Drawable.java revision f4c068b72e2dee2e6944488ef00b64c93217d7e8
1/* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package android.graphics.drawable; 18 19import android.annotation.NonNull; 20import android.content.res.ColorStateList; 21import android.content.res.Resources; 22import android.content.res.Resources.Theme; 23import android.content.res.TypedArray; 24import android.graphics.Bitmap; 25import android.graphics.BitmapFactory; 26import android.graphics.Canvas; 27import android.graphics.Color; 28import android.graphics.ColorFilter; 29import android.graphics.Insets; 30import android.graphics.NinePatch; 31import android.graphics.Outline; 32import android.graphics.PixelFormat; 33import android.graphics.PorterDuff; 34import android.graphics.PorterDuff.Mode; 35import android.graphics.PorterDuffColorFilter; 36import android.graphics.Rect; 37import android.graphics.Region; 38import android.graphics.Xfermode; 39import android.os.Trace; 40import android.util.AttributeSet; 41import android.util.DisplayMetrics; 42import android.util.StateSet; 43import android.util.TypedValue; 44import android.util.Xml; 45import android.view.View; 46 47import org.xmlpull.v1.XmlPullParser; 48import org.xmlpull.v1.XmlPullParserException; 49 50import java.io.IOException; 51import java.io.InputStream; 52import java.lang.ref.WeakReference; 53import java.util.Arrays; 54import java.util.Collection; 55 56/** 57 * A Drawable is a general abstraction for "something that can be drawn." Most 58 * often you will deal with Drawable as the type of resource retrieved for 59 * drawing things to the screen; the Drawable class provides a generic API for 60 * dealing with an underlying visual resource that may take a variety of forms. 61 * Unlike a {@link android.view.View}, a Drawable does not have any facility to 62 * receive events or otherwise interact with the user. 63 * 64 * <p>In addition to simple drawing, Drawable provides a number of generic 65 * mechanisms for its client to interact with what is being drawn: 66 * 67 * <ul> 68 * <li> The {@link #setBounds} method <var>must</var> be called to tell the 69 * Drawable where it is drawn and how large it should be. All Drawables 70 * should respect the requested size, often simply by scaling their 71 * imagery. A client can find the preferred size for some Drawables with 72 * the {@link #getIntrinsicHeight} and {@link #getIntrinsicWidth} methods. 73 * 74 * <li> The {@link #getPadding} method can return from some Drawables 75 * information about how to frame content that is placed inside of them. 76 * For example, a Drawable that is intended to be the frame for a button 77 * widget would need to return padding that correctly places the label 78 * inside of itself. 79 * 80 * <li> The {@link #setState} method allows the client to tell the Drawable 81 * in which state it is to be drawn, such as "focused", "selected", etc. 82 * Some drawables may modify their imagery based on the selected state. 83 * 84 * <li> The {@link #setLevel} method allows the client to supply a single 85 * continuous controller that can modify the Drawable is displayed, such as 86 * a battery level or progress level. Some drawables may modify their 87 * imagery based on the current level. 88 * 89 * <li> A Drawable can perform animations by calling back to its client 90 * through the {@link Callback} interface. All clients should support this 91 * interface (via {@link #setCallback}) so that animations will work. A 92 * simple way to do this is through the system facilities such as 93 * {@link android.view.View#setBackground(Drawable)} and 94 * {@link android.widget.ImageView}. 95 * </ul> 96 * 97 * Though usually not visible to the application, Drawables may take a variety 98 * of forms: 99 * 100 * <ul> 101 * <li> <b>Bitmap</b>: the simplest Drawable, a PNG or JPEG image. 102 * <li> <b>Nine Patch</b>: an extension to the PNG format allows it to 103 * specify information about how to stretch it and place things inside of 104 * it. 105 * <li> <b>Shape</b>: contains simple drawing commands instead of a raw 106 * bitmap, allowing it to resize better in some cases. 107 * <li> <b>Layers</b>: a compound drawable, which draws multiple underlying 108 * drawables on top of each other. 109 * <li> <b>States</b>: a compound drawable that selects one of a set of 110 * drawables based on its state. 111 * <li> <b>Levels</b>: a compound drawable that selects one of a set of 112 * drawables based on its level. 113 * <li> <b>Scale</b>: a compound drawable with a single child drawable, 114 * whose overall size is modified based on the current level. 115 * </ul> 116 * 117 * <div class="special reference"> 118 * <h3>Developer Guides</h3> 119 * <p>For more information about how to use drawables, read the 120 * <a href="{@docRoot}guide/topics/graphics/2d-graphics.html">Canvas and Drawables</a> developer 121 * guide. For information and examples of creating drawable resources (XML or bitmap files that 122 * can be loaded in code), read the 123 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a> 124 * document.</p></div> 125 */ 126public abstract class Drawable { 127 private static final Rect ZERO_BOUNDS_RECT = new Rect(); 128 129 static final PorterDuff.Mode DEFAULT_TINT_MODE = PorterDuff.Mode.SRC_IN; 130 131 private int[] mStateSet = StateSet.WILD_CARD; 132 private int mLevel = 0; 133 private int mChangingConfigurations = 0; 134 private Rect mBounds = ZERO_BOUNDS_RECT; // lazily becomes a new Rect() 135 private WeakReference<Callback> mCallback = null; 136 private boolean mVisible = true; 137 138 private int mLayoutDirection; 139 140 /** 141 * Draw in its bounds (set via setBounds) respecting optional effects such 142 * as alpha (set via setAlpha) and color filter (set via setColorFilter). 