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; 22import org.xmlpull.v1.XmlPullParser; 23import org.xmlpull.v1.XmlPullParserException; 24 25import android.content.res.Resources; 26import android.content.res.TypedArray; 27import android.graphics.Bitmap; 28import android.graphics.BitmapFactory; 29import android.graphics.Canvas; 30import android.graphics.ColorFilter; 31import android.graphics.NinePatch; 32import android.graphics.PixelFormat; 33import android.graphics.PorterDuff; 34import android.graphics.PorterDuffColorFilter; 35import android.graphics.Rect; 36import android.graphics.Region; 37import android.util.AttributeSet; 38import android.util.DisplayMetrics; 39import android.util.StateSet; 40import android.util.TypedValue; 41import android.util.Xml; 42 43import java.io.IOException; 44import java.io.InputStream; 45import java.lang.ref.WeakReference; 46import java.util.Arrays; 47 48/** 49 * A Drawable is a general abstraction for "something that can be drawn." Most 50 * often you will deal with Drawable as the type of resource retrieved for 51 * drawing things to the screen; the Drawable class provides a generic API for 52 * dealing with an underlying visual resource that may take a variety of forms. 53 * Unlike a {@link android.view.View}, a Drawable does not have any facility to 54 * receive events or otherwise interact with the user. 55 * 56 * <p>In addition to simple drawing, Drawable provides a number of generic 57 * mechanisms for its client to interact with what is being drawn: 58 * 59 * <ul> 60 * <li> The {@link #setBounds} method <var>must</var> be called to tell the 61 * Drawable where it is drawn and how large it should be. All Drawables 62 * should respect the requested size, often simply by scaling their 63 * imagery. A client can find the preferred size for some Drawables with 64 * the {@link #getIntrinsicHeight} and {@link #getIntrinsicWidth} methods. 65 * 66 * <li> The {@link #getPadding} method can return from some Drawables 67 * information about how to frame content that is placed inside of them. 68 * For example, a Drawable that is intended to be the frame for a button 69 * widget would need to return padding that correctly places the label 70 * inside of itself. 71 * 72 * <li> The {@link #setState} method allows the client to tell the Drawable 73 * in which state it is to be drawn, such as "focused", "selected", etc. 74 * Some drawables may modify their imagery based on the selected state. 75 * 76 * <li> The {@link #setLevel} method allows the client to supply a single 77 * continuous controller that can modify the Drawable is displayed, such as 78 * a battery level or progress level. Some drawables may modify their 79 * imagery based on the current level. 80 * 81 * <li> A Drawable can perform animations by calling back to its client 82 * through the {@link Callback} interface. All clients should support this 83 * interface (via {@link #setCallback}) so that animations will work. A 84 * simple way to do this is through the system facilities such as 85 * {@link android.view.View#setBackgroundDrawable(Drawable)} and 86 * {@link android.widget.ImageView}. 87 * </ul> 88 * 89 * Though usually not visible to the application, Drawables may take a variety 90 * of forms: 91 * 92 * <ul> 93 * <li> <b>Bitmap</b>: the simplest Drawable, a PNG or JPEG image. 94 * <li> <b>Nine Patch</b>: an extension to the PNG format allows it to 95 * specify information about how to stretch it and place things inside of 96 * it. 97 * <li> <b>Shape</b>: contains simple drawing commands instead of a raw 98 * bitmap, allowing it to resize better in some cases. 99 * <li> <b>Layers</b>: a compound drawable, which draws multiple underlying 100 * drawables on top of each other. 101 * <li> <b>States</b>: a compound drawable that selects one of a set of 102 * drawables based on its state. 103 * <li> <b>Levels</b>: a compound drawable that selects one of a set of 104 * drawables based on its level. 105 * <li> <b>Scale</b>: a compound drawable with a single child drawable, 106 * whose overall size is modified based on the current level. 107 * </ul> 108 * 109 * <div class="special reference"> 110 * <h3>Developer Guides</h3> 111 * <p>For more information about how to use drawables, read the 112 * <a href="{@docRoot}guide/topics/graphics/2d-graphics.html">Canvas and Drawables</a> developer 113 * guide. For information and examples of creating drawable resources (XML or bitmap files that 114 * can be loaded in code), read the 115 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a> 116 * document.