often simply by scaling their 66 * imagery. A client can find the preferred size for some Drawables with 67 * the {@link #getIntrinsicHeight} and {@link #getIntrinsicWidth} methods. 68 * 69 * <li> The {@link #getPadding} method can return from some Drawables 70 * information about how to frame content that is placed inside of them. 71 * For example, a Drawable that is intended to be the frame for a button 72 * widget would need to return padding that correctly places the label 73 * inside of itself. 74 * 75 * <li> The {@link #setState} method allows the client to tell the Drawable 76 * in which state it is to be drawn, such as "focused", "selected", etc. 77 * Some drawables may modify their imagery based on the selected state. 78 * 79 * <li> The {@link #setLevel} method allows the client to supply a single 80 * continuous controller that can modify the Drawable is displayed, such as 81 * a battery level or progress level. Some drawables may modify their 82 * imagery based on the current level. 83 * 84 * <li> A Drawable can perform animations by calling back to its client 85 * through the {@link Callback} interface. All clients should support this 86 * interface (via {@link #setCallback}) so that animations will work. A 87 * simple way to do this is through the system facilities such as 88 * {@link android.view.View#setBackground(Drawable)} and 89 * {@link android.widget.ImageView}. 90 * </ul> 91 * 92 * Though usually not visible to the application, Drawables may take a variety 93 * of forms: 94 * 95 * <ul> 96 * <li> <b>Bitmap</b>: the simplest Drawable, a PNG or JPEG image. 97 * <li> <b>Nine Patch</b>: an extension to the PNG format allows it to 98 * specify information about how to stretch it and place things inside of 99 * it. 100 * <li> <b>Shape</b>: contains simple drawing commands instead of a raw 101 * bitmap, allowing it to resize better in some cases. 102 * <li> <b>Layers</b>: a compound drawable, which draws multiple underlying 103 * drawables on top of each other. 104 * <li> <b>States</b>: a compound drawable that selects one of a set of 105 * drawables based on its state. 106 * <li> <b>Levels</b>: a compound drawable that selects one of a set of 107 * drawables based on its level. 108 * <li> <b>Scale</b>: a compound drawable with a single child drawable, 109 * whose overall size is modified based on the current level. 110 * </ul> 111 * 112 * <div class="special reference"> 113 * <h3>Developer Guides</h3> 114 * <p>For more information about how to use drawables, read the 115 * <a href="{@docRoot}guide/topics/graphics/2d-graphics.html">Canvas and Drawables</a> developer 116 * guide. For information and examples of creating drawable resources (XML or bitmap files that 117 * can be loaded in code), read the 118 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a> 119 * document.</p></div> 120 */ 121public abstract class Drawable { 122 /** 123 * Hotspot identifier mask for tracking touch points. 124 * 125 * @hide until hotspot APIs are finalized 126 */ 127 public static final int HOTSPOT_TOUCH_MASK = 0xFF; 128 129 /** 130 * Hotspot identifier for tracking keyboard focus. 131 * 132 * @hide until hotspot APIs are finalized 133 */ 134 public static final int HOTSPOT_FOCUS = 0x100; 135 136 private static final Rect ZERO_BOUNDS_RECT = new Rect(); 137 138 private int[] mStateSet = StateSet.WILD_CARD; 139 private int mLevel = 0; 140 private int mChangingConfigurations = 0; 141 private Rect mBounds = ZERO_BOUNDS_RECT; // lazily becomes a new Rect() 142 private WeakReference<Callback> mCallback = null; 143 private boolean mVisible = true; 144 145 private int mLayoutDirection; 146 147 /** 148 * Draw in its bounds (set via setBounds) respecting optional effects such 149 * as alpha (set via setAlpha) and color filter (set via setColorFilter). 150 * 151 * @param canvas The canvas to draw into 152 */ 153 public abstract void draw(Canvas canvas); 154 155 /** 156 * Specify a bounding rectangle for the Drawable. This is where the drawable 157 * will draw when its draw() method is called. 158 */ 159 public void setBounds(int left, int top, int right, int bottom) { 160 Rect oldBounds = mBounds; 161 162 if (oldBounds == ZERO_BOUNDS_RECT) { 163 oldBounds = mBounds = new Rect(); 164 } 165 166 if (oldBounds.left != left || oldBounds.top != top || 167 oldBounds.right != right || oldBounds.bottom != bottom) { 168 if (!oldBounds.isEmpty()) { 169 // first invalidate the previous bounds 170 invalidateSelf(); 171 } 172 mBounds.set(left, top, right, bottom); 173 onBoundsChange(mBounds); 174 } 175 } 176 177 /** 178 * Specify a bounding rectangle for the Drawable. This is where the drawable 179 * will draw when its draw() method is called. 