Drawable.java revision 9891e1fce5f29d0421d34aa481037417bd70853d
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 org.xmlpull.v1.XmlPullParser; 20import org.xmlpull.v1.XmlPullParserException; 21 22import android.content.res.Resources; 23import android.content.res.TypedArray; 24import android.graphics.Bitmap; 25import android.graphics.BitmapFactory; 26import android.graphics.Canvas; 27import android.graphics.ColorFilter; 28import android.graphics.NinePatch; 29import android.graphics.PixelFormat; 30import android.graphics.PorterDuff; 31import android.graphics.PorterDuffColorFilter; 32import android.graphics.Rect; 33import android.graphics.Region; 34import android.util.AttributeSet; 35import android.util.DisplayMetrics; 36import android.util.StateSet; 37import android.util.TypedValue; 38import android.util.Xml; 39 40import java.io.IOException; 41import java.io.InputStream; 42import java.util.Arrays; 43 44/** 45 * A Drawable is a general abstraction for "something that can be drawn." Most 46 * often you will deal with Drawable as the type of resource retrieved for 47 * drawing things to the screen; the Drawable class provides a generic API for 48 * dealing with an underlying visual resource that may take a variety of forms. 49 * Unlike a {@link android.view.View}, a Drawable does not have any facility to 50 * receive events or otherwise interact with the user. 51 * 52 * <p>In addition to simple drawing, Drawable provides a number of generic 53 * mechanisms for its client to interact with what is being drawn: 54 * 55 * <ul> 56 * <li> The {@link #setBounds} method <var>must</var> be called to tell the 57 * Drawable where it is drawn and how large it should be. All Drawables 58 * should respect the requested size, often simply by scaling their 59 * imagery. A client can find the preferred size for some Drawables with 60 * the {@link #getIntrinsicHeight} and {@link #getIntrinsicWidth} methods. 61 * 62 * <li> The {@link #getPadding} method can return from some Drawables 63 * information about how to frame content that is placed inside of them. 64 * For example, a Drawable that is intended to be the frame for a button 65 * widget would need to return padding that correctly places the label 66 * inside of itself. 67 * 68 * <li> The {@link #setState} method allows the client to tell the Drawable 69 * in which state it is to be drawn, such as "focused", "selected", etc. 70 * Some drawables may modify their imagery based on the selected state. 71 * 72 * <li> The {@link #setLevel} method allows the client to supply a single 73 * continuous controller that can modify the Drawable is displayed, such as 74 * a battery level or progress level. Some drawables may modify their 75 * imagery based on the current level. 76 * 77 * <li> A Drawable can perform animations by calling back to its client 78 * through the {@link Callback} interface. All clients should support this 79 * interface (via {@link #setCallback}) so that animations will work. A 80 * simple way to do this is through the system facilities such as 81 * {@link android.view.View#setBackgroundDrawable(Drawable)} and 82 * {@link android.widget.ImageView}. 83 * </ul> 84 * 85 * Though usually not visible to the application, Drawables may take a variety 86 * of forms: 87 * 88 * <ul> 89 * <li> <b>Bitmap</b>: the simplest Drawable, a PNG or JPEG image. 90 * <li> <b>Nine Patch</b>: an extension to the PNG format allows it to 91 * specify information about how to stretch it and place things inside of 92 * it. 93 * <li> <b>Shape</b>: contains simple drawing commands instead of a raw 94 * bitmap, allowing it to resize better in some cases. 95 * <li> <b>Layers</b>: a compound drawable, which draws multiple underlying 96 * drawables on top of each other. 97 * <li> <b>States</b>: a compound drawable that selects one of a set of 98 * drawables based on its state. 99 * <li> <b>Levels</b>: a compound drawable that selects one of a set of 100 * drawables based on its level. 101 * <li> <b>Scale</b>: a compound drawable with a single child drawable, 102 * whose overall size is modified based on the current level. 