Drawable.java revision 633326e29f008d2b86e523cfeedcbb2a0883181f
1/* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package android.graphics.drawable; 18 19import android.graphics.Insets; 20import org.xmlpull.v1.XmlPullParser; 21import org.xmlpull.v1.XmlPullParserException; 22 23import android.content.res.Resources; 24import android.content.res.TypedArray; 25import android.graphics.Bitmap; 26import android.graphics.BitmapFactory; 27import android.graphics.Canvas; 28import android.graphics.ColorFilter; 29import android.graphics.NinePatch; 30import android.graphics.PixelFormat; 31import android.graphics.PorterDuff; 32import android.graphics.PorterDuffColorFilter; 33import android.graphics.Rect; 34import android.graphics.Region; 35import android.util.AttributeSet; 36import android.util.DisplayMetrics; 37import android.util.StateSet; 38import android.util.TypedValue; 39import android.util.Xml; 40 41import java.io.IOException; 42import java.io.InputStream; 43import java.lang.ref.WeakReference; 44import java.util.Arrays; 45 46/** 47 * A Drawable is a general abstraction for "something that can be drawn." Most 48 * often you will deal with Drawable as the type of resource retrieved for 49 * drawing things to the screen; the Drawable class provides a generic API for 50 * dealing with an underlying visual resource that may take a variety of forms. 51 * Unlike a {@link android.view.View}, a Drawable does not have any facility to 52 * receive events or otherwise interact with the user. 53 * 54 * <p>In addition to simple drawing, Drawable provides a number of generic 55 * mechanisms for its client to interact with what is being drawn: 56 * 57 * <ul> 58 * <li> The {@link #setBounds} method <var>must</var> be called to tell the 59 * Drawable where it is drawn and how large it should be. All Drawables 60 * should respect the requested size, often simply by scaling their 61 * imagery. A client can find the preferred size for some Drawables with 62 * the {@link #getIntrinsicHeight} and {@link #getIntrinsicWidth} methods. 63 * 64 * <li> The {@link #getPadding} method can return from some Drawables 65 * information about how to frame content that is placed inside of them. 66 * For example, a Drawable that is intended to be the frame for a button 67 * widget would need to return padding that correctly places the label 68 * inside of itself. 69 * 70 * <li> The {@link #setState} method allows the client to tell the Drawable 71 * in which state it is to be drawn, such as "focused", "selected", etc. 72 * Some drawables may modify their imagery based on the selected state. 73 * 74 * <li> The {@link #setLevel} method allows the client to supply a single 75 * continuous controller that can modify the Drawable is displayed, such as 76 * a battery level or progress level. Some drawables may modify their 77 * imagery based on the current level. 78 * 79 * <li> A Drawable can perform animations by calling back to its client 80 * through the {@link Callback} interface. All clients should support this 81 * interface (via {@link #setCallback}) so that animations will work. A 82 * simple way to do this is through the system facilities such as 83 * {@link android.view.View#setBackgroundDrawable(Drawable)} and 84 * {@link android.widget.ImageView}. 85 * </ul> 86 * 87 * Though usually not visible to the application, Drawables may take a variety 88 * of forms: 89 * 90 * <ul> 91 * <li> <b>Bitmap</b>: the simplest Drawable, a PNG or JPEG image. 92 * <li> <b>Nine Patch</b>: an extension to the PNG format allows it to 93 * specify information about how to stretch it and place things inside of 94 * it. 95 * <li> <b>Shape</b>: contains simple drawing commands instead of a raw 96 * bitmap, allowing it to resize better in some cases. 97 * <li> <b>Layers</b>: a compound drawable, which draws multiple underlying 98 * drawables on top of each other. 99 * <li> <b>States</b>: a compound drawable that selects one of a set of 100 * drawables based on its state. 101 * <li> <b>Levels</b>: a compound drawable that selects one of a set of 102 * drawables based on its level. 103 * <li> <b>Scale</b>: a compound drawable with a single child drawable, 104 * whose overall size is modified based on the current level. 