180 */ 181 public void setBounds(Rect bounds) { 182 setBounds(bounds.left, bounds.top, bounds.right, bounds.bottom); 183 } 184 185 /** 186 * Return a copy of the drawable's bounds in the specified Rect (allocated 187 * by the caller). The bounds specify where this will draw when its draw() 188 * method is called. 189 * 190 * @param bounds Rect to receive the drawable's bounds (allocated by the 191 * caller). 192 */ 193 public final void copyBounds(Rect bounds) { 194 bounds.set(mBounds); 195 } 196 197 /** 198 * Return a copy of the drawable's bounds in a new Rect. This returns the 199 * same values as getBounds(), but the returned object is guaranteed to not 200 * be changed later by the drawable (i.e. it retains no reference to this 201 * rect). If the caller already has a Rect allocated, call copyBounds(rect). 202 * 203 * @return A copy of the drawable's bounds 204 */ 205 public final Rect copyBounds() { 206 return new Rect(mBounds); 207 } 208 209 /** 210 * Return the drawable's bounds Rect. Note: for efficiency, the returned 211 * object may be the same object stored in the drawable (though this is not 212 * guaranteed), so if a persistent copy of the bounds is needed, call 213 * copyBounds(rect) instead. 214 * You should also not change the object returned by this method as it may 215 * be the same object stored in the drawable. 216 * 217 * @return The bounds of the drawable (which may change later, so caller 218 * beware). DO NOT ALTER the returned object as it may change the 219 * stored bounds of this drawable. 220 * 221 * @see #copyBounds() 222 * @see #copyBounds(android.graphics.Rect) 223 */ 224 public final Rect getBounds() { 225 if (mBounds == ZERO_BOUNDS_RECT) { 226 mBounds = new Rect(); 227 } 228 229 return mBounds; 230 } 231 232 /** 233 * Return the drawable's dirty bounds Rect. Note: for efficiency, the 234 * returned object may be the same object stored in the drawable (though 235 * this is not guaranteed). 236 * <p> 237 * By default, this returns the full drawable bounds. Custom drawables may 238 * override this method to perform more precise invalidation. 239 * 240 * @hide 241 */ 242 public Rect getDirtyBounds() { 243 return getBounds(); 244 } 245 246 /** 247 * Set a mask of the configuration parameters for which this drawable 248 * may change, requiring that it be re-created. 249 * 250 * @param configs A mask of the changing configuration parameters, as 251 * defined by {@link android.content.res.Configuration}. 252 * 253 * @see android.content.res.Configuration 254 */ 255 public void setChangingConfigurations(int configs) { 256 mChangingConfigurations = configs; 257 } 258 259 /** 260 * Return a mask of the configuration parameters for which this drawable 261 * may change, requiring that it be re-created. The default implementation 262 * returns whatever was provided through 263 * {@link #setChangingConfigurations(int)} or 0 by default. Subclasses 264 * may extend this to or in the changing configurations of any other 265 * drawables they hold. 266 * 267 * @return Returns a mask of the changing configuration parameters, as 268 * defined by {@link android.content.res.Configuration}. 269 * 270 * @see android.content.res.Configuration 271 */ 272 public int getChangingConfigurations() { 273 return mChangingConfigurations; 274 } 275 276 /** 277 * Set to true to have the drawable dither its colors when drawn to a device 278 * with fewer than 8-bits per color component. This can improve the look on 279 * those devices, but can also slow down the drawing a little. 280 */ 281 public void setDither(boolean dither) {} 282 283 /** 284 * Set to true to have the drawable filter its bitmap when scaled or rotated 285 * (for drawables that use bitmaps). If the drawable does not use bitmaps, 286 * this call is ignored. This can improve the look when scaled or rotated, 287 * but also slows down the drawing. 288 */ 289 public void setFilterBitmap(boolean filter) {} 290 291 /** 292 * Implement this interface if you want to create an animated drawable that 293 * extends {@link android.graphics.drawable.Drawable Drawable}. 294 * Upon retrieving a drawable, use 295 * {@link Drawable#setCallback(android.graphics.drawable.Drawable.Callback)} 296 * to supply your implementation of the interface to the drawable; it uses 297 * this interface to schedule and execute animation changes. 298 */ 299 public static interface Callback { 300 /** 301 * Called when the drawable needs to be redrawn. A view at this point 302 * should invalidate itself (or at least the part of itself where the 303 * drawable appears). 304 * 305 * @param who The drawable that is requesting the update. 306 */ 307 public void invalidateDrawable(Drawable who); 308 309 /** 310 * A Drawable can call this to schedule the next frame of its 311 * animation. An implementation can generally simply call 312 * {@link android.os.Handler#postAtTime(Runnable, Object, long)} with 313 * the parameters <var>(what, who, when)</var> to perform the 314 * scheduling. 