103 * </ul> 104 * <p>For information and examples of creating drawable resources (XML or bitmap files that 105 * can be loaded in code), see <a 106 * href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. 107 */ 108public abstract class Drawable { 109 private static final Rect ZERO_BOUNDS_RECT = new Rect(); 110 111 private int[] mStateSet = StateSet.WILD_CARD; 112 private int mLevel = 0; 113 private int mChangingConfigurations = 0; 114 private Rect mBounds = ZERO_BOUNDS_RECT; // lazily becomes a new Rect() 115 /*package*/ Callback mCallback = null; 116 private boolean mVisible = true; 117 118 /** 119 * Draw in its bounds (set via setBounds) respecting optional effects such 120 * as alpha (set via setAlpha) and color filter (set via setColorFilter). 121 * 122 * @param canvas The canvas to draw into 123 */ 124 public abstract void draw(Canvas canvas); 125 126 /** 127 * Specify a bounding rectangle for the Drawable. This is where the drawable 128 * will draw when its draw() method is called. 129 */ 130 public void setBounds(int left, int top, int right, int bottom) { 131 Rect oldBounds = mBounds; 132 133 if (oldBounds == ZERO_BOUNDS_RECT) { 134 oldBounds = mBounds = new Rect(); 135 } 136 137 if (oldBounds.left != left || oldBounds.top != top || 138 oldBounds.right != right || oldBounds.bottom != bottom) { 139 mBounds.set(left, top, right, bottom); 140 onBoundsChange(mBounds); 141 } 142 } 143 144 /** 145 * Specify a bounding rectangle for the Drawable. This is where the drawable 146 * will draw when its draw() method is called. 147 */ 148 public void setBounds(Rect bounds) { 149 setBounds(bounds.left, bounds.top, bounds.right, bounds.bottom); 150 } 151 152 /** 153 * Return a copy of the drawable's bounds in the specified Rect (allocated 154 * by the caller). The bounds specify where this will draw when its draw() 155 * method is called. 156 * 157 * @param bounds Rect to receive the drawable's bounds (allocated by the 158 * caller). 159 */ 160 public final void copyBounds(Rect bounds) { 161 bounds.set(mBounds); 162 } 163 164 /** 165 * Return a copy of the drawable's bounds in a new Rect. This returns the 166 * same values as getBounds(), but the returned object is guaranteed to not 167 * be changed later by the drawable (i.e. it retains no reference to this 168 * rect). If the caller already has a Rect allocated, call copyBounds(rect). 169 * 170 * @return A copy of the drawable's bounds 171 */ 172 public final Rect copyBounds() { 173 return new Rect(mBounds); 174 } 175 176 /** 177 * Return the drawable's bounds Rect. Note: for efficiency, the returned 178 * object may be the same object stored in the drawable (though this is not 179 * guaranteed), so if a persistent copy of the bounds is needed, call 180 * copyBounds(rect) instead. 181 * You should also not change the object returned by this method as it may 182 * be the same object stored in the drawable. 183 * 184 * @return The bounds of the drawable (which may change later, so caller 185 * beware). DO NOT ALTER the returned object as it may change the 186 * stored bounds of this drawable. 187 * 188 * @see #copyBounds() 189 * @see #copyBounds(android.graphics.Rect) 190 */ 191 public final Rect getBounds() { 192 if (mBounds == ZERO_BOUNDS_RECT) { 193 mBounds = new Rect(); 194 } 195 196 return mBounds; 197 } 198 199 /** 200 * Set a mask of the configuration parameters for which this drawable 201 * may change, requiring that it be re-created. 202 * 203 * @param configs A mask of the changing configuration parameters, as 204 * defined by {@link android.content.res.Configuration}. 205 * 206 * @see android.content.res.Configuration 207 */ 208 public void setChangingConfigurations(int configs) { 209 mChangingConfigurations = configs; 210 } 211 212 /** 213 * Return a mask of the configuration parameters for which this drawable 214 * mau change, requiring that it be re-created. The default implementation 215 * returns whatever was provided through 216 * {@link #setChangingConfigurations(int)} or 0 by default. Subclasses 217 * may extend this to or in the changing configurations of any other 218 * drawables they hold. 219 * 220 * @return Returns a mask of the changing configuration parameters, as 221 * defined by {@link android.content.res.Configuration}. 