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 org.xmlpull.v1.XmlPullParser; 21import org.xmlpull.v1.XmlPullParserException; 22 23import android.content.res.Resources; 24import android.content.res.TypedArray; 25import android.graphics.Bitmap; 26import android.graphics.BitmapFactory; 27import android.graphics.Canvas; 28import android.graphics.ColorFilter; 29import android.graphics.NinePatch; 30import android.graphics.PixelFormat; 31import android.graphics.PorterDuff; 32import android.graphics.PorterDuffColorFilter; 33import android.graphics.Rect; 34import android.graphics.Region; 35import android.util.AttributeSet; 36import android.util.DisplayMetrics; 37import android.util.StateSet; 38import android.util.TypedValue; 39import android.util.Xml; 40 41import java.io.IOException; 42import java.io.InputStream; 43import java.lang.ref.WeakReference; 44import java.util.Arrays; 45 46/** 47 * A Drawable is a general abstraction for "something that can be drawn." Most 48 * often you will deal with Drawable as the type of resource retrieved for 49 * drawing things to the screen; the Drawable class provides a generic API for 50 * dealing with an underlying visual resource that may take a variety of forms. 51 * Unlike a {@link android.view.View}, a Drawable does not have any facility to 52 * receive events or otherwise interact with the user. 53 * 54 * <p>In addition to simple drawing, Drawable provides a number of generic 55 * mechanisms for its client to interact with what is being drawn: 56 * 57 * <ul> 58 * <li> The {@link #setBounds} method <var>must</var> be called to tell the 59 * Drawable where it is drawn and how large it should be. All Drawables 60 * should respect the requested size, often simply by scaling their 61 * imagery. A client can find the preferred size for some Drawables with 62 * the {@link #getIntrinsicHeight} and {@link #getIntrinsicWidth} methods. 63 * 64 * <li> The {@link #getPadding} method can return from some Drawables 65 * information about how to frame content that is placed inside of them. 66 * For example, a Drawable that is intended to be the frame for a button 67 * widget would need to return padding that correctly places the label 68 * inside of itself. 69 * 70 * <li> The {@link #setState} method allows the client to tell the Drawable 71 * in which state it is to be drawn, such as "focused", "selected", etc. 72 * Some drawables may modify their imagery based on the selected state. 73 * 74 * <li> The {@link #setLevel} method allows the client to supply a single 75 * continuous controller that can modify the Drawable is displayed, such as 76 * a battery level or progress level. Some drawables may modify their 77 * imagery based on the current level. 78 * 79 * <li> A Drawable can perform animations by calling back to its client 80 * through the {@link Callback} interface. All clients should support this 81 * interface (via {@link #setCallback}) so that animations will work. A 82 * simple way to do this is through the system facilities such as 83 * {@link android.view.View#setBackgroundDrawable(Drawable)} and 84 * {@link android.widget.ImageView}. 85 * </ul> 86 * 87 * Though usually not visible to the application, Drawables may take a variety 88 * of forms: 89 * 90 * <ul> 91 * <li> <b>Bitmap</b>: the simplest Drawable, a PNG or JPEG image. 92 * <li> <b>Nine Patch</b>: an extension to the PNG format allows it to 93 * specify information about how to stretch it and place things inside of 94 * it. 95 * <li> <b>Shape</b>: contains simple drawing commands instead of a raw 96 * bitmap, allowing it to resize better in some cases. 97 * <li> <b>Layers</b>: a compound drawable, which draws multiple underlying 98 * drawables on top of each other. 99 * <li> <b>States</b>: a compound drawable that selects one of a set of 100 * drawables based on its state. 101 * <li> <b>Levels</b>: a compound drawable that selects one of a set of 102 * drawables based on its level. 103 * <li> <b>Scale</b>: a compound drawable with a single child drawable, 104 * whose overall size is modified based on the current level. 105 * </ul> 106 * 107 * <div class="special reference"> 108 * <h3>Developer Guides</h3> 109 * <p>For more information about how to use drawables, read the 110 * <a href="{@docRoot}guide/topics/graphics/2d-graphics.html">Canvas and Drawables</a> developer 111 * guide. For information and examples of creating drawable resources (XML or bitmap files that 112 * can be loaded in code), read the 113 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a> 114 * document.