105 * </ul> 106 * 107 * <div class="special reference"> 108 * <h3>Developer Guides</h3> 109 * <p>For more information about how to use drawables, read the 110 * <a href="{@docRoot}guide/topics/graphics/2d-graphics.html">Canvas and Drawables</a> developer 111 * guide. For information and examples of creating drawable resources (XML or bitmap files that 112 * can be loaded in code), read the 113 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a> 114 * document.</p></div> 115 */ 116public abstract class Drawable { 117 private static final Rect ZERO_BOUNDS_RECT = new Rect(); 118 119 private int[] mStateSet = StateSet.WILD_CARD; 120 private int mLevel = 0; 121 private int mChangingConfigurations = 0; 122 private Rect mBounds = ZERO_BOUNDS_RECT; // lazily becomes a new Rect() 123 private WeakReference<Callback> mCallback = null; 124 private boolean mVisible = true; 125 126 private int mLayoutDirection; 127 128 /** 129 * Draw in its bounds (set via setBounds) respecting optional effects such 130 * as alpha (set via setAlpha) and color filter (set via setColorFilter). 131 * 132 * @param canvas The canvas to draw into 133 */ 134 public abstract void draw(Canvas canvas); 135 136 /** 137 * Specify a bounding rectangle for the Drawable. This is where the drawable 138 * will draw when its draw() method is called. 139 */ 140 public void setBounds(int left, int top, int right, int bottom) { 141 Rect oldBounds = mBounds; 142 143 if (oldBounds == ZERO_BOUNDS_RECT) { 144 oldBounds = mBounds = new Rect(); 145 } 146 147 if (oldBounds.left != left || oldBounds.top != top || 148 oldBounds.right != right || oldBounds.bottom != bottom) { 149 if (!oldBounds.isEmpty()) { 150 // first invalidate the previous bounds 151 invalidateSelf(); 152 } 153 mBounds.set(left, top, right, bottom); 154 onBoundsChange(mBounds); 155 } 156 } 157 158 /** 159 * Specify a bounding rectangle for the Drawable. This is where the drawable 160 * will draw when its draw() method is called. 161 */ 162 public void setBounds(Rect bounds) { 163 setBounds(bounds.left, bounds.top, bounds.right, bounds.bottom); 164 } 165 166 /** 167 * Return a copy of the drawable's bounds in the specified Rect (allocated 168 * by the caller). The bounds specify where this will draw when its draw() 169 * method is called. 170 * 171 * @param bounds Rect to receive the drawable's bounds (allocated by the 172 * caller). 173 */ 174 public final void copyBounds(Rect bounds) { 175 bounds.set(mBounds); 176 } 177 178 /** 179 * Return a copy of the drawable's bounds in a new Rect. This returns the 180 * same values as getBounds(), but the returned object is guaranteed to not 181 * be changed later by the drawable (i.e. it retains no reference to this 182 * rect). If the caller already has a Rect allocated, call copyBounds(rect). 183 * 184 * @return A copy of the drawable's bounds 185 */ 186 public final Rect copyBounds() { 187 return new Rect(mBounds); 188 } 189 190 /** 191 * Return the drawable's bounds Rect. Note: for efficiency, the returned 192 * object may be the same object stored in the drawable (though this is not 193 * guaranteed), so if a persistent copy of the bounds is needed, call 194 * copyBounds(rect) instead. 195 * You should also not change the object returned by this method as it may 196 * be the same object stored in the drawable. 197 * 198 * @return The bounds of the drawable (which may change later, so caller 199 * beware). DO NOT ALTER the returned object as it may change the 200 * stored bounds of this drawable. 201 * 202 * @see #copyBounds() 203 * @see #copyBounds(android.graphics.Rect) 204 */ 205 public final Rect getBounds() { 206 if (mBounds == ZERO_BOUNDS_RECT) { 207 mBounds = new Rect(); 208 } 209 210 return mBounds; 211 } 212 213 /** 214 * Set a mask of the configuration parameters for which this drawable 215 * may change, requiring that it be re-created. 216 * 217 * @param configs A mask of the changing configuration parameters, as 218 * defined by {@link android.content.res.Configuration}. 219 * 220 * @see android.content.res.Configuration 221 */ 222 public void setChangingConfigurations(int configs) { 223 mChangingConfigurations = configs; 224 } 225 226 /** 227 * Return a mask of the configuration parameters for which this drawable 228 * may change, requiring that it be re-created. The default implementation 229 * returns whatever was provided through 230 * {@link #setChangingConfigurations(int)} or 0 by default. Subclasses 231 * may extend this to or in the changing configurations of any other 232 * drawables they hold. 233 * 234 * @return Returns a mask of the changing configuration parameters, as 235 * defined by {@link android.content.res.Configuration}. 