222 * 223 * @see android.content.res.Configuration 224 */ 225 public int getChangingConfigurations() { 226 return mChangingConfigurations; 227 } 228 229 /** 230 * Set to true to have the drawable dither its colors when drawn to a device 231 * with fewer than 8-bits per color component. This can improve the look on 232 * those devices, but can also slow down the drawing a little. 233 */ 234 public void setDither(boolean dither) {} 235 236 /** 237 * Set to true to have the drawable filter its bitmap when scaled or rotated 238 * (for drawables that use bitmaps). If the drawable does not use bitmaps, 239 * this call is ignored. This can improve the look when scaled or rotated, 240 * but also slows down the drawing. 241 */ 242 public void setFilterBitmap(boolean filter) {} 243 244 /** 245 * Implement this interface if you want to create an animated drawable that 246 * extends {@link android.graphics.drawable.Drawable Drawable}. 247 * Upon retrieving a drawable, use 248 * {@link Drawable#setCallback(android.graphics.drawable.Drawable.Callback)} 249 * to supply your implementation of the interface to the drawable; it uses 250 * this interface to schedule and execute animation changes. 251 */ 252 public static interface Callback { 253 /** 254 * Called when the drawable needs to be redrawn. A view at this point 255 * should invalidate itself (or at least the part of itself where the 256 * drawable appears). 257 * 258 * @param who The drawable that is requesting the update. 259 */ 260 public void invalidateDrawable(Drawable who); 261 262 /** 263 * A Drawable can call this to schedule the next frame of its 264 * animation. An implementation can generally simply call 265 * {@link android.os.Handler#postAtTime(Runnable, Object, long)} with 266 * the parameters <var>(what, who, when)</var> to perform the 267 * scheduling. 268 * 269 * @param who The drawable being scheduled. 270 * @param what The action to execute. 271 * @param when The time (in milliseconds) to run. The timebase is 272 * {@link android.os.SystemClock#uptimeMillis} 273 */ 274 public void scheduleDrawable(Drawable who, Runnable what, long when); 275 276 /** 277 * A Drawable can call this to unschedule an action previously 278 * scheduled with {@link #scheduleDrawable}. An implementation can 279 * generally simply call 280 * {@link android.os.Handler#removeCallbacks(Runnable, Object)} with 281 * the parameters <var>(what, who)</var> to unschedule the drawable. 282 * 283 * @param who The drawable being unscheduled. 284 * @param what The action being unscheduled. 285 */ 286 public void unscheduleDrawable(Drawable who, Runnable what); 287 } 288 289 /** 290 * Bind a {@link Callback} object to this Drawable. Required for clients 291 * that want to support animated drawables. 292 * 293 * @param cb The client's Callback implementation. 294 */ 295 public final void setCallback(Callback cb) { 296 mCallback = cb; 297 } 298 299 /** 300 * Use the current {@link Callback} implementation to have this Drawable 301 * redrawn. Does nothing if there is no Callback attached to the 302 * Drawable. 303 * 304 * @see Callback#invalidateDrawable 305 */ 306 public void invalidateSelf() 307 { 308 if (mCallback != null) { 309 mCallback.invalidateDrawable(this); 310 } 311 } 312 313 /** 314 * Use the current {@link Callback} implementation to have this Drawable 315 * scheduled. Does nothing if there is no Callback attached to the 316 * Drawable. 317 * 318 * @param what The action being scheduled. 319 * @param when The time (in milliseconds) to run. 320 * 321 * @see Callback#scheduleDrawable 322 */ 323 public void scheduleSelf(Runnable what, long when) 324 { 325 if (mCallback != null) { 326 mCallback.scheduleDrawable(this, what, when); 327 } 328 } 329 330 /** 331 * Use the current {@link Callback} implementation to have this Drawable 332 * unscheduled. Does nothing if there is no Callback attached to the 333 * Drawable. 