</p></div> 115 */ 116public abstract class Drawable { 117 private static final Rect ZERO_BOUNDS_RECT = new Rect(); 118 119 private int[] mStateSet = StateSet.WILD_CARD; 120 private int mLevel = 0; 121 private int mChangingConfigurations = 0; 122 private Rect mBounds = ZERO_BOUNDS_RECT; // lazily becomes a new Rect() 123 private WeakReference<Callback> mCallback = null; 124 private boolean mVisible = true; 125 126 private int mLayoutDirection; 127 128 /** 129 * Draw in its bounds (set via setBounds) respecting optional effects such 130 * as alpha (set via setAlpha) and color filter (set via setColorFilter). 131 * 132 * @param canvas The canvas to draw into 133 */ 134 public abstract void draw(Canvas canvas); 135 136 /** 137 * Specify a bounding rectangle for the Drawable. This is where the drawable 138 * will draw when its draw() method is called. 139 */ 140 public void setBounds(int left, int top, int right, int bottom) { 141 Rect oldBounds = mBounds; 142 143 if (oldBounds == ZERO_BOUNDS_RECT) { 144 oldBounds = mBounds = new Rect(); 145 } 146 147 if (oldBounds.left != left || oldBounds.top != top || 148 oldBounds.right != right || oldBounds.bottom != bottom) { 149 mBounds.set(left, top, right, bottom); 150 onBoundsChange(mBounds); 151 } 152 } 153 154 /** 155 * Specify a bounding rectangle for the Drawable. This is where the drawable 156 * will draw when its draw() method is called. 157 */ 158 public void setBounds(Rect bounds) { 159 setBounds(bounds.left, bounds.top, bounds.right, bounds.bottom); 160 } 161 162 /** 163 * Return a copy of the drawable's bounds in the specified Rect (allocated 164 * by the caller). The bounds specify where this will draw when its draw() 165 * method is called. 166 * 167 * @param bounds Rect to receive the drawable's bounds (allocated by the 168 * caller). 169 */ 170 public final void copyBounds(Rect bounds) { 171 bounds.set(mBounds); 172 } 173 174 /** 175 * Return a copy of the drawable's bounds in a new Rect. This returns the 176 * same values as getBounds(), but the returned object is guaranteed to not 177 * be changed later by the drawable (i.e. it retains no reference to this 178 * rect). If the caller already has a Rect allocated, call copyBounds(rect). 179 * 180 * @return A copy of the drawable's bounds 181 */ 182 public final Rect copyBounds() { 183 return new Rect(mBounds); 184 } 185 186 /** 187 * Return the drawable's bounds Rect. Note: for efficiency, the returned 188 * object may be the same object stored in the drawable (though this is not 189 * guaranteed), so if a persistent copy of the bounds is needed, call 190 * copyBounds(rect) instead. 191 * You should also not change the object returned by this method as it may 192 * be the same object stored in the drawable. 193 * 194 * @return The bounds of the drawable (which may change later, so caller 195 * beware). DO NOT ALTER the returned object as it may change the 196 * stored bounds of this drawable. 197 * 198 * @see #copyBounds() 199 * @see #copyBounds(android.graphics.Rect) 200 */ 201 public final Rect getBounds() { 202 if (mBounds == ZERO_BOUNDS_RECT) { 203 mBounds = new Rect(); 204 } 205 206 return mBounds; 207 } 208 209 /** 210 * Set a mask of the configuration parameters for which this drawable 211 * may change, requiring that it be re-created. 212 * 213 * @param configs A mask of the changing configuration parameters, as 214 * defined by {@link android.content.res.Configuration}. 215 * 216 * @see android.content.res.Configuration 217 */ 218 public void setChangingConfigurations(int configs) { 219 mChangingConfigurations = configs; 220 } 221 222 /** 223 * Return a mask of the configuration parameters for which this drawable 224 * may change, requiring that it be re-created. The default implementation 225 * returns whatever was provided through 226 * {@link #setChangingConfigurations(int)} or 0 by default. Subclasses 227 * may extend this to or in the changing configurations of any other 228 * drawables they hold. 229 * 230 * @return Returns a mask of the changing configuration parameters, as 231 * defined by {@link android.content.res.Configuration}. 