236 * 237 * @see android.content.res.Configuration 238 */ 239 public int getChangingConfigurations() { 240 return mChangingConfigurations; 241 } 242 243 /** 244 * Set to true to have the drawable dither its colors when drawn to a device 245 * with fewer than 8-bits per color component. This can improve the look on 246 * those devices, but can also slow down the drawing a little. 247 */ 248 public void setDither(boolean dither) {} 249 250 /** 251 * Set to true to have the drawable filter its bitmap when scaled or rotated 252 * (for drawables that use bitmaps). If the drawable does not use bitmaps, 253 * this call is ignored. This can improve the look when scaled or rotated, 254 * but also slows down the drawing. 255 */ 256 public void setFilterBitmap(boolean filter) {} 257 258 /** 259 * Implement this interface if you want to create an animated drawable that 260 * extends {@link android.graphics.drawable.Drawable Drawable}. 261 * Upon retrieving a drawable, use 262 * {@link Drawable#setCallback(android.graphics.drawable.Drawable.Callback)} 263 * to supply your implementation of the interface to the drawable; it uses 264 * this interface to schedule and execute animation changes. 265 */ 266 public static interface Callback { 267 /** 268 * Called when the drawable needs to be redrawn. A view at this point 269 * should invalidate itself (or at least the part of itself where the 270 * drawable appears). 271 * 272 * @param who The drawable that is requesting the update. 273 */ 274 public void invalidateDrawable(Drawable who); 275 276 /** 277 * A Drawable can call this to schedule the next frame of its 278 * animation. An implementation can generally simply call 279 * {@link android.os.Handler#postAtTime(Runnable, Object, long)} with 280 * the parameters <var>(what, who, when)</var> to perform the 281 * scheduling. 282 * 283 * @param who The drawable being scheduled. 284 * @param what The action to execute. 285 * @param when The time (in milliseconds) to run. The timebase is 286 * {@link android.os.SystemClock#uptimeMillis} 287 */ 288 public void scheduleDrawable(Drawable who, Runnable what, long when); 289 290 /** 291 * A Drawable can call this to unschedule an action previously 292 * scheduled with {@link #scheduleDrawable}. An implementation can 293 * generally simply call 294 * {@link android.os.Handler#removeCallbacks(Runnable, Object)} with 295 * the parameters <var>(what, who)</var> to unschedule the drawable. 296 * 297 * @param who The drawable being unscheduled. 298 * @param what The action being unscheduled. 299 */ 300 public void unscheduleDrawable(Drawable who, Runnable what); 301 } 302 303 /** 304 * Bind a {@link Callback} object to this Drawable. Required for clients 305 * that want to support animated drawables. 306 * 307 * @param cb The client's Callback implementation. 308 * 309 * @see #getCallback() 310 */ 311 public final void setCallback(Callback cb) { 312 mCallback = new WeakReference<Callback>(cb); 313 } 314 315 /** 316 * Return the current {@link Callback} implementation attached to this 317 * Drawable. 318 * 319 * @return A {@link Callback} instance or null if no callback was set. 320 * 321 * @see #setCallback(android.graphics.drawable.Drawable.Callback) 322 */ 323 public Callback getCallback() { 324 if (mCallback != null) { 325 return mCallback.get(); 326 } 327 return null; 328 } 329 330 /** 331 * Use the current {@link Callback} implementation to have this Drawable 332 * redrawn. Does nothing if there is no Callback attached to the 333 * Drawable. 334 * 335 * @see Callback#invalidateDrawable 336 * @see #getCallback() 337 * @see #setCallback(android.graphics.drawable.Drawable.Callback) 338 */ 339 public void invalidateSelf() { 340 final Callback callback = getCallback(); 341 if (callback != null) { 342 callback.invalidateDrawable(this); 343 } 344 } 345 346 /** 347 * Use the current {@link Callback} implementation to have this Drawable 348 * scheduled. Does nothing if there is no Callback attached to the 349 * Drawable. 350 * 351 * @param what The action being scheduled. 352 * @param when The time (in milliseconds) to run. 353 * 354 * @see Callback#scheduleDrawable 355 */ 356 public void scheduleSelf(Runnable what, long when) { 357 final Callback callback = getCallback(); 358 if (callback != null) { 359 callback.scheduleDrawable(this, what, when); 360 } 361 } 362 363 /** 364 * Use the current {@link Callback} implementation to have this Drawable 365 * unscheduled. Does nothing if there is no Callback attached to the 366 * Drawable. 