143 * 144 * @param canvas The canvas to draw into 145 */ 146 public abstract void draw(Canvas canvas); 147 148 /** 149 * Specify a bounding rectangle for the Drawable. This is where the drawable 150 * will draw when its draw() method is called. 151 */ 152 public void setBounds(int left, int top, int right, int bottom) { 153 Rect oldBounds = mBounds; 154 155 if (oldBounds == ZERO_BOUNDS_RECT) { 156 oldBounds = mBounds = new Rect(); 157 } 158 159 if (oldBounds.left != left || oldBounds.top != top || 160 oldBounds.right != right || oldBounds.bottom != bottom) { 161 if (!oldBounds.isEmpty()) { 162 // first invalidate the previous bounds 163 invalidateSelf(); 164 } 165 mBounds.set(left, top, right, bottom); 166 onBoundsChange(mBounds); 167 } 168 } 169 170 /** 171 * Specify a bounding rectangle for the Drawable. This is where the drawable 172 * will draw when its draw() method is called. 173 */ 174 public void setBounds(Rect bounds) { 175 setBounds(bounds.left, bounds.top, bounds.right, bounds.bottom); 176 } 177 178 /** 179 * Return a copy of the drawable's bounds in the specified Rect (allocated 180 * by the caller). The bounds specify where this will draw when its draw() 181 * method is called. 182 * 183 * @param bounds Rect to receive the drawable's bounds (allocated by the 184 * caller). 185 */ 186 public final void copyBounds(Rect bounds) { 187 bounds.set(mBounds); 188 } 189 190 /** 191 * Return a copy of the drawable's bounds in a new Rect. This returns the 192 * same values as getBounds(), but the returned object is guaranteed to not 193 * be changed later by the drawable (i.e. it retains no reference to this 194 * rect). If the caller already has a Rect allocated, call copyBounds(rect). 195 * 196 * @return A copy of the drawable's bounds 197 */ 198 public final Rect copyBounds() { 199 return new Rect(mBounds); 200 } 201 202 /** 203 * Return the drawable's bounds Rect. Note: for efficiency, the returned 204 * object may be the same object stored in the drawable (though this is not 205 * guaranteed), so if a persistent copy of the bounds is needed, call 206 * copyBounds(rect) instead. 207 * You should also not change the object returned by this method as it may 208 * be the same object stored in the drawable. 209 * 210 * @return The bounds of the drawable (which may change later, so caller 211 * beware). DO NOT ALTER the returned object as it may change the 212 * stored bounds of this drawable. 213 * 214 * @see #copyBounds() 215 * @see #copyBounds(android.graphics.Rect) 216 */ 217 public final Rect getBounds() { 218 if (mBounds == ZERO_BOUNDS_RECT) { 219 mBounds = new Rect(); 220 } 221 222 return mBounds; 223 } 224 225 /** 226 * Return the drawable's dirty bounds Rect. Note: for efficiency, the 227 * returned object may be the same object stored in the drawable (though 228 * this is not guaranteed). 229 * <p> 230 * By default, this returns the full drawable bounds. Custom drawables may 231 * override this method to perform more precise invalidation. 232 * 233 * @return The dirty bounds of this drawable 234 */ 235 public Rect getDirtyBounds() { 236 return getBounds(); 237 } 238 239 /** 240 * Set a mask of the configuration parameters for which this drawable 241 * may change, requiring that it be re-created. 242 * 243 * @param configs A mask of the changing configuration parameters, as 244 * defined by {@link android.content.pm.ActivityInfo}. 245 * 246 * @see android.content.pm.ActivityInfo 247 */ 248 public void setChangingConfigurations(int configs) { 249 mChangingConfigurations = configs; 250 } 251 252 /** 253 * Return a mask of the configuration parameters for which this drawable 254 * may change, requiring that it be re-created. The default implementation 255 * returns whatever was provided through 256 * {@link #setChangingConfigurations(int)} or 0 by default. Subclasses 257 * may extend this to or in the changing configurations of any other 258 * drawables they hold. 259 * 260 * @return Returns a mask of the changing configuration parameters, as 261 * defined by {@link android.content.pm.ActivityInfo}. 262 * 263 * @see android.content.pm.ActivityInfo 264 */ 265 public int getChangingConfigurations() { 266 return mChangingConfigurations; 267 } 268 269 /** 270 * Set to true to have the drawable dither its colors when drawn to a device 271 * with fewer than 8-bits per color component. This can improve the look on 272 * those devices, but can also slow down the drawing a little. 273 */ 274 public void setDither(boolean dither) {} 275 276 /** 277 * @return whether this drawable dither its colors 278 * @see #setDither(boolean) 279 */ 280 public boolean getDither() { 281 return false; 282 } 283 284 /** 285 * Set to true to have the drawable filter its bitmap when scaled or rotated 286 * (for drawables that use bitmaps). If the drawable does not use bitmaps, 287 * this call is ignored. This can improve the look when scaled or rotated, 288 * but also slows down the drawing. 289 */ 290 public void setFilterBitmap(boolean filter) {} 291 292 /** 293 * @return whether this drawable filters its bitmap 294 * @see #setFilterBitmap(boolean) 295 */ 296 public boolean getFilterBitmap() { 297 return false; 298 } 299 300 /** 301 * Implement this interface if you want to create an animated drawable that 302 * extends {@link android.graphics.drawable.Drawable Drawable}. 303 * Upon retrieving a drawable, use 304 * {@link Drawable#setCallback(android.graphics.drawable.Drawable.Callback)} 305 * to supply your implementation of the interface to the drawable; it uses 306 * this interface to schedule and execute animation changes. 307 */ 308 public static interface Callback { 309 /** 310 * Called when the drawable needs to be redrawn. A view at this point 311 * should invalidate itself (or at least the part of itself where the 312 * drawable appears). 