232 * 233 * @see android.content.res.Configuration 234 */ 235 public int getChangingConfigurations() { 236 return mChangingConfigurations; 237 } 238 239 /** 240 * Set to true to have the drawable dither its colors when drawn to a device 241 * with fewer than 8-bits per color component. This can improve the look on 242 * those devices, but can also slow down the drawing a little. 243 */ 244 public void setDither(boolean dither) {} 245 246 /** 247 * Set to true to have the drawable filter its bitmap when scaled or rotated 248 * (for drawables that use bitmaps). If the drawable does not use bitmaps, 249 * this call is ignored. This can improve the look when scaled or rotated, 250 * but also slows down the drawing. 251 */ 252 public void setFilterBitmap(boolean filter) {} 253 254 /** 255 * Implement this interface if you want to create an animated drawable that 256 * extends {@link android.graphics.drawable.Drawable Drawable}. 257 * Upon retrieving a drawable, use 258 * {@link Drawable#setCallback(android.graphics.drawable.Drawable.Callback)} 259 * to supply your implementation of the interface to the drawable; it uses 260 * this interface to schedule and execute animation changes. 261 */ 262 public static interface Callback { 263 /** 264 * Called when the drawable needs to be redrawn. A view at this point 265 * should invalidate itself (or at least the part of itself where the 266 * drawable appears). 267 * 268 * @param who The drawable that is requesting the update. 269 */ 270 public void invalidateDrawable(Drawable who); 271 272 /** 273 * A Drawable can call this to schedule the next frame of its 274 * animation. An implementation can generally simply call 275 * {@link android.os.Handler#postAtTime(Runnable, Object, long)} with 276 * the parameters <var>(what, who, when)</var> to perform the 277 * scheduling. 278 * 279 * @param who The drawable being scheduled. 280 * @param what The action to execute. 281 * @param when The time (in milliseconds) to run. The timebase is 282 * {@link android.os.SystemClock#uptimeMillis} 283 */ 284 public void scheduleDrawable(Drawable who, Runnable what, long when); 285 286 /** 287 * A Drawable can call this to unschedule an action previously 288 * scheduled with {@link #scheduleDrawable}. An implementation can 289 * generally simply call 290 * {@link android.os.Handler#removeCallbacks(Runnable, Object)} with 291 * the parameters <var>(what, who)</var> to unschedule the drawable. 292 * 293 * @param who The drawable being unscheduled. 294 * @param what The action being unscheduled. 295 */ 296 public void unscheduleDrawable(Drawable who, Runnable what); 297 } 298 299 /** 300 * Bind a {@link Callback} object to this Drawable. Required for clients 301 * that want to support animated drawables. 302 * 303 * @param cb The client's Callback implementation. 304 * 305 * @see #getCallback() 306 */ 307 public final void setCallback(Callback cb) { 308 mCallback = new WeakReference<Callback>(cb); 309 } 310 311 /** 312 * Return the current {@link Callback} implementation attached to this 313 * Drawable. 314 * 315 * @return A {@link Callback} instance or null if no callback was set. 316 * 317 * @see #setCallback(android.graphics.drawable.Drawable.Callback) 318 */ 319 public Callback getCallback() { 320 if (mCallback != null) { 321 return mCallback.get(); 322 } 323 return null; 324 } 325 326 /** 327 * Use the current {@link Callback} implementation to have this Drawable 328 * redrawn. Does nothing if there is no Callback attached to the 329 * Drawable. 330 * 331 * @see Callback#invalidateDrawable 332 * @see #getCallback() 333 * @see #setCallback(android.graphics.drawable.Drawable.Callback) 334 */ 335 public void invalidateSelf() { 336 final Callback callback = getCallback(); 337 if (callback != null) { 338 callback.invalidateDrawable(this); 339 } 340 } 341 342 /** 343 * Use the current {@link Callback} implementation to have this Drawable 344 * scheduled. Does nothing if there is no Callback attached to the 345 * Drawable. 346 * 347 * @param what The action being scheduled. 348 * @param when The time (in milliseconds) to run. 349 * 350 * @see Callback#scheduleDrawable 351 */ 352 public void scheduleSelf(Runnable what, long when) { 353 final Callback callback = getCallback(); 354 if (callback != null) { 355 callback.scheduleDrawable(this, what, when); 356 } 357 } 358 359 /** 360 * Use the current {@link Callback} implementation to have this Drawable 361 * unscheduled. Does nothing if there is no Callback attached to the 362 * Drawable. 