367 * 368 * @param what The runnable that you no longer want called. 369 * 370 * @see Callback#unscheduleDrawable 371 */ 372 public void unscheduleSelf(Runnable what) { 373 final Callback callback = getCallback(); 374 if (callback != null) { 375 callback.unscheduleDrawable(this, what); 376 } 377 } 378 379 /** 380 * Returns the resolved layout direction for this Drawable. 381 * 382 * @return One of {@link android.view.View#LAYOUT_DIRECTION_LTR}, 383 * {@link android.view.View#LAYOUT_DIRECTION_RTL} 384 * 385 * @hide 386 */ 387 public int getLayoutDirection() { 388 return mLayoutDirection; 389 } 390 391 /** 392 * Set the layout direction for this drawable. Should be a resolved direction as the 393 * Drawable as no capacity to do the resolution on his own. 394 * 395 * @param layoutDirection One of {@link android.view.View#LAYOUT_DIRECTION_LTR}, 396 * {@link android.view.View#LAYOUT_DIRECTION_RTL} 397 * 398 * @hide 399 */ 400 public void setLayoutDirection(int layoutDirection) { 401 if (getLayoutDirection() != layoutDirection) { 402 mLayoutDirection = layoutDirection; 403 } 404 } 405 406 /** 407 * Specify an alpha value for the drawable. 0 means fully transparent, and 408 * 255 means fully opaque. 409 */ 410 public abstract void setAlpha(int alpha); 411 412 /** 413 * Specify an optional colorFilter for the drawable. Pass null to remove 414 * any filters. 415 */ 416 public abstract void setColorFilter(ColorFilter cf); 417 418 /** 419 * Specify a color and porterduff mode to be the colorfilter for this 420 * drawable. 421 */ 422 public void setColorFilter(int color, PorterDuff.Mode mode) { 423 setColorFilter(new PorterDuffColorFilter(color, mode)); 424 } 425 426 public void clearColorFilter() { 427 setColorFilter(null); 428 } 429 430 /** 431 * Indicates whether this view will change its appearance based on state. 432 * Clients can use this to determine whether it is necessary to calculate 433 * their state and call setState. 434 * 435 * @return True if this view changes its appearance based on state, false 436 * otherwise. 437 * 438 * @see #setState(int[]) 439 */ 440 public boolean isStateful() { 441 return false; 442 } 443 444 /** 445 * Specify a set of states for the drawable. These are use-case specific, 446 * so see the relevant documentation. As an example, the background for 447 * widgets like Button understand the following states: 448 * [{@link android.R.attr#state_focused}, 449 * {@link android.R.attr#state_pressed}]. 450 * 451 * <p>If the new state you are supplying causes the appearance of the 452 * Drawable to change, then it is responsible for calling 453 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 454 * true will be returned from this function. 455 * 456 * <p>Note: The Drawable holds a reference on to <var>stateSet</var> 457 * until a new state array is given to it, so you must not modify this 458 * array during that time.</p> 459 * 460 * @param stateSet The new set of states to be displayed. 461 * 462 * @return Returns true if this change in state has caused the appearance 463 * of the Drawable to change (hence requiring an invalidate), otherwise 464 * returns false. 465 */ 466 public boolean setState(final int[] stateSet) { 467 if (!Arrays.equals(mStateSet, stateSet)) { 468 mStateSet = stateSet; 469 return onStateChange(stateSet); 470 } 471 return false; 472 } 473 474 /** 475 * Describes the current state, as a union of primitve states, such as 476 * {@link android.R.attr#state_focused}, 477 * {@link android.R.attr#state_selected}, etc. 478 * Some drawables may modify their imagery based on the selected state. 479 * @return An array of resource Ids describing the current state. 480 */ 481 public int[] getState() { 482 return mStateSet; 483 } 484 485 /** 486 * If this Drawable does transition animations between states, ask that 487 * it immediately jump to the current state and skip any active animations. 488 */ 489 public void jumpToCurrentState() { 490 } 491 492 /** 493 * @return The current drawable that will be used by this drawable. For simple drawables, this 494 * is just the drawable itself. For drawables that change state like 495 * {@link StateListDrawable} and {@link LevelListDrawable} this will be the child drawable 496 * currently in use. 497 */ 498 public Drawable getCurrent() { 499 return this; 500 } 501 502 /** 503 * Specify the level for the drawable. This allows a drawable to vary its 504 * imagery based on a continuous controller, for example to show progress 505 * or volume level. 