315 * 316 * @param who The drawable being scheduled. 317 * @param what The action to execute. 318 * @param when The time (in milliseconds) to run. The timebase is 319 * {@link android.os.SystemClock#uptimeMillis} 320 */ 321 public void scheduleDrawable(Drawable who, Runnable what, long when); 322 323 /** 324 * A Drawable can call this to unschedule an action previously 325 * scheduled with {@link #scheduleDrawable}. An implementation can 326 * generally simply call 327 * {@link android.os.Handler#removeCallbacks(Runnable, Object)} with 328 * the parameters <var>(what, who)</var> to unschedule the drawable. 329 * 330 * @param who The drawable being unscheduled. 331 * @param what The action being unscheduled. 332 */ 333 public void unscheduleDrawable(Drawable who, Runnable what); 334 } 335 336 /** 337 * Bind a {@link Callback} object to this Drawable. Required for clients 338 * that want to support animated drawables. 339 * 340 * @param cb The client's Callback implementation. 341 * 342 * @see #getCallback() 343 */ 344 public final void setCallback(Callback cb) { 345 mCallback = new WeakReference<Callback>(cb); 346 } 347 348 /** 349 * Return the current {@link Callback} implementation attached to this 350 * Drawable. 351 * 352 * @return A {@link Callback} instance or null if no callback was set. 353 * 354 * @see #setCallback(android.graphics.drawable.Drawable.Callback) 355 */ 356 public Callback getCallback() { 357 if (mCallback != null) { 358 return mCallback.get(); 359 } 360 return null; 361 } 362 363 /** 364 * Use the current {@link Callback} implementation to have this Drawable 365 * redrawn. Does nothing if there is no Callback attached to the 366 * Drawable. 367 * 368 * @see Callback#invalidateDrawable 369 * @see #getCallback() 370 * @see #setCallback(android.graphics.drawable.Drawable.Callback) 371 */ 372 public void invalidateSelf() { 373 final Callback callback = getCallback(); 374 if (callback != null) { 375 callback.invalidateDrawable(this); 376 } 377 } 378 379 /** 380 * Use the current {@link Callback} implementation to have this Drawable 381 * scheduled. Does nothing if there is no Callback attached to the 382 * Drawable. 383 * 384 * @param what The action being scheduled. 385 * @param when The time (in milliseconds) to run. 386 * 387 * @see Callback#scheduleDrawable 388 */ 389 public void scheduleSelf(Runnable what, long when) { 390 final Callback callback = getCallback(); 391 if (callback != null) { 392 callback.scheduleDrawable(this, what, when); 393 } 394 } 395 396 /** 397 * Use the current {@link Callback} implementation to have this Drawable 398 * unscheduled. Does nothing if there is no Callback attached to the 399 * Drawable. 400 * 401 * @param what The runnable that you no longer want called. 402 * 403 * @see Callback#unscheduleDrawable 404 */ 405 public void unscheduleSelf(Runnable what) { 406 final Callback callback = getCallback(); 407 if (callback != null) { 408 callback.unscheduleDrawable(this, what); 409 } 410 } 411 412 /** 413 * Returns the resolved layout direction for this Drawable. 414 * 415 * @return One of {@link android.view.View#LAYOUT_DIRECTION_LTR}, 416 * {@link android.view.View#LAYOUT_DIRECTION_RTL} 417 * 418 * @hide 419 */ 420 public int getLayoutDirection() { 421 return mLayoutDirection; 422 } 423 424 /** 425 * Set the layout direction for this drawable. Should be a resolved direction as the 426 * Drawable as no capacity to do the resolution on his own. 427 * 428 * @param layoutDirection One of {@link android.view.View#LAYOUT_DIRECTION_LTR}, 429 * {@link android.view.View#LAYOUT_DIRECTION_RTL} 430 * 431 * @hide 432 */ 433 public void setLayoutDirection(@View.ResolvedLayoutDir int layoutDirection) { 434 if (getLayoutDirection() != layoutDirection) { 435 mLayoutDirection = layoutDirection; 436 } 437 } 438 439 /** 440 * Specify an alpha value for the drawable. 0 means fully transparent, and 441 * 255 means fully opaque. 442 */ 443 public abstract void setAlpha(int alpha); 444 445 /** 446 * Gets the current alpha value for the drawable. 0 means fully transparent, 447 * 255 means fully opaque. This method is implemented by 448 * Drawable subclasses and the value returned is specific to how that class treats alpha. 449 * The default return value is 255 if the class does not override this method to return a value 450 * specific to its use of alpha. 451 */ 452 public int getAlpha() { 453 return 0xFF; 454 } 455 456 /** 457 * Specify an optional color filter for the drawable. Pass null to remove 458 * any existing color filter. 