Drawable.java revision 5e92c95d847a68178cf6099c801f82dcb7e4fa47
1/* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package android.graphics.drawable; 18 19import android.graphics.Insets; 20import android.graphics.Xfermode; 21import android.os.Trace; 22 23import org.xmlpull.v1.XmlPullParser; 24import org.xmlpull.v1.XmlPullParserException; 25 26import android.content.res.Resources; 27import android.content.res.Resources.Theme; 28import android.content.res.TypedArray; 29import android.graphics.Bitmap; 30import android.graphics.BitmapFactory; 31import android.graphics.Canvas; 32import android.graphics.ColorFilter; 33import android.graphics.NinePatch; 34import android.graphics.Outline; 35import android.graphics.PixelFormat; 36import android.graphics.PorterDuff; 37import android.graphics.PorterDuffColorFilter; 38import android.graphics.Rect; 39import android.graphics.Region; 40import android.graphics.PorterDuff.Mode; 41import android.util.AttributeSet; 42import android.util.DisplayMetrics; 43import android.util.StateSet; 44import android.util.TypedValue; 45import android.util.Xml; 46import android.view.View; 47 48import java.io.IOException; 49import java.io.InputStream; 50import java.lang.ref.WeakReference; 51import java.util.Arrays; 52 53/** 54 * A Drawable is a general abstraction for "something that can be drawn." Most 55 * often you will deal with Drawable as the type of resource retrieved for 56 * drawing things to the screen; the Drawable class provides a generic API for 57 * dealing with an underlying visual resource that may take a variety of forms. 58 * Unlike a {@link android.view.View}, a Drawable does not have any facility to 59 * receive events or otherwise interact with the user. 60 * 61 * <p>In addition to simple drawing, Drawable provides a number of generic 62 * mechanisms for its client to interact with what is being drawn: 63 * 64 * <ul> 65 * <li> The {@link #setBounds} method <var>must</var> be called to tell the 66 * Drawable where it is drawn and how large it should be. All Drawables 67 * should respect the requested size, often simply by scaling their 68 * imagery. A client can find the preferred size for some Drawables with 69 * the {@link #getIntrinsicHeight} and {@link #getIntrinsicWidth} methods. 70 * 71 * <li> The {@link #getPadding} method can return from some Drawables 72 * information about how to frame content that is placed inside of them. 73 * For example, a Drawable that is intended to be the frame for a button 74 * widget would need to return padding that correctly places the label 75 * inside of itself. 76 * 77 * <li> The {@link #setState} method allows the client to tell the Drawable 78 * in which state it is to be drawn, such as "focused", "selected", etc. 79 * Some drawables may modify their imagery based on the selected state. 80 * 81 * <li> The {@link #setLevel} method allows the client to supply a single 82 * continuous controller that can modify the Drawable is displayed, such as 83 * a battery level or progress level. Some drawables may modify their 84 * imagery based on the current level. 85 * 86 * <li> A Drawable can perform animations by calling back to its client 87 * through the {@link Callback} interface. All clients should support this 88 * interface (via {@link #setCallback}) so that animations will work. A 89 * simple way to do this is through the system facilities such as 90 * {@link android.view.View#setBackground(Drawable)} and 91 * {@link android.widget.ImageView}. 92 * </ul> 93 * 94 * Though usually not visible to the application, Drawables may take a variety 95 * of forms: 96 * 97 * <ul> 98 * <li> <b>Bitmap</b>: the simplest Drawable, a PNG or JPEG image. 99 * <li> <b>Nine Patch</b>: an extension to the PNG format allows it to 100 * specify information about how to stretch it and place things inside of 101 * it. 102 * <li> <b>Shape</b>: contains simple drawing commands instead of a raw 103 * bitmap, allowing it to resize better in some cases. 104 * <li> <b>Layers</b>: a compound drawable, which draws multiple underlying 105 * drawables on top of each other. 106 * <li> <b>States</b>: a compound drawable that selects one of a set of 107 * drawables based on its state. 108 * <li> <b>Levels</b>: a compound drawable that selects one of a set of 109 * drawables based on its level. 110 * <li> <b>Scale</b>: a compound drawable with a single child drawable, 111 * whose overall size is modified based on the current level. 112 * </ul> 113 * 114 * <div class="special reference"> 115 * <h3>Developer Guides</h3> 116 * <p>For more information about how to use drawables, read the 117 * <a href="{@docRoot}guide/topics/graphics/2d-graphics.html">Canvas and Drawables</a> developer 118 * guide. For information and examples of creating drawable resources (XML or bitmap files that 119 * can be loaded in code), read the 120 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a> 121 * document.</p></div> 122 */ 123public abstract class Drawable { 124 private static final Rect ZERO_BOUNDS_RECT = new Rect(); 125 126 private int[] mStateSet = StateSet.WILD_CARD; 127 private int mLevel = 0; 128 private int mChangingConfigurations = 0; 129 private Rect mBounds = ZERO_BOUNDS_RECT; // lazily becomes a new Rect() 130 private WeakReference<Callback> mCallback = null; 131 private boolean mVisible = true; 132 133 private int mLayoutDirection; 134 135 /** 136 * Draw in its bounds (set via setBounds) respecting optional effects such 137 * as alpha (set via setAlpha) and color filter (set via setColorFilter). 