313 * 314 * @param who The drawable that is requesting the update. 315 */ 316 public void invalidateDrawable(Drawable who); 317 318 /** 319 * A Drawable can call this to schedule the next frame of its 320 * animation. An implementation can generally simply call 321 * {@link android.os.Handler#postAtTime(Runnable, Object, long)} with 322 * the parameters <var>(what, who, when)</var> to perform the 323 * scheduling. 324 * 325 * @param who The drawable being scheduled. 326 * @param what The action to execute. 327 * @param when The time (in milliseconds) to run. The timebase is 328 * {@link android.os.SystemClock#uptimeMillis} 329 */ 330 public void scheduleDrawable(Drawable who, Runnable what, long when); 331 332 /** 333 * A Drawable can call this to unschedule an action previously 334 * scheduled with {@link #scheduleDrawable}. An implementation can 335 * generally simply call 336 * {@link android.os.Handler#removeCallbacks(Runnable, Object)} with 337 * the parameters <var>(what, who)</var> to unschedule the drawable. 338 * 339 * @param who The drawable being unscheduled. 340 * @param what The action being unscheduled. 341 */ 342 public void unscheduleDrawable(Drawable who, Runnable what); 343 } 344 345 /** 346 * Bind a {@link Callback} object to this Drawable. Required for clients 347 * that want to support animated drawables. 348 * 349 * @param cb The client's Callback implementation. 350 * 351 * @see #getCallback() 352 */ 353 public final void setCallback(Callback cb) { 354 mCallback = new WeakReference<Callback>(cb); 355 } 356 357 /** 358 * Return the current {@link Callback} implementation attached to this 359 * Drawable. 360 * 361 * @return A {@link Callback} instance or null if no callback was set. 362 * 363 * @see #setCallback(android.graphics.drawable.Drawable.Callback) 364 */ 365 public Callback getCallback() { 366 if (mCallback != null) { 367 return mCallback.get(); 368 } 369 return null; 370 } 371 372 /** 373 * Use the current {@link Callback} implementation to have this Drawable 374 * redrawn. Does nothing if there is no Callback attached to the 375 * Drawable. 376 * 377 * @see Callback#invalidateDrawable 378 * @see #getCallback() 379 * @see #setCallback(android.graphics.drawable.Drawable.Callback) 380 */ 381 public void invalidateSelf() { 382 final Callback callback = getCallback(); 383 if (callback != null) { 384 callback.invalidateDrawable(this); 385 } 386 } 387 388 /** 389 * Use the current {@link Callback} implementation to have this Drawable 390 * scheduled. Does nothing if there is no Callback attached to the 391 * Drawable. 392 * 393 * @param what The action being scheduled. 394 * @param when The time (in milliseconds) to run. 395 * 396 * @see Callback#scheduleDrawable 397 */ 398 public void scheduleSelf(Runnable what, long when) { 399 final Callback callback = getCallback(); 400 if (callback != null) { 401 callback.scheduleDrawable(this, what, when); 402 } 403 } 404 405 /** 406 * Use the current {@link Callback} implementation to have this Drawable 407 * unscheduled. Does nothing if there is no Callback attached to the 408 * Drawable. 409 * 410 * @param what The runnable that you no longer want called. 411 * 412 * @see Callback#unscheduleDrawable 413 */ 414 public void unscheduleSelf(Runnable what) { 415 final Callback callback = getCallback(); 416 if (callback != null) { 417 callback.unscheduleDrawable(this, what); 418 } 419 } 420 421 /** 422 * Returns the resolved layout direction for this Drawable. 423 * 424 * @return One of {@link android.view.View#LAYOUT_DIRECTION_LTR}, 425 * {@link android.view.View#LAYOUT_DIRECTION_RTL} 426 * 427 * @hide 428 */ 429 public int getLayoutDirection() { 430 return mLayoutDirection; 431 } 432 433 /** 434 * Set the layout direction for this drawable. Should be a resolved direction as the 435 * Drawable as no capacity to do the resolution on his own. 436 * 437 * @param layoutDirection One of {@link android.view.View#LAYOUT_DIRECTION_LTR}, 438 * {@link android.view.View#LAYOUT_DIRECTION_RTL} 439 * 440 * @hide 441 */ 442 public void setLayoutDirection(@View.ResolvedLayoutDir int layoutDirection) { 443 if (getLayoutDirection() != layoutDirection) { 444 mLayoutDirection = layoutDirection; 445 } 446 } 447 448 /** 449 * Specify an alpha value for the drawable. 0 means fully transparent, and 450 * 255 means fully opaque. 451 */ 452 public abstract void setAlpha(int alpha); 453 454 /** 455 * Gets the current alpha value for the drawable. 0 means fully transparent, 456 * 255 means fully opaque. This method is implemented by 457 * Drawable subclasses and the value returned is specific to how that class treats alpha. 458 * The default return value is 255 if the class does not override this method to return a value 459 * specific to its use of alpha. 460 */ 461 public int getAlpha() { 462 return 0xFF; 463 } 464 465 /** 466 * @hide Consider for future API inclusion 467 */ 468 public void setXfermode(Xfermode mode) { 469 // Base implementation drops it on the floor for compatibility. Whee! 470 // TODO: For this to be included in the API proper, all framework drawables need impls. 471 // For right now only BitmapDrawable has it. 472 } 473 474 /** 475 * Specify an optional color filter for the drawable. Pass {@code null} to 476 * remove any existing color filter. 477 * 478 * @param cf the color filter to apply, or {@code null} to remove the 479 * existing color filter 480 */ 481 public abstract void setColorFilter(ColorFilter cf); 482 483 /** 484 * Specify a color and Porter-Duff mode to be the color filter for this 485 * drawable. 486 */ 487 public void setColorFilter(int color, PorterDuff.Mode mode) { 488 setColorFilter(new PorterDuffColorFilter(color, mode)); 489 } 490 491 /** 492 * Specifies a tint for this drawable. 