Drawable.java revision 9066cfe9886ac131c34d59ed0e2d287b0e3c0087
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 java.io.InputStream; 20import java.io.IOException; 21import java.util.Arrays; 22 23import org.xmlpull.v1.XmlPullParser; 24import org.xmlpull.v1.XmlPullParserException; 25 26import android.content.res.Resources; 27import android.content.res.TypedArray; 28import android.graphics.*; 29import android.util.AttributeSet; 30import android.util.StateSet; 31import android.util.Xml; 32import android.util.TypedValue; 33 34/** 35 * A Drawable is a general abstraction for "something that can be drawn." Most 36 * often you will deal with Drawable as the type of resource retrieved for 37 * drawing things to the screen; the Drawable class provides a generic API for 38 * dealing with an underlying visual resource that may take a variety of forms. 39 * Unlike a {@link android.view.View}, a Drawable does not have any facility to 40 * receive events or otherwise interact with the user. 41 * 42 * <p>In addition to simple drawing, Drawable provides a number of generic 43 * mechanisms for its client to interact with what is being drawn: 44 * 45 * <ul> 46 * <li> The {@link #setBounds} method <var>must</var> be called to tell the 47 * Drawable where it is drawn and how large it should be. All Drawables 48 * should respect the requested size, often simply by scaling their 49 * imagery. A client can find the preferred size for some Drawables with 50 * the {@link #getIntrinsicHeight} and {@link #getIntrinsicWidth} methods. 51 * 52 * <li> The {@link #getPadding} method can return from some Drawables 53 * information about how to frame content that is placed inside of them. 54 * For example, a Drawable that is intended to be the frame for a button 55 * widget would need to return padding that correctly places the label 56 * inside of itself. 57 * 58 * <li> The {@link #setState} method allows the client to tell the Drawable 59 * in which state it is to be drawn, such as "focused", "selected", etc. 60 * Some drawables may modify their imagery based on the selected state. 61 * 62 * <li> The {@link #setLevel} method allows the client to supply a single 63 * continuous controller that can modify the Drawable is displayed, such as 64 * a battery level or progress level. Some drawables may modify their 65 * imagery based on the current level. 66 * 67 * <li> A Drawable can perform animations by calling back to its client 68 * through the {@link Callback} interface. All clients should support this 69 * interface (via {@link #setCallback}) so that animations will work. A 70 * simple way to do this is through the system facilities such as 71 * {@link android.view.View#setBackgroundDrawable(Drawable)} and 72 * {@link android.widget.ImageView}. 73 * </ul> 74 * 75 * Though usually not visible to the application, Drawables may take a variety 76 * of forms: 77 * 78 * <ul> 79 * <li> <b>Bitmap</b>: the simplest Drawable, a PNG or JPEG image. 80 * <li> <b>Nine Patch</b>: an extension to the PNG format allows it to 81 * specify information about how to stretch it and place things inside of 82 * it. 83 * <li> <b>Shape</b>: contains simple drawing commands instead of a raw 84 * bitmap, allowing it to resize better in some cases. 85 * <li> <b>Layers</b>: a compound drawable, which draws multiple underlying 86 * drawables on top of each other. 87 * <li> <b>States</b>: a compound drawable that selects one of a set of 88 * drawables based on its state. 89 * <li> <b>Levels</b>: a compound drawable that selects one of a set of 90 * drawables based on its level. 91 * <li> <b>Scale</b>: a compound drawable with a single child drawable, 92 * whose overall size is modified based on the current level. 93 * </ul> 94 * <p>For information and examples of creating drawable resources (XML or bitmap files that 95 * can be loaded in code), see <a href="{@docRoot}guide/topics/resources/resources-i18n.html">Resources 96 * and Internationalization</a>. 