138 * 139 * @param canvas The canvas to draw into 140 */ 141 public abstract void draw(Canvas canvas); 142 143 /** 144 * Specify a bounding rectangle for the Drawable. This is where the drawable 145 * will draw when its draw() method is called. 146 */ 147 public void setBounds(int left, int top, int right, int bottom) { 148 Rect oldBounds = mBounds; 149 150 if (oldBounds == ZERO_BOUNDS_RECT) { 151 oldBounds = mBounds = new Rect(); 152 } 153 154 if (oldBounds.left != left || oldBounds.top != top || 155 oldBounds.right != right || oldBounds.bottom != bottom) { 156 if (!oldBounds.isEmpty()) { 157 // first invalidate the previous bounds 158 invalidateSelf(); 159 } 160 mBounds.set(left, top, right, bottom); 161 onBoundsChange(mBounds); 162 } 163 } 164 165 /** 166 * Specify a bounding rectangle for the Drawable. This is where the drawable 167 * will draw when its draw() method is called. 168 */ 169 public void setBounds(Rect bounds) { 170 setBounds(bounds.left, bounds.top, bounds.right, bounds.bottom); 171 } 172 173 /** 174 * Return a copy of the drawable's bounds in the specified Rect (allocated 175 * by the caller). The bounds specify where this will draw when its draw() 176 * method is called. 177 * 178 * @param bounds Rect to receive the drawable's bounds (allocated by the 179 * caller). 180 */ 181 public final void copyBounds(Rect bounds) { 182 bounds.set(mBounds); 183 } 184 185 /** 186 * Return a copy of the drawable's bounds in a new Rect. This returns the 187 * same values as getBounds(), but the returned object is guaranteed to not 188 * be changed later by the drawable (i.e. it retains no reference to this 189 * rect). If the caller already has a Rect allocated, call copyBounds(rect). 190 * 191 * @return A copy of the drawable's bounds 192 */ 193 public final Rect copyBounds() { 194 return new Rect(mBounds); 195 } 196 197 /** 198 * Return the drawable's bounds Rect. Note: for efficiency, the returned 199 * object may be the same object stored in the drawable (though this is not 200 * guaranteed), so if a persistent copy of the bounds is needed, call 201 * copyBounds(rect) instead. 202 * You should also not change the object returned by this method as it may 203 * be the same object stored in the drawable. 204 * 205 * @return The bounds of the drawable (which may change later, so caller 206 * beware). DO NOT ALTER the returned object as it may change the 207 * stored bounds of this drawable. 208 * 209 * @see #copyBounds() 210 * @see #copyBounds(android.graphics.Rect) 211 */ 212 public final Rect getBounds() { 213 if (mBounds == ZERO_BOUNDS_RECT) { 214 mBounds = new Rect(); 215 } 216 217 return mBounds; 218 } 219 220 /** 221 * Return the drawable's dirty bounds Rect. Note: for efficiency, the 222 * returned object may be the same object stored in the drawable (though 223 * this is not guaranteed). 224 * <p> 225 * By default, this returns the full drawable bounds. Custom drawables may 226 * override this method to perform more precise invalidation. 227 * 228 * @hide 229 */ 230 public Rect getDirtyBounds() { 231 return getBounds(); 232 } 233 234 /** 235 * Set a mask of the configuration parameters for which this drawable 236 * may change, requiring that it be re-created. 237 * 238 * @param configs A mask of the changing configuration parameters, as 239 * defined by {@link android.content.res.Configuration}. 240 * 241 * @see android.content.res.Configuration 242 */ 243 public void setChangingConfigurations(int configs) { 244 mChangingConfigurations = configs; 245 } 246 247 /** 248 * Return a mask of the configuration parameters for which this drawable 249 * may change, requiring that it be re-created. The default implementation 250 * returns whatever was provided through 251 * {@link #setChangingConfigurations(int)} or 0 by default. Subclasses 252 * may extend this to or in the changing configurations of any other 253 * drawables they hold. 254 * 255 * @return Returns a mask of the changing configuration parameters, as 256 * defined by {@link android.content.res.Configuration}. 257 * 258 * @see android.content.res.Configuration 259 */ 260 public int getChangingConfigurations() { 261 return mChangingConfigurations; 262 } 263 264 /** 265 * Set to true to have the drawable dither its colors when drawn to a device 266 * with fewer than 8-bits per color component. This can improve the look on 267 * those devices, but can also slow down the drawing a little. 268 */ 269 public void setDither(boolean dither) {} 270 271 /** 272 * Set to true to have the drawable filter its bitmap when scaled or rotated 273 * (for drawables that use bitmaps). If the drawable does not use bitmaps, 274 * this call is ignored. This can improve the look when scaled or rotated, 275 * but also slows down the drawing. 276 */ 277 public void setFilterBitmap(boolean filter) {} 278 279 /** 280 * Implement this interface if you want to create an animated drawable that 281 * extends {@link android.graphics.drawable.Drawable Drawable}. 282 * Upon retrieving a drawable, use 283 * {@link Drawable#setCallback(android.graphics.drawable.Drawable.Callback)} 284 * to supply your implementation of the interface to the drawable; it uses 285 * this interface to schedule and execute animation changes. 286 */ 287 public static interface Callback { 288 /** 289 * Called when the drawable needs to be redrawn. A view at this point 290 * should invalidate itself (or at least the part of itself where the 291 * drawable appears). 292 * 293 * @param who The drawable that is requesting the update. 