493 * <p> 494 * Setting a color filter via {@link #setColorFilter(ColorFilter)} overrides 495 * tint. 496 * 497 * @param tint Color to use for tinting this drawable 498 * @see #setTintMode(PorterDuff.Mode) 499 */ 500 public void setTint(int tint) { 501 setTintList(ColorStateList.valueOf(tint)); 502 } 503 504 /** 505 * Specifies a tint for this drawable as a color state list. 506 * <p> 507 * Setting a color filter via {@link #setColorFilter(ColorFilter)} overrides 508 * tint. 509 * 510 * @param tint Color state list to use for tinting this drawable, or null to 511 * clear the tint 512 * @see #setTintMode(PorterDuff.Mode) 513 */ 514 public void setTintList(ColorStateList tint) {} 515 516 /** 517 * Specifies a tint blending mode for this drawable. 518 * <p> 519 * Setting a color filter via {@link #setColorFilter(ColorFilter)} overrides 520 * tint. 521 * 522 * @param tintMode Color state list to use for tinting this drawable, or null to 523 * clear the tint 524 * @param tintMode A Porter-Duff blending mode 525 */ 526 public void setTintMode(PorterDuff.Mode tintMode) {} 527 528 /** 529 * Returns the current color filter, or {@code null} if none set. 530 * 531 * @return the current color filter, or {@code null} if none set 532 */ 533 public ColorFilter getColorFilter() { 534 return null; 535 } 536 537 /** 538 * Removes the color filter for this drawable. 539 */ 540 public void clearColorFilter() { 541 setColorFilter(null); 542 } 543 544 /** 545 * Specifies the hotspot's location within the drawable. 546 * 547 * @param x The X coordinate of the center of the hotspot 548 * @param y The Y coordinate of the center of the hotspot 549 */ 550 public void setHotspot(float x, float y) {} 551 552 /** 553 * Sets the bounds to which the hotspot is constrained, if they should be 554 * different from the drawable bounds. 555 * 556 * @param left 557 * @param top 558 * @param right 559 * @param bottom 560 */ 561 public void setHotspotBounds(int left, int top, int right, int bottom) {} 562 563 /** @hide For internal use only. Individual results may vary. */ 564 public void getHotspotBounds(Rect outRect) { 565 outRect.set(getBounds()); 566 } 567 568 /** 569 * Whether this drawable requests projection. 570 * 571 * @hide magic! 572 */ 573 public boolean isProjected() { 574 return false; 575 } 576 577 /** 578 * Indicates whether this drawable will change its appearance based on 579 * state. Clients can use this to determine whether it is necessary to 580 * calculate their state and call setState. 581 * 582 * @return True if this drawable changes its appearance based on state, 583 * false otherwise. 584 * @see #setState(int[]) 585 */ 586 public boolean isStateful() { 587 return false; 588 } 589 590 /** 591 * Specify a set of states for the drawable. These are use-case specific, 592 * so see the relevant documentation. As an example, the background for 593 * widgets like Button understand the following states: 594 * [{@link android.R.attr#state_focused}, 595 * {@link android.R.attr#state_pressed}]. 596 * 597 * <p>If the new state you are supplying causes the appearance of the 598 * Drawable to change, then it is responsible for calling 599 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 600 * true will be returned from this function. 601 * 602 * <p>Note: The Drawable holds a reference on to <var>stateSet</var> 603 * until a new state array is given to it, so you must not modify this 604 * array during that time.</p> 605 * 606 * @param stateSet The new set of states to be displayed. 607 * 608 * @return Returns true if this change in state has caused the appearance 609 * of the Drawable to change (hence requiring an invalidate), otherwise 610 * returns false. 611 */ 612 public boolean setState(final int[] stateSet) { 613 if (!Arrays.equals(mStateSet, stateSet)) { 614 mStateSet = stateSet; 615 return onStateChange(stateSet); 616 } 617 return false; 618 } 619 620 /** 621 * Describes the current state, as a union of primitve states, such as 622 * {@link android.R.attr#state_focused}, 623 * {@link android.R.attr#state_selected}, etc. 624 * Some drawables may modify their imagery based on the selected state. 625 * @return An array of resource Ids describing the current state. 626 */ 627 public int[] getState() { 628 return mStateSet; 629 } 630 631 /** 632 * If this Drawable does transition animations between states, ask that 633 * it immediately jump to the current state and skip any active animations. 634 */ 635 public void jumpToCurrentState() { 636 } 637 638 /** 639 * @return The current drawable that will be used by this drawable. For simple drawables, this 640 * is just the drawable itself. For drawables that change state like 641 * {@link StateListDrawable} and {@link LevelListDrawable} this will be the child drawable 642 * currently in use. 643 */ 644 public Drawable getCurrent() { 645 return this; 646 } 647 648 /** 649 * Specify the level for the drawable. This allows a drawable to vary its 650 * imagery based on a continuous controller, for example to show progress 651 * or volume level. 652 * 653 * <p>If the new level you are supplying causes the appearance of the 654 * Drawable to change, then it is responsible for calling 655 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 656 * true will be returned from this function. 657 * 658 * @param level The new level, from 0 (minimum) to 10000 (maximum). 659 * 660 * @return Returns true if this change in level has caused the appearance 661 * of the Drawable to change (hence requiring an invalidate), otherwise 662 * returns false. 663 */ 664 public final boolean setLevel(int level) { 665 if (mLevel != level) { 666 mLevel = level; 667 return onLevelChange(level); 668 } 669 return false; 670 } 671 672 /** 673 * Retrieve the current level. 674 * 675 * @return int Current level, from 0 (minimum) to 10000 (maximum). 