459 */ 460 public abstract void setColorFilter(ColorFilter cf); 461 462 /** 463 * @hide Consider for future API inclusion 464 */ 465 public void setXfermode(Xfermode mode) { 466 // Base implementation drops it on the floor for compatibility. Whee! 467 // TODO: For this to be included in the API proper, all framework drawables need impls. 468 // For right now only BitmapDrawable has it. 469 } 470 471 /** 472 * Specify a color and Porter-Duff mode to be the color filter for this 473 * drawable. 474 */ 475 public void setColorFilter(int color, PorterDuff.Mode mode) { 476 setColorFilter(new PorterDuffColorFilter(color, mode)); 477 } 478 479 /** 480 * Removes the color filter for this drawable. 481 */ 482 public void clearColorFilter() { 483 setColorFilter(null); 484 } 485 486 /** 487 * Indicates whether the drawable supports hotspots. Hotspots are uniquely 488 * identifiable coordinates the may be added, updated and removed within the 489 * drawable. 490 * 491 * @return true if hotspots are supported 492 * @see #setHotspot(int, float, float) 493 * @see #removeHotspot(int) 494 * @see #clearHotspots() 495 * @hide until hotspot APIs are finalized 496 */ 497 public boolean supportsHotspots() { 498 return false; 499 } 500 501 /** 502 * Specifies a hotspot's location within the drawable. 503 * 504 * @param id unique identifier for the hotspot 505 * @param x x-coordinate 506 * @param y y-coordinate 507 * @hide until hotspot APIs are finalized 508 */ 509 public void setHotspot(int id, float x, float y) {} 510 511 /** 512 * Removes the specified hotspot from the drawable. 513 * 514 * @param id unique identifier for the hotspot 515 * @hide until hotspot APIs are finalized 516 */ 517 public void removeHotspot(int id) {} 518 519 /** 520 * Removes all hotspots from the drawable. 521 * 522 * @hide until hotspot APIs are finalized 523 */ 524 public void clearHotspots() {} 525 526 /** 527 * Whether this drawable requests projection. 528 * 529 * @hide 530 */ 531 public boolean isProjected() { 532 return false; 533 } 534 535 /** 536 * Indicates whether this view will change its appearance based on state. 537 * Clients can use this to determine whether it is necessary to calculate 538 * their state and call setState. 539 * 540 * @return True if this view changes its appearance based on state, false 541 * otherwise. 542 * 543 * @see #setState(int[]) 544 */ 545 public boolean isStateful() { 546 return false; 547 } 548 549 /** 550 * Specify a set of states for the drawable. These are use-case specific, 551 * so see the relevant documentation. As an example, the background for 552 * widgets like Button understand the following states: 553 * [{@link android.R.attr#state_focused}, 554 * {@link android.R.attr#state_pressed}]. 555 * 556 * <p>If the new state you are supplying causes the appearance of the 557 * Drawable to change, then it is responsible for calling 558 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 559 * true will be returned from this function. 560 * 561 * <p>Note: The Drawable holds a reference on to <var>stateSet</var> 562 * until a new state array is given to it, so you must not modify this 563 * array during that time.</p> 564 * 565 * @param stateSet The new set of states to be displayed. 566 * 567 * @return Returns true if this change in state has caused the appearance 568 * of the Drawable to change (hence requiring an invalidate), otherwise 569 * returns false. 570 */ 571 public boolean setState(final int[] stateSet) { 572 if (!Arrays.equals(mStateSet, stateSet)) { 573 mStateSet = stateSet; 574 return onStateChange(stateSet); 575 } 576 return false; 577 } 578 579 /** 580 * Describes the current state, as a union of primitve states, such as 581 * {@link android.R.attr#state_focused}, 582 * {@link android.R.attr#state_selected}, etc. 583 * Some drawables may modify their imagery based on the selected state. 584 * @return An array of resource Ids describing the current state. 585 */ 586 public int[] getState() { 587 return mStateSet; 588 } 589 590 /** 591 * If this Drawable does transition animations between states, ask that 592 * it immediately jump to the current state and skip any active animations. 593 */ 594 public void jumpToCurrentState() { 595 } 596 597 /** 598 * @return The current drawable that will be used by this drawable. For simple drawables, this 599 * is just the drawable itself. For drawables that change state like 600 * {@link StateListDrawable} and {@link LevelListDrawable} this will be the child drawable 601 * currently in use. 602 */ 603 public Drawable getCurrent() { 604 return this; 605 } 606 607 /** 608 * Specify the level for the drawable. This allows a drawable to vary its 609 * imagery based on a continuous controller, for example to show progress 610 * or volume level. 