Drawable.java revision 70588bf864f961974c93aace7586d3e2773a54a8
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.lang.ref.WeakReference; 43import java.util.Arrays; 44 45/** 46 * A Drawable is a general abstraction for "something that can be drawn." Most 47 * often you will deal with Drawable as the type of resource retrieved for 48 * drawing things to the screen; the Drawable class provides a generic API for 49 * dealing with an underlying visual resource that may take a variety of forms. 50 * Unlike a {@link android.view.View}, a Drawable does not have any facility to 51 * receive events or otherwise interact with the user. 52 * 53 * <p>In addition to simple drawing, Drawable provides a number of generic 54 * mechanisms for its client to interact with what is being drawn: 55 * 56 * <ul> 57 * <li> The {@link #setBounds} method <var>must</var> be called to tell the 58 * Drawable where it is drawn and how large it should be. All Drawables 59 * should respect the requested size, often simply by scaling their 60 * imagery. A client can find the preferred size for some Drawables with 61 * the {@link #getIntrinsicHeight} and {@link #getIntrinsicWidth} methods. 62 * 63 * <li> The {@link #getPadding} method can return from some Drawables 64 * information about how to frame content that is placed inside of them. 65 * For example, a Drawable that is intended to be the frame for a button 66 * widget would need to return padding that correctly places the label 67 * inside of itself. 68 * 69 * <li> The {@link #setState} method allows the client to tell the Drawable 70 * in which state it is to be drawn, such as "focused", "selected", etc. 71 * Some drawables may modify their imagery based on the selected state. 72 * 73 * <li> The {@link #setLevel} method allows the client to supply a single 74 * continuous controller that can modify the Drawable is displayed, such as 75 * a battery level or progress level. Some drawables may modify their 76 * imagery based on the current level. 77 * 78 * <li> A Drawable can perform animations by calling back to its client 79 * through the {@link Callback} interface. All clients should support this 80 * interface (via {@link #setCallback}) so that animations will work. A 81 * simple way to do this is through the system facilities such as 82 * {@link android.view.View#setBackgroundDrawable(Drawable)} and 83 * {@link android.widget.ImageView}. 84 * </ul> 85 * 86 * Though usually not visible to the application, Drawables may take a variety 87 * of forms: 88 * 89 * <ul> 90 * <li> <b>Bitmap</b>: the simplest Drawable, a PNG or JPEG image. 91 * <li> <b>Nine Patch</b>: an extension to the PNG format allows it to 92 * specify information about how to stretch it and place things inside of 93 * it. 94 * <li> <b>Shape</b>: contains simple drawing commands instead of a raw 95 * bitmap, allowing it to resize better in some cases. 96 * <li> <b>Layers</b>: a compound drawable, which draws multiple underlying 97 * drawables on top of each other. 98 * <li> <b>States</b>: a compound drawable that selects one of a set of 99 * drawables based on its state. 100 * <li> <b>Levels</b>: a compound drawable that selects one of a set of 101 * drawables based on its level. 102 * <li> <b>Scale</b>: a compound drawable with a single child drawable, 103 * whose overall size is modified based on the current level. 104 * </ul> 105 * <p>For information and examples of creating drawable resources (XML or bitmap files that 106 * can be loaded in code), see <a 107 * href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. 108 */ 109public abstract class Drawable { 110 private static final Rect ZERO_BOUNDS_RECT = new Rect(); 111 112 private int[] mStateSet = StateSet.WILD_CARD; 113 private int mLevel = 0; 114 private int mChangingConfigurations = 0; 115 private Rect mBounds = ZERO_BOUNDS_RECT; // lazily becomes a new Rect() 116 private WeakReference<Callback> mCallback = null; 117 private boolean mVisible = true; 118 119 /** 120 * Draw in its bounds (set via setBounds) respecting optional effects such 121 * as alpha (set via setAlpha) and color filter (set via setColorFilter). 