Drawable.java revision 2273b1e4eae27fa60b0b90d16a1891b4526c9b9c
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; 39import android.view.View; 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 * <p>For information and examples of creating drawable resources (XML or bitmap files that 107 * can be loaded in code), see <a 108 * href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. 109 */ 110public abstract class Drawable { 111 private static final Rect ZERO_BOUNDS_RECT = new Rect(); 112 113 private int[] mStateSet = StateSet.WILD_CARD; 114 private int mLevel = 0; 115 private int mChangingConfigurations = 0; 116 private Rect mBounds = ZERO_BOUNDS_RECT; // lazily becomes a new Rect() 117 private WeakReference<Callback> mCallback = null; 118 private boolean mVisible = true; 119 120 /** 121 * Draw in its bounds (set via setBounds) respecting optional effects such 122 * as alpha (set via setAlpha) and color filter (set via setColorFilter). 123 * 124 * @param canvas The canvas to draw into 125 */ 126 public abstract void draw(Canvas canvas); 127 128 /** 129 * Specify a bounding rectangle for the Drawable. This is where the drawable 130 * will draw when its draw() method is called. 131 */ 132 public void setBounds(int left, int top, int right, int bottom) { 133 Rect oldBounds = mBounds; 134 135 if (oldBounds == ZERO_BOUNDS_RECT) { 136 oldBounds = mBounds = new Rect(); 137 } 138 139 if (oldBounds.left != left || oldBounds.top != top || 140 oldBounds.right != right || oldBounds.bottom != bottom) { 141 mBounds.set(left, top, right, bottom); 142 onBoundsChange(mBounds); 143 } 144 } 145 146 /** 147 * Specify a bounding rectangle for the Drawable. This is where the drawable 148 * will draw when its draw() method is called. 149 */ 150 public void setBounds(Rect bounds) { 151 setBounds(bounds.left, bounds.top, bounds.right, bounds.bottom); 152 } 153 154 /** 155 * Return a copy of the drawable's bounds in the specified Rect (allocated 156 * by the caller). The bounds specify where this will draw when its draw() 157 * method is called. 158 * 159 * @param bounds Rect to receive the drawable's bounds (allocated by the 160 * caller). 161 */ 162 public final void copyBounds(Rect bounds) { 163 bounds.set(mBounds); 164 } 165 166 /** 167 * Return a copy of the drawable's bounds in a new Rect. This returns the 168 * same values as getBounds(), but the returned object is guaranteed to not 169 * be changed later by the drawable (i.e. it retains no reference to this 170 * rect). If the caller already has a Rect allocated, call copyBounds(rect). 171 * 172 * @return A copy of the drawable's bounds 173 */ 174 public final Rect copyBounds() { 175 return new Rect(mBounds); 176 } 177 178 /** 179 * Return the drawable's bounds Rect. Note: for efficiency, the returned 180 * object may be the same object stored in the drawable (though this is not 181 * guaranteed), so if a persistent copy of the bounds is needed, call 182 * copyBounds(rect) instead. 183 * You should also not change the object returned by this method as it may 184 * be the same object stored in the drawable. 185 * 186 * @return The bounds of the drawable (which may change later, so caller 187 * beware). DO NOT ALTER the returned object as it may change the 188 * stored bounds of this drawable. 189 * 190 * @see #copyBounds() 191 * @see #copyBounds(android.graphics.Rect) 192 */ 193 public final Rect getBounds() { 194 if (mBounds == ZERO_BOUNDS_RECT) { 195 mBounds = new Rect(); 196 } 197 198 return mBounds; 199 } 200 201 /** 202 * Set a mask of the configuration parameters for which this drawable 203 * may change, requiring that it be re-created. 204 * 205 * @param configs A mask of the changing configuration parameters, as 206 * defined by {@link android.content.res.Configuration}. 