506 * 507 * <p>If the new level you are supplying causes the appearance of the 508 * Drawable to change, then it is responsible for calling 509 * {@link #invalidateSelf} in order to have itself redrawn, <em>and</em> 510 * true will be returned from this function. 511 * 512 * @param level The new level, from 0 (minimum) to 10000 (maximum). 513 * 514 * @return Returns true if this change in level has caused the appearance 515 * of the Drawable to change (hence requiring an invalidate), otherwise 516 * returns false. 517 */ 518 public final boolean setLevel(int level) { 519 if (mLevel != level) { 520 mLevel = level; 521 return onLevelChange(level); 522 } 523 return false; 524 } 525 526 /** 527 * Retrieve the current level. 528 * 529 * @return int Current level, from 0 (minimum) to 10000 (maximum). 530 */ 531 public final int getLevel() { 532 return mLevel; 533 } 534 535 /** 536 * Set whether this Drawable is visible. This generally does not impact 537 * the Drawable's behavior, but is a hint that can be used by some 538 * Drawables, for example, to decide whether run animations. 539 * 540 * @param visible Set to true if visible, false if not. 541 * @param restart You can supply true here to force the drawable to behave 542 * as if it has just become visible, even if it had last 543 * been set visible. Used for example to force animations 544 * to restart. 545 * 546 * @return boolean Returns true if the new visibility is different than 547 * its previous state. 548 */ 549 public boolean setVisible(boolean visible, boolean restart) { 550 boolean changed = mVisible != visible; 551 if (changed) { 552 mVisible = visible; 553 invalidateSelf(); 554 } 555 return changed; 556 } 557 558 public final boolean isVisible() { 559 return mVisible; 560 } 561 562 /** 563 * Return the opacity/transparency of this Drawable. The returned value is 564 * one of the abstract format constants in 565 * {@link android.graphics.PixelFormat}: 566 * {@link android.graphics.PixelFormat#UNKNOWN}, 567 * {@link android.graphics.PixelFormat#TRANSLUCENT}, 568 * {@link android.graphics.PixelFormat#TRANSPARENT}, or 569 * {@link android.graphics.PixelFormat#OPAQUE}. 570 * 571 * <p>Generally a Drawable should be as conservative as possible with the 572 * value it returns. For example, if it contains multiple child drawables 573 * and only shows one of them at a time, if only one of the children is 574 * TRANSLUCENT and the others are OPAQUE then TRANSLUCENT should be 575 * returned. You can use the method {@link #resolveOpacity} to perform a 576 * standard reduction of two opacities to the appropriate single output. 577 * 578 * <p>Note that the returned value does <em>not</em> take into account a 579 * custom alpha or color filter that has been applied by the client through 580 * the {@link #setAlpha} or {@link #setColorFilter} methods. 581 * 582 * @return int The opacity class of the Drawable. 583 * 584 * @see android.graphics.PixelFormat 585 */ 586 public abstract int getOpacity(); 587 588 /** 589 * Return the appropriate opacity value for two source opacities. If 590 * either is UNKNOWN, that is returned; else, if either is TRANSLUCENT, 591 * that is returned; else, if either is TRANSPARENT, that is returned; 592 * else, OPAQUE is returned. 593 * 594 * <p>This is to help in implementing {@link #getOpacity}. 595 * 596 * @param op1 One opacity value. 597 * @param op2 Another opacity value. 598 * 599 * @return int The combined opacity value. 600 * 601 * @see #getOpacity 602 */ 603 public static int resolveOpacity(int op1, int op2) { 604 if (op1 == op2) { 605 return op1; 606 } 607 if (op1 == PixelFormat.UNKNOWN || op2 == PixelFormat.UNKNOWN) { 608 return PixelFormat.UNKNOWN; 609 } 610 if (op1 == PixelFormat.TRANSLUCENT || op2 == PixelFormat.TRANSLUCENT) { 611 return PixelFormat.TRANSLUCENT; 612 } 613 if (op1 == PixelFormat.TRANSPARENT || op2 == PixelFormat.TRANSPARENT) { 614 return PixelFormat.TRANSPARENT; 615 } 616 return PixelFormat.OPAQUE; 617 } 618 619 /** 620 * Returns a Region representing the part of the Drawable that is completely 621 * transparent. This can be used to perform drawing operations, identifying 622 * which parts of the target will not change when rendering the Drawable. 