122 * 123 * @param canvas The canvas to draw into 124 */ 125 public abstract void draw(Canvas canvas); 126 127 /** 128 * Specify a bounding rectangle for the Drawable. This is where the drawable 129 * will draw when its draw() method is called. 130 */ 131 public void setBounds(int left, int top, int right, int bottom) { 132 Rect oldBounds = mBounds; 133 134 if (oldBounds == ZERO_BOUNDS_RECT) { 135 oldBounds = mBounds = new Rect(); 136 } 137 138 if (oldBounds.left != left || oldBounds.top != top || 139 oldBounds.right != right || oldBounds.bottom != bottom) { 140 mBounds.set(left, top, right, bottom); 141 onBoundsChange(mBounds); 142 } 143 } 144 145 /** 146 * Specify a bounding rectangle for the Drawable. This is where the drawable 147 * will draw when its draw() method is called. 148 */ 149 public void setBounds(Rect bounds) { 150 setBounds(bounds.left, bounds.top, bounds.right, bounds.bottom); 151 } 152 153 /** 154 * Return a copy of the drawable's bounds in the specified Rect (allocated 155 * by the caller). The bounds specify where this will draw when its draw() 156 * method is called. 157 * 158 * @param bounds Rect to receive the drawable's bounds (allocated by the 159 * caller). 160 */ 161 public final void copyBounds(Rect bounds) { 162 bounds.set(mBounds); 163 } 164 165 /** 166 * Return a copy of the drawable's bounds in a new Rect. This returns the 167 * same values as getBounds(), but the returned object is guaranteed to not 168 * be changed later by the drawable (i.e. it retains no reference to this 169 * rect). If the caller already has a Rect allocated, call copyBounds(rect). 170 * 171 * @return A copy of the drawable's bounds 172 */ 173 public final Rect copyBounds() { 174 return new Rect(mBounds); 175 } 176 177 /** 178 * Return the drawable's bounds Rect. Note: for efficiency, the returned 179 * object may be the same object stored in the drawable (though this is not 180 * guaranteed), so if a persistent copy of the bounds is needed, call 181 * copyBounds(rect) instead. 182 * You should also not change the object returned by this method as it may 183 * be the same object stored in the drawable. 184 * 185 * @return The bounds of the drawable (which may change later, so caller 186 * beware). DO NOT ALTER the returned object as it may change the 187 * stored bounds of this drawable. 188 * 189 * @see #copyBounds() 190 * @see #copyBounds(android.graphics.Rect) 191 */ 192 public final Rect getBounds() { 193 if (mBounds == ZERO_BOUNDS_RECT) { 194 mBounds = new Rect(); 195 } 196 197 return mBounds; 198 } 199 200 /** 201 * Set a mask of the configuration parameters for which this drawable 202 * may change, requiring that it be re-created. 203 * 204 * @param configs A mask of the changing configuration parameters, as 205 * defined by {@link android.content.res.Configuration}. 206 * 207 * @see android.content.res.Configuration 208 */ 209 public void setChangingConfigurations(int configs) { 210 mChangingConfigurations = configs; 211 } 212 213 /** 214 * Return a mask of the configuration parameters for which this drawable 215 * may change, requiring that it be re-created. The default implementation 216 * returns whatever was provided through 217 * {@link #setChangingConfigurations(int)} or 0 by default. Subclasses 218 * may extend this to or in the changing configurations of any other 219 * drawables they hold. 220 * 221 * @return Returns a mask of the changing configuration parameters, as 222 * defined by {@link android.content.res.Configuration}. 223 * 224 * @see android.content.res.Configuration 225 */ 226 public int getChangingConfigurations() { 227 return mChangingConfigurations; 228 } 229 230 /** 231 * Set to true to have the drawable dither its colors when drawn to a device 232 * with fewer than 8-bits per color component. This can improve the look on 233 * those devices, but can also slow down the drawing a little. 