</p></div> 117 */ 118public abstract class Drawable { 119 private static final Rect ZERO_BOUNDS_RECT = new Rect(); 120 121 private int[] mStateSet = StateSet.WILD_CARD; 122 private int mLevel = 0; 123 private int mChangingConfigurations = 0; 124 private Rect mBounds = ZERO_BOUNDS_RECT; // lazily becomes a new Rect() 125 private WeakReference<Callback> mCallback = null; 126 private boolean mVisible = true; 127 128 private int mLayoutDirection; 129 130 /** 131 * Draw in its bounds (set via setBounds) respecting optional effects such 132 * as alpha (set via setAlpha) and color filter (set via setColorFilter). 133 * 134 * @param canvas The canvas to draw into 135 */ 136 public abstract void draw(Canvas canvas); 137 138 /** 139 * Specify a bounding rectangle for the Drawable. This is where the drawable 140 * will draw when its draw() method is called. 141 */ 142 public void setBounds(int left, int top, int right, int bottom) { 143 Rect oldBounds = mBounds; 144 145 if (oldBounds == ZERO_BOUNDS_RECT) { 146 oldBounds = mBounds = new Rect(); 147 } 148 149 if (oldBounds.left != left || oldBounds.top != top || 150 oldBounds.right != right || oldBounds.bottom != bottom) { 151 if (!oldBounds.isEmpty()) { 152 // first invalidate the previous bounds 153 invalidateSelf(); 154 } 155 mBounds.set(left, top, right, bottom); 156 onBoundsChange(mBounds); 157 } 158 } 159 160 /** 161 * Specify a bounding rectangle for the Drawable. This is where the drawable 162 * will draw when its draw() method is called. 163 */ 164 public void setBounds(Rect bounds) { 165 setBounds(bounds.left, bounds.top, bounds.right, bounds.bottom); 166 } 167 168 /** 169 * Return a copy of the drawable's bounds in the specified Rect (allocated 170 * by the caller). The bounds specify where this will draw when its draw() 171 * method is called. 172 * 173 * @param bounds Rect to receive the drawable's bounds (allocated by the 174 * caller). 175 */ 176 public final void copyBounds(Rect bounds) { 177 bounds.set(mBounds); 178 } 179 180 /** 181 * Return a copy of the drawable's bounds in a new Rect. This returns the 182 * same values as getBounds(), but the returned object is guaranteed to not 183 * be changed later by the drawable (i.e. it retains no reference to this 184 * rect). If the caller already has a Rect allocated, call copyBounds(rect). 185 * 186 * @return A copy of the drawable's bounds 187 */ 188 public final Rect copyBounds() { 189 return new Rect(mBounds); 190 } 191 192 /** 193 * Return the drawable's bounds Rect. Note: for efficiency, the returned 194 * object may be the same object stored in the drawable (though this is not 195 * guaranteed), so if a persistent copy of the bounds is needed, call 196 * copyBounds(rect) instead. 197 * You should also not change the object returned by this method as it may 198 * be the same object stored in the drawable. 199 * 200 * @return The bounds of the drawable (which may change later, so caller 201 * beware). DO NOT ALTER the returned object as it may change the 202 * stored bounds of this drawable. 203 * 204 * @see #copyBounds() 205 * @see #copyBounds(android.graphics.Rect) 206 */ 207 public final Rect getBounds() { 208 if (mBounds == ZERO_BOUNDS_RECT) { 209 mBounds = new Rect(); 210 } 211 212 return mBounds; 213 } 214 215 /** 216 * Set a mask of the configuration parameters for which this drawable 217 * may change, requiring that it be re-created. 218 * 219 * @param configs A mask of the changing configuration parameters, as 220 * defined by {@link android.content.res.Configuration}. 221 * 222 * @see android.content.res.Configuration 223 */ 224 public void setChangingConfigurations(int configs) { 225 mChangingConfigurations = configs; 226 } 227 228 /** 229 * Return a mask of the configuration parameters for which this drawable 230 * may change, requiring that it be re-created. The default implementation 231 * returns whatever was provided through 232 * {@link #setChangingConfigurations(int)} or 0 by default. Subclasses 233 * may extend this to or in the changing configurations of any other 234 * drawables they hold. 235 * 236 * @return Returns a mask of the changing configuration parameters, as 237 * defined by {@link android.content.res.Configuration}. 238 * 239 * @see android.content.res.Configuration 240 */ 241 public int getChangingConfigurations() { 242 return mChangingConfigurations; 243 } 244 245 /** 246 * Set to true to have the drawable dither its colors when drawn to a device 247 * with fewer than 8-bits per color component. This can improve the look on 248 * those devices, but can also slow down the drawing a little. 