334 * 335 * @param what The runnable that you no longer want called. 336 * 337 * @see Callback#unscheduleDrawable 338 */ 339 public void unscheduleSelf(Runnable what) 340 { 341 if (mCallback != null) { 342 mCallback.unscheduleDrawable(this, what); 343 } 344 } 345 346 /** 347 * Specify an alpha value for the drawable. 0 means fully transparent, and 348 * 255 means fully opaque. 349 */ 350 public abstract void setAlpha(int alpha); 351 352 /** 353 * Specify an optional colorFilter for the drawable. Pass null to remove 354 * any filters. 355 */ 356 public abstract void setColorFilter(ColorFilter cf); 357 358 /** 359 * Specify a color and porterduff mode to be the colorfilter for this 360 * drawable. 361 */ 362 public void setColorFilter(int color, PorterDuff.Mode mode) { 363 setColorFilter(new PorterDuffColorFilter(color, mode)); 364 } 365 366 public void clearColorFilter() { 367 setColorFilter(null); 368 } 369 370 /** 371 * Indicates whether this view will change its appearance based on state. 372 * Clients can use this to determine whether it is necessary to calculate 373 * their state and call setState. 374 * 375 * @return True if this view changes its appearance based on state, false 376 * otherwise. 377 * 378 * @see #setState(int[]) 379 */ 380 public boolean isStateful() { 381 return false; 382 } 383 384 /** 385 * Specify a set of states for the drawable. These are use-case specific, 386 * so see the relevant documentation. As an example, the background for 387 * widgets like Button understand the following states: 388 * [{@link android.R.attr#state_focused}, 389 * {@link android.R.attr#state_pressed}]. 390 * 391 * <p>If the new state you are supplying causes the appearance of the 392 * Drawable to change, then it is responsible for calling 393 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 394 * true will be returned from this function. 395 * 396 * <p>Note: The Drawable holds a reference on to <var>stateSet</var> 397 * until a new state array is given to it, so you must not modify this 398 * array during that time.</p> 399 * 400 * @param stateSet The new set of states to be displayed. 401 * 402 * @return Returns true if this change in state has caused the appearance 403 * of the Drawable to change (hence requiring an invalidate), otherwise 404 * returns false. 405 */ 406 public boolean setState(final int[] stateSet) { 407 if (!Arrays.equals(mStateSet, stateSet)) { 408 mStateSet = stateSet; 409 return onStateChange(stateSet); 410 } 411 return false; 412 } 413 414 /** 415 * Describes the current state, as a union of primitve states, such as 416 * {@link android.R.attr#state_focused}, 417 * {@link android.R.attr#state_selected}, etc. 418 * Some drawables may modify their imagery based on the selected state. 419 * @return An array of resource Ids describing the current state. 420 */ 421 public int[] getState() { 422 return mStateSet; 423 } 424 425 /** 426 * If this Drawable does transition animations between states, ask that 427 * it immediately jump to the current state and skip any active animations. 428 */ 429 public void jumpToCurrentState() { 430 } 431 432 /** 433 * @return The current drawable that will be used by this drawable. For simple drawables, this 434 * is just the drawable itself. For drawables that change state like 435 * {@link StateListDrawable} and {@link LevelListDrawable} this will be the child drawable 436 * currently in use. 437 */ 438 public Drawable getCurrent() { 439 return this; 440 } 441 442 /** 443 * Specify the level for the drawable. This allows a drawable to vary its 444 * imagery based on a continuous controller, for example to show progress 445 * or volume level. 446 * 447 * <p>If the new level 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 * @param level The new level, from 0 (minimum) to 10000 (maximum). 453 * 454 * @return Returns true if this change in level has caused the appearance 455 * of the Drawable to change (hence requiring an invalidate), otherwise 456 * returns false. 