234 */ 235 public void setDither(boolean dither) {} 236 237 /** 238 * Set to true to have the drawable filter its bitmap when scaled or rotated 239 * (for drawables that use bitmaps). If the drawable does not use bitmaps, 240 * this call is ignored. This can improve the look when scaled or rotated, 241 * but also slows down the drawing. 242 */ 243 public void setFilterBitmap(boolean filter) {} 244 245 /** 246 * Implement this interface if you want to create an animated drawable that 247 * extends {@link android.graphics.drawable.Drawable Drawable}. 248 * Upon retrieving a drawable, use 249 * {@link Drawable#setCallback(android.graphics.drawable.Drawable.Callback)} 250 * to supply your implementation of the interface to the drawable; it uses 251 * this interface to schedule and execute animation changes. 252 */ 253 public static interface Callback { 254 /** 255 * Called when the drawable needs to be redrawn. A view at this point 256 * should invalidate itself (or at least the part of itself where the 257 * drawable appears). 258 * 259 * @param who The drawable that is requesting the update. 260 */ 261 public void invalidateDrawable(Drawable who); 262 263 /** 264 * A Drawable can call this to schedule the next frame of its 265 * animation. An implementation can generally simply call 266 * {@link android.os.Handler#postAtTime(Runnable, Object, long)} with 267 * the parameters <var>(what, who, when)</var> to perform the 268 * scheduling. 269 * 270 * @param who The drawable being scheduled. 271 * @param what The action to execute. 272 * @param when The time (in milliseconds) to run. The timebase is 273 * {@link android.os.SystemClock#uptimeMillis} 274 */ 275 public void scheduleDrawable(Drawable who, Runnable what, long when); 276 277 /** 278 * A Drawable can call this to unschedule an action previously 279 * scheduled with {@link #scheduleDrawable}. An implementation can 280 * generally simply call 281 * {@link android.os.Handler#removeCallbacks(Runnable, Object)} with 282 * the parameters <var>(what, who)</var> to unschedule the drawable. 283 * 284 * @param who The drawable being unscheduled. 285 * @param what The action being unscheduled. 286 */ 287 public void unscheduleDrawable(Drawable who, Runnable what); 288 } 289 290 /** 291 * Bind a {@link Callback} object to this Drawable. Required for clients 292 * that want to support animated drawables. 293 * 294 * @param cb The client's Callback implementation. 295 * 296 * @see #getCallback() 297 */ 298 public final void setCallback(Callback cb) { 299 mCallback = new WeakReference<Callback>(cb); 300 } 301 302 /** 303 * Return the current {@link Callback} implementation attached to this 304 * Drawable. 305 * 306 * @return A {@link Callback} instance or null if no callback was set. 307 * 308 * @see #setCallback(android.graphics.drawable.Drawable.Callback) 309 */ 310 public Callback getCallback() { 311 if (mCallback != null) { 312 return mCallback.get(); 313 } 314 return null; 315 } 316 317 /** 318 * Use the current {@link Callback} implementation to have this Drawable 319 * redrawn. Does nothing if there is no Callback attached to the 320 * Drawable. 321 * 322 * @see Callback#invalidateDrawable 323 * @see #getCallback() 324 * @see #setCallback(android.graphics.drawable.Drawable.Callback) 325 */ 326 public void invalidateSelf() { 327 final Callback callback = getCallback(); 328 if (callback != null) { 329 callback.invalidateDrawable(this); 330 } 331 } 332 333 /** 334 * Use the current {@link Callback} implementation to have this Drawable 335 * scheduled. Does nothing if there is no Callback attached to the 336 * Drawable. 337 * 338 * @param what The action being scheduled. 339 * @param when The time (in milliseconds) to run. 340 * 341 * @see Callback#scheduleDrawable 342 */ 343 public void scheduleSelf(Runnable what, long when) { 344 final Callback callback = getCallback(); 345 if (callback != null) { 346 callback.scheduleDrawable(this, what, when); 347 } 348 } 349 350 /** 351 * Use the current {@link Callback} implementation to have this Drawable 352 * unscheduled. Does nothing if there is no Callback attached to the 353 * Drawable. 354 * 355 * @param what The runnable that you no longer want called. 