207 * 208 * @see android.content.res.Configuration 209 */ 210 public void setChangingConfigurations(int configs) { 211 mChangingConfigurations = configs; 212 } 213 214 /** 215 * Return a mask of the configuration parameters for which this drawable 216 * may change, requiring that it be re-created. The default implementation 217 * returns whatever was provided through 218 * {@link #setChangingConfigurations(int)} or 0 by default. Subclasses 219 * may extend this to or in the changing configurations of any other 220 * drawables they hold. 221 * 222 * @return Returns a mask of the changing configuration parameters, as 223 * defined by {@link android.content.res.Configuration}. 224 * 225 * @see android.content.res.Configuration 226 */ 227 public int getChangingConfigurations() { 228 return mChangingConfigurations; 229 } 230 231 /** 232 * Set to true to have the drawable dither its colors when drawn to a device 233 * with fewer than 8-bits per color component. This can improve the look on 234 * those devices, but can also slow down the drawing a little. 235 */ 236 public void setDither(boolean dither) {} 237 238 /** 239 * Set to true to have the drawable filter its bitmap when scaled or rotated 240 * (for drawables that use bitmaps). If the drawable does not use bitmaps, 241 * this call is ignored. This can improve the look when scaled or rotated, 242 * but also slows down the drawing. 243 */ 244 public void setFilterBitmap(boolean filter) {} 245 246 /** 247 * Implement this interface if you want to create an animated drawable that 248 * extends {@link android.graphics.drawable.Drawable Drawable}. 249 * Upon retrieving a drawable, use 250 * {@link Drawable#setCallback(android.graphics.drawable.Drawable.Callback)} 251 * to supply your implementation of the interface to the drawable; it uses 252 * this interface to schedule and execute animation changes. 253 */ 254 public static interface Callback { 255 /** 256 * Called when the drawable needs to be redrawn. A view at this point 257 * should invalidate itself (or at least the part of itself where the 258 * drawable appears). 259 * 260 * @param who The drawable that is requesting the update. 261 */ 262 public void invalidateDrawable(Drawable who); 263 264 /** 265 * A Drawable can call this to schedule the next frame of its 266 * animation. An implementation can generally simply call 267 * {@link android.os.Handler#postAtTime(Runnable, Object, long)} with 268 * the parameters <var>(what, who, when)</var> to perform the 269 * scheduling. 270 * 271 * @param who The drawable being scheduled. 272 * @param what The action to execute. 273 * @param when The time (in milliseconds) to run. The timebase is 274 * {@link android.os.SystemClock#uptimeMillis} 275 */ 276 public void scheduleDrawable(Drawable who, Runnable what, long when); 277 278 /** 279 * A Drawable can call this to unschedule an action previously 280 * scheduled with {@link #scheduleDrawable}. An implementation can 281 * generally simply call 282 * {@link android.os.Handler#removeCallbacks(Runnable, Object)} with 283 * the parameters <var>(what, who)</var> to unschedule the drawable. 284 * 285 * @param who The drawable being unscheduled. 286 * @param what The action being unscheduled. 287 */ 288 public void unscheduleDrawable(Drawable who, Runnable what); 289 } 290 291 /** 292 * Implement this interface if you want to create an drawable that is RTL aware 293 * 294 * @hide 295 */ 296 public static interface Callback2 extends Callback { 297 /** 298 * A Drawable can call this to get the resolved layout direction of the <var>who</var>. 299 * 300 * @param who The drawable being queried. 301 */ 302 public int getResolvedLayoutDirection(Drawable who); 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 * Use the current {@link android.graphics.drawable.Drawable.Callback2} implementation to get 383 * the resolved layout direction of this Drawable. 384 * 385 * @hide 386 */ 387 public int getResolvedLayoutDirectionSelf() { 388 final Callback callback = getCallback(); 389 if (callback == null || !(callback instanceof Callback2)) { 390 return View.LAYOUT_DIRECTION_LTR; 391 } 392 return ((Callback2) callback).getResolvedLayoutDirection(this); 393 } 394 395 /** 396 * Specify an alpha value for the drawable. 