97 */ 98public abstract class Drawable { 99 100 private int[] mStateSet = StateSet.WILD_CARD; 101 private int mLevel = 0; 102 private int mChangingConfigurations = 0; 103 private Rect mBounds = new Rect(); 104 /*package*/ Callback mCallback = null; 105 private boolean mVisible = true; 106 107 /** 108 * Draw in its bounds (set via setBounds) respecting optional effects such 109 * as alpha (set via setAlpha) and color filter (set via setColorFilter). 110 * 111 * @param canvas The canvas to draw into 112 */ 113 public abstract void draw(Canvas canvas); 114 115 /** 116 * Specify a bounding rectangle for the Drawable. This is where the drawable 117 * will draw when its draw() method is called. 118 */ 119 public void setBounds(int left, int top, int right, int bottom) { 120 Rect oldBounds = mBounds; 121 122 if (oldBounds.left != left || oldBounds.top != top || 123 oldBounds.right != right || oldBounds.bottom != bottom) { 124 mBounds.set(left, top, right, bottom); 125 onBoundsChange(mBounds); 126 } 127 } 128 129 /** 130 * Specify a bounding rectangle for the Drawable. This is where the drawable 131 * will draw when its draw() method is called. 132 */ 133 public void setBounds(Rect bounds) { 134 setBounds(bounds.left, bounds.top, bounds.right, bounds.bottom); 135 } 136 137 /** 138 * Return a copy of the drawable's bounds in the specified Rect (allocated 139 * by the caller). The bounds specify where this will draw when its draw() 140 * method is called. 141 * 142 * @param bounds Rect to receive the drawable's bounds (allocated by the 143 * caller). 144 */ 145 public final void copyBounds(Rect bounds) { 146 bounds.set(mBounds); 147 } 148 149 /** 150 * Return a copy of the drawable's bounds in a new Rect. This returns the 151 * same values as getBounds(), but the returned object is guaranteed to not 152 * be changed later by the drawable (i.e. it retains no reference to this 153 * rect). If the caller already has a Rect allocated, call copyBounds(rect) 154 * 155 * @return A copy of the drawable's bounds 156 */ 157 public final Rect copyBounds() { 158 return new Rect(mBounds); 159 } 160 161 /** 162 * Return the drawable's bounds Rect. Note: for efficiency, the returned 163 * object may be the same object stored in the drawable (though this is not 164 * guaranteed), so if a persistent copy of the bounds is needed, call 165 * copyBounds(rect) instead. 166 * 167 * @return The bounds of the drawable (which may change later, so caller 168 * beware). 169 */ 170 public final Rect getBounds() { 171 return mBounds; 172 } 173 174 /** 175 * Set a mask of the configuration parameters for which this drawable 176 * may change, requiring that it be re-created. 177 * 178 * @param configs A mask of the changing configuration parameters, as 179 * defined by {@link android.content.res.Configuration}. 180 * 181 * @see android.content.res.Configuration 182 */ 183 public void setChangingConfigurations(int configs) { 184 mChangingConfigurations = configs; 185 } 186 187 /** 188 * Return a mask of the configuration parameters for which this drawable 189 * mau change, requiring that it be re-created. The default implementation 190 * returns whatever was provided through 191 * {@link #setChangingConfigurations(int)} or 0 by default. Subclasses 192 * may extend this to or in the changing configurations of any other 193 * drawables they hold. 194 * 195 * @return Returns a mask of the changing configuration parameters, as 196 * defined by {@link android.content.res.Configuration}. 197 * 198 * @see android.content.res.Configuration 199 */ 200 public int getChangingConfigurations() { 201 return mChangingConfigurations; 202 } 203 204 /** 205 * Set to true to have the drawable dither its colors when drawn to a device 206 * with fewer than 8-bits per color component. This can improve the look on 207 * those devices, but can also slow down the drawing a little. 208 */ 209 public void setDither(boolean dither) {} 210 211 /** 212 * Set to true to have the drawable filter its bitmap when scaled or rotated 213 * (for drawables that use bitmaps). If the drawable does not use bitmaps, 214 * this call is ignored. This can improve the look when scaled or rotated, 215 * but also slows down the drawing. 