457 */ 458 public final boolean setLevel(int level) { 459 if (mLevel != level) { 460 mLevel = level; 461 return onLevelChange(level); 462 } 463 return false; 464 } 465 466 /** 467 * Retrieve the current level. 468 * 469 * @return int Current level, from 0 (minimum) to 10000 (maximum). 470 */ 471 public final int getLevel() { 472 return mLevel; 473 } 474 475 /** 476 * Set whether this Drawable is visible. This generally does not impact 477 * the Drawable's behavior, but is a hint that can be used by some 478 * Drawables, for example, to decide whether run animations. 479 * 480 * @param visible Set to true if visible, false if not. 481 * @param restart You can supply true here to force the drawable to behave 482 * as if it has just become visible, even if it had last 483 * been set visible. Used for example to force animations 484 * to restart. 485 * 486 * @return boolean Returns true if the new visibility is different than 487 * its previous state. 488 */ 489 public boolean setVisible(boolean visible, boolean restart) { 490 boolean changed = mVisible != visible; 491 if (changed) { 492 mVisible = visible; 493 invalidateSelf(); 494 } 495 return changed; 496 } 497 498 public final boolean isVisible() { 499 return mVisible; 500 } 501 502 /** 503 * Return the opacity/transparency of this Drawable. The returned value is 504 * one of the abstract format constants in 505 * {@link android.graphics.PixelFormat}: 506 * {@link android.graphics.PixelFormat#UNKNOWN}, 507 * {@link android.graphics.PixelFormat#TRANSLUCENT}, 508 * {@link android.graphics.PixelFormat#TRANSPARENT}, or 509 * {@link android.graphics.PixelFormat#OPAQUE}. 510 * 511 * <p>Generally a Drawable should be as conservative as possible with the 512 * value it returns. For example, if it contains multiple child drawables 513 * and only shows one of them at a time, if only one of the children is 514 * TRANSLUCENT and the others are OPAQUE then TRANSLUCENT should be 515 * returned. You can use the method {@link #resolveOpacity} to perform a 516 * standard reduction of two opacities to the appropriate single output. 517 * 518 * <p>Note that the returned value does <em>not</em> take into account a 519 * custom alpha or color filter that has been applied by the client through 520 * the {@link #setAlpha} or {@link #setColorFilter} methods. 521 * 522 * @return int The opacity class of the Drawable. 523 * 524 * @see android.graphics.PixelFormat 525 */ 526 public abstract int getOpacity(); 527 528 /** 529 * Return the appropriate opacity value for two source opacities. If 530 * either is UNKNOWN, that is returned; else, if either is TRANSLUCENT, 531 * that is returned; else, if either is TRANSPARENT, that is returned; 532 * else, OPAQUE is returned. 533 * 534 * <p>This is to help in implementing {@link #getOpacity}. 535 * 536 * @param op1 One opacity value. 537 * @param op2 Another opacity value. 538 * 539 * @return int The combined opacity value. 540 * 541 * @see #getOpacity 542 */ 543 public static int resolveOpacity(int op1, int op2) { 544 if (op1 == op2) { 545 return op1; 546 } 547 if (op1 == PixelFormat.UNKNOWN || op2 == PixelFormat.UNKNOWN) { 548 return PixelFormat.UNKNOWN; 549 } 550 if (op1 == PixelFormat.TRANSLUCENT || op2 == PixelFormat.TRANSLUCENT) { 551 return PixelFormat.TRANSLUCENT; 552 } 553 if (op1 == PixelFormat.TRANSPARENT || op2 == PixelFormat.TRANSPARENT) { 554 return PixelFormat.TRANSPARENT; 555 } 556 return PixelFormat.OPAQUE; 557 } 558 559 /** 560 * Returns a Region representing the part of the Drawable that is completely 561 * transparent. This can be used to perform drawing operations, identifying 562 * which parts of the target will not change when rendering the Drawable. 563 * The default implementation returns null, indicating no transparent 564 * region; subclasses can optionally override this to return an actual 565 * Region if they want to supply this optimization information, but it is 566 * not required that they do so. 567 * 568 * @return Returns null if the Drawables has no transparent region to 569 * report, else a Region holding the parts of the Drawable's bounds that 570 * are transparent. 