623 * The default implementation returns null, indicating no transparent 624 * region; subclasses can optionally override this to return an actual 625 * Region if they want to supply this optimization information, but it is 626 * not required that they do so. 627 * 628 * @return Returns null if the Drawables has no transparent region to 629 * report, else a Region holding the parts of the Drawable's bounds that 630 * are transparent. 631 */ 632 public Region getTransparentRegion() { 633 return null; 634 } 635 636 /** 637 * Override this in your subclass to change appearance if you recognize the 638 * specified state. 639 * 640 * @return Returns true if the state change has caused the appearance of 641 * the Drawable to change (that is, it needs to be drawn), else false 642 * if it looks the same and there is no need to redraw it since its 643 * last state. 644 */ 645 protected boolean onStateChange(int[] state) { return false; } 646 /** Override this in your subclass to change appearance if you vary based 647 * on level. 648 * @return Returns true if the level change has caused the appearance of 649 * the Drawable to change (that is, it needs to be drawn), else false 650 * if it looks the same and there is no need to redraw it since its 651 * last level. 652 */ 653 protected boolean onLevelChange(int level) { return false; } 654 /** 655 * Override this in your subclass to change appearance if you recognize the 656 * specified state. 657 */ 658 protected void onBoundsChange(Rect bounds) {} 659 660 /** 661 * Return the intrinsic width of the underlying drawable object. Returns 662 * -1 if it has no intrinsic width, such as with a solid color. 663 */ 664 public int getIntrinsicWidth() { 665 return -1; 666 } 667 668 /** 669 * Return the intrinsic height of the underlying drawable object. Returns 670 * -1 if it has no intrinsic height, such as with a solid color. 671 */ 672 public int getIntrinsicHeight() { 673 return -1; 674 } 675 676 /** 677 * Returns the minimum width suggested by this Drawable. If a View uses this 678 * Drawable as a background, it is suggested that the View use at least this 679 * value for its width. (There will be some scenarios where this will not be 680 * possible.) This value should INCLUDE any padding. 681 * 682 * @return The minimum width suggested by this Drawable. If this Drawable 683 * doesn't have a suggested minimum width, 0 is returned. 684 */ 685 public int getMinimumWidth() { 686 final int intrinsicWidth = getIntrinsicWidth(); 687 return intrinsicWidth > 0 ? intrinsicWidth : 0; 688 } 689 690 /** 691 * Returns the minimum height suggested by this Drawable. If a View uses this 692 * Drawable as a background, it is suggested that the View use at least this 693 * value for its height. (There will be some scenarios where this will not be 694 * possible.) This value should INCLUDE any padding. 695 * 696 * @return The minimum height suggested by this Drawable. If this Drawable 697 * doesn't have a suggested minimum height, 0 is returned. 698 */ 699 public int getMinimumHeight() { 700 final int intrinsicHeight = getIntrinsicHeight(); 701 return intrinsicHeight > 0 ? intrinsicHeight : 0; 702 } 703 704 /** 705 * Return in padding the insets suggested by this Drawable for placing 706 * content inside the drawable's bounds. Positive values move toward the 707 * center of the Drawable (set Rect.inset). Returns true if this drawable 708 * actually has a padding, else false. When false is returned, the padding 709 * is always set to 0. 710 */ 711 public boolean getPadding(Rect padding) { 712 padding.set(0, 0, 0, 0); 713 return false; 714 } 715 716 /** 717 * Return in insets the layout insets suggested by this Drawable for use with alignment 718 * operations during layout. 719 * 720 * @hide 721 */ 722 public Insets getOpticalInsets() { 723 return Insets.NONE; 724 } 725 726 /** 727 * Make this drawable mutable. This operation cannot be reversed. A mutable 728 * drawable is guaranteed to not share its state with any other drawable. 729 * This is especially useful when you need to modify properties of drawables 730 * loaded from resources. By default, all drawables instances loaded from 731 * the same resource share a common state; if you modify the state of one 732 * instance, all the other instances will receive the same modification. 733 * 734 * Calling this method on a mutable Drawable will have no effect. 735 * 736 * @return This drawable. 