216 */ 217 public void setFilterBitmap(boolean filter) {} 218 219 /** 220 * Implement this interface if you want to create an animated drawable that 221 * extends {@link android.graphics.drawable.Drawable Drawable}. 222 * Upon retrieving a drawable, use 223 * {@link Drawable#setCallback(android.graphics.drawable.Drawable.Callback)} 224 * to supply your implementation of the interface to the drawable; it uses 225 * this interface to schedule and execute animation changes. 226 */ 227 public static interface Callback { 228 /** 229 * Called when the drawable needs to be redrawn. A view at this point 230 * should invalidate itself (or at least the part of itself where the 231 * drawable appears). 232 * 233 * @param who The drawable that is requesting the update. 234 */ 235 public void invalidateDrawable(Drawable who); 236 237 /** 238 * A Drawable can call this to schedule the next frame of its 239 * animation. An implementation can generally simply call 240 * {@link android.os.Handler#postAtTime(Runnable, Object, long)} with 241 * the parameters <var>(what, who, when)</var> to perform the 242 * scheduling. 243 * 244 * @param who The drawable being scheduled. 245 * @param what The action to execute. 246 * @param when The time (in milliseconds) to run. The timebase is 247 * {@link android.os.SystemClock#uptimeMillis} 248 */ 249 public void scheduleDrawable(Drawable who, Runnable what, long when); 250 251 /** 252 * A Drawable can call this to unschedule an action previously 253 * scheduled with {@link #scheduleDrawable}. An implementation can 254 * generally simply call 255 * {@link android.os.Handler#removeCallbacks(Runnable, Object)} with 256 * the parameters <var>(what, who)</var> to unschedule the drawable. 257 * 258 * @param who The drawable being unscheduled. 259 * @param what The action being unscheduled. 260 */ 261 public void unscheduleDrawable(Drawable who, Runnable what); 262 } 263 264 /** 265 * Bind a {@link Callback} object to this Drawable. Required for clients 266 * that want to support animated drawables. 267 * 268 * @param cb The client's Callback implementation. 269 */ 270 public final void setCallback(Callback cb) { 271 mCallback = cb; 272 } 273 274 /** 275 * Use the current {@link Callback} implementation to have this Drawable 276 * redrawn. Does nothing if there is no Callback attached to the 277 * Drawable. 278 * 279 * @see Callback#invalidateDrawable 280 */ 281 public void invalidateSelf() 282 { 283 if (mCallback != null) { 284 mCallback.invalidateDrawable(this); 285 } 286 } 287 288 /** 289 * Use the current {@link Callback} implementation to have this Drawable 290 * scheduled. Does nothing if there is no Callback attached to the 291 * Drawable. 292 * 293 * @param what The action being scheduled. 294 * @param when The time (in milliseconds) to run. 295 * 296 * @see Callback#scheduleDrawable 297 */ 298 public void scheduleSelf(Runnable what, long when) 299 { 300 if (mCallback != null) { 301 mCallback.scheduleDrawable(this, what, when); 302 } 303 } 304 305 /** 306 * Use the current {@link Callback} implementation to have this Drawable 307 * unscheduled. Does nothing if there is no Callback attached to the 308 * Drawable. 309 * 310 * @param what The runnable that you no longer want called. 311 * 312 * @see Callback#unscheduleDrawable 313 */ 314 public void unscheduleSelf(Runnable what) 315 { 316 if (mCallback != null) { 317 mCallback.unscheduleDrawable(this, what); 318 } 319 } 320 321 /** 322 * Specify an alpha value for the drawable. 0 means fully transparent, and 323 * 255 means fully opaque. 324 */ 325 public abstract void setAlpha(int alpha); 326 327 /** 328 * Specify an optional colorFilter for the drawable. Pass null to remove 329 * any filters. 330 */ 331 public abstract void setColorFilter(ColorFilter cf); 332 333 /** 334 * Specify a color and porterduff mode to be the colorfilter for this 335 * drawable. 336 */ 337 public void setColorFilter(int color, PorterDuff.Mode mode) { 338 setColorFilter(new PorterDuffColorFilter(color, mode)); 339 } 340 341 public void clearColorFilter() { 342 setColorFilter(null); 343 } 344 345 /** 346 * Indicates whether this view will change its appearance based on state. 