363 * 364 * @param what The runnable that you no longer want called. 365 * 366 * @see Callback#unscheduleDrawable 367 */ 368 public void unscheduleSelf(Runnable what) { 369 final Callback callback = getCallback(); 370 if (callback != null) { 371 callback.unscheduleDrawable(this, what); 372 } 373 } 374 375 /** 376 * Returns the resolved layout direction for this Drawable. 377 * 378 * @return One of {@link android.view.View#LAYOUT_DIRECTION_LTR}, 379 * {@link android.view.View#LAYOUT_DIRECTION_RTL} 380 * 381 * @hide 382 */ 383 public int getLayoutDirection() { 384 return mLayoutDirection; 385 } 386 387 /** 388 * Set the layout direction for this drawable. Should be a resolved direction as the 389 * Drawable as no capacity to do the resolution on his own. 390 * 391 * @param layoutDirection One of {@link android.view.View#LAYOUT_DIRECTION_LTR}, 392 * {@link android.view.View#LAYOUT_DIRECTION_RTL} 393 * 394 * @hide 395 */ 396 public void setLayoutDirection(int layoutDirection) { 397 if (getLayoutDirection() != layoutDirection) { 398 mLayoutDirection = layoutDirection; 399 } 400 } 401 402 /** 403 * Specify an alpha value for the drawable. 0 means fully transparent, and 404 * 255 means fully opaque. 405 */ 406 public abstract void setAlpha(int alpha); 407 408 /** 409 * Specify an optional colorFilter for the drawable. Pass null to remove 410 * any filters. 411 */ 412 public abstract void setColorFilter(ColorFilter cf); 413 414 /** 415 * Specify a color and porterduff mode to be the colorfilter for this 416 * drawable. 417 */ 418 public void setColorFilter(int color, PorterDuff.Mode mode) { 419 setColorFilter(new PorterDuffColorFilter(color, mode)); 420 } 421 422 public void clearColorFilter() { 423 setColorFilter(null); 424 } 425 426 /** 427 * Indicates whether this view will change its appearance based on state. 428 * Clients can use this to determine whether it is necessary to calculate 429 * their state and call setState. 430 * 431 * @return True if this view changes its appearance based on state, false 432 * otherwise. 433 * 434 * @see #setState(int[]) 435 */ 436 public boolean isStateful() { 437 return false; 438 } 439 440 /** 441 * Specify a set of states for the drawable. These are use-case specific, 442 * so see the relevant documentation. As an example, the background for 443 * widgets like Button understand the following states: 444 * [{@link android.R.attr#state_focused}, 445 * {@link android.R.attr#state_pressed}]. 446 * 447 * <p>If the new state you are supplying causes the appearance of the 448 * Drawable to change, then it is responsible for calling 449 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 450 * true will be returned from this function. 451 * 452 * <p>Note: The Drawable holds a reference on to <var>stateSet</var> 453 * until a new state array is given to it, so you must not modify this 454 * array during that time.</p> 455 * 456 * @param stateSet The new set of states to be displayed. 457 * 458 * @return Returns true if this change in state has caused the appearance 459 * of the Drawable to change (hence requiring an invalidate), otherwise 460 * returns false. 461 */ 462 public boolean setState(final int[] stateSet) { 463 if (!Arrays.equals(mStateSet, stateSet)) { 464 mStateSet = stateSet; 465 return onStateChange(stateSet); 466 } 467 return false; 468 } 469 470 /** 471 * Describes the current state, as a union of primitve states, such as 472 * {@link android.R.attr#state_focused}, 473 * {@link android.R.attr#state_selected}, etc. 474 * Some drawables may modify their imagery based on the selected state. 475 * @return An array of resource Ids describing the current state. 476 */ 477 public int[] getState() { 478 return mStateSet; 479 } 480 481 /** 482 * If this Drawable does transition animations between states, ask that 483 * it immediately jump to the current state and skip any active animations. 484 */ 485 public void jumpToCurrentState() { 486 } 487 488 /** 489 * @return The current drawable that will be used by this drawable. For simple drawables, this 490 * is just the drawable itself. For drawables that change state like 491 * {@link StateListDrawable} and {@link LevelListDrawable} this will be the child drawable 492 * currently in use. 493 */ 494 public Drawable getCurrent() { 495 return this; 496 } 497 498 /** 499 * Specify the level for the drawable. This allows a drawable to vary its 500 * imagery based on a continuous controller, for example to show progress 501 * or volume level. 