737 * @see ConstantState 738 * @see #getConstantState() 739 */ 740 public Drawable mutate() { 741 return this; 742 } 743 744 /** 745 * Create a drawable from an inputstream 746 */ 747 public static Drawable createFromStream(InputStream is, String srcName) { 748 return createFromResourceStream(null, null, is, srcName, null); 749 } 750 751 /** 752 * Create a drawable from an inputstream, using the given resources and 753 * value to determine density information. 754 */ 755 public static Drawable createFromResourceStream(Resources res, TypedValue value, 756 InputStream is, String srcName) { 757 return createFromResourceStream(res, value, is, srcName, null); 758 } 759 760 /** 761 * Create a drawable from an inputstream, using the given resources and 762 * value to determine density information. 763 */ 764 public static Drawable createFromResourceStream(Resources res, TypedValue value, 765 InputStream is, String srcName, BitmapFactory.Options opts) { 766 767 if (is == null) { 768 return null; 769 } 770 771 /* ugh. The decodeStream contract is that we have already allocated 772 the pad rect, but if the bitmap does not had a ninepatch chunk, 773 then the pad will be ignored. If we could change this to lazily 774 alloc/assign the rect, we could avoid the GC churn of making new 775 Rects only to drop them on the floor. 776 */ 777 Rect pad = new Rect(); 778 779 // Special stuff for compatibility mode: if the target density is not 780 // the same as the display density, but the resource -is- the same as 781 // the display density, then don't scale it down to the target density. 782 // This allows us to load the system's density-correct resources into 783 // an application in compatibility mode, without scaling those down 784 // to the compatibility density only to have them scaled back up when 785 // drawn to the screen. 786 if (opts == null) opts = new BitmapFactory.Options(); 787 opts.inScreenDensity = res != null 788 ? res.getDisplayMetrics().noncompatDensityDpi : DisplayMetrics.DENSITY_DEVICE; 789 Bitmap bm = BitmapFactory.decodeResourceStream(res, value, is, pad, opts); 790 if (bm != null) { 791 byte[] np = bm.getNinePatchChunk(); 792 if (np == null || !NinePatch.isNinePatchChunk(np)) { 793 np = null; 794 pad = null; 795 } 796 int[] layoutBounds = bm.getLayoutBounds(); 797 Rect layoutBoundsRect = null; 798 if (layoutBounds != null) { 799 layoutBoundsRect = new Rect(layoutBounds[0], layoutBounds[1], 800 layoutBounds[2], layoutBounds[3]); 801 } 802 return drawableFromBitmap(res, bm, np, pad, layoutBoundsRect, srcName); 803 } 804 return null; 805 } 806 807 /** 808 * Create a drawable from an XML document. For more information on how to 809 * create resources in XML, see 810 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. 811 */ 812 public static Drawable createFromXml(Resources r, XmlPullParser parser) 813 throws XmlPullParserException, IOException { 814 AttributeSet attrs = Xml.asAttributeSet(parser); 815 816 int type; 817 while ((type=parser.next()) != XmlPullParser.START_TAG && 818 type != XmlPullParser.END_DOCUMENT) { 819 // Empty loop 820 } 821 822 if (type != XmlPullParser.START_TAG) { 823 throw new XmlPullParserException("No start tag found"); 824 } 825 826 Drawable drawable = createFromXmlInner(r, parser, attrs); 827 828 if (drawable == null) { 829 throw new RuntimeException("Unknown initial tag: " + parser.getName()); 830 } 831 832 return drawable; 833 } 834 835 /** 836 * Create from inside an XML document. Called on a parser positioned at 837 * a tag in an XML document, tries to create a Drawable from that tag. 838 * Returns null if the tag is not a valid drawable. 839 */ 840 public static Drawable createFromXmlInner(Resources r, XmlPullParser parser, AttributeSet attrs) 841 throws XmlPullParserException, IOException { 842 Drawable drawable; 843 844 final String name = parser.getName(); 845 846 if (name.equals("selector")) { 847 drawable = new StateListDrawable(); 848 } else if (name.equals("level-list")) { 849 drawable = new LevelListDrawable(); 850 /* Probably not doing this. 851 } else if (name.equals("mipmap")) { 852 drawable = new MipmapDrawable(); 853 */ 854 } else if (name.equals("layer-list")) { 855 drawable = new LayerDrawable(); 856 } else if (name.equals("transition")) { 857 drawable = new TransitionDrawable(); 858 } else if (name.equals("color")) { 859 drawable = new ColorDrawable(); 860 } else if (name.equals("shape")) { 