347 * Clients can use this to determine whether it is necessary to calculate 348 * their state and call setState. 349 * 350 * @return True if this view changes its appearance based on state, false 351 * otherwise. 352 * 353 * @see #setState(int[]) 354 */ 355 public boolean isStateful() { 356 return false; 357 } 358 359 /** 360 * Specify a set of states for the drawable. These are use-case specific, 361 * so see the relevant documentation. As an example, the background for 362 * widgets like Button understand the following states: 363 * [{@link android.R.attr#state_focused}, 364 * {@link android.R.attr#state_pressed}]. 365 * 366 * <p>If the new state you are supplying causes the appearance of the 367 * Drawable to change, then it is responsible for calling 368 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 369 * true will be returned from this function. 370 * 371 * <p>Note: The Drawable holds a reference on to <var>stateSet</var> 372 * until a new state array is given to it, so you must not modify this 373 * array during that time.</p> 374 * 375 * @param stateSet The new set of states to be displayed. 376 * 377 * @return Returns true if this change in state has caused the appearance 378 * of the Drawable to change (hence requiring an invalidate), otherwise 379 * returns false. 380 */ 381 public boolean setState(final int[] stateSet) { 382 if (!Arrays.equals(mStateSet, stateSet)) { 383 mStateSet = stateSet; 384 return onStateChange(stateSet); 385 } 386 return false; 387 } 388 389 /** 390 * Describes the current state, as a union of primitve states, such as 391 * {@link android.R.attr#state_focused}, 392 * {@link android.R.attr#state_selected}, etc. 393 * Some drawables may modify their imagery based on the selected state. 394 * @return An array of resource Ids describing the current state. 395 */ 396 public int[] getState() { 397 return mStateSet; 398 } 399 400 /** 401 * @return The current drawable that will be used by this drawable. For simple drawables, this 402 * is just the drawable itself. For drawables that change state like 403 * {@link StateListDrawable} and {@link LevelListDrawable} this will be the child drawable 404 * currently in use. 405 */ 406 public Drawable getCurrent() { 407 return this; 408 } 409 410 /** 411 * Specify the level for the drawable. This allows a drawable to vary its 412 * imagery based on a continuous controller, for example to show progress 413 * or volume level. 414 * 415 * <p>If the new level you are supplying causes the appearance of the 416 * Drawable to change, then it is responsible for calling 417 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 418 * true will be returned from this function. 419 * 420 * @param level The new level, from 0 (minimum) to 10000 (maximum). 421 * 422 * @return Returns true if this change in level has caused the appearance 423 * of the Drawable to change (hence requiring an invalidate), otherwise 424 * returns false. 425 */ 426 public final boolean setLevel(int level) { 427 if (mLevel != level) { 428 mLevel = level; 429 return onLevelChange(level); 430 } 431 return false; 432 } 433 434 /** 435 * Retrieve the current level. 436 * 437 * @return int Current level, from 0 (minimum) to 10000 (maximum). 438 */ 439 public final int getLevel() { 440 return mLevel; 441 } 442 443 /** 444 * Set whether this Drawable is visible. This generally does not impact 445 * the Drawable's behavior, but is a hint that can be used by some 446 * Drawables, for example, to decide whether run animations. 447 * 448 * @param visible Set to true if visible, false if not. 449 * @param restart You can supply true here to force the drawable to behave 450 * as if it has just become visible, even if it had last 451 * been set visible. Used for example to force animations 452 * to restart. 453 * 454 * @return boolean Returns true if the new visibility is different than 455 * its previous state. 