294 */ 295 public void invalidateDrawable(Drawable who); 296 297 /** 298 * A Drawable can call this to schedule the next frame of its 299 * animation. An implementation can generally simply call 300 * {@link android.os.Handler#postAtTime(Runnable, Object, long)} with 301 * the parameters <var>(what, who, when)</var> to perform the 302 * scheduling. 303 * 304 * @param who The drawable being scheduled. 305 * @param what The action to execute. 306 * @param when The time (in milliseconds) to run. The timebase is 307 * {@link android.os.SystemClock#uptimeMillis} 308 */ 309 public void scheduleDrawable(Drawable who, Runnable what, long when); 310 311 /** 312 * A Drawable can call this to unschedule an action previously 313 * scheduled with {@link #scheduleDrawable}. An implementation can 314 * generally simply call 315 * {@link android.os.Handler#removeCallbacks(Runnable, Object)} with 316 * the parameters <var>(what, who)</var> to unschedule the drawable. 317 * 318 * @param who The drawable being unscheduled. 319 * @param what The action being unscheduled. 320 */ 321 public void unscheduleDrawable(Drawable who, Runnable what); 322 } 323 324 /** 325 * Bind a {@link Callback} object to this Drawable. Required for clients 326 * that want to support animated drawables. 327 * 328 * @param cb The client's Callback implementation. 329 * 330 * @see #getCallback() 331 */ 332 public final void setCallback(Callback cb) { 333 mCallback = new WeakReference<Callback>(cb); 334 } 335 336 /** 337 * Return the current {@link Callback} implementation attached to this 338 * Drawable. 339 * 340 * @return A {@link Callback} instance or null if no callback was set. 341 * 342 * @see #setCallback(android.graphics.drawable.Drawable.Callback) 343 */ 344 public Callback getCallback() { 345 if (mCallback != null) { 346 return mCallback.get(); 347 } 348 return null; 349 } 350 351 /** 352 * Use the current {@link Callback} implementation to have this Drawable 353 * redrawn. Does nothing if there is no Callback attached to the 354 * Drawable. 355 * 356 * @see Callback#invalidateDrawable 357 * @see #getCallback() 358 * @see #setCallback(android.graphics.drawable.Drawable.Callback) 359 */ 360 public void invalidateSelf() { 361 final Callback callback = getCallback(); 362 if (callback != null) { 363 callback.invalidateDrawable(this); 364 } 365 } 366 367 /** 368 * Use the current {@link Callback} implementation to have this Drawable 369 * scheduled. Does nothing if there is no Callback attached to the 370 * Drawable. 371 * 372 * @param what The action being scheduled. 373 * @param when The time (in milliseconds) to run. 374 * 375 * @see Callback#scheduleDrawable 376 */ 377 public void scheduleSelf(Runnable what, long when) { 378 final Callback callback = getCallback(); 379 if (callback != null) { 380 callback.scheduleDrawable(this, what, when); 381 } 382 } 383 384 /** 385 * Use the current {@link Callback} implementation to have this Drawable 386 * unscheduled. Does nothing if there is no Callback attached to the 387 * Drawable. 388 * 389 * @param what The runnable that you no longer want called. 390 * 391 * @see Callback#unscheduleDrawable 392 */ 393 public void unscheduleSelf(Runnable what) { 394 final Callback callback = getCallback(); 395 if (callback != null) { 396 callback.unscheduleDrawable(this, what); 397 } 398 } 399 400 /** 401 * Returns the resolved layout direction for this Drawable. 402 * 403 * @return One of {@link android.view.View#LAYOUT_DIRECTION_LTR}, 404 * {@link android.view.View#LAYOUT_DIRECTION_RTL} 405 * 406 * @hide 407 */ 408 public int getLayoutDirection() { 409 return mLayoutDirection; 410 } 411 412 /** 413 * Set the layout direction for this drawable. Should be a resolved direction as the 414 * Drawable as no capacity to do the resolution on his own. 415 * 416 * @param layoutDirection One of {@link android.view.View#LAYOUT_DIRECTION_LTR}, 417 * {@link android.view.View#LAYOUT_DIRECTION_RTL} 418 * 419 * @hide 420 */ 421 public void setLayoutDirection(@View.ResolvedLayoutDir int layoutDirection) { 422 if (getLayoutDirection() != layoutDirection) { 423 mLayoutDirection = layoutDirection; 424 } 425 } 426 427 /** 428 * Specify an alpha value for the drawable. 0 means fully transparent, and 429 * 255 means fully opaque. 430 */ 431 public abstract void setAlpha(int alpha); 432 433 /** 434 * Gets the current alpha value for the drawable. 0 means fully transparent, 435 * 255 means fully opaque. This method is implemented by 436 * Drawable subclasses and the value returned is specific to how that class treats alpha. 437 * The default return value is 255 if the class does not override this method to return a value 438 * specific to its use of alpha. 439 */ 440 public int getAlpha() { 441 return 0xFF; 442 } 443 444 /** 445 * @hide Consider for future API inclusion 446 */ 447 public void setXfermode(Xfermode mode) { 448 // Base implementation drops it on the floor for compatibility. Whee! 449 // TODO: For this to be included in the API proper, all framework drawables need impls. 450 // For right now only BitmapDrawable has it. 451 } 452 453 /** 454 * Specify an optional color filter for the drawable. Pass {@code null} to 455 * remove any existing color filter. 456 * 457 * @param cf the color filter to apply, or {@code null} to remove the 458 * existing color filter 459 */ 460 public abstract void setColorFilter(ColorFilter cf); 461 462 /** 463 * Specify a color and Porter-Duff mode to be the color filter for this 464 * drawable. 