676 */ 677 public final int getLevel() { 678 return mLevel; 679 } 680 681 /** 682 * Set whether this Drawable is visible. This generally does not impact 683 * the Drawable's behavior, but is a hint that can be used by some 684 * Drawables, for example, to decide whether run animations. 685 * 686 * @param visible Set to true if visible, false if not. 687 * @param restart You can supply true here to force the drawable to behave 688 * as if it has just become visible, even if it had last 689 * been set visible. Used for example to force animations 690 * to restart. 691 * 692 * @return boolean Returns true if the new visibility is different than 693 * its previous state. 694 */ 695 public boolean setVisible(boolean visible, boolean restart) { 696 boolean changed = mVisible != visible; 697 if (changed) { 698 mVisible = visible; 699 invalidateSelf(); 700 } 701 return changed; 702 } 703 704 public final boolean isVisible() { 705 return mVisible; 706 } 707 708 /** 709 * Set whether this Drawable is automatically mirrored when its layout direction is RTL 710 * (right-to left). See {@link android.util.LayoutDirection}. 711 * 712 * @param mirrored Set to true if the Drawable should be mirrored, false if not. 713 */ 714 public void setAutoMirrored(boolean mirrored) { 715 } 716 717 /** 718 * Tells if this Drawable will be automatically mirrored when its layout direction is RTL 719 * right-to-left. See {@link android.util.LayoutDirection}. 720 * 721 * @return boolean Returns true if this Drawable will be automatically mirrored. 722 */ 723 public boolean isAutoMirrored() { 724 return false; 725 } 726 727 /** 728 * Applies the specified theme to this Drawable and its children. 729 */ 730 public void applyTheme(@SuppressWarnings("unused") Theme t) { 731 } 732 733 public boolean canApplyTheme() { 734 return false; 735 } 736 737 /** 738 * Return the opacity/transparency of this Drawable. The returned value is 739 * one of the abstract format constants in 740 * {@link android.graphics.PixelFormat}: 741 * {@link android.graphics.PixelFormat#UNKNOWN}, 742 * {@link android.graphics.PixelFormat#TRANSLUCENT}, 743 * {@link android.graphics.PixelFormat#TRANSPARENT}, or 744 * {@link android.graphics.PixelFormat#OPAQUE}. 745 * 746 * <p>Generally a Drawable should be as conservative as possible with the 747 * value it returns. For example, if it contains multiple child drawables 748 * and only shows one of them at a time, if only one of the children is 749 * TRANSLUCENT and the others are OPAQUE then TRANSLUCENT should be 750 * returned. You can use the method {@link #resolveOpacity} to perform a 751 * standard reduction of two opacities to the appropriate single output. 752 * 753 * <p>Note that the returned value does <em>not</em> take into account a 754 * custom alpha or color filter that has been applied by the client through 755 * the {@link #setAlpha} or {@link #setColorFilter} methods. 756 * 757 * @return int The opacity class of the Drawable. 758 * 759 * @see android.graphics.PixelFormat 760 */ 761 public abstract int getOpacity(); 762 763 /** 764 * Return the appropriate opacity value for two source opacities. If 765 * either is UNKNOWN, that is returned; else, if either is TRANSLUCENT, 766 * that is returned; else, if either is TRANSPARENT, that is returned; 767 * else, OPAQUE is returned. 768 * 769 * <p>This is to help in implementing {@link #getOpacity}. 770 * 771 * @param op1 One opacity value. 772 * @param op2 Another opacity value. 773 * 774 * @return int The combined opacity value. 775 * 776 * @see #getOpacity 777 */ 778 public static int resolveOpacity(int op1, int op2) { 779 if (op1 == op2) { 780 return op1; 781 } 782 if (op1 == PixelFormat.UNKNOWN || op2 == PixelFormat.UNKNOWN) { 783 return PixelFormat.UNKNOWN; 784 } 785 if (op1 == PixelFormat.TRANSLUCENT || op2 == PixelFormat.TRANSLUCENT) { 786 return PixelFormat.TRANSLUCENT; 787 } 788 if (op1 == PixelFormat.TRANSPARENT || op2 == PixelFormat.TRANSPARENT) { 789 return PixelFormat.TRANSPARENT; 790 } 791 return PixelFormat.OPAQUE; 792 } 793 794 /** 795 * Returns a Region representing the part of the Drawable that is completely 796 * transparent. This can be used to perform drawing operations, identifying 797 * which parts of the target will not change when rendering the Drawable. 798 * The default implementation returns null, indicating no transparent 799 * region; subclasses can optionally override this to return an actual 800 * Region if they want to supply this optimization information, but it is 801 * not required that they do so. 802 * 803 * @return Returns null if the Drawables has no transparent region to 804 * report, else a Region holding the parts of the Drawable's bounds that 805 * are transparent. 806 */ 807 public Region getTransparentRegion() { 808 return null; 809 } 810 811 /** 812 * Override this in your subclass to change appearance if you recognize the 813 * specified state. 814 * 815 * @return Returns true if the state change has caused the appearance of 816 * the Drawable to change (that is, it needs to be drawn), else false 817 * if it looks the same and there is no need to redraw it since its 818 * last state. 819 */ 820 protected boolean onStateChange(int[] state) { return false; } 821 /** Override this in your subclass to change appearance if you vary based 822 * on level. 823 * @return Returns true if the level change has caused the appearance of 824 * the Drawable to change (that is, it needs to be drawn), else false 825 * if it looks the same and there is no need to redraw it since its 826 * last level. 827 */ 828 protected boolean onLevelChange(int level) { return false; } 829 /** 830 * Override this in your subclass to change appearance if you vary based on 831 * the bounds. 