611 * 612 * <p>If the new level you are supplying causes the appearance of the 613 * Drawable to change, then it is responsible for calling 614 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 615 * true will be returned from this function. 616 * 617 * @param level The new level, from 0 (minimum) to 10000 (maximum). 618 * 619 * @return Returns true if this change in level has caused the appearance 620 * of the Drawable to change (hence requiring an invalidate), otherwise 621 * returns false. 622 */ 623 public final boolean setLevel(int level) { 624 if (mLevel != level) { 625 mLevel = level; 626 return onLevelChange(level); 627 } 628 return false; 629 } 630 631 /** 632 * Retrieve the current level. 633 * 634 * @return int Current level, from 0 (minimum) to 10000 (maximum). 635 */ 636 public final int getLevel() { 637 return mLevel; 638 } 639 640 /** 641 * Set whether this Drawable is visible. This generally does not impact 642 * the Drawable's behavior, but is a hint that can be used by some 643 * Drawables, for example, to decide whether run animations. 644 * 645 * @param visible Set to true if visible, false if not. 646 * @param restart You can supply true here to force the drawable to behave 647 * as if it has just become visible, even if it had last 648 * been set visible. Used for example to force animations 649 * to restart. 650 * 651 * @return boolean Returns true if the new visibility is different than 652 * its previous state. 653 */ 654 public boolean setVisible(boolean visible, boolean restart) { 655 boolean changed = mVisible != visible; 656 if (changed) { 657 mVisible = visible; 658 invalidateSelf(); 659 } 660 return changed; 661 } 662 663 public final boolean isVisible() { 664 return mVisible; 665 } 666 667 /** 668 * Set whether this Drawable is automatically mirrored when its layout direction is RTL 669 * (right-to left). See {@link android.util.LayoutDirection}. 670 * 671 * @param mirrored Set to true if the Drawable should be mirrored, false if not. 672 */ 673 public void setAutoMirrored(boolean mirrored) { 674 } 675 676 /** 677 * Tells if this Drawable will be automatically mirrored when its layout direction is RTL 678 * right-to-left. See {@link android.util.LayoutDirection}. 679 * 680 * @return boolean Returns true if this Drawable will be automatically mirrored. 681 */ 682 public boolean isAutoMirrored() { 683 return false; 684 } 685 686 /** 687 * Return the opacity/transparency of this Drawable. The returned value is 688 * one of the abstract format constants in 689 * {@link android.graphics.PixelFormat}: 690 * {@link android.graphics.PixelFormat#UNKNOWN}, 691 * {@link android.graphics.PixelFormat#TRANSLUCENT}, 692 * {@link android.graphics.PixelFormat#TRANSPARENT}, or 693 * {@link android.graphics.PixelFormat#OPAQUE}. 694 * 695 * <p>Generally a Drawable should be as conservative as possible with the 696 * value it returns. For example, if it contains multiple child drawables 697 * and only shows one of them at a time, if only one of the children is 698 * TRANSLUCENT and the others are OPAQUE then TRANSLUCENT should be 699 * returned. You can use the method {@link #resolveOpacity} to perform a 700 * standard reduction of two opacities to the appropriate single output. 701 * 702 * <p>Note that the returned value does <em>not</em> take into account a 703 * custom alpha or color filter that has been applied by the client through 704 * the {@link #setAlpha} or {@link #setColorFilter} methods. 705 * 706 * @return int The opacity class of the Drawable. 707 * 708 * @see android.graphics.PixelFormat 709 */ 710 public abstract int getOpacity(); 711 712 /** 713 * Return the appropriate opacity value for two source opacities. If 714 * either is UNKNOWN, that is returned; else, if either is TRANSLUCENT, 715 * that is returned; else, if either is TRANSPARENT, that is returned; 716 * else, OPAQUE is returned. 717 * 718 * <p>This is to help in implementing {@link #getOpacity}. 719 * 720 * @param op1 One opacity value. 721 * @param op2 Another opacity value. 722 * 723 * @return int The combined opacity value. 724 * 725 * @see #getOpacity 726 */ 727 public static int resolveOpacity(int op1, int op2) { 728 if (op1 == op2) { 729 return op1; 730 } 731 if (op1 == PixelFormat.UNKNOWN || op2 == PixelFormat.UNKNOWN) { 732 return PixelFormat.UNKNOWN; 733 } 734 if (op1 == PixelFormat.TRANSLUCENT || op2 == PixelFormat.TRANSLUCENT) { 735 return PixelFormat.TRANSLUCENT; 736 } 737 if (op1 == PixelFormat.TRANSPARENT || op2 == PixelFormat.TRANSPARENT) { 738 return PixelFormat.TRANSPARENT; 739 } 740 return PixelFormat.OPAQUE; 741 } 742 743 /** 744 * Returns a Region representing the part of the Drawable that is completely 745 * transparent. This can be used to perform drawing operations, identifying 746 * which parts of the target will not change when rendering the Drawable. 