571 */ 572 public Region getTransparentRegion() { 573 return null; 574 } 575 576 /** 577 * Override this in your subclass to change appearance if you recognize the 578 * specified state. 579 * 580 * @return Returns true if the state change has caused the appearance of 581 * the Drawable to change (that is, it needs to be drawn), else false 582 * if it looks the same and there is no need to redraw it since its 583 * last state. 584 */ 585 protected boolean onStateChange(int[] state) { return false; } 586 /** Override this in your subclass to change appearance if you vary based 587 * on level. 588 * @return Returns true if the level change has caused the appearance of 589 * the Drawable to change (that is, it needs to be drawn), else false 590 * if it looks the same and there is no need to redraw it since its 591 * last level. 592 */ 593 protected boolean onLevelChange(int level) { return false; } 594 /** 595 * Override this in your subclass to change appearance if you recognize the 596 * specified state. 597 */ 598 protected void onBoundsChange(Rect bounds) {} 599 600 /** 601 * Return the intrinsic width of the underlying drawable object. Returns 602 * -1 if it has no intrinsic width, such as with a solid color. 603 */ 604 public int getIntrinsicWidth() { 605 return -1; 606 } 607 608 /** 609 * Return the intrinsic height of the underlying drawable object. Returns 610 * -1 if it has no intrinsic height, such as with a solid color. 611 */ 612 public int getIntrinsicHeight() { 613 return -1; 614 } 615 616 /** 617 * Returns the minimum width suggested by this Drawable. If a View uses this 618 * Drawable as a background, it is suggested that the View use at least this 619 * value for its width. (There will be some scenarios where this will not be 620 * possible.) This value should INCLUDE any padding. 621 * 622 * @return The minimum width suggested by this Drawable. If this Drawable 623 * doesn't have a suggested minimum width, 0 is returned. 624 */ 625 public int getMinimumWidth() { 626 final int intrinsicWidth = getIntrinsicWidth(); 627 return intrinsicWidth > 0 ? intrinsicWidth : 0; 628 } 629 630 /** 631 * Returns the minimum height suggested by this Drawable. If a View uses this 632 * Drawable as a background, it is suggested that the View use at least this 633 * value for its height. (There will be some scenarios where this will not be 634 * possible.) This value should INCLUDE any padding. 635 * 636 * @return The minimum height suggested by this Drawable. If this Drawable 637 * doesn't have a suggested minimum height, 0 is returned. 638 */ 639 public int getMinimumHeight() { 640 final int intrinsicHeight = getIntrinsicHeight(); 641 return intrinsicHeight > 0 ? intrinsicHeight : 0; 642 } 643 644 /** 645 * Return in padding the insets suggested by this Drawable for placing 646 * content inside the drawable's bounds. Positive values move toward the 647 * center of the Drawable (set Rect.inset). Returns true if this drawable 648 * actually has a padding, else false. When false is returned, the padding 649 * is always set to 0. 650 */ 651 public boolean getPadding(Rect padding) { 652 padding.set(0, 0, 0, 0); 653 return false; 654 } 655 656 /** 657 * Make this drawable mutable. This operation cannot be reversed. A mutable 658 * drawable is guaranteed to not share its state with any other drawable. 659 * This is especially useful when you need to modify properties of drawables 660 * loaded from resources. By default, all drawables instances loaded from 661 * the same resource share a common state; if you modify the state of one 662 * instance, all the other instances will receive the same modification. 663 * 664 * Calling this method on a mutable Drawable will have no effect. 665 * 666 * @return This drawable. 667 * @see ConstantState 668 * @see #getConstantState() 669 */ 670 public Drawable mutate() { 671 return this; 672 } 673 674 /** 675 * Create a drawable from an inputstream 676 */ 677 public static Drawable createFromStream(InputStream is, String srcName) { 678 return createFromResourceStream(null, null, is, srcName, null); 679 } 680 681 /** 682 * Create a drawable from an inputstream, using the given resources and 683 * value to determine density information. 