832 */ 833 protected void onBoundsChange(Rect bounds) {} 834 835 /** 836 * Return the intrinsic width of the underlying drawable object. Returns 837 * -1 if it has no intrinsic width, such as with a solid color. 838 */ 839 public int getIntrinsicWidth() { 840 return -1; 841 } 842 843 /** 844 * Return the intrinsic height of the underlying drawable object. Returns 845 * -1 if it has no intrinsic height, such as with a solid color. 846 */ 847 public int getIntrinsicHeight() { 848 return -1; 849 } 850 851 /** 852 * Returns the minimum width suggested by this Drawable. If a View uses this 853 * Drawable as a background, it is suggested that the View use at least this 854 * value for its width. (There will be some scenarios where this will not be 855 * possible.) This value should INCLUDE any padding. 856 * 857 * @return The minimum width suggested by this Drawable. If this Drawable 858 * doesn't have a suggested minimum width, 0 is returned. 859 */ 860 public int getMinimumWidth() { 861 final int intrinsicWidth = getIntrinsicWidth(); 862 return intrinsicWidth > 0 ? intrinsicWidth : 0; 863 } 864 865 /** 866 * Returns the minimum height suggested by this Drawable. If a View uses this 867 * Drawable as a background, it is suggested that the View use at least this 868 * value for its height. (There will be some scenarios where this will not be 869 * possible.) This value should INCLUDE any padding. 870 * 871 * @return The minimum height suggested by this Drawable. If this Drawable 872 * doesn't have a suggested minimum height, 0 is returned. 873 */ 874 public int getMinimumHeight() { 875 final int intrinsicHeight = getIntrinsicHeight(); 876 return intrinsicHeight > 0 ? intrinsicHeight : 0; 877 } 878 879 /** 880 * Return in padding the insets suggested by this Drawable for placing 881 * content inside the drawable's bounds. Positive values move toward the 882 * center of the Drawable (set Rect.inset). 883 * 884 * @return true if this drawable actually has a padding, else false. When false is returned, 885 * the padding is always set to 0. 886 */ 887 public boolean getPadding(@NonNull Rect padding) { 888 padding.set(0, 0, 0, 0); 889 return false; 890 } 891 892 /** 893 * Return in insets the layout insets suggested by this Drawable for use with alignment 894 * operations during layout. 895 * 896 * @hide 897 */ 898 public Insets getOpticalInsets() { 899 return Insets.NONE; 900 } 901 902 /** 903 * Called to get the drawable to populate the Outline that defines its drawing area. 904 * <p> 905 * This method is called by the default {@link android.view.ViewOutlineProvider} to define 906 * the outline of the View. 907 * <p> 908 * The default behavior defines the outline to be the bounding rectangle of 0 alpha. 909 * Subclasses that wish to convey a different shape or alpha value must override this method. 910 * 911 * @see android.view.View#setOutlineProvider(android.view.ViewOutlineProvider) 912 */ 913 public void getOutline(@NonNull Outline outline) { 914 outline.setRect(getBounds()); 915 outline.setAlpha(0); 916 } 917 918 /** 919 * Make this drawable mutable. This operation cannot be reversed. A mutable 920 * drawable is guaranteed to not share its state with any other drawable. 921 * This is especially useful when you need to modify properties of drawables 922 * loaded from resources. By default, all drawables instances loaded from 923 * the same resource share a common state; if you modify the state of one 924 * instance, all the other instances will receive the same modification. 925 * 926 * Calling this method on a mutable Drawable will have no effect. 927 * 928 * @return This drawable. 929 * @see ConstantState 930 * @see #getConstantState() 931 */ 932 public Drawable mutate() { 933 return this; 934 } 935 936 /** 937 * Clears the mutated state, allowing this drawable to be cached and 938 * mutated again. 939 * <p> 940 * This is hidden because only framework drawables can be cached, so 941 * custom drawables don't need to support constant state, mutate(), or 942 * clearMutated(). 943 * 944 * @hide 945 */ 946 public void clearMutated() { 947 // Default implementation is no-op. 948 } 949 950 /** 951 * Create a drawable from an inputstream 952 */ 953 public static Drawable createFromStream(InputStream is, String srcName) { 954 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, srcName != null ? srcName : "Unknown drawable"); 955 try { 956 return createFromResourceStream(null, null, is, srcName); 957 } finally { 958 Trace.traceEnd(Trace.TRACE_TAG_RESOURCES); 959 } 960 } 961 962 /** 963 * Create a drawable from an inputstream, using the given resources and 964 * value to determine density information. 965 */ 966 public static Drawable createFromResourceStream(Resources res, TypedValue value, 967 InputStream is, String srcName) { 968 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, srcName != null ? srcName : "Unknown drawable"); 969 try { 970 return createFromResourceStream(res, value, is, srcName, null); 971 } finally { 972 Trace.traceEnd(Trace.TRACE_TAG_RESOURCES); 973 } 974 } 975 976 /** 977 * Create a drawable from an inputstream, using the given resources and 978 * value to determine density information. 979 */ 980 public static Drawable createFromResourceStream(Resources res, TypedValue value, 981 InputStream is, String srcName, BitmapFactory.Options opts) { 982 if (is == null) { 983 return null; 984 } 985 986 /* ugh. The decodeStream contract is that we have already allocated 987 the pad rect, but if the bitmap does not had a ninepatch chunk, 988 then the pad will be ignored. If we could change this to lazily 989 alloc/assign the rect, we could avoid the GC churn of making new 990 Rects only to drop them on the floor. 991 */ 992 Rect pad = new Rect(); 993 994 // Special stuff for compatibility mode: if the target density is not 995 // the same as the display density, but the resource -is- the same as 996 // the display density, then don't scale it down to the target density. 