747 * The default implementation returns null, indicating no transparent 748 * region; subclasses can optionally override this to return an actual 749 * Region if they want to supply this optimization information, but it is 750 * not required that they do so. 751 * 752 * @return Returns null if the Drawables has no transparent region to 753 * report, else a Region holding the parts of the Drawable's bounds that 754 * are transparent. 755 */ 756 public Region getTransparentRegion() { 757 return null; 758 } 759 760 /** 761 * Override this in your subclass to change appearance if you recognize the 762 * specified state. 763 * 764 * @return Returns true if the state change has caused the appearance of 765 * the Drawable to change (that is, it needs to be drawn), else false 766 * if it looks the same and there is no need to redraw it since its 767 * last state. 768 */ 769 protected boolean onStateChange(int[] state) { return false; } 770 /** Override this in your subclass to change appearance if you vary based 771 * on level. 772 * @return Returns true if the level change has caused the appearance of 773 * the Drawable to change (that is, it needs to be drawn), else false 774 * if it looks the same and there is no need to redraw it since its 775 * last level. 776 */ 777 protected boolean onLevelChange(int level) { return false; } 778 /** 779 * Override this in your subclass to change appearance if you vary based on 780 * the bounds. 781 */ 782 protected void onBoundsChange(Rect bounds) {} 783 784 /** 785 * Return the intrinsic width of the underlying drawable object. Returns 786 * -1 if it has no intrinsic width, such as with a solid color. 787 */ 788 public int getIntrinsicWidth() { 789 return -1; 790 } 791 792 /** 793 * Return the intrinsic height of the underlying drawable object. Returns 794 * -1 if it has no intrinsic height, such as with a solid color. 795 */ 796 public int getIntrinsicHeight() { 797 return -1; 798 } 799 800 /** 801 * Returns the minimum width suggested by this Drawable. If a View uses this 802 * Drawable as a background, it is suggested that the View use at least this 803 * value for its width. (There will be some scenarios where this will not be 804 * possible.) This value should INCLUDE any padding. 805 * 806 * @return The minimum width suggested by this Drawable. If this Drawable 807 * doesn't have a suggested minimum width, 0 is returned. 808 */ 809 public int getMinimumWidth() { 810 final int intrinsicWidth = getIntrinsicWidth(); 811 return intrinsicWidth > 0 ? intrinsicWidth : 0; 812 } 813 814 /** 815 * Returns the minimum height suggested by this Drawable. If a View uses this 816 * Drawable as a background, it is suggested that the View use at least this 817 * value for its height. (There will be some scenarios where this will not be 818 * possible.) This value should INCLUDE any padding. 819 * 820 * @return The minimum height suggested by this Drawable. If this Drawable 821 * doesn't have a suggested minimum height, 0 is returned. 822 */ 823 public int getMinimumHeight() { 824 final int intrinsicHeight = getIntrinsicHeight(); 825 return intrinsicHeight > 0 ? intrinsicHeight : 0; 826 } 827 828 /** 829 * Return in padding the insets suggested by this Drawable for placing 830 * content inside the drawable's bounds. Positive values move toward the 831 * center of the Drawable (set Rect.inset). Returns true if this drawable 832 * actually has a padding, else false. When false is returned, the padding 833 * is always set to 0. 834 */ 835 public boolean getPadding(Rect padding) { 836 padding.set(0, 0, 0, 0); 837 return false; 838 } 839 840 /** 841 * Return in insets the layout insets suggested by this Drawable for use with alignment 842 * operations during layout. 843 * 844 * @hide 845 */ 846 public Insets getOpticalInsets() { 847 return Insets.NONE; 848 } 849 850 /** 851 * Make this drawable mutable. This operation cannot be reversed. A mutable 852 * drawable is guaranteed to not share its state with any other drawable. 853 * This is especially useful when you need to modify properties of drawables 854 * loaded from resources. By default, all drawables instances loaded from 855 * the same resource share a common state; if you modify the state of one 856 * instance, all the other instances will receive the same modification. 857 * 858 * Calling this method on a mutable Drawable will have no effect. 859 * 860 * @return This drawable. 