249 */ 250 public void setDither(boolean dither) {} 251 252 /** 253 * Set to true to have the drawable filter its bitmap when scaled or rotated 254 * (for drawables that use bitmaps). If the drawable does not use bitmaps, 255 * this call is ignored. This can improve the look when scaled or rotated, 256 * but also slows down the drawing. 257 */ 258 public void setFilterBitmap(boolean filter) {} 259 260 /** 261 * Implement this interface if you want to create an animated drawable that 262 * extends {@link android.graphics.drawable.Drawable Drawable}. 263 * Upon retrieving a drawable, use 264 * {@link Drawable#setCallback(android.graphics.drawable.Drawable.Callback)} 265 * to supply your implementation of the interface to the drawable; it uses 266 * this interface to schedule and execute animation changes. 267 */ 268 public static interface Callback { 269 /** 270 * Called when the drawable needs to be redrawn. A view at this point 271 * should invalidate itself (or at least the part of itself where the 272 * drawable appears). 273 * 274 * @param who The drawable that is requesting the update. 275 */ 276 public void invalidateDrawable(Drawable who); 277 278 /** 279 * A Drawable can call this to schedule the next frame of its 280 * animation. An implementation can generally simply call 281 * {@link android.os.Handler#postAtTime(Runnable, Object, long)} with 282 * the parameters <var>(what, who, when)</var> to perform the 283 * scheduling. 284 * 285 * @param who The drawable being scheduled. 286 * @param what The action to execute. 287 * @param when The time (in milliseconds) to run. The timebase is 288 * {@link android.os.SystemClock#uptimeMillis} 289 */ 290 public void scheduleDrawable(Drawable who, Runnable what, long when); 291 292 /** 293 * A Drawable can call this to unschedule an action previously 294 * scheduled with {@link #scheduleDrawable}. An implementation can 295 * generally simply call 296 * {@link android.os.Handler#removeCallbacks(Runnable, Object)} with 297 * the parameters <var>(what, who)</var> to unschedule the drawable. 298 * 299 * @param who The drawable being unscheduled. 300 * @param what The action being unscheduled. 301 */ 302 public void unscheduleDrawable(Drawable who, Runnable what); 303 } 304 305 /** 306 * Bind a {@link Callback} object to this Drawable. Required for clients 307 * that want to support animated drawables. 308 * 309 * @param cb The client's Callback implementation. 310 * 311 * @see #getCallback() 312 */ 313 public final void setCallback(Callback cb) { 314 mCallback = new WeakReference<Callback>(cb); 315 } 316 317 /** 318 * Return the current {@link Callback} implementation attached to this 319 * Drawable. 320 * 321 * @return A {@link Callback} instance or null if no callback was set. 322 * 323 * @see #setCallback(android.graphics.drawable.Drawable.Callback) 324 */ 325 public Callback getCallback() { 326 if (mCallback != null) { 327 return mCallback.get(); 328 } 329 return null; 330 } 331 332 /** 333 * Use the current {@link Callback} implementation to have this Drawable 334 * redrawn. Does nothing if there is no Callback attached to the 335 * Drawable. 336 * 337 * @see Callback#invalidateDrawable 338 * @see #getCallback() 339 * @see #setCallback(android.graphics.drawable.Drawable.Callback) 340 */ 341 public void invalidateSelf() { 342 final Callback callback = getCallback(); 343 if (callback != null) { 344 callback.invalidateDrawable(this); 345 } 346 } 347 348 /** 349 * Use the current {@link Callback} implementation to have this Drawable 350 * scheduled. Does nothing if there is no Callback attached to the 351 * Drawable. 352 * 353 * @param what The action being scheduled. 354 * @param when The time (in milliseconds) to run. 355 * 356 * @see Callback#scheduleDrawable 357 */ 358 public void scheduleSelf(Runnable what, long when) { 359 final Callback callback = getCallback(); 360 if (callback != null) { 361 callback.scheduleDrawable(this, what, when); 362 } 363 } 364 365 /** 366 * Use the current {@link Callback} implementation to have this Drawable 367 * unscheduled. Does nothing if there is no Callback attached to the 368 * Drawable. 369 * 370 * @param what The runnable that you no longer want called. 371 * 372 * @see Callback#unscheduleDrawable 373 */ 374 public void unscheduleSelf(Runnable what) { 375 final Callback callback = getCallback(); 376 if (callback != null) { 377 callback.unscheduleDrawable(this, what); 378 } 379 } 380 381 /** 382 * Returns the resolved layout direction for this Drawable. 