456 */ 457 public boolean setVisible(boolean visible, boolean restart) { 458 boolean changed = mVisible != visible; 459 mVisible = visible; 460 return changed; 461 } 462 463 public final boolean isVisible() { 464 return mVisible; 465 } 466 467 /** 468 * Return the opacity/transparency of this Drawable. The returned value is 469 * one of the abstract format constants in 470 * {@link android.graphics.PixelFormat}: 471 * {@link android.graphics.PixelFormat#UNKNOWN}, 472 * {@link android.graphics.PixelFormat#TRANSLUCENT}, 473 * {@link android.graphics.PixelFormat#TRANSPARENT}, or 474 * {@link android.graphics.PixelFormat#OPAQUE}. 475 * 476 * <p>Generally a Drawable should be as conservative as possible with the 477 * value it returns. For example, if it contains multiple child drawables 478 * and only shows one of them at a time, if only one of the children is 479 * TRANSLUCENT and the others are OPAQUE then TRANSLUCENT should be 480 * returned. You can use the method {@link #resolveOpacity} to perform a 481 * standard reduction of two opacities to the appropriate single output. 482 * 483 * <p>Note that the returned value does <em>not</em> take into account a 484 * custom alpha or color filter that has been applied by the client through 485 * the {@link #setAlpha} or {@link #setColorFilter} methods. 486 * 487 * @return int The opacity class of the Drawable. 488 * 489 * @see android.graphics.PixelFormat 490 */ 491 public abstract int getOpacity(); 492 493 /** 494 * Return the appropriate opacity value for two source opacities. If 495 * either is UNKNOWN, that is returned; else, if either is TRANSLUCENT, 496 * that is returned; else, if either is TRANSPARENT, that is returned; 497 * else, OPAQUE is returned. 498 * 499 * <p>This is to help in implementing {@link #getOpacity}. 500 * 501 * @param op1 One opacity value. 502 * @param op2 Another opacity value. 503 * 504 * @return int The combined opacity value. 505 * 506 * @see #getOpacity 507 */ 508 public static int resolveOpacity(int op1, int op2) { 509 if (op1 == op2) { 510 return op1; 511 } 512 if (op1 == PixelFormat.UNKNOWN || op2 == PixelFormat.UNKNOWN) { 513 return PixelFormat.UNKNOWN; 514 } 515 if (op1 == PixelFormat.TRANSLUCENT || op2 == PixelFormat.TRANSLUCENT) { 516 return PixelFormat.TRANSLUCENT; 517 } 518 if (op1 == PixelFormat.TRANSPARENT || op2 == PixelFormat.TRANSPARENT) { 519 return PixelFormat.TRANSPARENT; 520 } 521 return PixelFormat.OPAQUE; 522 } 523 524 /** 525 * Returns a Region representing the part of the Drawable that is completely 526 * transparent. This can be used to perform drawing operations, identifying 527 * which parts of the target will not change when rendering the Drawable. 528 * The default implementation returns null, indicating no transparent 529 * region; subclasses can optionally override this to return an actual 530 * Region if they want to supply this optimization information, but it is 531 * not required that they do so. 532 * 533 * @return Returns null if the Drawables has no transparent region to 534 * report, else a Region holding the parts of the Drawable's bounds that 535 * are transparent. 536 */ 537 public Region getTransparentRegion() { 538 return null; 539 } 540 541 /** 542 * Override this in your subclass to change appearance if you recognize the 543 * specified state. 544 * 545 * @return Returns true if the state change has caused the appearance of 546 * the Drawable to change (that is, it needs to be drawn), else false 547 * if it looks the same and there is no need to redraw it since its 548 * last state. 549 */ 550 protected boolean onStateChange(int[] state) { return false; } 551 /** Override this in your subclass to change appearance if you vary based 552 * on level. 553 * @return Returns true if the level change has caused the appearance of 554 * the Drawable to change (that is, it needs to be drawn), else false 555 * if it looks the same and there is no need to redraw it since its 556 * last level. 557 */ 558 protected boolean onLevelChange(int level) { return false; } 559 /** 560 * Override this in your subclass to change appearance if you recognize the 561 * specified state. 