465 */ 466 public void setColorFilter(int color, PorterDuff.Mode mode) { 467 setColorFilter(new PorterDuffColorFilter(color, mode)); 468 } 469 470 /** 471 * Returns the current color filter, or {@code null} if none set. 472 * 473 * @return the current color filter, or {@code null} if none set 474 */ 475 public ColorFilter getColorFilter() { 476 return null; 477 } 478 479 /** 480 * Removes the color filter for this drawable. 481 */ 482 public void clearColorFilter() { 483 setColorFilter(null); 484 } 485 486 /** 487 * Indicates whether the drawable supports hotspots. Hotspots are uniquely 488 * identifiable coordinates the may be added, updated and removed within a 489 * drawable. 490 * 491 * @return true if hotspots are supported 492 * @see #setHotspot(int, float, float) 493 * @see #removeHotspot(int) 494 * @see #clearHotspots() 495 */ 496 public boolean supportsHotspots() { 497 return false; 498 } 499 500 /** 501 * Specifies a hotspot's location within the drawable. 502 * <p> 503 * The specified key should be an id declared in the resources of the 504 * application to ensure it is unique (see the <a 505 * href={@docRoot}guide/topics/resources/more-resources.html#Id">ID resource type</a>). 506 * 507 * @param key The key identifying the hotspot 508 * @param x The X coordinate of the center of the hotspot 509 * @param y The Y coordinate of the center of the hotspot 510 */ 511 public void setHotspot(int key, float x, float y) {} 512 513 /** 514 * Removes the hotspot with the specified key from the drawable. 515 * 516 * @param key The key identifying the hotspot 517 */ 518 public void removeHotspot(int key) {} 519 520 /** 521 * Immediately removes all hotspots from the drawable. 522 */ 523 public void clearHotspots() {} 524 525 /** 526 * Sets the bounds to which hotspots are constrained. 527 * 528 * @hide until we finalize these APIs 529 */ 530 public void setHotspotBounds(int left, int top, int right, int bottom) {} 531 532 /** 533 * Whether this drawable requests projection. 534 * 535 * @hide until we finalize these APIs 536 */ 537 public boolean isProjected() { 538 return false; 539 } 540 541 /** 542 * Indicates whether this view will change its appearance based on state. 543 * Clients can use this to determine whether it is necessary to calculate 544 * their state and call setState. 545 * 546 * @return True if this view changes its appearance based on state, false 547 * otherwise. 548 * 549 * @see #setState(int[]) 550 */ 551 public boolean isStateful() { 552 return false; 553 } 554 555 /** 556 * Specify a set of states for the drawable. These are use-case specific, 557 * so see the relevant documentation. As an example, the background for 558 * widgets like Button understand the following states: 559 * [{@link android.R.attr#state_focused}, 560 * {@link android.R.attr#state_pressed}]. 561 * 562 * <p>If the new state you are supplying causes the appearance of the 563 * Drawable to change, then it is responsible for calling 564 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 565 * true will be returned from this function. 566 * 567 * <p>Note: The Drawable holds a reference on to <var>stateSet</var> 568 * until a new state array is given to it, so you must not modify this 569 * array during that time.</p> 570 * 571 * @param stateSet The new set of states to be displayed. 572 * 573 * @return Returns true if this change in state has caused the appearance 574 * of the Drawable to change (hence requiring an invalidate), otherwise 575 * returns false. 576 */ 577 public boolean setState(final int[] stateSet) { 578 if (!Arrays.equals(mStateSet, stateSet)) { 579 mStateSet = stateSet; 580 return onStateChange(stateSet); 581 } 582 return false; 583 } 584 585 /** 586 * Describes the current state, as a union of primitve states, such as 587 * {@link android.R.attr#state_focused}, 588 * {@link android.R.attr#state_selected}, etc. 589 * Some drawables may modify their imagery based on the selected state. 590 * @return An array of resource Ids describing the current state. 591 */ 592 public int[] getState() { 593 return mStateSet; 594 } 595 596 /** 597 * If this Drawable does transition animations between states, ask that 598 * it immediately jump to the current state and skip any active animations. 599 */ 600 public void jumpToCurrentState() { 601 } 602 603 /** 604 * @return The current drawable that will be used by this drawable. For simple drawables, this 605 * is just the drawable itself. For drawables that change state like 606 * {@link StateListDrawable} and {@link LevelListDrawable} this will be the child drawable 607 * currently in use. 608 */ 609 public Drawable getCurrent() { 610 return this; 611 } 612 613 /** 614 * Specify the level for the drawable. This allows a drawable to vary its 615 * imagery based on a continuous controller, for example to show progress 616 * or volume level. 617 * 618 * <p>If the new level you are supplying causes the appearance of the 619 * Drawable to change, then it is responsible for calling 620 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 621 * true will be returned from this function. 622 * 623 * @param level The new level, from 0 (minimum) to 10000 (maximum). 624 * 625 * @return Returns true if this change in level has caused the appearance 626 * of the Drawable to change (hence requiring an invalidate), otherwise 627 * returns false. 628 */ 629 public final boolean setLevel(int level) { 630 if (mLevel != level) { 631 mLevel = level; 632 return onLevelChange(level); 633 } 634 return false; 635 } 636 637 /** 638 * Retrieve the current level. 639 * 640 * @return int Current level, from 0 (minimum) to 10000 (maximum). 