0 means fully transparent, and 397 * 255 means fully opaque. 398 */ 399 public abstract void setAlpha(int alpha); 400 401 /** 402 * Specify an optional colorFilter for the drawable. Pass null to remove 403 * any filters. 404 */ 405 public abstract void setColorFilter(ColorFilter cf); 406 407 /** 408 * Specify a color and porterduff mode to be the colorfilter for this 409 * drawable. 410 */ 411 public void setColorFilter(int color, PorterDuff.Mode mode) { 412 setColorFilter(new PorterDuffColorFilter(color, mode)); 413 } 414 415 public void clearColorFilter() { 416 setColorFilter(null); 417 } 418 419 /** 420 * Indicates whether this view will change its appearance based on state. 421 * Clients can use this to determine whether it is necessary to calculate 422 * their state and call setState. 423 * 424 * @return True if this view changes its appearance based on state, false 425 * otherwise. 426 * 427 * @see #setState(int[]) 428 */ 429 public boolean isStateful() { 430 return false; 431 } 432 433 /** 434 * Specify a set of states for the drawable. These are use-case specific, 435 * so see the relevant documentation. As an example, the background for 436 * widgets like Button understand the following states: 437 * [{@link android.R.attr#state_focused}, 438 * {@link android.R.attr#state_pressed}]. 439 * 440 * <p>If the new state you are supplying causes the appearance of the 441 * Drawable to change, then it is responsible for calling 442 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 443 * true will be returned from this function. 444 * 445 * <p>Note: The Drawable holds a reference on to <var>stateSet</var> 446 * until a new state array is given to it, so you must not modify this 447 * array during that time.</p> 448 * 449 * @param stateSet The new set of states to be displayed. 450 * 451 * @return Returns true if this change in state has caused the appearance 452 * of the Drawable to change (hence requiring an invalidate), otherwise 453 * returns false. 454 */ 455 public boolean setState(final int[] stateSet) { 456 if (!Arrays.equals(mStateSet, stateSet)) { 457 mStateSet = stateSet; 458 return onStateChange(stateSet); 459 } 460 return false; 461 } 462 463 /** 464 * Describes the current state, as a union of primitve states, such as 465 * {@link android.R.attr#state_focused}, 466 * {@link android.R.attr#state_selected}, etc. 467 * Some drawables may modify their imagery based on the selected state. 468 * @return An array of resource Ids describing the current state. 469 */ 470 public int[] getState() { 471 return mStateSet; 472 } 473 474 /** 475 * If this Drawable does transition animations between states, ask that 476 * it immediately jump to the current state and skip any active animations. 477 */ 478 public void jumpToCurrentState() { 479 } 480 481 /** 482 * @return The current drawable that will be used by this drawable. For simple drawables, this 483 * is just the drawable itself. For drawables that change state like 484 * {@link StateListDrawable} and {@link LevelListDrawable} this will be the child drawable 485 * currently in use. 486 */ 487 public Drawable getCurrent() { 488 return this; 489 } 490 491 /** 492 * Specify the level for the drawable. This allows a drawable to vary its 493 * imagery based on a continuous controller, for example to show progress 494 * or volume level. 495 * 496 * <p>If the new level you are supplying causes the appearance of the 497 * Drawable to change, then it is responsible for calling 498 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 499 * true will be returned from this function. 500 * 501 * @param level The new level, from 0 (minimum) to 10000 (maximum). 502 * 503 * @return Returns true if this change in level has caused the appearance 504 * of the Drawable to change (hence requiring an invalidate), otherwise 505 * returns false. 506 */ 507 public final boolean setLevel(int level) { 508 if (mLevel != level) { 509 mLevel = level; 510 return onLevelChange(level); 511 } 512 return false; 513 } 514 515 /** 516 * Retrieve the current level. 