383 * 384 * @return One of {@link android.view.View#LAYOUT_DIRECTION_LTR}, 385 * {@link android.view.View#LAYOUT_DIRECTION_RTL} 386 * 387 * @hide 388 */ 389 public int getLayoutDirection() { 390 return mLayoutDirection; 391 } 392 393 /** 394 * Set the layout direction for this drawable. Should be a resolved direction as the 395 * Drawable as no capacity to do the resolution on his own. 396 * 397 * @param layoutDirection One of {@link android.view.View#LAYOUT_DIRECTION_LTR}, 398 * {@link android.view.View#LAYOUT_DIRECTION_RTL} 399 * 400 * @hide 401 */ 402 public void setLayoutDirection(int layoutDirection) { 403 if (getLayoutDirection() != layoutDirection) { 404 mLayoutDirection = layoutDirection; 405 } 406 } 407 408 /** 409 * Specify an alpha value for the drawable. 0 means fully transparent, and 410 * 255 means fully opaque. 411 */ 412 public abstract void setAlpha(int alpha); 413 414 /** 415 * Gets the current alpha value for the drawable. 0 means fully transparent, 416 * 255 means fully opaque. This method is implemented by 417 * Drawable subclasses and the value returned is specific to how that class treats alpha. 418 * The default return value is 255 if the class does not override this method to return a value 419 * specific to its use of alpha. 420 */ 421 public int getAlpha() { 422 return 0xFF; 423 } 424 425 /** 426 * Specify an optional colorFilter for the drawable. Pass null to remove 427 * any filters. 428 */ 429 public abstract void setColorFilter(ColorFilter cf); 430 431 /** 432 * @hide Consider for future API inclusion 433 */ 434 public void setXfermode(Xfermode mode) { 435 // Base implementation drops it on the floor for compatibility. Whee! 436 // TODO: For this to be included in the API proper, all framework drawables need impls. 437 // For right now only BitmapDrawable has it. 438 } 439 440 /** 441 * Specify a color and porterduff mode to be the colorfilter for this 442 * drawable. 443 */ 444 public void setColorFilter(int color, PorterDuff.Mode mode) { 445 setColorFilter(new PorterDuffColorFilter(color, mode)); 446 } 447 448 public void clearColorFilter() { 449 setColorFilter(null); 450 } 451 452 /** 453 * Indicates whether this view will change its appearance based on state. 454 * Clients can use this to determine whether it is necessary to calculate 455 * their state and call setState. 456 * 457 * @return True if this view changes its appearance based on state, false 458 * otherwise. 459 * 460 * @see #setState(int[]) 461 */ 462 public boolean isStateful() { 463 return false; 464 } 465 466 /** 467 * Specify a set of states for the drawable. These are use-case specific, 468 * so see the relevant documentation. As an example, the background for 469 * widgets like Button understand the following states: 470 * [{@link android.R.attr#state_focused}, 471 * {@link android.R.attr#state_pressed}]. 472 * 473 * <p>If the new state you are supplying causes the appearance of the 474 * Drawable to change, then it is responsible for calling 475 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 476 * true will be returned from this function. 477 * 478 * <p>Note: The Drawable holds a reference on to <var>stateSet</var> 479 * until a new state array is given to it, so you must not modify this 480 * array during that time.</p> 481 * 482 * @param stateSet The new set of states to be displayed. 483 * 484 * @return Returns true if this change in state has caused the appearance 485 * of the Drawable to change (hence requiring an invalidate), otherwise 486 * returns false. 487 */ 488 public boolean setState(final int[] stateSet) { 489 if (!Arrays.equals(mStateSet, stateSet)) { 490 mStateSet = stateSet; 491 return onStateChange(stateSet); 492 } 493 return false; 494 } 495 496 /** 497 * Describes the current state, as a union of primitve states, such as 498 * {@link android.R.attr#state_focused}, 499 * {@link android.R.attr#state_selected}, etc. 500 * Some drawables may modify their imagery based on the selected state. 501 * @return An array of resource Ids describing the current state. 502 */ 503 public int[] getState() { 504 return mStateSet; 505 } 506 507 /** 508 * If this Drawable does transition animations between states, ask that 509 * it immediately jump to the current state and skip any active animations. 510 */ 511 public void jumpToCurrentState() { 512 } 513 514 /** 515 * @return The current drawable that will be used by this drawable. For simple drawables, this 516 * is just the drawable itself. For drawables that change state like 517 * {@link StateListDrawable} and {@link LevelListDrawable} this will be the child drawable 518 * currently in use. 519 */ 520 public Drawable getCurrent() { 521 return this; 522 } 523 524 /** 525 * Specify the level for the drawable. This allows a drawable to vary its 526 * imagery based on a continuous controller, for example to show progress 527 * or volume level. 