502 * 503 * <p>If the new level you are supplying causes the appearance of the 504 * Drawable to change, then it is responsible for calling 505 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 506 * true will be returned from this function. 507 * 508 * @param level The new level, from 0 (minimum) to 10000 (maximum). 509 * 510 * @return Returns true if this change in level has caused the appearance 511 * of the Drawable to change (hence requiring an invalidate), otherwise 512 * returns false. 513 */ 514 public final boolean setLevel(int level) { 515 if (mLevel != level) { 516 mLevel = level; 517 return onLevelChange(level); 518 } 519 return false; 520 } 521 522 /** 523 * Retrieve the current level. 524 * 525 * @return int Current level, from 0 (minimum) to 10000 (maximum). 526 */ 527 public final int getLevel() { 528 return mLevel; 529 } 530 531 /** 532 * Set whether this Drawable is visible. This generally does not impact 533 * the Drawable's behavior, but is a hint that can be used by some 534 * Drawables, for example, to decide whether run animations. 535 * 536 * @param visible Set to true if visible, false if not. 537 * @param restart You can supply true here to force the drawable to behave 538 * as if it has just become visible, even if it had last 539 * been set visible. Used for example to force animations 540 * to restart. 541 * 542 * @return boolean Returns true if the new visibility is different than 543 * its previous state. 544 */ 545 public boolean setVisible(boolean visible, boolean restart) { 546 boolean changed = mVisible != visible; 547 if (changed) { 548 mVisible = visible; 549 invalidateSelf(); 550 } 551 return changed; 552 } 553 554 public final boolean isVisible() { 555 return mVisible; 556 } 557 558 /** 559 * Return the opacity/transparency of this Drawable. The returned value is 560 * one of the abstract format constants in 561 * {@link android.graphics.PixelFormat}: 562 * {@link android.graphics.PixelFormat#UNKNOWN}, 563 * {@link android.graphics.PixelFormat#TRANSLUCENT}, 564 * {@link android.graphics.PixelFormat#TRANSPARENT}, or 565 * {@link android.graphics.PixelFormat#OPAQUE}. 566 * 567 * <p>Generally a Drawable should be as conservative as possible with the 568 * value it returns. For example, if it contains multiple child drawables 569 * and only shows one of them at a time, if only one of the children is 570 * TRANSLUCENT and the others are OPAQUE then TRANSLUCENT should be 571 * returned. You can use the method {@link #resolveOpacity} to perform a 572 * standard reduction of two opacities to the appropriate single output. 573 * 574 * <p>Note that the returned value does <em>not</em> take into account a 575 * custom alpha or color filter that has been applied by the client through 576 * the {@link #setAlpha} or {@link #setColorFilter} methods. 577 * 578 * @return int The opacity class of the Drawable. 579 * 580 * @see android.graphics.PixelFormat 581 */ 582 public abstract int getOpacity(); 583 584 /** 585 * Return the appropriate opacity value for two source opacities. If 586 * either is UNKNOWN, that is returned; else, if either is TRANSLUCENT, 587 * that is returned; else, if either is TRANSPARENT, that is returned; 588 * else, OPAQUE is returned. 589 * 590 * <p>This is to help in implementing {@link #getOpacity}. 591 * 592 * @param op1 One opacity value. 593 * @param op2 Another opacity value. 594 * 595 * @return int The combined opacity value. 596 * 597 * @see #getOpacity 598 */ 599 public static int resolveOpacity(int op1, int op2) { 600 if (op1 == op2) { 601 return op1; 602 } 603 if (op1 == PixelFormat.UNKNOWN || op2 == PixelFormat.UNKNOWN) { 604 return PixelFormat.UNKNOWN; 605 } 606 if (op1 == PixelFormat.TRANSLUCENT || op2 == PixelFormat.TRANSLUCENT) { 607 return PixelFormat.TRANSLUCENT; 608 } 609 if (op1 == PixelFormat.TRANSPARENT || op2 == PixelFormat.TRANSPARENT) { 610 return PixelFormat.TRANSPARENT; 611 } 612 return PixelFormat.OPAQUE; 613 } 614 615 /** 616 * Returns a Region representing the part of the Drawable that is completely 617 * transparent. This can be used to perform drawing operations, identifying 618 * which parts of the target will not change when rendering the Drawable. 