997 // This allows us to load the system's density-correct resources into 998 // an application in compatibility mode, without scaling those down 999 // to the compatibility density only to have them scaled back up when 1000 // drawn to the screen. 1001 if (opts == null) opts = new BitmapFactory.Options(); 1002 opts.inScreenDensity = res != null 1003 ? res.getDisplayMetrics().noncompatDensityDpi : DisplayMetrics.DENSITY_DEVICE; 1004 Bitmap bm = BitmapFactory.decodeResourceStream(res, value, is, pad, opts); 1005 if (bm != null) { 1006 byte[] np = bm.getNinePatchChunk(); 1007 if (np == null || !NinePatch.isNinePatchChunk(np)) { 1008 np = null; 1009 pad = null; 1010 } 1011 1012 final Rect opticalInsets = new Rect(); 1013 bm.getOpticalInsets(opticalInsets); 1014 return drawableFromBitmap(res, bm, np, pad, opticalInsets, srcName); 1015 } 1016 return null; 1017 } 1018 1019 /** 1020 * Create a drawable from an XML document. For more information on how to 1021 * create resources in XML, see 1022 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. 1023 */ 1024 public static Drawable createFromXml(Resources r, XmlPullParser parser) 1025 throws XmlPullParserException, IOException { 1026 return createFromXml(r, parser, null); 1027 } 1028 1029 /** 1030 * Create a drawable from an XML document using an optional {@link Theme}. 1031 * For more information on how to create resources in XML, see 1032 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. 1033 */ 1034 public static Drawable createFromXml(Resources r, XmlPullParser parser, Theme theme) 1035 throws XmlPullParserException, IOException { 1036 AttributeSet attrs = Xml.asAttributeSet(parser); 1037 1038 int type; 1039 while ((type=parser.next()) != XmlPullParser.START_TAG && 1040 type != XmlPullParser.END_DOCUMENT) { 1041 // Empty loop 1042 } 1043 1044 if (type != XmlPullParser.START_TAG) { 1045 throw new XmlPullParserException("No start tag found"); 1046 } 1047 1048 Drawable drawable = createFromXmlInner(r, parser, attrs, theme); 1049 1050 if (drawable == null) { 1051 throw new RuntimeException("Unknown initial tag: " + parser.getName()); 1052 } 1053 1054 return drawable; 1055 } 1056 1057 /** 1058 * Create from inside an XML document. Called on a parser positioned at 1059 * a tag in an XML document, tries to create a Drawable from that tag. 1060 * Returns null if the tag is not a valid drawable. 1061 */ 1062 public static Drawable createFromXmlInner(Resources r, XmlPullParser parser, AttributeSet attrs) 1063 throws XmlPullParserException, IOException { 1064 return createFromXmlInner(r, parser, attrs, null); 1065 } 1066 1067 /** 1068 * Create a drawable from inside an XML document using an optional 1069 * {@link Theme}. Called on a parser positioned at a tag in an XML 1070 * document, tries to create a Drawable from that tag. Returns {@code null} 1071 * if the tag is not a valid drawable. 1072 */ 1073 public static Drawable createFromXmlInner(Resources r, XmlPullParser parser, AttributeSet attrs, 1074 Theme theme) throws XmlPullParserException, IOException { 1075 final Drawable drawable; 1076 1077 final String name = parser.getName(); 1078 switch (name) { 1079 case "selector": 1080 drawable = new StateListDrawable(); 1081 break; 1082 case "animated-selector": 1083 drawable = new AnimatedStateListDrawable(); 1084 break; 1085 case "level-list": 1086 drawable = new LevelListDrawable(); 1087 break; 1088 case "layer-list": 1089 drawable = new LayerDrawable(); 1090 break; 1091 case "transition": 1092 drawable = new TransitionDrawable(); 1093 break; 1094 case "ripple": 1095 drawable = new RippleDrawable(); 1096 break; 1097 case "color": 1098 drawable = new ColorDrawable(); 1099 break; 1100 case "shape": 1101 drawable = new GradientDrawable(); 1102 break; 1103 case "vector": 1104 drawable = new VectorDrawable(); 1105 break; 1106 case "animated-vector": 1107 drawable = new AnimatedVectorDrawable(); 1108 break; 1109 case "scale": 1110 drawable = new ScaleDrawable(); 1111 break; 1112 case "clip": 1113 drawable = new ClipDrawable(); 1114 break; 1115 case "rotate": 1116 drawable = new RotateDrawable(); 1117 break; 1118 case "animated-rotate": 1119 drawable = new AnimatedRotateDrawable(); 1120 break; 1121 case "animation-list": 1122 drawable = new AnimationDrawable(); 1123 break; 1124 case "inset": 1125 drawable = new InsetDrawable(); 1126 break; 1127 case "bitmap": 1128 drawable = new BitmapDrawable(r); 1129 if (r != null) { 1130 ((BitmapDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 1131 } 1132 break; 1133 case "nine-patch": 1134 drawable = new NinePatchDrawable(); 1135 if (r != null) { 1136 ((NinePatchDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 1137 } 1138 break; 1139 default: 1140 throw new XmlPullParserException(parser.getPositionDescription() + 1141 ": invalid drawable tag " + name); 1142 1143 } 1144 drawable.inflate(r, parser, attrs, theme); 1145 return drawable; 1146 } 1147 1148 1149 /** 1150 * Create a drawable from file path name. 1151 */ 1152 public static Drawable createFromPath(String pathName) { 1153 if (pathName == null) { 1154 return null; 1155 } 1156 1157 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, pathName); 1158 try { 1159 Bitmap bm = BitmapFactory.decodeFile(pathName); 1160 if (bm != null) { 1161 return drawableFromBitmap(null, bm, null, null, null, pathName); 1162 } 1163 } finally { 1164 Trace.traceEnd(Trace.TRACE_TAG_RESOURCES); 1165 } 1166 1167 return null; 1168 } 1169 1170 /** 1171 * Inflate this Drawable from an XML resource. Does not apply a theme. 1172 * 1173 * @see #inflate(Resources, XmlPullParser, AttributeSet, Theme) 1174 */ 1175 public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs) 1176 throws XmlPullParserException, IOException { 1177 inflate(r, parser, attrs, null); 1178 } 1179 1180 /** 1181 * Inflate this Drawable from an XML resource optionally styled by a theme. 