528 * 529 * <p>If the new level you are supplying causes the appearance of the 530 * Drawable to change, then it is responsible for calling 531 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 532 * true will be returned from this function. 533 * 534 * @param level The new level, from 0 (minimum) to 10000 (maximum). 535 * 536 * @return Returns true if this change in level has caused the appearance 537 * of the Drawable to change (hence requiring an invalidate), otherwise 538 * returns false. 539 */ 540 public final boolean setLevel(int level) { 541 if (mLevel != level) { 542 mLevel = level; 543 return onLevelChange(level); 544 } 545 return false; 546 } 547 548 /** 549 * Retrieve the current level. 550 * 551 * @return int Current level, from 0 (minimum) to 10000 (maximum). 552 */ 553 public final int getLevel() { 554 return mLevel; 555 } 556 557 /** 558 * Set whether this Drawable is visible. This generally does not impact 559 * the Drawable's behavior, but is a hint that can be used by some 560 * Drawables, for example, to decide whether run animations. 561 * 562 * @param visible Set to true if visible, false if not. 563 * @param restart You can supply true here to force the drawable to behave 564 * as if it has just become visible, even if it had last 565 * been set visible. Used for example to force animations 566 * to restart. 567 * 568 * @return boolean Returns true if the new visibility is different than 569 * its previous state. 570 */ 571 public boolean setVisible(boolean visible, boolean restart) { 572 boolean changed = mVisible != visible; 573 if (changed) { 574 mVisible = visible; 575 invalidateSelf(); 576 } 577 return changed; 578 } 579 580 public final boolean isVisible() { 581 return mVisible; 582 } 583 584 /** 585 * Set whether this Drawable is automatically mirrored when its layout direction is RTL 586 * (right-to left). See {@link android.util.LayoutDirection}. 587 * 588 * @param mirrored Set to true if the Drawable should be mirrored, false if not. 589 */ 590 public void setAutoMirrored(boolean mirrored) { 591 } 592 593 /** 594 * Tells if this Drawable will be automatically mirrored when its layout direction is RTL 595 * right-to-left. See {@link android.util.LayoutDirection}. 596 * 597 * @return boolean Returns true if this Drawable will be automatically mirrored. 598 */ 599 public boolean isAutoMirrored() { 600 return false; 601 } 602 603 /** 604 * Return the opacity/transparency of this Drawable. The returned value is 605 * one of the abstract format constants in 606 * {@link android.graphics.PixelFormat}: 607 * {@link android.graphics.PixelFormat#UNKNOWN}, 608 * {@link android.graphics.PixelFormat#TRANSLUCENT}, 609 * {@link android.graphics.PixelFormat#TRANSPARENT}, or 610 * {@link android.graphics.PixelFormat#OPAQUE}. 611 * 612 * <p>Generally a Drawable should be as conservative as possible with the 613 * value it returns. For example, if it contains multiple child drawables 614 * and only shows one of them at a time, if only one of the children is 615 * TRANSLUCENT and the others are OPAQUE then TRANSLUCENT should be 616 * returned. You can use the method {@link #resolveOpacity} to perform a 617 * standard reduction of two opacities to the appropriate single output. 618 * 619 * <p>Note that the returned value does <em>not</em> take into account a 620 * custom alpha or color filter that has been applied by the client through 621 * the {@link #setAlpha} or {@link #setColorFilter} methods. 622 * 623 * @return int The opacity class of the Drawable. 624 * 625 * @see android.graphics.PixelFormat 626 */ 627 public abstract int getOpacity(); 628 629 /** 630 * Return the appropriate opacity value for two source opacities. If 631 * either is UNKNOWN, that is returned; else, if either is TRANSLUCENT, 632 * that is returned; else, if either is TRANSPARENT, that is returned; 633 * else, OPAQUE is returned. 634 * 635 * <p>This is to help in implementing {@link #getOpacity}. 636 * 637 * @param op1 One opacity value. 638 * @param op2 Another opacity value. 639 * 640 * @return int The combined opacity value. 641 * 642 * @see #getOpacity 643 */ 644 public static int resolveOpacity(int op1, int op2) { 645 if (op1 == op2) { 646 return op1; 647 } 648 if (op1 == PixelFormat.UNKNOWN || op2 == PixelFormat.UNKNOWN) { 649 return PixelFormat.UNKNOWN; 650 } 651 if (op1 == PixelFormat.TRANSLUCENT || op2 == PixelFormat.TRANSLUCENT) { 652 return PixelFormat.TRANSLUCENT; 653 } 654 if (op1 == PixelFormat.TRANSPARENT || op2 == PixelFormat.TRANSPARENT) { 655 return PixelFormat.TRANSPARENT; 656 } 657 return PixelFormat.OPAQUE; 658 } 659 660 /** 661 * Returns a Region representing the part of the Drawable that is completely 662 * transparent. This can be used to perform drawing operations, identifying 663 * which parts of the target will not change when rendering the Drawable. 