684 */ 685 public static Drawable createFromResourceStream(Resources res, TypedValue value, 686 InputStream is, String srcName) { 687 return createFromResourceStream(res, value, is, srcName, null); 688 } 689 690 /** 691 * Create a drawable from an inputstream, using the given resources and 692 * value to determine density information. 693 */ 694 public static Drawable createFromResourceStream(Resources res, TypedValue value, 695 InputStream is, String srcName, BitmapFactory.Options opts) { 696 697 if (is == null) { 698 return null; 699 } 700 701 /* ugh. The decodeStream contract is that we have already allocated 702 the pad rect, but if the bitmap does not had a ninepatch chunk, 703 then the pad will be ignored. If we could change this to lazily 704 alloc/assign the rect, we could avoid the GC churn of making new 705 Rects only to drop them on the floor. 706 */ 707 Rect pad = new Rect(); 708 709 // Special stuff for compatibility mode: if the target density is not 710 // the same as the display density, but the resource -is- the same as 711 // the display density, then don't scale it down to the target density. 712 // This allows us to load the system's density-correct resources into 713 // an application in compatibility mode, without scaling those down 714 // to the compatibility density only to have them scaled back up when 715 // drawn to the screen. 716 if (opts == null) opts = new BitmapFactory.Options(); 717 opts.inScreenDensity = DisplayMetrics.DENSITY_DEVICE; 718 Bitmap bm = BitmapFactory.decodeResourceStream(res, value, is, pad, opts); 719 if (bm != null) { 720 byte[] np = bm.getNinePatchChunk(); 721 if (np == null || !NinePatch.isNinePatchChunk(np)) { 722 np = null; 723 pad = null; 724 } 725 return drawableFromBitmap(res, bm, np, pad, srcName); 726 } 727 return null; 728 } 729 730 /** 731 * Create a drawable from an XML document. For more information on how to 732 * create resources in XML, see 733 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. 734 */ 735 public static Drawable createFromXml(Resources r, XmlPullParser parser) 736 throws XmlPullParserException, IOException { 737 AttributeSet attrs = Xml.asAttributeSet(parser); 738 739 int type; 740 while ((type=parser.next()) != XmlPullParser.START_TAG && 741 type != XmlPullParser.END_DOCUMENT) { 742 // Empty loop 743 } 744 745 if (type != XmlPullParser.START_TAG) { 746 throw new XmlPullParserException("No start tag found"); 747 } 748 749 Drawable drawable = createFromXmlInner(r, parser, attrs); 750 751 if (drawable == null) { 752 throw new RuntimeException("Unknown initial tag: " + parser.getName()); 753 } 754 755 return drawable; 756 } 757 758 /** 759 * Create from inside an XML document. Called on a parser positioned at 760 * a tag in an XML document, tries to create a Drawable from that tag. 761 * Returns null if the tag is not a valid drawable. 762 */ 763 public static Drawable createFromXmlInner(Resources r, XmlPullParser parser, AttributeSet attrs) 764 throws XmlPullParserException, IOException { 765 Drawable drawable; 766 767 final String name = parser.getName(); 768 769 if (name.equals("selector")) { 770 drawable = new StateListDrawable(); 771 } else if (name.equals("level-list")) { 772 drawable = new LevelListDrawable(); 773 } else if (name.equals("mipmap")) { 774 drawable = new MipmapDrawable(); 775 } else if (name.equals("layer-list")) { 776 drawable = new LayerDrawable(); 777 } else if (name.equals("transition")) { 778 drawable = new TransitionDrawable(); 779 } else if (name.equals("color")) { 780 drawable = new ColorDrawable(); 781 } else if (name.equals("shape")) { 782 drawable = new GradientDrawable(); 783 } else if (name.equals("scale")) { 784 drawable = new ScaleDrawable(); 785 } else if (name.equals("clip")) { 786 drawable = new ClipDrawable(); 787 } else if (name.equals("rotate")) { 788 drawable = new RotateDrawable(); 789 } else