619 * The default implementation returns null, indicating no transparent 620 * region; subclasses can optionally override this to return an actual 621 * Region if they want to supply this optimization information, but it is 622 * not required that they do so. 623 * 624 * @return Returns null if the Drawables has no transparent region to 625 * report, else a Region holding the parts of the Drawable's bounds that 626 * are transparent. 627 */ 628 public Region getTransparentRegion() { 629 return null; 630 } 631 632 /** 633 * Override this in your subclass to change appearance if you recognize the 634 * specified state. 635 * 636 * @return Returns true if the state change has caused the appearance of 637 * the Drawable to change (that is, it needs to be drawn), else false 638 * if it looks the same and there is no need to redraw it since its 639 * last state. 640 */ 641 protected boolean onStateChange(int[] state) { return false; } 642 /** Override this in your subclass to change appearance if you vary based 643 * on level. 644 * @return Returns true if the level change has caused the appearance of 645 * the Drawable to change (that is, it needs to be drawn), else false 646 * if it looks the same and there is no need to redraw it since its 647 * last level. 648 */ 649 protected boolean onLevelChange(int level) { return false; } 650 /** 651 * Override this in your subclass to change appearance if you recognize the 652 * specified state. 653 */ 654 protected void onBoundsChange(Rect bounds) {} 655 656 /** 657 * Return the intrinsic width of the underlying drawable object. Returns 658 * -1 if it has no intrinsic width, such as with a solid color. 659 */ 660 public int getIntrinsicWidth() { 661 return -1; 662 } 663 664 /** 665 * Return the intrinsic height of the underlying drawable object. Returns 666 * -1 if it has no intrinsic height, such as with a solid color. 667 */ 668 public int getIntrinsicHeight() { 669 return -1; 670 } 671 672 /** 673 * Returns the minimum width suggested by this Drawable. If a View uses this 674 * Drawable as a background, it is suggested that the View use at least this 675 * value for its width. (There will be some scenarios where this will not be 676 * possible.) This value should INCLUDE any padding. 677 * 678 * @return The minimum width suggested by this Drawable. If this Drawable 679 * doesn't have a suggested minimum width, 0 is returned. 680 */ 681 public int getMinimumWidth() { 682 final int intrinsicWidth = getIntrinsicWidth(); 683 return intrinsicWidth > 0 ? intrinsicWidth : 0; 684 } 685 686 /** 687 * Returns the minimum height suggested by this Drawable. If a View uses this 688 * Drawable as a background, it is suggested that the View use at least this 689 * value for its height. (There will be some scenarios where this will not be 690 * possible.) This value should INCLUDE any padding. 691 * 692 * @return The minimum height suggested by this Drawable. If this Drawable 693 * doesn't have a suggested minimum height, 0 is returned. 694 */ 695 public int getMinimumHeight() { 696 final int intrinsicHeight = getIntrinsicHeight(); 697 return intrinsicHeight > 0 ? intrinsicHeight : 0; 698 } 699 700 /** 701 * Return in padding the insets suggested by this Drawable for placing 702 * content inside the drawable's bounds. Positive values move toward the 703 * center of the Drawable (set Rect.inset). Returns true if this drawable 704 * actually has a padding, else false. When false is returned, the padding 705 * is always set to 0. 706 */ 707 public boolean getPadding(Rect padding) { 708 padding.set(0, 0, 0, 0); 709 return false; 710 } 711 712 /** 713 * Return in insets the layout insets suggested by this Drawable for use with alignment 714 * operations during layout. 715 * 716 * @hide 717 */ 718 public Insets getLayoutInsets() { 719 return Insets.NONE; 720 } 721 722 /** 723 * Make this drawable mutable. This operation cannot be reversed. A mutable 724 * drawable is guaranteed to not share its state with any other drawable. 725 * This is especially useful when you need to modify properties of drawables 726 * loaded from resources. By default, all drawables instances loaded from 727 * the same resource share a common state; if you modify the state of one 728 * instance, all the other instances will receive the same modification. 729 * 730 * Calling this method on a mutable Drawable will have no effect. 731 * 732 * @return This drawable. 