1182 * 1183 * @param r Resources used to resolve attribute values 1184 * @param parser XML parser from which to inflate this Drawable 1185 * @param attrs Base set of attribute values 1186 * @param theme Theme to apply, may be null 1187 * @throws XmlPullParserException 1188 * @throws IOException 1189 */ 1190 public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs, Theme theme) 1191 throws XmlPullParserException, IOException { 1192 final TypedArray a; 1193 if (theme != null) { 1194 a = theme.obtainStyledAttributes( 1195 attrs, com.android.internal.R.styleable.Drawable, 0, 0); 1196 } else { 1197 a = r.obtainAttributes(attrs, com.android.internal.R.styleable.Drawable); 1198 } 1199 1200 inflateWithAttributes(r, parser, a, com.android.internal.R.styleable.Drawable_visible); 1201 a.recycle(); 1202 } 1203 1204 /** 1205 * Inflate a Drawable from an XML resource. 1206 * 1207 * @throws XmlPullParserException 1208 * @throws IOException 1209 */ 1210 void inflateWithAttributes(Resources r, XmlPullParser parser, TypedArray attrs, int visibleAttr) 1211 throws XmlPullParserException, IOException { 1212 mVisible = attrs.getBoolean(visibleAttr, mVisible); 1213 } 1214 1215 /** 1216 * This abstract class is used by {@link Drawable}s to store shared constant state and data 1217 * between Drawables. {@link BitmapDrawable}s created from the same resource will for instance 1218 * share a unique bitmap stored in their ConstantState. 1219 * 1220 * <p> 1221 * {@link #newDrawable(Resources)} can be used as a factory to create new Drawable instances 1222 * from this ConstantState. 1223 * </p> 1224 * 1225 * Use {@link Drawable#getConstantState()} to retrieve the ConstantState of a Drawable. Calling 1226 * {@link Drawable#mutate()} on a Drawable should typically create a new ConstantState for that 1227 * Drawable. 1228 */ 1229 public static abstract class ConstantState { 1230 /** 1231 * Create a new drawable without supplying resources the caller 1232 * is running in. Note that using this means the density-dependent 1233 * drawables (like bitmaps) will not be able to update their target 1234 * density correctly. One should use {@link #newDrawable(Resources)} 1235 * instead to provide a resource. 1236 */ 1237 public abstract Drawable newDrawable(); 1238 1239 /** 1240 * Create a new Drawable instance from its constant state. This 1241 * must be implemented for drawables that change based on the target 1242 * density of their caller (that is depending on whether it is 1243 * in compatibility mode). 1244 */ 1245 public Drawable newDrawable(Resources res) { 1246 return newDrawable(); 1247 } 1248 1249 /** 1250 * Create a new Drawable instance from its constant state. This must be 1251 * implemented for drawables that can have a theme applied. 1252 */ 1253 public Drawable newDrawable(Resources res, Theme theme) { 1254 return newDrawable(null); 1255 } 1256 1257 /** 1258 * Return a bit mask of configuration changes that will impact 1259 * this drawable (and thus require completely reloading it). 1260 */ 1261 public abstract int getChangingConfigurations(); 1262 1263 /** 1264 * @return Total pixel count 1265 * @hide 1266 */ 1267 public int addAtlasableBitmaps(Collection<Bitmap> atlasList) { 1268 return 0; 1269 } 1270 1271 /** @hide */ 1272 protected final boolean isAtlasable(Bitmap bitmap) { 1273 return bitmap != null && bitmap.getConfig() == Bitmap.Config.ARGB_8888; 1274 } 1275 1276 /** 1277 * Return whether this constant state can have a theme applied. 1278 */ 1279 public boolean canApplyTheme() { 1280 return false; 1281 } 1282 } 1283 1284 /** 1285 * Return a {@link ConstantState} instance that holds the shared state of this Drawable. 1286 * 1287 * @return The ConstantState associated to that Drawable. 1288 * @see ConstantState 1289 * @see Drawable#mutate() 1290 */ 1291 public ConstantState getConstantState() { 1292 return null; 1293 } 1294 1295 private static Drawable drawableFromBitmap(Resources res, Bitmap bm, byte[] np, 1296 Rect pad, Rect layoutBounds, String srcName) { 1297 1298 if (np != null) { 1299 return new NinePatchDrawable(res, bm, np, pad, layoutBounds, srcName); 1300 } 1301 1302 return new BitmapDrawable(res, bm); 1303 } 1304 1305 /** 1306 * Ensures the tint filter is consistent with the current tint color and 1307 * mode. 1308 */ 1309 PorterDuffColorFilter updateTintFilter(PorterDuffColorFilter tintFilter, ColorStateList tint, 1310 PorterDuff.Mode tintMode) { 1311 if (tint == null || tintMode == null) { 1312 return null; 1313 } 1314 1315 final int color = tint.getColorForState(getState(), Color.TRANSPARENT); 1316 if (tintFilter == null) { 1317 return new PorterDuffColorFilter(color, tintMode); 1318 } 1319 1320 tintFilter.setColor(color); 1321 tintFilter.setMode(tintMode); 1322 return tintFilter; 1323 } 1324 1325 /** 1326 * Obtains styled attributes from the theme, if available, or unstyled 1327 * resources if the theme is null. 1328 */ 1329 static TypedArray obtainAttributes( 1330 Resources res, Theme theme, AttributeSet set, int[] attrs) { 1331 if (theme == null) { 1332 return res.obtainAttributes(set, attrs); 1333 } 1334 return theme.obtainStyledAttributes(set, attrs, 0, 0); 1335 } 1336 1337 /** 1338 * Parses a {@link android.graphics.PorterDuff.Mode} from a tintMode 1339 * attribute's enum value. 1340 * 1341 * @hide 1342 */ 1343 public static PorterDuff.Mode parseTintMode(int value, Mode defaultMode) { 1344 switch (value) { 1345 case 3: return Mode.SRC_OVER; 1346 case 5: return Mode.SRC_IN; 1347 case 9: return Mode.SRC_ATOP; 1348 case 14: return Mode.MULTIPLY; 1349 case 15: return Mode.SCREEN; 1350 case 16: return Mode.ADD; 1351 default: return defaultMode; 1352 } 1353 } 1354} 1355 1356