641 */ 642 public final int getLevel() { 643 return mLevel; 644 } 645 646 /** 647 * Set whether this Drawable is visible. This generally does not impact 648 * the Drawable's behavior, but is a hint that can be used by some 649 * Drawables, for example, to decide whether run animations. 650 * 651 * @param visible Set to true if visible, false if not. 652 * @param restart You can supply true here to force the drawable to behave 653 * as if it has just become visible, even if it had last 654 * been set visible. Used for example to force animations 655 * to restart. 656 * 657 * @return boolean Returns true if the new visibility is different than 658 * its previous state. 659 */ 660 public boolean setVisible(boolean visible, boolean restart) { 661 boolean changed = mVisible != visible; 662 if (changed) { 663 mVisible = visible; 664 invalidateSelf(); 665 } 666 return changed; 667 } 668 669 public final boolean isVisible() { 670 return mVisible; 671 } 672 673 /** 674 * Set whether this Drawable is automatically mirrored when its layout direction is RTL 675 * (right-to left). See {@link android.util.LayoutDirection}. 676 * 677 * @param mirrored Set to true if the Drawable should be mirrored, false if not. 678 */ 679 public void setAutoMirrored(boolean mirrored) { 680 } 681 682 /** 683 * Tells if this Drawable will be automatically mirrored when its layout direction is RTL 684 * right-to-left. See {@link android.util.LayoutDirection}. 685 * 686 * @return boolean Returns true if this Drawable will be automatically mirrored. 687 */ 688 public boolean isAutoMirrored() { 689 return false; 690 } 691 692 /** 693 * Applies the specified theme to this Drawable and its children. 694 */ 695 public void applyTheme(@SuppressWarnings("unused") Theme t) { 696 } 697 698 public boolean canApplyTheme() { 699 return false; 700 } 701 702 /** 703 * Return the opacity/transparency of this Drawable. The returned value is 704 * one of the abstract format constants in 705 * {@link android.graphics.PixelFormat}: 706 * {@link android.graphics.PixelFormat#UNKNOWN}, 707 * {@link android.graphics.PixelFormat#TRANSLUCENT}, 708 * {@link android.graphics.PixelFormat#TRANSPARENT}, or 709 * {@link android.graphics.PixelFormat#OPAQUE}. 710 * 711 * <p>Generally a Drawable should be as conservative as possible with the 712 * value it returns. For example, if it contains multiple child drawables 713 * and only shows one of them at a time, if only one of the children is 714 * TRANSLUCENT and the others are OPAQUE then TRANSLUCENT should be 715 * returned. You can use the method {@link #resolveOpacity} to perform a 716 * standard reduction of two opacities to the appropriate single output. 717 * 718 * <p>Note that the returned value does <em>not</em> take into account a 719 * custom alpha or color filter that has been applied by the client through 720 * the {@link #setAlpha} or {@link #setColorFilter} methods. 721 * 722 * @return int The opacity class of the Drawable. 723 * 724 * @see android.graphics.PixelFormat 725 */ 726 public abstract int getOpacity(); 727 728 /** 729 * Return the appropriate opacity value for two source opacities. If 730 * either is UNKNOWN, that is returned; else, if either is TRANSLUCENT, 731 * that is returned; else, if either is TRANSPARENT, that is returned; 732 * else, OPAQUE is returned. 733 * 734 * <p>This is to help in implementing {@link #getOpacity}. 735 * 736 * @param op1 One opacity value. 737 * @param op2 Another opacity value. 738 * 739 * @return int The combined opacity value. 740 * 741 * @see #getOpacity 742 */ 743 public static int resolveOpacity(int op1, int op2) { 744 if (op1 == op2) { 745 return op1; 746 } 747 if (op1 == PixelFormat.UNKNOWN || op2 == PixelFormat.UNKNOWN) { 748 return PixelFormat.UNKNOWN; 749 } 750 if (op1 == PixelFormat.TRANSLUCENT || op2 == PixelFormat.TRANSLUCENT) { 751 return PixelFormat.TRANSLUCENT; 752 } 753 if (op1 == PixelFormat.TRANSPARENT || op2 == PixelFormat.TRANSPARENT) { 754 return PixelFormat.TRANSPARENT; 755 } 756 return PixelFormat.OPAQUE; 757 } 758 759 /** 760 * Returns a Region representing the part of the Drawable that is completely 761 * transparent. This can be used to perform drawing operations, identifying 762 * which parts of the target will not change when rendering the Drawable. 763 * The default implementation returns null, indicating no transparent 764 * region; subclasses can optionally override this to return an actual 765 * Region if they want to supply this optimization information, but it is 766 * not required that they do so. 767 * 768 * @return Returns null if the Drawables has no transparent region to 769 * report, else a Region holding the parts of the Drawable's bounds that 770 * are transparent. 771 */ 772 public Region getTransparentRegion() { 773 return null; 774 } 775 776 /** 777 * Override this in your subclass to change appearance if you recognize the 778 * specified state. 779 * 780 * @return Returns true if the state change has caused the appearance of 781 * the Drawable to change (that is, it needs to be drawn), else false 782 * if it looks the same and there is no need to redraw it since its 783 * last state. 784 */ 785 protected boolean onStateChange(int[] state) { return false; } 786 /** Override this in your subclass to change appearance if you vary based 787 * on level. 788 * @return Returns true if the level 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 level. 792 */ 793 protected boolean onLevelChange(int level) { return false; } 794 /** 795 * Override this in your subclass to change appearance if you vary based on 796 * the bounds. 797 */ 798 protected void onBoundsChange(Rect bounds) {} 799 800 /** 801 * Return the intrinsic width of the underlying drawable object. Returns 802 * -1 if it has no intrinsic width, such as with a solid color. 