664 * The default implementation returns null, indicating no transparent 665 * region; subclasses can optionally override this to return an actual 666 * Region if they want to supply this optimization information, but it is 667 * not required that they do so. 668 * 669 * @return Returns null if the Drawables has no transparent region to 670 * report, else a Region holding the parts of the Drawable's bounds that 671 * are transparent. 672 */ 673 public Region getTransparentRegion() { 674 return null; 675 } 676 677 /** 678 * Override this in your subclass to change appearance if you recognize the 679 * specified state. 680 * 681 * @return Returns true if the state change has caused the appearance of 682 * the Drawable to change (that is, it needs to be drawn), else false 683 * if it looks the same and there is no need to redraw it since its 684 * last state. 685 */ 686 protected boolean onStateChange(int[] state) { return false; } 687 /** Override this in your subclass to change appearance if you vary based 688 * on level. 689 * @return Returns true if the level change has caused the appearance of 690 * the Drawable to change (that is, it needs to be drawn), else false 691 * if it looks the same and there is no need to redraw it since its 692 * last level. 693 */ 694 protected boolean onLevelChange(int level) { return false; } 695 /** 696 * Override this in your subclass to change appearance if you recognize the 697 * specified state. 698 */ 699 protected void onBoundsChange(Rect bounds) {} 700 701 /** 702 * Return the intrinsic width of the underlying drawable object. Returns 703 * -1 if it has no intrinsic width, such as with a solid color. 704 */ 705 public int getIntrinsicWidth() { 706 return -1; 707 } 708 709 /** 710 * Return the intrinsic height of the underlying drawable object. Returns 711 * -1 if it has no intrinsic height, such as with a solid color. 712 */ 713 public int getIntrinsicHeight() { 714 return -1; 715 } 716 717 /** 718 * Returns the minimum width suggested by this Drawable. If a View uses this 719 * Drawable as a background, it is suggested that the View use at least this 720 * value for its width. (There will be some scenarios where this will not be 721 * possible.) This value should INCLUDE any padding. 722 * 723 * @return The minimum width suggested by this Drawable. If this Drawable 724 * doesn't have a suggested minimum width, 0 is returned. 725 */ 726 public int getMinimumWidth() { 727 final int intrinsicWidth = getIntrinsicWidth(); 728 return intrinsicWidth > 0 ? intrinsicWidth : 0; 729 } 730 731 /** 732 * Returns the minimum height suggested by this Drawable. If a View uses this 733 * Drawable as a background, it is suggested that the View use at least this 734 * value for its height. (There will be some scenarios where this will not be 735 * possible.) This value should INCLUDE any padding. 736 * 737 * @return The minimum height suggested by this Drawable. If this Drawable 738 * doesn't have a suggested minimum height, 0 is returned. 739 */ 740 public int getMinimumHeight() { 741 final int intrinsicHeight = getIntrinsicHeight(); 742 return intrinsicHeight > 0 ? intrinsicHeight : 0; 743 } 744 745 /** 746 * Return in padding the insets suggested by this Drawable for placing 747 * content inside the drawable's bounds. Positive values move toward the 748 * center of the Drawable (set Rect.inset). Returns true if this drawable 749 * actually has a padding, else false. When false is returned, the padding 750 * is always set to 0. 751 */ 752 public boolean getPadding(Rect padding) { 753 padding.set(0, 0, 0, 0); 754 return false; 755 } 756 757 /** 758 * Return in insets the layout insets suggested by this Drawable for use with alignment 759 * operations during layout. 760 * 761 * @hide 762 */ 763 public Insets getOpticalInsets() { 764 return Insets.NONE; 765 } 766 767 /** 768 * Make this drawable mutable. This operation cannot be reversed. A mutable 769 * drawable is guaranteed to not share its state with any other drawable. 770 * This is especially useful when you need to modify properties of drawables 771 * loaded from resources. By default, all drawables instances loaded from 772 * the same resource share a common state; if you modify the state of one 773 * instance, all the other instances will receive the same modification. 774 * 775 * Calling this method on a mutable Drawable will have no effect. 776 * 777 * @return This drawable. 