562 */ 563 protected void onBoundsChange(Rect bounds) {} 564 565 /** 566 * Return the intrinsic width of the underlying drawable object. Returns 567 * -1 if it has no intrinsic width, such as with a solid color. 568 */ 569 public int getIntrinsicWidth() { 570 return -1; 571 } 572 573 /** 574 * Return the intrinsic height of the underlying drawable object. Returns 575 * -1 if it has no intrinsic height, such as with a solid color. 576 */ 577 public int getIntrinsicHeight() { 578 return -1; 579 } 580 581 /** 582 * Returns the minimum width suggested by this Drawable. If a View uses this 583 * Drawable as a background, it is suggested that the View use at least this 584 * value for its width. (There will be some scenarios where this will not be 585 * possible.) This value should INCLUDE any padding. 586 * 587 * @return The minimum width suggested by this Drawable. If this Drawable 588 * doesn't have a suggested minimum width, 0 is returned. 589 */ 590 public int getMinimumWidth() { 591 final int intrinsicWidth = getIntrinsicWidth(); 592 return intrinsicWidth > 0 ? intrinsicWidth : 0; 593 } 594 595 /** 596 * Returns the minimum height suggested by this Drawable. If a View uses this 597 * Drawable as a background, it is suggested that the View use at least this 598 * value for its height. (There will be some scenarios where this will not be 599 * possible.) This value should INCLUDE any padding. 600 * 601 * @return The minimum height suggested by this Drawable. If this Drawable 602 * doesn't have a suggested minimum height, 0 is returned. 603 */ 604 public int getMinimumHeight() { 605 final int intrinsicHeight = getIntrinsicHeight(); 606 return intrinsicHeight > 0 ? intrinsicHeight : 0; 607 } 608 609 /** 610 * Return in padding the insets suggested by this Drawable for placing 611 * content inside the drawable's bounds. Positive values move toward the 612 * center of the Drawable (set Rect.inset). Returns true if this drawable 613 * actually has a padding, else false. When false is returned, the padding 614 * is always set to 0. 615 */ 616 public boolean getPadding(Rect padding) { 617 padding.set(0, 0, 0, 0); 618 return false; 619 } 620 621 /** 622 * Make this drawable mutable. This operation cannot be reversed. A mutable 623 * drawable is guaranteed to not share its state with any other drawable. 624 * This is especially useful when you need to modify properties of drawables 625 * loaded from resources. By default, all drawables instances loaded from 626 * the same resource share a common state; if you modify the state of one 627 * instance, all the other instances will receive the same modification. 628 * 629 * Calling this method on a mutable Drawable will have no effect. 630 * 631 * @return This drawable. 632 */ 633 public Drawable mutate() { 634 return this; 635 } 636 637 /** 638 * Create a drawable from an inputstream 639 */ 640 public static Drawable createFromStream(InputStream is, String srcName) { 641 return createFromResourceStream(null, null, is, srcName); 642 } 643 644 /** 645 * Create a drawable from an inputstream 646 * 647 * @hide pending API council approval 648 */ 649 public static Drawable createFromResourceStream(Resources res, TypedValue value, 650 InputStream is, String srcName) { 651 652 if (is == null) { 653 return null; 654 } 655 656 /* ugh. The decodeStream contract is that we have already allocated 657 the pad rect, but if the bitmap does not had a ninepatch chunk, 658 then the pad will be ignored. If we could change this to lazily 659 alloc/assign the rect, we could avoid the GC churn of making new 660 Rects only to drop them on the floor. 661 */ 662 Rect pad = new Rect(); 663 Bitmap bm = BitmapFactory.decodeStream(res, value, is, pad, null); 664 if (bm != null) { 665 byte[] np = bm.getNinePatchChunk(); 666 if (np == null || !NinePatch.isNinePatchChunk(np)) { 667 np = null; 668 pad = null; 669 } 670 return drawableFromBitmap(res, bm, np, pad, srcName); 671 } 672 return null; 673 } 674 675 /** 676 * Create a drawable from an XML document. For more information on how to 677 * create resources in XML, see 678 * <a href="{@docRoot}guide/topics/resources/resources-i18n.html">Resources and 679 * Internationalization</a>. 