803 */ 804 public int getIntrinsicWidth() { 805 return -1; 806 } 807 808 /** 809 * Return the intrinsic height of the underlying drawable object. Returns 810 * -1 if it has no intrinsic height, such as with a solid color. 811 */ 812 public int getIntrinsicHeight() { 813 return -1; 814 } 815 816 /** 817 * Returns the minimum width suggested by this Drawable. If a View uses this 818 * Drawable as a background, it is suggested that the View use at least this 819 * value for its width. (There will be some scenarios where this will not be 820 * possible.) This value should INCLUDE any padding. 821 * 822 * @return The minimum width suggested by this Drawable. If this Drawable 823 * doesn't have a suggested minimum width, 0 is returned. 824 */ 825 public int getMinimumWidth() { 826 final int intrinsicWidth = getIntrinsicWidth(); 827 return intrinsicWidth > 0 ? intrinsicWidth : 0; 828 } 829 830 /** 831 * Returns the minimum height suggested by this Drawable. If a View uses this 832 * Drawable as a background, it is suggested that the View use at least this 833 * value for its height. (There will be some scenarios where this will not be 834 * possible.) This value should INCLUDE any padding. 835 * 836 * @return The minimum height suggested by this Drawable. If this Drawable 837 * doesn't have a suggested minimum height, 0 is returned. 838 */ 839 public int getMinimumHeight() { 840 final int intrinsicHeight = getIntrinsicHeight(); 841 return intrinsicHeight > 0 ? intrinsicHeight : 0; 842 } 843 844 /** 845 * Return in padding the insets suggested by this Drawable for placing 846 * content inside the drawable's bounds. Positive values move toward the 847 * center of the Drawable (set Rect.inset). Returns true if this drawable 848 * actually has a padding, else false. When false is returned, the padding 849 * is always set to 0. 850 */ 851 public boolean getPadding(Rect padding) { 852 padding.set(0, 0, 0, 0); 853 return false; 854 } 855 856 /** 857 * Return in insets the layout insets suggested by this Drawable for use with alignment 858 * operations during layout. 859 * 860 * @hide 861 */ 862 public Insets getOpticalInsets() { 863 return Insets.NONE; 864 } 865 866 /** 867 * Called to get the drawable to populate the Outline. 868 * <p> 869 * This method will be called by a View on its background Drawable after bounds change, or its 870 * Drawable is invalidated, if the View's Outline isn't set explicitly. This allows the 871 * background Drawable to define the shape of the shadow cast by the View. 872 * 873 * The default behavior defines the outline to be the bounding rectangle. Subclasses that wish 874 * to convey a different shape must override this method. 875 * 876 * @see View#setOutline(android.graphics.Outline) 877 */ 878 public boolean getOutline(Outline outline) { 879 outline.setRect(getBounds()); 880 return true; 881 } 882 883 /** 884 * Make this drawable mutable. This operation cannot be reversed. A mutable 885 * drawable is guaranteed to not share its state with any other drawable. 886 * This is especially useful when you need to modify properties of drawables 887 * loaded from resources. By default, all drawables instances loaded from 888 * the same resource share a common state; if you modify the state of one 889 * instance, all the other instances will receive the same modification. 890 * 891 * Calling this method on a mutable Drawable will have no effect. 892 * 893 * @return This drawable. 894 * @see ConstantState 895 * @see #getConstantState() 896 */ 897 public Drawable mutate() { 898 return this; 899 } 900 901 /** 902 * Create a drawable from an inputstream 903 */ 904 public static Drawable createFromStream(InputStream is, String srcName) { 905 return createFromStreamThemed(is, srcName, null); 906 } 907 908 public static Drawable createFromStreamThemed(InputStream is, String srcName, Theme theme) { 909 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, srcName != null ? srcName : "Unknown drawable"); 910 try { 911 return createFromResourceStreamThemed(null, null, is, srcName, theme); 912 } finally { 913 Trace.traceEnd(Trace.TRACE_TAG_RESOURCES); 914 } 915 } 916 917 /** 918 * Create a drawable from an inputstream, using the given resources and 919 * value to determine density information. 920 */ 921 public static Drawable createFromResourceStream(Resources res, TypedValue value, 922 InputStream is, String srcName) { 923 return createFromResourceStreamThemed(res, value, is, srcName, null); 924 } 925 926 public static Drawable createFromResourceStreamThemed(Resources res, TypedValue value, 927 InputStream is, String srcName, Theme theme) { 928 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, srcName != null ? srcName : "Unknown drawable"); 929 try { 930 return createFromResourceStreamThemed(res, value, is, srcName, null, theme); 931 } finally { 932 Trace.traceEnd(Trace.TRACE_TAG_RESOURCES); 933 } 934 } 935 936 /** 937 * Create a drawable from an inputstream, using the given resources and 938 * value to determine density information. 939 */ 940 public static Drawable createFromResourceStream(Resources res, TypedValue value, 941 InputStream is, String srcName, BitmapFactory.Options opts) { 942 return createFromResourceStreamThemed(res, value, is, srcName, opts, null); 943 } 944 945 public static Drawable createFromResourceStreamThemed(Resources res, TypedValue value, 946 InputStream is, String srcName, BitmapFactory.Options opts, Theme theme) { 947 if (is == null) { 948 return null; 949 } 950 951 /* ugh. The decodeStream contract is that we have already allocated 952 the pad rect, but if the bitmap does not had a ninepatch chunk, 953 then the pad will be ignored. If we could change this to lazily 954 alloc/assign the rect, we could avoid the GC churn of making new 955 Rects only to drop them on the floor. 