778 * @see ConstantState 779 * @see #getConstantState() 780 */ 781 public Drawable mutate() { 782 return this; 783 } 784 785 /** 786 * Create a drawable from an inputstream 787 */ 788 public static Drawable createFromStream(InputStream is, String srcName) { 789 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, srcName != null ? srcName : "Unknown drawable"); 790 try { 791 return createFromResourceStream(null, null, is, srcName, null); 792 } finally { 793 Trace.traceEnd(Trace.TRACE_TAG_RESOURCES); 794 } 795 } 796 797 /** 798 * Create a drawable from an inputstream, using the given resources and 799 * value to determine density information. 800 */ 801 public static Drawable createFromResourceStream(Resources res, TypedValue value, 802 InputStream is, String srcName) { 803 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, srcName != null ? srcName : "Unknown drawable"); 804 try { 805 return createFromResourceStream(res, value, is, srcName, null); 806 } finally { 807 Trace.traceEnd(Trace.TRACE_TAG_RESOURCES); 808 } 809 } 810 811 /** 812 * Create a drawable from an inputstream, using the given resources and 813 * value to determine density information. 814 */ 815 public static Drawable createFromResourceStream(Resources res, TypedValue value, 816 InputStream is, String srcName, BitmapFactory.Options opts) { 817 818 if (is == null) { 819 return null; 820 } 821 822 /* ugh. The decodeStream contract is that we have already allocated 823 the pad rect, but if the bitmap does not had a ninepatch chunk, 824 then the pad will be ignored. If we could change this to lazily 825 alloc/assign the rect, we could avoid the GC churn of making new 826 Rects only to drop them on the floor. 827 */ 828 Rect pad = new Rect(); 829 830 // Special stuff for compatibility mode: if the target density is not 831 // the same as the display density, but the resource -is- the same as 832 // the display density, then don't scale it down to the target density. 833 // This allows us to load the system's density-correct resources into 834 // an application in compatibility mode, without scaling those down 835 // to the compatibility density only to have them scaled back up when 836 // drawn to the screen. 837 if (opts == null) opts = new BitmapFactory.Options(); 838 opts.inScreenDensity = res != null 839 ? res.getDisplayMetrics().noncompatDensityDpi : DisplayMetrics.DENSITY_DEVICE; 840 Bitmap bm = BitmapFactory.decodeResourceStream(res, value, is, pad, opts); 841 if (bm != null) { 842 byte[] np = bm.getNinePatchChunk(); 843 if (np == null || !NinePatch.isNinePatchChunk(np)) { 844 np = null; 845 pad = null; 846 } 847 int[] layoutBounds = bm.getLayoutBounds(); 848 Rect layoutBoundsRect = null; 849 if (layoutBounds != null) { 850 layoutBoundsRect = new Rect(layoutBounds[0], layoutBounds[1], 851 layoutBounds[2], layoutBounds[3]); 852 } 853 return drawableFromBitmap(res, bm, np, pad, layoutBoundsRect, srcName); 854 } 855 return null; 856 } 857 858 /** 859 * Create a drawable from an XML document. For more information on how to 860 * create resources in XML, see 861 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. 862 */ 863 public static Drawable createFromXml(Resources r, XmlPullParser parser) 864 throws XmlPullParserException, IOException { 865 AttributeSet attrs = Xml.asAttributeSet(parser); 866 867 int type; 868 while ((type=parser.next()) != XmlPullParser.START_TAG && 869 type != XmlPullParser.END_DOCUMENT) { 870 // Empty loop 871 } 872 873 if (type != XmlPullParser.START_TAG) { 874 throw new XmlPullParserException("No start tag found"); 875 } 876 877 Drawable drawable = createFromXmlInner(r, parser, attrs); 878 879 if (drawable == null) { 880 throw new RuntimeException("Unknown initial tag: " + parser.getName()); 881 } 882 883 return drawable; 884 } 885 886 /** 887 * Create from inside an XML document. Called on a parser positioned at 888 * a tag in an XML document, tries to create a Drawable from that tag. 889 * Returns null if the tag is not a valid drawable. 890 */ 891 public static Drawable createFromXmlInner(Resources r, XmlPullParser parser, AttributeSet attrs) 892 throws XmlPullParserException, IOException { 893 Drawable drawable; 894 895 final String name = parser.getName(); 896 897 if (name.equals("selector")) { 898 drawable = new StateListDrawable(); 899 } else if (name.equals("level-list")) { 900 drawable = new LevelListDrawable(); 901 } else if (name.equals("layer-list")) { 902 drawable = new LayerDrawable(); 903 } else if (name.equals("transition")) { 904 drawable = new TransitionDrawable(); 905 } else if (name.equals("color")) { 906 drawable = new ColorDrawable(); 907 } else if (name.equals("shape")) { 908 drawable = new GradientDrawable(); 909 } else if (name.equals("scale")) { 910 drawable = new ScaleDrawable(); 911 } else if (name.equals("clip")) { 912 drawable = new ClipDrawable(); 913 } else if (name.equals("rotate")) { 914 drawable = new RotateDrawable(); 915 } else if (name.equals("animated-rotate")) { 916 drawable = new AnimatedRotateDrawable(); 917 } else if (name.equals("animation-list")) { 918 drawable = new AnimationDrawable(); 919 } else if (name.equals("inset")) { 920 drawable = new InsetDrawable(); 921 } else if (name.equals("bitmap")) { 922 //noinspection deprecation 923 drawable = new BitmapDrawable(r); 924 if (r != null) { 925 ((BitmapDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 926 } 927 } else if (name.equals("nine-patch")) { 928 drawable = new NinePatchDrawable(); 929 if (r != null) { 930 ((NinePatchDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 931 } 932 } else { 933 throw new XmlPullParserException(parser.getPositionDescription() + 934 ": invalid drawable tag " + name); 935 } 936 937 drawable.inflate(r, parser, attrs); 938 return drawable; 939 } 940 941 942 /** 943 * Create a drawable from file path name. 944 */ 945 public static Drawable createFromPath(String pathName) { 946 if (pathName == null) { 947 return null; 948 } 949 950 Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, pathName); 951 try { 952 Bitmap bm = BitmapFactory.decodeFile(pathName); 953 if (bm != null) { 954 return drawableFromBitmap(null, bm, null, null, null, pathName); 955 } 956 } finally { 957 Trace.traceEnd(Trace.TRACE_TAG_RESOURCES); 958 } 959 960 return null; 961 } 962 963 /** 964 * Inflate this Drawable from an XML resource. 965 */ 966 public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs) 967 throws XmlPullParserException, IOException { 968 969 TypedArray a = r.obtainAttributes(attrs, com.android.internal.R.styleable.Drawable); 970 inflateWithAttributes(r, parser, a, com.android.internal.R.styleable.Drawable_visible); 971 a.recycle(); 972 } 973 974 /** 975 * Inflate a Drawable from an XML resource. 976 * 977 * @throws XmlPullParserException 978 * @throws IOException 979 */ 980 void inflateWithAttributes(Resources r, XmlPullParser parser, 981 TypedArray attrs, int visibleAttr) 982 throws XmlPullParserException, IOException { 983 984 mVisible = attrs.getBoolean(visibleAttr, mVisible); 985 } 986 987 /** 988 * This abstract class is used by {@link Drawable}s to store shared constant state and data 989 * between Drawables. {@link BitmapDrawable}s created from the same resource will for instance 990 * share a unique bitmap stored in their ConstantState. 991 * 992 * <p> 993 * {@link #newDrawable(Resources)} can be used as a factory to create new Drawable instances 994 * from this ConstantState. 995 * </p> 996 * 997 * Use {@link Drawable#getConstantState()} to retrieve the ConstantState of a Drawable. Calling 998 * {@link Drawable#mutate()} on a Drawable should typically create a new ConstantState for that 999 * Drawable. 1000 */ 1001 public static abstract class ConstantState { 1002 /** 1003 * Create a new drawable without supplying resources the caller 1004 * is running in. Note that using this means the density-dependent 1005 * drawables (like bitmaps) will not be able to update their target 1006 * density correctly. One should use {@link #newDrawable(Resources)} 1007 * instead to provide a resource. 1008 */ 1009 public abstract Drawable newDrawable(); 1010 /** 1011 * Create a new Drawable instance from its constant state. This 1012 * must be implemented for drawables that change based on the target 1013 * density of their caller (that is depending on whether it is 1014 * in compatibility mode). 1015 */ 1016 public Drawable newDrawable(Resources res) { 1017 return newDrawable(); 1018 } 1019 /** 1020 * Return a bit mask of configuration changes that will impact 1021 * this drawable (and thus require completely reloading it). 1022 */ 1023 public abstract int getChangingConfigurations(); 1024 1025 /** 1026 * @hide 1027 */ 1028 public Bitmap getBitmap() { 1029 return null; 1030 } 1031 } 1032 1033 /** 1034 * Return a {@link ConstantState} instance that holds the shared state of this Drawable. 1035 *q 1036 * @return The ConstantState associated to that Drawable. 1037 * @see ConstantState 1038 * @see Drawable#mutate() 1039 */ 1040 public ConstantState getConstantState() { 1041 return null; 1042 } 1043 1044 private static Drawable drawableFromBitmap(Resources res, Bitmap bm, byte[] np, 1045 Rect pad, Rect layoutBounds, String srcName) { 1046 1047 if (np != null) { 1048 return new NinePatchDrawable(res, bm, np, pad, layoutBounds, srcName); 1049 } 1050 1051 return new BitmapDrawable(res, bm); 1052 } 1053} 1054 1055