733 * @see ConstantState 734 * @see #getConstantState() 735 */ 736 public Drawable mutate() { 737 return this; 738 } 739 740 /** 741 * Create a drawable from an inputstream 742 */ 743 public static Drawable createFromStream(InputStream is, String srcName) { 744 return createFromResourceStream(null, null, is, srcName, null); 745 } 746 747 /** 748 * Create a drawable from an inputstream, using the given resources and 749 * value to determine density information. 750 */ 751 public static Drawable createFromResourceStream(Resources res, TypedValue value, 752 InputStream is, String srcName) { 753 return createFromResourceStream(res, value, is, srcName, null); 754 } 755 756 /** 757 * Create a drawable from an inputstream, using the given resources and 758 * value to determine density information. 759 */ 760 public static Drawable createFromResourceStream(Resources res, TypedValue value, 761 InputStream is, String srcName, BitmapFactory.Options opts) { 762 763 if (is == null) { 764 return null; 765 } 766 767 /* ugh. The decodeStream contract is that we have already allocated 768 the pad rect, but if the bitmap does not had a ninepatch chunk, 769 then the pad will be ignored. If we could change this to lazily 770 alloc/assign the rect, we could avoid the GC churn of making new 771 Rects only to drop them on the floor. 772 */ 773 Rect pad = new Rect(); 774 775 // Special stuff for compatibility mode: if the target density is not 776 // the same as the display density, but the resource -is- the same as 777 // the display density, then don't scale it down to the target density. 778 // This allows us to load the system's density-correct resources into 779 // an application in compatibility mode, without scaling those down 780 // to the compatibility density only to have them scaled back up when 781 // drawn to the screen. 782 if (opts == null) opts = new BitmapFactory.Options(); 783 opts.inScreenDensity = res != null 784 ? res.getDisplayMetrics().noncompatDensityDpi : DisplayMetrics.DENSITY_DEVICE; 785 Bitmap bm = BitmapFactory.decodeResourceStream(res, value, is, pad, opts); 786 if (bm != null) { 787 byte[] np = bm.getNinePatchChunk(); 788 if (np == null || !NinePatch.isNinePatchChunk(np)) { 789 np = null; 790 pad = null; 791 } 792 int[] layoutBounds = bm.getLayoutBounds(); 793 Rect layoutBoundsRect = null; 794 if (layoutBounds != null) { 795 layoutBoundsRect = new Rect(layoutBounds[0], layoutBounds[1], 796 layoutBounds[2], layoutBounds[3]); 797 } 798 return drawableFromBitmap(res, bm, np, pad, layoutBoundsRect, srcName); 799 } 800 return null; 801 } 802 803 /** 804 * Create a drawable from an XML document. For more information on how to 805 * create resources in XML, see 806 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. 807 */ 808 public static Drawable createFromXml(Resources r, XmlPullParser parser) 809 throws XmlPullParserException, IOException { 810 AttributeSet attrs = Xml.asAttributeSet(parser); 811 812 int type; 813 while ((type=parser.next()) != XmlPullParser.START_TAG && 814 type != XmlPullParser.END_DOCUMENT) { 815 // Empty loop 816 } 817 818 if (type != XmlPullParser.START_TAG) { 819 throw new XmlPullParserException("No start tag found"); 820 } 821 822 Drawable drawable = createFromXmlInner(r, parser, attrs); 823 824 if (drawable == null) { 825 throw new RuntimeException("Unknown initial tag: " + parser.getName()); 826 } 827 828 return drawable; 829 } 830 831 /** 832 * Create from inside an XML document. Called on a parser positioned at 833 * a tag in an XML document, tries to create a Drawable from that tag. 834 * Returns null if the tag is not a valid drawable. 835 */ 836 public static Drawable createFromXmlInner(Resources r, XmlPullParser parser, AttributeSet attrs) 837 throws XmlPullParserException, IOException { 838 Drawable drawable; 839 840 final String name = parser.getName(); 841 842 if (name.equals("selector")) { 843 drawable = new StateListDrawable(); 844 } else if (name.equals("level-list")) { 845 drawable = new LevelListDrawable(); 846 /* Probably not doing this. 847 } else if (name.equals("mipmap")) { 848 drawable = new MipmapDrawable(); 849 */ 850 } else if (name.equals("layer-list")) { 851 drawable = new LayerDrawable(); 852 } else if (name.equals("transition")) { 853 drawable = new TransitionDrawable(); 854 } else if (name.equals("color")) { 855 drawable = new ColorDrawable(); 856 } else if (name.equals("shape")) { 