956 */ 957 Rect pad = new Rect(); 958 959 // Special stuff for compatibility mode: if the target density is not 960 // the same as the display density, but the resource -is- the same as 961 // the display density, then don't scale it down to the target density. 962 // This allows us to load the system's density-correct resources into 963 // an application in compatibility mode, without scaling those down 964 // to the compatibility density only to have them scaled back up when 965 // drawn to the screen. 966 if (opts == null) opts = new BitmapFactory.Options(); 967 opts.inScreenDensity = res != null 968 ? res.getDisplayMetrics().noncompatDensityDpi : DisplayMetrics.DENSITY_DEVICE; 969 Bitmap bm = BitmapFactory.decodeResourceStream(res, value, is, pad, opts); 970 if (bm != null) { 971 byte[] np = bm.getNinePatchChunk(); 972 if (np == null || !NinePatch.isNinePatchChunk(np)) { 973 np = null; 974 pad = null; 975 } 976 int[] layoutBounds = bm.getLayoutBounds(); 977 Rect layoutBoundsRect = null; 978 if (layoutBounds != null) { 979 layoutBoundsRect = new Rect(layoutBounds[0], layoutBounds[1], 980 layoutBounds[2], layoutBounds[3]); 981 } 982 return drawableFromBitmap(res, bm, np, pad, layoutBoundsRect, srcName); 983 } 984 return null; 985 } 986 987 /** 988 * Create a drawable from an XML document. For more information on how to 989 * create resources in XML, see 990 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. 991 */ 992 public static Drawable createFromXml(Resources r, XmlPullParser parser) 993 throws XmlPullParserException, IOException { 994 return createFromXmlThemed(r, parser, null); 995 } 996 997 /** 998 * Create a themed drawable from an XML document. For more information on 999 * how to create resources in XML, see 1000 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. 1001 */ 1002 public static Drawable createFromXmlThemed(Resources r, XmlPullParser parser, Theme theme) 1003 throws XmlPullParserException, IOException { 1004 AttributeSet attrs = Xml.asAttributeSet(parser); 1005 1006 int type; 1007 while ((type=parser.next()) != XmlPullParser.START_TAG && 1008 type != XmlPullParser.END_DOCUMENT) { 1009 // Empty loop 1010 } 1011 1012 if (type != XmlPullParser.START_TAG) { 1013 throw new XmlPullParserException("No start tag found"); 1014 } 1015 1016 Drawable drawable = createFromXmlInnerThemed(r, parser, attrs, theme); 1017 1018 if (drawable == null) { 1019 throw new RuntimeException("Unknown initial tag: " + parser.getName()); 1020 } 1021 1022 return drawable; 1023 } 1024 1025 /** 1026 * Create from inside an XML document. Called on a parser positioned at 1027 * a tag in an XML document, tries to create a Drawable from that tag. 1028 * Returns null if the tag is not a valid drawable. 1029 */ 1030 public static Drawable createFromXmlInner(Resources r, XmlPullParser parser, AttributeSet attrs) 1031 throws XmlPullParserException, IOException { 1032 return createFromXmlInnerThemed(r, parser, attrs, null); 1033 } 1034 1035 public static Drawable createFromXmlInnerThemed(Resources r, XmlPullParser parser, 1036 AttributeSet attrs, Theme theme) throws XmlPullParserException, IOException { 1037 final Drawable drawable; 1038 1039 final String name = parser.getName(); 1040 if (name.equals("selector")) { 1041 drawable = new StateListDrawable(); 1042 } else if (name.equals("animated-selector")) { 1043 drawable = new AnimatedStateListDrawable(); 1044 } else if (name.equals("level-list")) { 1045 drawable = new LevelListDrawable(); 1046 } else if (name.equals("layer-list")) { 1047 drawable = new LayerDrawable(); 1048 } else if (name.equals("transition")) { 1049 drawable = new TransitionDrawable(); 1050 } else if (name.equals("touch-feedback")) { 1051 drawable = new TouchFeedbackDrawable(); 1052 } else if (name.equals("color")) { 1053 drawable = new ColorDrawable(); 1054 } else if (name.equals("shape")) { 1055 drawable = new GradientDrawable(); 1056 } else if (name.equals("vector")) { 1057 drawable = new VectorDrawable(); 1058 } else if (name.equals("scale")) { 1059 drawable = new ScaleDrawable(); 1060 } else if (name.equals("clip")) { 1061 drawable = new ClipDrawable(); 1062 } else if (name.equals("rotate")) { 1063 drawable = new RotateDrawable(); 1064 } else if (name.equals("animated-rotate")) { 1065 drawable = new AnimatedRotateDrawable(); 1066 } else if (name.equals("animation-list")) { 1067 drawable = new AnimationDrawable(); 1068 } else if (name.equals("inset")) { 1069 drawable = new InsetDrawable(); 1070 } else if (name.equals("bitmap")) { 1071 //noinspection deprecation 1072 drawable = new BitmapDrawable(r); 1073 if (r != null) { 1074 ((BitmapDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 1075 } 1076 } else if (name.equals("nine-patch")) { 1077 drawable = new NinePatchDrawable(); 1078 if (r != null) { 1079 ((NinePatchDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 1080 } 1081 } else { 1082 throw new XmlPullParserException(parser.getPositionDescription() + 1083 ": invalid drawable tag " + name); 1084 } 1085 1086 drawable.inflate(r, parser, attrs, theme); 1087 return drawable; 1088 } 1089 1090 1091 /** 1092 * Create a drawable from file path name. 1093 */ 1094 public static Drawable createFromPath(String pathName) { 1095 if (pathName == null) { 1096 return null; 1097 } 1098 1099 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, pathName); 1100 try { 1101 Bitmap bm = BitmapFactory.decodeFile(pathName); 1102 if (bm != null) { 1103 return drawableFromBitmap(null, bm, null, null, null, pathName); 1104 } 1105 } finally { 1106 Trace.traceEnd(Trace.TRACE_TAG_RESOURCES); 1107 } 1108 1109 return null; 1110 } 1111 1112 /** 1113 * Inflate this Drawable from an XML resource. Does not apply a theme. 