356 * 357 * @see Callback#unscheduleDrawable 358 */ 359 public void unscheduleSelf(Runnable what) { 360 final Callback callback = getCallback(); 361 if (callback != null) { 362 callback.unscheduleDrawable(this, what); 363 } 364 } 365 366 /** 367 * Specify an alpha value for the drawable. 0 means fully transparent, and 368 * 255 means fully opaque. 369 */ 370 public abstract void setAlpha(int alpha); 371 372 /** 373 * Specify an optional colorFilter for the drawable. Pass null to remove 374 * any filters. 375 */ 376 public abstract void setColorFilter(ColorFilter cf); 377 378 /** 379 * Specify a color and porterduff mode to be the colorfilter for this 380 * drawable. 381 */ 382 public void setColorFilter(int color, PorterDuff.Mode mode) { 383 setColorFilter(new PorterDuffColorFilter(color, mode)); 384 } 385 386 public void clearColorFilter() { 387 setColorFilter(null); 388 } 389 390 /** 391 * Indicates whether this view will change its appearance based on state. 392 * Clients can use this to determine whether it is necessary to calculate 393 * their state and call setState. 394 * 395 * @return True if this view changes its appearance based on state, false 396 * otherwise. 397 * 398 * @see #setState(int[]) 399 */ 400 public boolean isStateful() { 401 return false; 402 } 403 404 /** 405 * Specify a set of states for the drawable. These are use-case specific, 406 * so see the relevant documentation. As an example, the background for 407 * widgets like Button understand the following states: 408 * [{@link android.R.attr#state_focused}, 409 * {@link android.R.attr#state_pressed}]. 410 * 411 * <p>If the new state you are supplying causes the appearance of the 412 * Drawable to change, then it is responsible for calling 413 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 414 * true will be returned from this function. 415 * 416 * <p>Note: The Drawable holds a reference on to <var>stateSet</var> 417 * until a new state array is given to it, so you must not modify this 418 * array during that time.</p> 419 * 420 * @param stateSet The new set of states to be displayed. 421 * 422 * @return Returns true if this change in state has caused the appearance 423 * of the Drawable to change (hence requiring an invalidate), otherwise 424 * returns false. 425 */ 426 public boolean setState(final int[] stateSet) { 427 if (!Arrays.equals(mStateSet, stateSet)) { 428 mStateSet = stateSet; 429 return onStateChange(stateSet); 430 } 431 return false; 432 } 433 434 /** 435 * Describes the current state, as a union of primitve states, such as 436 * {@link android.R.attr#state_focused}, 437 * {@link android.R.attr#state_selected}, etc. 438 * Some drawables may modify their imagery based on the selected state. 439 * @return An array of resource Ids describing the current state. 440 */ 441 public int[] getState() { 442 return mStateSet; 443 } 444 445 /** 446 * If this Drawable does transition animations between states, ask that 447 * it immediately jump to the current state and skip any active animations. 448 */ 449 public void jumpToCurrentState() { 450 } 451 452 /** 453 * @return The current drawable that will be used by this drawable. For simple drawables, this 454 * is just the drawable itself. For drawables that change state like 455 * {@link StateListDrawable} and {@link LevelListDrawable} this will be the child drawable 456 * currently in use. 457 */ 458 public Drawable getCurrent() { 459 return this; 460 } 461 462 /** 463 * Specify the level for the drawable. This allows a drawable to vary its 464 * imagery based on a continuous controller, for example to show progress 465 * or volume level. 466 * 467 * <p>If the new level you are supplying causes the appearance of the 468 * Drawable to change, then it is responsible for calling 469 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 470 * true will be returned from this function. 471 * 472 * @param level The new level, from 0 (minimum) to 10000 (maximum). 473 * 474 * @return Returns true if this change in level has caused the appearance 475 * of the Drawable to change (hence requiring an invalidate), otherwise 476 * returns false. 