857 drawable = new GradientDrawable(); 858 } else if (name.equals("scale")) { 859 drawable = new ScaleDrawable(); 860 } else if (name.equals("clip")) { 861 drawable = new ClipDrawable(); 862 } else if (name.equals("rotate")) { 863 drawable = new RotateDrawable(); 864 } else if (name.equals("animated-rotate")) { 865 drawable = new AnimatedRotateDrawable(); 866 } else if (name.equals("animation-list")) { 867 drawable = new AnimationDrawable(); 868 } else if (name.equals("inset")) { 869 drawable = new InsetDrawable(); 870 } else if (name.equals("bitmap")) { 871 drawable = new BitmapDrawable(r); 872 if (r != null) { 873 ((BitmapDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 874 } 875 } else if (name.equals("nine-patch")) { 876 drawable = new NinePatchDrawable(); 877 if (r != null) { 878 ((NinePatchDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 879 } 880 } else { 881 throw new XmlPullParserException(parser.getPositionDescription() + 882 ": invalid drawable tag " + name); 883 } 884 885 drawable.inflate(r, parser, attrs); 886 return drawable; 887 } 888 889 890 /** 891 * Create a drawable from file path name. 892 */ 893 public static Drawable createFromPath(String pathName) { 894 if (pathName == null) { 895 return null; 896 } 897 898 Bitmap bm = BitmapFactory.decodeFile(pathName); 899 if (bm != null) { 900 return drawableFromBitmap(null, bm, null, null, null, pathName); 901 } 902 903 return null; 904 } 905 906 /** 907 * Inflate this Drawable from an XML resource. 908 */ 909 public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs) 910 throws XmlPullParserException, IOException { 911 912 TypedArray a = r.obtainAttributes(attrs, com.android.internal.R.styleable.Drawable); 913 inflateWithAttributes(r, parser, a, com.android.internal.R.styleable.Drawable_visible); 914 a.recycle(); 915 } 916 917 /** 918 * Inflate a Drawable from an XML resource. 919 * 920 * @throws XmlPullParserException 921 * @throws IOException 922 */ 923 void inflateWithAttributes(Resources r, XmlPullParser parser, 924 TypedArray attrs, int visibleAttr) 925 throws XmlPullParserException, IOException { 926 927 mVisible = attrs.getBoolean(visibleAttr, mVisible); 928 } 929 930 /** 931 * This abstract class is used by {@link Drawable}s to store shared constant state and data 932 * between Drawables. {@link BitmapDrawable}s created from the same resource will for instance 933 * share a unique bitmap stored in their ConstantState. 934 * 935 * <p> 936 * {@link #newDrawable(Resources)} can be used as a factory to create new Drawable instances 937 * from this ConstantState. 938 * </p> 939 * 940 * Use {@link Drawable#getConstantState()} to retrieve the ConstantState of a Drawable. Calling 941 * {@link Drawable#mutate()} on a Drawable should typically create a new ConstantState for that 942 * Drawable. 943 */ 944 public static abstract class ConstantState { 945 /** 946 * Create a new drawable without supplying resources the caller 947 * is running in. Note that using this means the density-dependent 948 * drawables (like bitmaps) will not be able to update their target 949 * density correctly. One should use {@link #newDrawable(Resources)} 950 * instead to provide a resource. 951 */ 952 public abstract Drawable newDrawable(); 953 /** 954 * Create a new Drawable instance from its constant state. This 955 * must be implemented for drawables that change based on the target 956 * density of their caller (that is depending on whether it is 957 * in compatibility mode). 958 */ 959 public Drawable newDrawable(Resources res) { 960 return newDrawable(); 961 } 962 /** 963 * Return a bit mask of configuration changes that will impact 964 * this drawable (and thus require completely reloading it). 965 */ 966 public abstract int getChangingConfigurations(); 967 } 968 969 /** 970 * Return a {@link ConstantState} instance that holds the shared state of this Drawable. 971 *q 972 * @return The ConstantState associated to that Drawable. 973 * @see ConstantState 974 * @see Drawable#mutate() 975 */ 976 public ConstantState getConstantState() { 977 return null; 978 } 979 980 private static Drawable drawableFromBitmap(Resources res, Bitmap bm, byte[] np, 981 Rect pad, Rect layoutBounds, String srcName) { 982 983 if (np != null) { 984 return new NinePatchDrawable(res, bm, np, pad, layoutBounds, srcName); 985 } 986 987 return new BitmapDrawable(res, bm); 988 } 989} 990 991