517 * 518 * @return int Current level, from 0 (minimum) to 10000 (maximum). 519 */ 520 public final int getLevel() { 521 return mLevel; 522 } 523 524 /** 525 * Set whether this Drawable is visible. This generally does not impact 526 * the Drawable's behavior, but is a hint that can be used by some 527 * Drawables, for example, to decide whether run animations. 528 * 529 * @param visible Set to true if visible, false if not. 530 * @param restart You can supply true here to force the drawable to behave 531 * as if it has just become visible, even if it had last 532 * been set visible. Used for example to force animations 533 * to restart. 534 * 535 * @return boolean Returns true if the new visibility is different than 536 * its previous state. 537 */ 538 public boolean setVisible(boolean visible, boolean restart) { 539 boolean changed = mVisible != visible; 540 if (changed) { 541 mVisible = visible; 542 invalidateSelf(); 543 } 544 return changed; 545 } 546 547 public final boolean isVisible() { 548 return mVisible; 549 } 550 551 /** 552 * Return the opacity/transparency of this Drawable. The returned value is 553 * one of the abstract format constants in 554 * {@link android.graphics.PixelFormat}: 555 * {@link android.graphics.PixelFormat#UNKNOWN}, 556 * {@link android.graphics.PixelFormat#TRANSLUCENT}, 557 * {@link android.graphics.PixelFormat#TRANSPARENT}, or 558 * {@link android.graphics.PixelFormat#OPAQUE}. 559 * 560 * <p>Generally a Drawable should be as conservative as possible with the 561 * value it returns. For example, if it contains multiple child drawables 562 * and only shows one of them at a time, if only one of the children is 563 * TRANSLUCENT and the others are OPAQUE then TRANSLUCENT should be 564 * returned. You can use the method {@link #resolveOpacity} to perform a 565 * standard reduction of two opacities to the appropriate single output. 566 * 567 * <p>Note that the returned value does <em>not</em> take into account a 568 * custom alpha or color filter that has been applied by the client through 569 * the {@link #setAlpha} or {@link #setColorFilter} methods. 570 * 571 * @return int The opacity class of the Drawable. 572 * 573 * @see android.graphics.PixelFormat 574 */ 575 public abstract int getOpacity(); 576 577 /** 578 * Return the appropriate opacity value for two source opacities. If 579 * either is UNKNOWN, that is returned; else, if either is TRANSLUCENT, 580 * that is returned; else, if either is TRANSPARENT, that is returned; 581 * else, OPAQUE is returned. 582 * 583 * <p>This is to help in implementing {@link #getOpacity}. 584 * 585 * @param op1 One opacity value. 586 * @param op2 Another opacity value. 587 * 588 * @return int The combined opacity value. 589 * 590 * @see #getOpacity 591 */ 592 public static int resolveOpacity(int op1, int op2) { 593 if (op1 == op2) { 594 return op1; 595 } 596 if (op1 == PixelFormat.UNKNOWN || op2 == PixelFormat.UNKNOWN) { 597 return PixelFormat.UNKNOWN; 598 } 599 if (op1 == PixelFormat.TRANSLUCENT || op2 == PixelFormat.TRANSLUCENT) { 600 return PixelFormat.TRANSLUCENT; 601 } 602 if (op1 == PixelFormat.TRANSPARENT || op2 == PixelFormat.TRANSPARENT) { 603 return PixelFormat.TRANSPARENT; 604 } 605 return PixelFormat.OPAQUE; 606 } 607 608 /** 609 * Returns a Region representing the part of the Drawable that is completely 610 * transparent. This can be used to perform drawing operations, identifying 611 * which parts of the target will not change when rendering the Drawable. 612 * The default implementation returns null, indicating no transparent 613 * region; subclasses can optionally override this to return an actual 614 * Region if they want to supply this optimization information, but it is 615 * not required that they do so. 616 * 617 * @return Returns null if the Drawables has no transparent region to 618 * report, else a Region holding the parts of the Drawable's bounds that 619 * are transparent. 620 */ 621 public Region getTransparentRegion() { 622 return null; 623 } 624 625 /** 626 * Override this in your subclass to change appearance if you recognize the 627 * specified state. 