477 */ 478 public final boolean setLevel(int level) { 479 if (mLevel != level) { 480 mLevel = level; 481 return onLevelChange(level); 482 } 483 return false; 484 } 485 486 /** 487 * Retrieve the current level. 488 * 489 * @return int Current level, from 0 (minimum) to 10000 (maximum). 490 */ 491 public final int getLevel() { 492 return mLevel; 493 } 494 495 /** 496 * Set whether this Drawable is visible. This generally does not impact 497 * the Drawable's behavior, but is a hint that can be used by some 498 * Drawables, for example, to decide whether run animations. 499 * 500 * @param visible Set to true if visible, false if not. 501 * @param restart You can supply true here to force the drawable to behave 502 * as if it has just become visible, even if it had last 503 * been set visible. Used for example to force animations 504 * to restart. 505 * 506 * @return boolean Returns true if the new visibility is different than 507 * its previous state. 508 */ 509 public boolean setVisible(boolean visible, boolean restart) { 510 boolean changed = mVisible != visible; 511 if (changed) { 512 mVisible = visible; 513 invalidateSelf(); 514 } 515 return changed; 516 } 517 518 public final boolean isVisible() { 519 return mVisible; 520 } 521 522 /** 523 * Return the opacity/transparency of this Drawable. The returned value is 524 * one of the abstract format constants in 525 * {@link android.graphics.PixelFormat}: 526 * {@link android.graphics.PixelFormat#UNKNOWN}, 527 * {@link android.graphics.PixelFormat#TRANSLUCENT}, 528 * {@link android.graphics.PixelFormat#TRANSPARENT}, or 529 * {@link android.graphics.PixelFormat#OPAQUE}. 530 * 531 * <p>Generally a Drawable should be as conservative as possible with the 532 * value it returns. For example, if it contains multiple child drawables 533 * and only shows one of them at a time, if only one of the children is 534 * TRANSLUCENT and the others are OPAQUE then TRANSLUCENT should be 535 * returned. You can use the method {@link #resolveOpacity} to perform a 536 * standard reduction of two opacities to the appropriate single output. 537 * 538 * <p>Note that the returned value does <em>not</em> take into account a 539 * custom alpha or color filter that has been applied by the client through 540 * the {@link #setAlpha} or {@link #setColorFilter} methods. 541 * 542 * @return int The opacity class of the Drawable. 543 * 544 * @see android.graphics.PixelFormat 545 */ 546 public abstract int getOpacity(); 547 548 /** 549 * Return the appropriate opacity value for two source opacities. If 550 * either is UNKNOWN, that is returned; else, if either is TRANSLUCENT, 551 * that is returned; else, if either is TRANSPARENT, that is returned; 552 * else, OPAQUE is returned. 553 * 554 * <p>This is to help in implementing {@link #getOpacity}. 555 * 556 * @param op1 One opacity value. 557 * @param op2 Another opacity value. 558 * 559 * @return int The combined opacity value. 560 * 561 * @see #getOpacity 562 */ 563 public static int resolveOpacity(int op1, int op2) { 564 if (op1 == op2) { 565 return op1; 566 } 567 if (op1 == PixelFormat.UNKNOWN || op2 == PixelFormat.UNKNOWN) { 568 return PixelFormat.UNKNOWN; 569 } 570 if (op1 == PixelFormat.TRANSLUCENT || op2 == PixelFormat.TRANSLUCENT) { 571 return PixelFormat.TRANSLUCENT; 572 } 573 if (op1 == PixelFormat.TRANSPARENT || op2 == PixelFormat.TRANSPARENT) { 574 return PixelFormat.TRANSPARENT; 575 } 576 return PixelFormat.OPAQUE; 577 } 578 579 /** 580 * Returns a Region representing the part of the Drawable that is completely 581 * transparent. This can be used to perform drawing operations, identifying 582 * which parts of the target will not change when rendering the Drawable. 583 * The default implementation returns null, indicating no transparent 584 * region; subclasses can optionally override this to return an actual 585 * Region if they want to supply this optimization information, but it is 586 * not required that they do so. 587 * 588 * @return Returns null if the Drawables has no transparent region to 589 * report, else a Region holding the parts of the Drawable's bounds that 590 * are transparent. 