1114 * 1115 * @see #inflate(Resources, XmlPullParser, AttributeSet, Theme) 1116 */ 1117 public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs) 1118 throws XmlPullParserException, IOException { 1119 inflate(r, parser, attrs, null); 1120 } 1121 1122 /** 1123 * Inflate this Drawable from an XML resource optionally styled by a theme. 1124 * 1125 * @param r Resources used to resolve attribute values 1126 * @param parser XML parser from which to inflate this Drawable 1127 * @param attrs Base set of attribute values 1128 * @param theme Theme to apply, may be null 1129 * @throws XmlPullParserException 1130 * @throws IOException 1131 */ 1132 public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs, Theme theme) 1133 throws XmlPullParserException, IOException { 1134 final TypedArray a; 1135 if (theme != null) { 1136 a = theme.obtainStyledAttributes( 1137 attrs, com.android.internal.R.styleable.Drawable, 0, 0); 1138 } else { 1139 a = r.obtainAttributes(attrs, com.android.internal.R.styleable.Drawable); 1140 } 1141 1142 inflateWithAttributes(r, parser, a, com.android.internal.R.styleable.Drawable_visible); 1143 a.recycle(); 1144 } 1145 1146 /** 1147 * Inflate a Drawable from an XML resource. 1148 * 1149 * @throws XmlPullParserException 1150 * @throws IOException 1151 */ 1152 void inflateWithAttributes(Resources r, XmlPullParser parser, TypedArray attrs, int visibleAttr) 1153 throws XmlPullParserException, IOException { 1154 mVisible = attrs.getBoolean(visibleAttr, mVisible); 1155 } 1156 1157 /** 1158 * This abstract class is used by {@link Drawable}s to store shared constant state and data 1159 * between Drawables. {@link BitmapDrawable}s created from the same resource will for instance 1160 * share a unique bitmap stored in their ConstantState. 1161 * 1162 * <p> 1163 * {@link #newDrawable(Resources)} can be used as a factory to create new Drawable instances 1164 * from this ConstantState. 1165 * </p> 1166 * 1167 * Use {@link Drawable#getConstantState()} to retrieve the ConstantState of a Drawable. Calling 1168 * {@link Drawable#mutate()} on a Drawable should typically create a new ConstantState for that 1169 * Drawable. 1170 */ 1171 public static abstract class ConstantState { 1172 /** 1173 * Create a new drawable without supplying resources the caller 1174 * is running in. Note that using this means the density-dependent 1175 * drawables (like bitmaps) will not be able to update their target 1176 * density correctly. One should use {@link #newDrawable(Resources)} 1177 * instead to provide a resource. 1178 */ 1179 public abstract Drawable newDrawable(); 1180 1181 /** 1182 * Create a new Drawable instance from its constant state. This 1183 * must be implemented for drawables that change based on the target 1184 * density of their caller (that is depending on whether it is 1185 * in compatibility mode). 1186 */ 1187 public Drawable newDrawable(Resources res) { 1188 return newDrawable(); 1189 } 1190 1191 /** 1192 * Create a new Drawable instance from its constant state. This must be 1193 * implemented for drawables that can have a theme applied. 1194 */ 1195 public Drawable newDrawable(Resources res, Theme theme) { 1196 return newDrawable(); 1197 } 1198 1199 /** 1200 * Return a bit mask of configuration changes that will impact 1201 * this drawable (and thus require completely reloading it). 1202 */ 1203 public abstract int getChangingConfigurations(); 1204 1205 /** 1206 * @hide 1207 */ 1208 public Bitmap getBitmap() { 1209 return null; 1210 } 1211 1212 /** 1213 * Return whether this constant state can have a theme applied. 1214 */ 1215 public boolean canApplyTheme() { 1216 return false; 1217 } 1218 } 1219 1220 /** 1221 * Return a {@link ConstantState} instance that holds the shared state of this Drawable. 1222 * 1223 * @return The ConstantState associated to that Drawable. 1224 * @see ConstantState 1225 * @see Drawable#mutate() 1226 */ 1227 public ConstantState getConstantState() { 1228 return null; 1229 } 1230 1231 private static Drawable drawableFromBitmap(Resources res, Bitmap bm, byte[] np, 1232 Rect pad, Rect layoutBounds, String srcName) { 1233 1234 if (np != null) { 1235 return new NinePatchDrawable(res, bm, np, pad, layoutBounds, srcName); 1236 } 1237 1238 return new BitmapDrawable(res, bm); 1239 } 1240 1241 /** 1242 * Obtains styled attributes from the theme, if available, or unstyled 1243 * resources if the theme is null. 1244 */ 1245 static TypedArray obtainAttributes( 1246 Resources res, Theme theme, AttributeSet set, int[] attrs) { 1247 if (theme == null) { 1248 return res.obtainAttributes(set, attrs); 1249 } 1250 return theme.obtainStyledAttributes(set, attrs, 0, 0); 1251 } 1252 1253 /** 1254 * Parses a {@link android.graphics.PorterDuff.Mode} from a tintMode 1255 * attribute's enum value. 1256 */ 1257 static PorterDuff.Mode parseTintMode(int value, Mode defaultMode) { 1258 switch (value) { 1259 case 3: return Mode.SRC_OVER; 1260 case 5: return Mode.SRC_IN; 1261 case 9: return Mode.SRC_ATOP; 1262 case 14: return Mode.MULTIPLY; 1263 case 15: return Mode.SCREEN; 1264 case 16: return Mode.ADD; 1265 default: return defaultMode; 1266 } 1267 } 1268} 1269 1270