628 * 629 * @return Returns true if the state change has caused the appearance of 630 * the Drawable to change (that is, it needs to be drawn), else false 631 * if it looks the same and there is no need to redraw it since its 632 * last state. 633 */ 634 protected boolean onStateChange(int[] state) { return false; } 635 /** Override this in your subclass to change appearance if you vary based 636 * on level. 637 * @return Returns true if the level change has caused the appearance of 638 * the Drawable to change (that is, it needs to be drawn), else false 639 * if it looks the same and there is no need to redraw it since its 640 * last level. 641 */ 642 protected boolean onLevelChange(int level) { return false; } 643 /** 644 * Override this in your subclass to change appearance if you recognize the 645 * specified state. 646 */ 647 protected void onBoundsChange(Rect bounds) {} 648 649 /** 650 * Return the intrinsic width of the underlying drawable object. Returns 651 * -1 if it has no intrinsic width, such as with a solid color. 652 */ 653 public int getIntrinsicWidth() { 654 return -1; 655 } 656 657 /** 658 * Return the intrinsic height of the underlying drawable object. Returns 659 * -1 if it has no intrinsic height, such as with a solid color. 660 */ 661 public int getIntrinsicHeight() { 662 return -1; 663 } 664 665 /** 666 * Returns the minimum width suggested by this Drawable. If a View uses this 667 * Drawable as a background, it is suggested that the View use at least this 668 * value for its width. (There will be some scenarios where this will not be 669 * possible.) This value should INCLUDE any padding. 670 * 671 * @return The minimum width suggested by this Drawable. If this Drawable 672 * doesn't have a suggested minimum width, 0 is returned. 673 */ 674 public int getMinimumWidth() { 675 final int intrinsicWidth = getIntrinsicWidth(); 676 return intrinsicWidth > 0 ? intrinsicWidth : 0; 677 } 678 679 /** 680 * Returns the minimum height suggested by this Drawable. If a View uses this 681 * Drawable as a background, it is suggested that the View use at least this 682 * value for its height. (There will be some scenarios where this will not be 683 * possible.) This value should INCLUDE any padding. 684 * 685 * @return The minimum height suggested by this Drawable. If this Drawable 686 * doesn't have a suggested minimum height, 0 is returned. 687 */ 688 public int getMinimumHeight() { 689 final int intrinsicHeight = getIntrinsicHeight(); 690 return intrinsicHeight > 0 ? intrinsicHeight : 0; 691 } 692 693 /** 694 * Return in padding the insets suggested by this Drawable for placing 695 * content inside the drawable's bounds. Positive values move toward the 696 * center of the Drawable (set Rect.inset). Returns true if this drawable 697 * actually has a padding, else false. When false is returned, the padding 698 * is always set to 0. 699 */ 700 public boolean getPadding(Rect padding) { 701 padding.set(0, 0, 0, 0); 702 return false; 703 } 704 705 /** 706 * Make this drawable mutable. This operation cannot be reversed. A mutable 707 * drawable is guaranteed to not share its state with any other drawable. 708 * This is especially useful when you need to modify properties of drawables 709 * loaded from resources. By default, all drawables instances loaded from 710 * the same resource share a common state; if you modify the state of one 711 * instance, all the other instances will receive the same modification. 712 * 713 * Calling this method on a mutable Drawable will have no effect. 714 * 715 * @return This drawable. 716 * @see ConstantState 717 * @see #getConstantState() 718 */ 719 public Drawable mutate() { 720 return this; 721 } 722 723 /** 724 * Create a drawable from an inputstream 725 */ 726 public static Drawable createFromStream(InputStream is, String srcName) { 727 return createFromResourceStream(null, null, is, srcName, null); 728 } 729 730 /** 731 * Create a drawable from an inputstream, using the given resources and 732 * value to determine density information. 