591 */ 592 public Region getTransparentRegion() { 593 return null; 594 } 595 596 /** 597 * Override this in your subclass to change appearance if you recognize the 598 * specified state. 599 * 600 * @return Returns true if the state change has caused the appearance of 601 * the Drawable to change (that is, it needs to be drawn), else false 602 * if it looks the same and there is no need to redraw it since its 603 * last state. 604 */ 605 protected boolean onStateChange(int[] state) { return false; } 606 /** Override this in your subclass to change appearance if you vary based 607 * on level. 608 * @return Returns true if the level change has caused the appearance of 609 * the Drawable to change (that is, it needs to be drawn), else false 610 * if it looks the same and there is no need to redraw it since its 611 * last level. 612 */ 613 protected boolean onLevelChange(int level) { return false; } 614 /** 615 * Override this in your subclass to change appearance if you recognize the 616 * specified state. 617 */ 618 protected void onBoundsChange(Rect bounds) {} 619 620 /** 621 * Return the intrinsic width of the underlying drawable object. Returns 622 * -1 if it has no intrinsic width, such as with a solid color. 623 */ 624 public int getIntrinsicWidth() { 625 return -1; 626 } 627 628 /** 629 * Return the intrinsic height of the underlying drawable object. Returns 630 * -1 if it has no intrinsic height, such as with a solid color. 631 */ 632 public int getIntrinsicHeight() { 633 return -1; 634 } 635 636 /** 637 * Returns the minimum width suggested by this Drawable. If a View uses this 638 * Drawable as a background, it is suggested that the View use at least this 639 * value for its width. (There will be some scenarios where this will not be 640 * possible.) This value should INCLUDE any padding. 641 * 642 * @return The minimum width suggested by this Drawable. If this Drawable 643 * doesn't have a suggested minimum width, 0 is returned. 644 */ 645 public int getMinimumWidth() { 646 final int intrinsicWidth = getIntrinsicWidth(); 647 return intrinsicWidth > 0 ? intrinsicWidth : 0; 648 } 649 650 /** 651 * Returns the minimum height suggested by this Drawable. If a View uses this 652 * Drawable as a background, it is suggested that the View use at least this 653 * value for its height. (There will be some scenarios where this will not be 654 * possible.) This value should INCLUDE any padding. 655 * 656 * @return The minimum height suggested by this Drawable. If this Drawable 657 * doesn't have a suggested minimum height, 0 is returned. 658 */ 659 public int getMinimumHeight() { 660 final int intrinsicHeight = getIntrinsicHeight(); 661 return intrinsicHeight > 0 ? intrinsicHeight : 0; 662 } 663 664 /** 665 * Return in padding the insets suggested by this Drawable for placing 666 * content inside the drawable's bounds. Positive values move toward the 667 * center of the Drawable (set Rect.inset). Returns true if this drawable 668 * actually has a padding, else false. When false is returned, the padding 669 * is always set to 0. 670 */ 671 public boolean getPadding(Rect padding) { 672 padding.set(0, 0, 0, 0); 673 return false; 674 } 675 676 /** 677 * Make this drawable mutable. This operation cannot be reversed. A mutable 678 * drawable is guaranteed to not share its state with any other drawable. 679 * This is especially useful when you need to modify properties of drawables 680 * loaded from resources. By default, all drawables instances loaded from 681 * the same resource share a common state; if you modify the state of one 682 * instance, all the other instances will receive the same modification. 683 * 684 * Calling this method on a mutable Drawable will have no effect. 685 * 686 * @return This drawable. 687 * @see ConstantState 688 * @see #getConstantState() 689 */ 690 public Drawable mutate() { 691 return this; 692 } 693 694 /** 695 * Create a drawable from an inputstream 696 */ 697 public static Drawable createFromStream(InputStream is, String srcName) { 698 return createFromResourceStream(null, null, is, srcName, null); 699 } 700 701 /** 702 * Create a drawable from an inputstream, using the given resources and 703 * value to determine density information. 