861 drawable = new GradientDrawable(); 862 } else if (name.equals("scale")) { 863 drawable = new ScaleDrawable(); 864 } else if (name.equals("clip")) { 865 drawable = new ClipDrawable(); 866 } else if (name.equals("rotate")) { 867 drawable = new RotateDrawable(); 868 } else if (name.equals("animated-rotate")) { 869 drawable = new AnimatedRotateDrawable(); 870 } else if (name.equals("animation-list")) { 871 drawable = new AnimationDrawable(); 872 } else if (name.equals("inset")) { 873 drawable = new InsetDrawable(); 874 } else if (name.equals("bitmap")) { 875 //noinspection deprecation 876 drawable = new BitmapDrawable(r); 877 if (r != null) { 878 ((BitmapDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 879 } 880 } else if (name.equals("nine-patch")) { 881 drawable = new NinePatchDrawable(); 882 if (r != null) { 883 ((NinePatchDrawable) drawable).setTargetDensity(r.getDisplayMetrics()); 884 } 885 } else { 886 throw new XmlPullParserException(parser.getPositionDescription() + 887 ": invalid drawable tag " + name); 888 } 889 890 drawable.inflate(r, parser, attrs); 891 return drawable; 892 } 893 894 895 /** 896 * Create a drawable from file path name. 897 */ 898 public static Drawable createFromPath(String pathName) { 899 if (pathName == null) { 900 return null; 901 } 902 903 Bitmap bm = BitmapFactory.decodeFile(pathName); 904 if (bm != null) { 905 return drawableFromBitmap(null, bm, null, null, null, pathName); 906 } 907 908 return null; 909 } 910 911 /** 912 * Inflate this Drawable from an XML resource. 913 */ 914 public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs) 915 throws XmlPullParserException, IOException { 916 917 TypedArray a = r.obtainAttributes(attrs, com.android.internal.R.styleable.Drawable); 918 inflateWithAttributes(r, parser, a, com.android.internal.R.styleable.Drawable_visible); 919 a.recycle(); 920 } 921 922 /** 923 * Inflate a Drawable from an XML resource. 924 * 925 * @throws XmlPullParserException 926 * @throws IOException 927 */ 928 void inflateWithAttributes(Resources r, XmlPullParser parser, 929 TypedArray attrs, int visibleAttr) 930 throws XmlPullParserException, IOException { 931 932 mVisible = attrs.getBoolean(visibleAttr, mVisible); 933 } 934 935 /** 936 * This abstract class is used by {@link Drawable}s to store shared constant state and data 937 * between Drawables. {@link BitmapDrawable}s created from the same resource will for instance 938 * share a unique bitmap stored in their ConstantState. 939 * 940 * <p> 941 * {@link #newDrawable(Resources)} can be used as a factory to create new Drawable instances 942 * from this ConstantState. 943 * </p> 944 * 945 * Use {@link Drawable#getConstantState()} to retrieve the ConstantState of a Drawable. Calling 946 * {@link Drawable#mutate()} on a Drawable should typically create a new ConstantState for that 947 * Drawable. 948 */ 949 public static abstract class ConstantState { 950 /** 951 * Create a new drawable without supplying resources the caller 952 * is running in. Note that using this means the density-dependent 953 * drawables (like bitmaps) will not be able to update their target 954 * density correctly. One should use {@link #newDrawable(Resources)} 955 * instead to provide a resource. 956 */ 957 public abstract Drawable newDrawable(); 958 /** 959 * Create a new Drawable instance from its constant state. This 960 * must be implemented for drawables that change based on the target 961 * density of their caller (that is depending on whether it is 962 * in compatibility mode). 963 */ 964 public Drawable newDrawable(Resources res) { 965 return newDrawable(); 966 } 967 /** 968 * Return a bit mask of configuration changes that will impact 969 * this drawable (and thus require completely reloading it). 970 */ 971 public abstract int getChangingConfigurations(); 972 } 973 974 /** 975 * Return a {@link ConstantState} instance that holds the shared state of this Drawable. 976 *q 977 * @return The ConstantState associated to that Drawable. 978 * @see ConstantState 979 * @see Drawable#mutate() 980 */ 981 public ConstantState getConstantState() { 982 return null; 983 } 984 985 private static Drawable drawableFromBitmap(Resources res, Bitmap bm, byte[] np, 986 Rect pad, Rect layoutBounds, String srcName) { 987 988 if (np != null) { 989 return new NinePatchDrawable(res, bm, np, pad, layoutBounds, srcName); 990 } 991 992 return new BitmapDrawable(res, bm); 993 } 994} 995 996