733 */ 734 public static Drawable createFromResourceStream(Resources res, TypedValue value, 735 InputStream is, String srcName) { 736 return createFromResourceStream(res, value, is, srcName, null); 737 } 738 739 /** 740 * Create a drawable from an inputstream, using the given resources and 741 * value to determine density information. 742 */ 743 public static Drawable createFromResourceStream(Resources res, TypedValue value, 744 InputStream is, String srcName, BitmapFactory.Options opts) { 745 746 if (is == null) { 747 return null; 748 } 749 750 /* ugh. The decodeStream contract is that we have already allocated 751 the pad rect, but if the bitmap does not had a ninepatch chunk, 752 then the pad will be ignored. If we could change this to lazily 753 alloc/assign the rect, we could avoid the GC churn of making new 754 Rects only to drop them on the floor. 755 */ 756 Rect pad = new Rect(); 757 758 // Special stuff for compatibility mode: if the target density is not 759 // the same as the display density, but the resource -is- the same as 760 // the display density, then don't scale it down to the target density. 761 // This allows us to load the system's density-correct resources into 762 // an application in compatibility mode, without scaling those down 763 // to the compatibility density only to have them scaled back up when 764 // drawn to the screen. 765 if (opts == null) opts = new BitmapFactory.Options(); 766 opts.inScreenDensity = DisplayMetrics.DENSITY_DEVICE; 767 Bitmap bm = BitmapFactory.decodeResourceStream(res, value, is, pad, opts); 768 if (bm != null) { 769 byte[] np = bm.getNinePatchChunk(); 770 if (np == null || !NinePatch.isNinePatchChunk(np)) { 771 np = null; 772 pad = null; 773 } 774 return drawableFromBitmap(res, bm, np, pad, srcName); 775 } 776 return null; 777 } 778 779 /** 780 * Create a drawable from an XML document. For more information on how to 781 * create resources in XML, see 782 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. 783 */ 784 public static Drawable createFromXml(Resources r, XmlPullParser parser) 785 throws XmlPullParserException, IOException { 786 AttributeSet attrs = Xml.asAttributeSet(parser); 787 788 int type; 789 while ((type=parser.next()) != XmlPullParser.START_TAG && 790 type != XmlPullParser.END_DOCUMENT) { 791 // Empty loop 792 } 793 794 if (type != XmlPullParser.START_TAG) { 795 throw new XmlPullParserException("No start tag found"); 796 } 797 798 Drawable drawable = createFromXmlInner(r, parser, attrs); 799 800 if (drawable == null) { 801 throw new RuntimeException("Unknown initial tag: " + parser.getName()); 802 } 803 804 return drawable; 805 } 806 807 /** 808 * Create from inside an XML document. Called on a parser positioned at 809 * a tag in an XML document, tries to create a Drawable from that tag. 810 * Returns null if the tag is not a valid drawable. 811 */ 812 public static Drawable createFromXmlInner(Resources r, XmlPullParser parser, AttributeSet attrs) 813 throws XmlPullParserException, IOException { 814 Drawable drawable; 815 816 final String name = parser.getName(); 817 818 if (name.equals("selector")) { 819 drawable = new StateListDrawable(); 820 } else if (name.equals("level-list")) { 821 drawable = new LevelListDrawable(); 822 /* Probably not doing this. 823 } else if (name.equals("mipmap")) { 824 drawable = new MipmapDrawable(); 825 */ 826 } else if (name.equals("layer-list")) { 827 drawable = new LayerDrawable(); 828 } else if (name.equals("transition")) { 829 drawable = new TransitionDrawable(); 830 } else if (name.equals("color")) { 831 drawable = new ColorDrawable(); 832 } else if (name.equals("shape")) { 833 drawable = new GradientDrawable(); 834 } else if (name.equals("scale")) { 835 drawable = new ScaleDrawable(); 836 } else if (name.equals("clip")) { 837 drawable = new ClipDrawable(); 838 } else if (name.equals("rotate")) { 839 drawable = new RotateDrawable(); 840 } else if (name.equals("animated-rotate")) { 