861 * @see ConstantState 862 * @see #getConstantState() 863 */ 864 public Drawable mutate() { 865 return this; 866 } 867 868 /** 869 * Create a drawable from an inputstream 870 */ 871 public static Drawable createFromStream(InputStream is, String srcName) { 872 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, srcName != null ? srcName : "Unknown drawable"); 873 try { 874 return createFromResourceStream(null, null, is, srcName, null); 875 } finally { 876 Trace.traceEnd(Trace.TRACE_TAG_RESOURCES); 877 } 878 } 879 880 /** 881 * Create a drawable from an inputstream, using the given resources and 882 * value to determine density information. 883 */ 884 public static Drawable createFromResourceStream(Resources res, TypedValue value, 885 InputStream is, String srcName) { 886 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, srcName != null ? srcName : "Unknown drawable"); 887 try { 888 return createFromResourceStream(res, value, is, srcName, null); 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, BitmapFactory.Options opts) { 900 901 if (is == null) { 902 return null; 903 } 904 905 /* ugh. The decodeStream contract is that we have already allocated 906 the pad rect, but if the bitmap does not had a ninepatch chunk, 907 then the pad will be ignored. If we could change this to lazily 908 alloc/assign the rect, we could avoid the GC churn of making new 909 Rects only to drop them on the floor. 910 */ 911 Rect pad = new Rect(); 912 913 // Special stuff for compatibility mode: if the target density is not 914 // the same as the display density, but the resource -is- the same as 915 // the display density, then don't scale it down to the target density. 916 // This allows us to load the system's density-correct resources into 917 // an application in compatibility mode, without scaling those down 918 // to the compatibility density only to have them scaled back up when 919 // drawn to the screen. 920 if (opts == null) opts = new BitmapFactory.Options(); 921 opts.inScreenDensity = res != null 922 ? res.getDisplayMetrics().noncompatDensityDpi : DisplayMetrics.DENSITY_DEVICE; 923 Bitmap bm = BitmapFactory.decodeResourceStream(res, value, is, pad, opts); 924 if (bm != null) { 925 byte[] np = bm.getNinePatchChunk(); 926 if (np == null || !NinePatch.isNinePatchChunk(np)) { 927 np = null; 928 pad = null; 929 } 930 int[] layoutBounds = bm.getLayoutBounds(); 931 Rect layoutBoundsRect = null; 932 if (layoutBounds != null) { 933 layoutBoundsRect = new Rect(layoutBounds[0], layoutBounds[1], 934 layoutBounds[2], layoutBounds[3]); 935 } 936 return drawableFromBitmap(res, bm, np, pad, layoutBoundsRect, srcName); 937 } 938 return null; 939 } 940 941 /** 942 * Create a drawable from an XML document. For more information on how to 943 * create resources in XML, see 944 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. 945 */ 946 public static Drawable createFromXml(Resources r, XmlPullParser parser) 947 throws XmlPullParserException, IOException { 948 AttributeSet attrs = Xml.asAttributeSet(parser); 949 950 int type; 951 while ((type=parser.next()) != XmlPullParser.START_TAG && 952 type != XmlPullParser.END_DOCUMENT) { 953 // Empty loop 954 } 955 956 if (type != XmlPullParser.START_TAG) { 957 throw new XmlPullParserException("No start tag found"); 958 } 959 960 Drawable drawable = createFromXmlInner(r, parser, attrs); 961 962 if (drawable == null) { 963 throw new RuntimeException("Unknown initial tag: " + parser.getName()); 964 } 965 966 return drawable; 967 } 968 969 /** 970 * Create from inside an XML document. Called on a parser positioned at 971 * a tag in an XML document, tries to create a Drawable from that tag. 972 * Returns null if the tag is not a valid drawable. 973 */ 974 public static Drawable createFromXmlInner(Resources r, XmlPullParser parser, AttributeSet attrs) 975 throws XmlPullParserException, IOException { 976 Drawable drawable; 977 978 final String name = parser.getName(); 979 980 if (name.equals("selector")) { 981 drawable = new StateListDrawable(); 982 } else if (name.equals("level-list")) { 983 drawable = new LevelListDrawable(); 984 } else if (name.equals("layer-list")) { 985 drawable = new LayerDrawable(); 986 } else if (name.equals("transition")) { 987 drawable = new TransitionDrawable(); 988 } else if (name.equals("reveal")) { 989 drawable = new RevealDrawable(); 990 } else if (name.equals("touch-feedback")) { 991 drawable = new TouchFeedbackDrawable(); 992 } else if (name.equals("color")) { 993 drawable = new ColorDrawable(); 994 } else if (name.equals("shape")) { 995 drawable = new GradientDrawable(); 996 } else if (name.equals("scale")) { 997 drawable = new ScaleDrawable(); 998 } else if (name.equals("clip")) { 999 drawable = new ClipDrawable(); 1000 } else if (name.equals("rotate")) { 1001 drawable = new RotateDrawable(); 1002 } else if (name.equals("animated-rotate")) { 1003 drawable = new AnimatedRotateDrawable(); 1004 } else if (name.equals("animation-list")) { 1005 drawable = new AnimationDrawable(); 1006 } else if (name.equals("inset")) { 1007 drawable = new InsetDrawable(); 1008 } else if (name.equals("bitmap")) { 1009 //noinspection deprecation 1010 drawable = new BitmapDrawable(r); 1011 if (r != null) { 1012 ((BitmapDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 1013 } 1014 } else if (name.equals("nine-patch")) { 1015 drawable = new NinePatchDrawable(); 1016 if (r != null) { 1017 ((NinePatchDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 1018 } 1019 } else { 1020 throw new XmlPullParserException(parser.getPositionDescription() + 1021 ": invalid drawable tag " + name); 1022 } 1023 1024 drawable.inflate(r, parser, attrs); 1025 return drawable; 1026 } 1027 1028 1029 /** 1030 * Create a drawable from file path name. 1031 */ 1032 public static Drawable createFromPath(String pathName) { 1033 if (pathName == null) { 1034 return null; 1035 } 1036 1037 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, pathName); 1038 try { 1039 Bitmap bm = BitmapFactory.decodeFile(pathName); 1040 if (bm != null) { 1041 return drawableFromBitmap(null, bm, null, null, null, pathName); 1042 } 1043 } finally { 1044 Trace.traceEnd(Trace.TRACE_TAG_RESOURCES); 1045 } 1046 1047 return null; 1048 } 1049 1050 /** 1051 * Inflate this Drawable from an XML resource. 1052 */ 1053 public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs) 1054 throws XmlPullParserException, IOException { 1055 1056 TypedArray a = r.obtainAttributes(attrs, com.android.internal.R.styleable.Drawable); 1057 inflateWithAttributes(r, parser, a, com.android.internal.R.styleable.Drawable_visible); 1058 a.recycle(); 1059 } 1060 1061 /** 1062 * Inflate a Drawable from an XML resource. 1063 * 1064 * @throws XmlPullParserException 1065 * @throws IOException 1066 */ 1067 void inflateWithAttributes(Resources r, XmlPullParser parser, 1068 TypedArray attrs, int visibleAttr) 1069 throws XmlPullParserException, IOException { 1070 1071 mVisible = attrs.getBoolean(visibleAttr, mVisible); 1072 } 1073 1074 /** 1075 * This abstract class is used by {@link Drawable}s to store shared constant state and data 1076 * between Drawables. {@link BitmapDrawable}s created from the same resource will for instance 1077 * share a unique bitmap stored in their ConstantState. 1078 * 1079 * <p> 1080 * {@link #newDrawable(Resources)} can be used as a factory to create new Drawable instances 1081 * from this ConstantState. 1082 * </p> 1083 * 1084 * Use {@link Drawable#getConstantState()} to retrieve the ConstantState of a Drawable. Calling 1085 * {@link Drawable#mutate()} on a Drawable should typically create a new ConstantState for that 1086 * Drawable. 1087 */ 1088 public static abstract class ConstantState { 1089 /** 1090 * Create a new drawable without supplying resources the caller 1091 * is running in. Note that using this means the density-dependent 1092 * drawables (like bitmaps) will not be able to update their target 1093 * density correctly. One should use {@link #newDrawable(Resources)} 1094 * instead to provide a resource. 1095 */ 1096 public abstract Drawable newDrawable(); 1097 /** 1098 * Create a new Drawable instance from its constant state. This 1099 * must be implemented for drawables that change based on the target 1100 * density of their caller (that is depending on whether it is 1101 * in compatibility mode). 1102 */ 1103 public Drawable newDrawable(Resources res) { 1104 return newDrawable(); 1105 } 1106 /** 1107 * Return a bit mask of configuration changes that will impact 1108 * this drawable (and thus require completely reloading it). 1109 */ 1110 public abstract int getChangingConfigurations(); 1111 1112 /** 1113 * @hide 1114 */ 1115 public Bitmap getBitmap() { 1116 return null; 1117 } 1118 } 1119 1120 /** 1121 * Return a {@link ConstantState} instance that holds the shared state of this Drawable. 1122 * 1123 * @return The ConstantState associated to that Drawable. 1124 * @see ConstantState 1125 * @see Drawable#mutate() 1126 */ 1127 public ConstantState getConstantState() { 1128 return null; 1129 } 1130 1131 private static Drawable drawableFromBitmap(Resources res, Bitmap bm, byte[] np, 1132 Rect pad, Rect layoutBounds, String srcName) { 1133 1134 if (np != null) { 1135 return new NinePatchDrawable(res, bm, np, pad, layoutBounds, srcName); 1136 } 1137 1138 return new BitmapDrawable(res, bm); 1139 } 1140 1141 /** 1142 * Parses a {@link android.graphics.PorterDuff.Mode} from a tintMode 1143 * attribute's enum value. 1144 */ 1145 static PorterDuff.Mode parseTintMode(int value, Mode defaultMode) { 1146 switch (value) { 1147 case 0: 1148 return Mode.SRC_IN; 1149 case 1: 1150 return Mode.SRC_ATOP; 1151 case 2: 1152 return Mode.MULTIPLY; 1153 case 3: 1154 return Mode.SCREEN; 1155 } 1156 return defaultMode; 1157 } 1158} 1159 1160