704 */ 705 public static Drawable createFromResourceStream(Resources res, TypedValue value, 706 InputStream is, String srcName) { 707 return createFromResourceStream(res, value, is, srcName, null); 708 } 709 710 /** 711 * Create a drawable from an inputstream, using the given resources and 712 * value to determine density information. 713 */ 714 public static Drawable createFromResourceStream(Resources res, TypedValue value, 715 InputStream is, String srcName, BitmapFactory.Options opts) { 716 717 if (is == null) { 718 return null; 719 } 720 721 /* ugh. The decodeStream contract is that we have already allocated 722 the pad rect, but if the bitmap does not had a ninepatch chunk, 723 then the pad will be ignored. If we could change this to lazily 724 alloc/assign the rect, we could avoid the GC churn of making new 725 Rects only to drop them on the floor. 726 */ 727 Rect pad = new Rect(); 728 729 // Special stuff for compatibility mode: if the target density is not 730 // the same as the display density, but the resource -is- the same as 731 // the display density, then don't scale it down to the target density. 732 // This allows us to load the system's density-correct resources into 733 // an application in compatibility mode, without scaling those down 734 // to the compatibility density only to have them scaled back up when 735 // drawn to the screen. 736 if (opts == null) opts = new BitmapFactory.Options(); 737 opts.inScreenDensity = DisplayMetrics.DENSITY_DEVICE; 738 Bitmap bm = BitmapFactory.decodeResourceStream(res, value, is, pad, opts); 739 if (bm != null) { 740 byte[] np = bm.getNinePatchChunk(); 741 if (np == null || !NinePatch.isNinePatchChunk(np)) { 742 np = null; 743 pad = null; 744 } 745 return drawableFromBitmap(res, bm, np, pad, srcName); 746 } 747 return null; 748 } 749 750 /** 751 * Create a drawable from an XML document. For more information on how to 752 * create resources in XML, see 753 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. 754 */ 755 public static Drawable createFromXml(Resources r, XmlPullParser parser) 756 throws XmlPullParserException, IOException { 757 AttributeSet attrs = Xml.asAttributeSet(parser); 758 759 int type; 760 while ((type=parser.next()) != XmlPullParser.START_TAG && 761 type != XmlPullParser.END_DOCUMENT) { 762 // Empty loop 763 } 764 765 if (type != XmlPullParser.START_TAG) { 766 throw new XmlPullParserException("No start tag found"); 767 } 768 769 Drawable drawable = createFromXmlInner(r, parser, attrs); 770 771 if (drawable == null) { 772 throw new RuntimeException("Unknown initial tag: " + parser.getName()); 773 } 774 775 return drawable; 776 } 777 778 /** 779 * Create from inside an XML document. Called on a parser positioned at 780 * a tag in an XML document, tries to create a Drawable from that tag. 781 * Returns null if the tag is not a valid drawable. 782 */ 783 public static Drawable createFromXmlInner(Resources r, XmlPullParser parser, AttributeSet attrs) 784 throws XmlPullParserException, IOException { 785 Drawable drawable; 786 787 final String name = parser.getName(); 788 789 if (name.equals("selector")) { 790 drawable = new StateListDrawable(); 791 } else if (name.equals("level-list")) { 792 drawable = new LevelListDrawable(); 793 /* Probably not doing this. 794 } else if (name.equals("mipmap")) { 795 drawable = new MipmapDrawable(); 796 */ 797 } else if (name.equals("layer-list")) { 798 drawable = new LayerDrawable(); 799 } else if (name.equals("transition")) { 800 drawable = new TransitionDrawable(); 801 } else if (name.equals("color")) { 802 drawable = new ColorDrawable(); 803 } else if (name.equals("shape")) { 804 drawable = new GradientDrawable(); 805 } else if (name.equals("scale")) { 806 drawable = new ScaleDrawable(); 807 } else if (name.equals("clip")) { 808 drawable = new ClipDrawable(); 809 } else if (name.equals("rotate")) { 810 drawable = new RotateDrawable(); 