841 drawable = new AnimatedRotateDrawable(); 842 } else if (name.equals("animation-list")) { 843 drawable = new AnimationDrawable(); 844 } else if (name.equals("inset")) { 845 drawable = new InsetDrawable(); 846 } else if (name.equals("bitmap")) { 847 drawable = new BitmapDrawable(r); 848 if (r != null) { 849 ((BitmapDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 850 } 851 } else if (name.equals("nine-patch")) { 852 drawable = new NinePatchDrawable(); 853 if (r != null) { 854 ((NinePatchDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 855 } 856 } else { 857 throw new XmlPullParserException(parser.getPositionDescription() + 858 ": invalid drawable tag " + name); 859 } 860 861 drawable.inflate(r, parser, attrs); 862 return drawable; 863 } 864 865 866 /** 867 * Create a drawable from file path name. 868 */ 869 public static Drawable createFromPath(String pathName) { 870 if (pathName == null) { 871 return null; 872 } 873 874 Bitmap bm = BitmapFactory.decodeFile(pathName); 875 if (bm != null) { 876 return drawableFromBitmap(null, bm, null, null, pathName); 877 } 878 879 return null; 880 } 881 882 /** 883 * Inflate this Drawable from an XML resource. 884 */ 885 public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs) 886 throws XmlPullParserException, IOException { 887 888 TypedArray a = r.obtainAttributes(attrs, com.android.internal.R.styleable.Drawable); 889 inflateWithAttributes(r, parser, a, com.android.internal.R.styleable.Drawable_visible); 890 a.recycle(); 891 } 892 893 /** 894 * Inflate a Drawable from an XML resource. 895 * 896 * @throws XmlPullParserException 897 * @throws IOException 898 */ 899 void inflateWithAttributes(Resources r, XmlPullParser parser, 900 TypedArray attrs, int visibleAttr) 901 throws XmlPullParserException, IOException { 902 903 mVisible = attrs.getBoolean(visibleAttr, mVisible); 904 } 905 906 /** 907 * This abstract class is used by {@link Drawable}s to store shared constant state and data 908 * between Drawables. {@link BitmapDrawable}s created from the same resource will for instance 909 * share a unique bitmap stored in their ConstantState. 910 * 911 * <p> 912 * {@link #newDrawable(Resources)} can be used as a factory to create new Drawable instances 913 * from this ConstantState. 914 * </p> 915 * 916 * Use {@link Drawable#getConstantState()} to retrieve the ConstantState of a Drawable. Calling 917 * {@link Drawable#mutate()} on a Drawable should typically create a new ConstantState for that 918 * Drawable. 919 */ 920 public static abstract class ConstantState { 921 /** 922 * Create a new drawable without supplying resources the caller 923 * is running in. Note that using this means the density-dependent 924 * drawables (like bitmaps) will not be able to update their target 925 * density correctly. One should use {@link #newDrawable(Resources)} 926 * instead to provide a resource. 927 */ 928 public abstract Drawable newDrawable(); 929 /** 930 * Create a new Drawable instance from its constant state. This 931 * must be implemented for drawables that change based on the target 932 * density of their caller (that is depending on whether it is 933 * in compatibility mode). 934 */ 935 public Drawable newDrawable(Resources res) { 936 return newDrawable(); 937 } 938 /** 939 * Return a bit mask of configuration changes that will impact 940 * this drawable (and thus require completely reloading it). 941 */ 942 public abstract int getChangingConfigurations(); 943 } 944 945 /** 946 * Return a {@link ConstantState} instance that holds the shared state of this Drawable. 947 *q 948 * @return The ConstantState associated to that Drawable. 949 * @see ConstantState 950 * @see Drawable#mutate() 951 */ 952 public ConstantState getConstantState() { 953 return null; 954 } 955 956 private static Drawable drawableFromBitmap(Resources res, Bitmap bm, byte[] np, 957 Rect pad, String srcName) { 958 959 if (np != null) { 960 return new NinePatchDrawable(res, bm, np, pad, srcName); 961 } 962 963 return new BitmapDrawable(res, bm); 964 } 965} 966 967