if (name.equals("animated-rotate")) { 790 drawable = new AnimatedRotateDrawable(); 791 } else if (name.equals("animation-list")) { 792 drawable = new AnimationDrawable(); 793 } else if (name.equals("inset")) { 794 drawable = new InsetDrawable(); 795 } else if (name.equals("bitmap")) { 796 drawable = new BitmapDrawable(r); 797 if (r != null) { 798 ((BitmapDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 799 } 800 } else if (name.equals("nine-patch")) { 801 drawable = new NinePatchDrawable(); 802 if (r != null) { 803 ((NinePatchDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 804 } 805 } else { 806 throw new XmlPullParserException(parser.getPositionDescription() + 807 ": invalid drawable tag " + name); 808 } 809 810 drawable.inflate(r, parser, attrs); 811 return drawable; 812 } 813 814 815 /** 816 * Create a drawable from file path name. 817 */ 818 public static Drawable createFromPath(String pathName) { 819 if (pathName == null) { 820 return null; 821 } 822 823 Bitmap bm = BitmapFactory.decodeFile(pathName); 824 if (bm != null) { 825 return drawableFromBitmap(null, bm, null, null, pathName); 826 } 827 828 return null; 829 } 830 831 /** 832 * Inflate this Drawable from an XML resource. 833 */ 834 public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs) 835 throws XmlPullParserException, IOException { 836 837 TypedArray a = r.obtainAttributes(attrs, com.android.internal.R.styleable.Drawable); 838 inflateWithAttributes(r, parser, a, com.android.internal.R.styleable.Drawable_visible); 839 a.recycle(); 840 } 841 842 /** 843 * Inflate a Drawable from an XML resource. 844 * 845 * @throws XmlPullParserException 846 * @throws IOException 847 */ 848 void inflateWithAttributes(Resources r, XmlPullParser parser, 849 TypedArray attrs, int visibleAttr) 850 throws XmlPullParserException, IOException { 851 852 mVisible = attrs.getBoolean(visibleAttr, mVisible); 853 } 854 855 /** 856 * This abstract class is used by {@link Drawable}s to store shared constant state and data 857 * between Drawables. {@link BitmapDrawable}s created from the same resource will for instance 858 * share a unique bitmap stored in their ConstantState. 859 * 860 * <p> 861 * {@link #newDrawable(Resources)} can be used as a factory to create new Drawable instances 862 * from this ConstantState. 863 * </p> 864 * 865 * Use {@link Drawable#getConstantState()} to retrieve the ConstantState of a Drawable. Calling 866 * {@link Drawable#mutate()} on a Drawable should typically create a new ConstantState for that 867 * Drawable. 868 */ 869 public static abstract class ConstantState { 870 /** 871 * Create a new drawable without supplying resources the caller 872 * is running in. Note that using this means the density-dependent 873 * drawables (like bitmaps) will not be able to update their target 874 * density correctly. One should use {@link #newDrawable(Resources)} 875 * instead to provide a resource. 876 */ 877 public abstract Drawable newDrawable(); 878 /** 879 * Create a new Drawable instance from its constant state. This 880 * must be implemented for drawables that change based on the target 881 * density of their caller (that is depending on whether it is 882 * in compatibility mode). 883 */ 884 public Drawable newDrawable(Resources res) { 885 return newDrawable(); 886 } 887 /** 888 * Return a bit mask of configuration changes that will impact 889 * this drawable (and thus require completely reloading it). 890 */ 891 public abstract int getChangingConfigurations(); 892 } 893 894 /** 895 * Return a {@link ConstantState} instance that holds the shared state of this Drawable. 896 *q 897 * @return The ConstantState associated to that Drawable. 898 * @see ConstantState 899 * @see Drawable#mutate() 900 */ 901 public ConstantState getConstantState() { 902 return null; 903 } 904 905 private static Drawable drawableFromBitmap(Resources res, Bitmap bm, byte[] np, 906 Rect pad, String srcName) { 907 908 if (np != null) { 909 return new NinePatchDrawable(res, bm, np, pad, srcName); 910 } 911 912 return new BitmapDrawable(res, bm); 913 } 914} 915 916