680 */ 681 public static Drawable createFromXml(Resources r, XmlPullParser parser) 682 throws XmlPullParserException, IOException { 683 AttributeSet attrs = Xml.asAttributeSet(parser); 684 685 int type; 686 while ((type=parser.next()) != XmlPullParser.START_TAG && 687 type != XmlPullParser.END_DOCUMENT) { 688 // Empty loop 689 } 690 691 if (type != XmlPullParser.START_TAG) { 692 throw new XmlPullParserException("No start tag found"); 693 } 694 695 Drawable drawable = createFromXmlInner(r, parser, attrs); 696 697 if (drawable == null) { 698 throw new RuntimeException("Unknown initial tag: " + parser.getName()); 699 } 700 701 return drawable; 702 } 703 704 /** 705 * Create from inside an XML document. Called on a parser positioned at 706 * a tag in an XML document, tries to create a Drawable from that tag. 707 * Returns null if the tag is not a valid drawable. 708 */ 709 public static Drawable createFromXmlInner(Resources r, XmlPullParser parser, AttributeSet attrs) 710 throws XmlPullParserException, IOException { 711 Drawable drawable; 712 713 final String name = parser.getName(); 714 715 if (name.equals("selector")) { 716 drawable = new StateListDrawable(); 717 } else if (name.equals("level-list")) { 718 drawable = new LevelListDrawable(); 719 } else if (name.equals("layer-list")) { 720 drawable = new LayerDrawable(); 721 } else if (name.equals("transition")) { 722 drawable = new TransitionDrawable(); 723 } else if (name.equals("color")) { 724 drawable = new ColorDrawable(); 725 } else if (name.equals("shape")) { 726 drawable = new GradientDrawable(); 727 } else if (name.equals("scale")) { 728 drawable = new ScaleDrawable(); 729 } else if (name.equals("clip")) { 730 drawable = new ClipDrawable(); 731 } else if (name.equals("rotate")) { 732 drawable = new RotateDrawable(); 733 } else if (name.equals("animation-list")) { 734 drawable = new AnimationDrawable(); 735 } else if (name.equals("inset")) { 736 drawable = new InsetDrawable(); 737 } else if (name.equals("bitmap")) { 738 drawable = new BitmapDrawable(); 739 if (r != null) { 740 ((BitmapDrawable) drawable).setDensityScale(r.getDisplayMetrics()); 741 } 742 } else if (name.equals("nine-patch")) { 743 drawable = new NinePatchDrawable(); 744 } else { 745 throw new XmlPullParserException(parser.getPositionDescription() + 746 ": invalid drawable tag " + name); 747 } 748 749 drawable.inflate(r, parser, attrs); 750 return drawable; 751 } 752 753 754 /** 755 * Create a drawable from file path name. 756 */ 757 public static Drawable createFromPath(String pathName) { 758 if (pathName == null) { 759 return null; 760 } 761 762 Bitmap bm = BitmapFactory.decodeFile(pathName); 763 if (bm != null) { 764 return drawableFromBitmap(null, bm, null, null, pathName); 765 } 766 767 return null; 768 } 769 770 public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs) 771 throws XmlPullParserException, IOException { 772 773 TypedArray a = r.obtainAttributes(attrs, com.android.internal.R.styleable.Drawable); 774 inflateWithAttributes(r, parser, a, com.android.internal.R.styleable.Drawable_visible); 775 a.recycle(); 776 } 777 778 void inflateWithAttributes(Resources r, XmlPullParser parser, 779 TypedArray attrs, int visibleAttr) 780 throws XmlPullParserException, IOException { 781 782 mVisible = attrs.getBoolean(visibleAttr, mVisible); 783 } 784 785 public static abstract class ConstantState { 786 public abstract Drawable newDrawable(); 787 public abstract int getChangingConfigurations(); 788 } 789 790 public ConstantState getConstantState() { 791 return null; 792 } 793 794 private static Drawable drawableFromBitmap(Resources res, Bitmap bm, byte[] np, 795 Rect pad, String srcName) { 796 797 if (np != null) { 798 return new NinePatchDrawable(bm, np, pad, srcName); 799 } 800 801 final BitmapDrawable drawable = new BitmapDrawable(bm); 802 if (res != null) { 803 drawable.setDensityScale(res.getDisplayMetrics()); 804 } 805 806 return drawable; 807 } 808} 809 810