811 } else if (name.equals("animated-rotate")) { 812 drawable = new AnimatedRotateDrawable(); 813 } else if (name.equals("animation-list")) { 814 drawable = new AnimationDrawable(); 815 } else if (name.equals("inset")) { 816 drawable = new InsetDrawable(); 817 } else if (name.equals("bitmap")) { 818 drawable = new BitmapDrawable(r); 819 if (r != null) { 820 ((BitmapDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 821 } 822 } else if (name.equals("nine-patch")) { 823 drawable = new NinePatchDrawable(); 824 if (r != null) { 825 ((NinePatchDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 826 } 827 } else { 828 throw new XmlPullParserException(parser.getPositionDescription() + 829 ": invalid drawable tag " + name); 830 } 831 832 drawable.inflate(r, parser, attrs); 833 return drawable; 834 } 835 836 837 /** 838 * Create a drawable from file path name. 839 */ 840 public static Drawable createFromPath(String pathName) { 841 if (pathName == null) { 842 return null; 843 } 844 845 Bitmap bm = BitmapFactory.decodeFile(pathName); 846 if (bm != null) { 847 return drawableFromBitmap(null, bm, null, null, pathName); 848 } 849 850 return null; 851 } 852 853 /** 854 * Inflate this Drawable from an XML resource. 855 */ 856 public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs) 857 throws XmlPullParserException, IOException { 858 859 TypedArray a = r.obtainAttributes(attrs, com.android.internal.R.styleable.Drawable); 860 inflateWithAttributes(r, parser, a, com.android.internal.R.styleable.Drawable_visible); 861 a.recycle(); 862 } 863 864 /** 865 * Inflate a Drawable from an XML resource. 866 * 867 * @throws XmlPullParserException 868 * @throws IOException 869 */ 870 void inflateWithAttributes(Resources r, XmlPullParser parser, 871 TypedArray attrs, int visibleAttr) 872 throws XmlPullParserException, IOException { 873 874 mVisible = attrs.getBoolean(visibleAttr, mVisible); 875 } 876 877 /** 878 * This abstract class is used by {@link Drawable}s to store shared constant state and data 879 * between Drawables. {@link BitmapDrawable}s created from the same resource will for instance 880 * share a unique bitmap stored in their ConstantState. 881 * 882 * <p> 883 * {@link #newDrawable(Resources)} can be used as a factory to create new Drawable instances 884 * from this ConstantState. 885 * </p> 886 * 887 * Use {@link Drawable#getConstantState()} to retrieve the ConstantState of a Drawable. Calling 888 * {@link Drawable#mutate()} on a Drawable should typically create a new ConstantState for that 889 * Drawable. 890 */ 891 public static abstract class ConstantState { 892 /** 893 * Create a new drawable without supplying resources the caller 894 * is running in. Note that using this means the density-dependent 895 * drawables (like bitmaps) will not be able to update their target 896 * density correctly. One should use {@link #newDrawable(Resources)} 897 * instead to provide a resource. 898 */ 899 public abstract Drawable newDrawable(); 900 /** 901 * Create a new Drawable instance from its constant state. This 902 * must be implemented for drawables that change based on the target 903 * density of their caller (that is depending on whether it is 904 * in compatibility mode). 905 */ 906 public Drawable newDrawable(Resources res) { 907 return newDrawable(); 908 } 909 /** 910 * Return a bit mask of configuration changes that will impact 911 * this drawable (and thus require completely reloading it). 912 */ 913 public abstract int getChangingConfigurations(); 914 } 915 916 /** 917 * Return a {@link ConstantState} instance that holds the shared state of this Drawable. 918 *q 919 * @return The ConstantState associated to that Drawable. 920 * @see ConstantState 921 * @see Drawable#mutate() 922 */ 923 public ConstantState getConstantState() { 924 return null; 925 } 926 927 private static Drawable drawableFromBitmap(Resources res, Bitmap bm, byte[] np, 928 Rect pad, String srcName) { 929 930 if (np != null) { 931 return new NinePatchDrawable(res, bm, np, pad, srcName); 932 } 933 934 return new BitmapDrawable(res, bm); 935 } 936} 937 938