Fragment.java revision 87121accdb0ce318482ac51270763a6faab2ed63
1/* 2 * Copyright (C) 2010 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.app; 18 19import android.animation.Animator; 20import android.content.ComponentCallbacks; 21import android.content.Context; 22import android.content.Intent; 23import android.content.res.Configuration; 24import android.content.res.Resources; 25import android.os.Bundle; 26import android.os.Parcel; 27import android.os.Parcelable; 28import android.util.AndroidRuntimeException; 29import android.util.AttributeSet; 30import android.util.DebugUtils; 31import android.util.SparseArray; 32import android.view.ContextMenu; 33import android.view.LayoutInflater; 34import android.view.Menu; 35import android.view.MenuInflater; 36import android.view.MenuItem; 37import android.view.View; 38import android.view.ViewGroup; 39import android.view.ContextMenu.ContextMenuInfo; 40import android.view.View.OnCreateContextMenuListener; 41import android.widget.AdapterView; 42 43import java.io.FileDescriptor; 44import java.io.PrintWriter; 45import java.util.HashMap; 46 47final class FragmentState implements Parcelable { 48 final String mClassName; 49 final int mIndex; 50 final boolean mFromLayout; 51 final int mFragmentId; 52 final int mContainerId; 53 final String mTag; 54 final boolean mRetainInstance; 55 final Bundle mArguments; 56 57 Bundle mSavedFragmentState; 58 59 Fragment mInstance; 60 61 public FragmentState(Fragment frag) { 62 mClassName = frag.getClass().getName(); 63 mIndex = frag.mIndex; 64 mFromLayout = frag.mFromLayout; 65 mFragmentId = frag.mFragmentId; 66 mContainerId = frag.mContainerId; 67 mTag = frag.mTag; 68 mRetainInstance = frag.mRetainInstance; 69 mArguments = frag.mArguments; 70 } 71 72 public FragmentState(Parcel in) { 73 mClassName = in.readString(); 74 mIndex = in.readInt(); 75 mFromLayout = in.readInt() != 0; 76 mFragmentId = in.readInt(); 77 mContainerId = in.readInt(); 78 mTag = in.readString(); 79 mRetainInstance = in.readInt() != 0; 80 mArguments = in.readBundle(); 81 mSavedFragmentState = in.readBundle(); 82 } 83 84 public Fragment instantiate(Activity activity) { 85 if (mInstance != null) { 86 return mInstance; 87 } 88 89 if (mArguments != null) { 90 mArguments.setClassLoader(activity.getClassLoader()); 91 } 92 93 mInstance = Fragment.instantiate(activity, mClassName, mArguments); 94 95 if (mSavedFragmentState != null) { 96 mSavedFragmentState.setClassLoader(activity.getClassLoader()); 97 mInstance.mSavedFragmentState = mSavedFragmentState; 98 } 99 mInstance.setIndex(mIndex); 100 mInstance.mFromLayout = mFromLayout; 101 mInstance.mRestored = true; 102 mInstance.mFragmentId = mFragmentId; 103 mInstance.mContainerId = mContainerId; 104 mInstance.mTag = mTag; 105 mInstance.mRetainInstance = mRetainInstance; 106 mInstance.mFragmentManager = activity.mFragments; 107 108 return mInstance; 109 } 110 111 public int describeContents() { 112 return 0; 113 } 114 115 public void writeToParcel(Parcel dest, int flags) { 116 dest.writeString(mClassName); 117 dest.writeInt(mIndex); 118 dest.writeInt(mFromLayout ? 1 : 0); 119 dest.writeInt(mFragmentId); 120 dest.writeInt(mContainerId); 121 dest.writeString(mTag); 122 dest.writeInt(mRetainInstance ? 1 : 0); 123 dest.writeBundle(mArguments); 124 dest.writeBundle(mSavedFragmentState); 125 } 126 127 public static final Parcelable.Creator<FragmentState> CREATOR 128 = new Parcelable.Creator<FragmentState>() { 129 public FragmentState createFromParcel(Parcel in) { 130 return new FragmentState(in); 131 } 132 133 public FragmentState[] newArray(int size) { 134 return new FragmentState[size]; 135 } 136 }; 137} 138 139/** 140 * A Fragment is a piece of an application's user interface or behavior 141 * that can be placed in an {@link Activity}. Interaction with fragments 142 * is done through {@link FragmentManager}, which can be obtained via 143 * {@link Activity#getFragmentManager() Activity.getFragmentManager()} and 144 * {@link Fragment#getFragmentManager() Fragment.getFragmentManager()}. 145 * 146 * <p>The Fragment class can be used many ways to achieve a wide variety of 147 * results. It is core, it represents a particular operation or interface 148 * that is running within a larger {@link Activity}. A Fragment is closely 149 * tied to the Activity it is in, and can not be used apart from one. Though 150 * Fragment defines its own lifecycle, that lifecycle is dependent on its 151 * activity: if the activity is stopped, no fragments inside of it can be 152 * started; when the activity is destroyed, all fragments will be destroyed. 153 * 154 * <p>All subclasses of Fragment must include a public empty constructor. 155 * The framework will often re-instantiate a fragment class when needed, 156 * in particular during state restore, and needs to be able to find this 157 * constructor to instantiate it. If the empty constructor is not available, 158 * a runtime exception will occur in some cases during state restore. 159 * 160 * <p>Topics covered here: 161 * <ol> 162 * <li><a href="#Lifecycle">Lifecycle</a> 163 * <li><a href="#Layout">Layout</a> 164 * <li><a href="#BackStack">Back Stack</a> 165 * </ol> 166 * 167 * <a name="Lifecycle"></a> 168 * <h3>Lifecycle</h3> 169 * 170 * <p>Though a Fragment's lifecycle is tied to its owning activity, it has 171 * its own wrinkle on the standard activity lifecycle. It includes basic 172 * activity lifecycle methods such as {@link #onResume}, but also important 173 * are methods related to interactions with the activity and UI generation. 174 * 175 * <p>The core series of lifecycle methods that are called to bring a fragment 176 * up to resumed state (interacting with the user) are: 177 * 178 * <ol> 179 * <li> {@link #onAttach} called once the fragment is associated with its activity. 180 * <li> {@link #onCreate} called to do initial creation of the fragment. 181 * <li> {@link #onCreateView} creates and returns the view hierarchy associated 182 * with the fragment. 183 * <li> {@link #onActivityCreated} tells the fragment that its activity has 184 * completed its own {@link Activity#onCreate Activity.onCreaate}. 185 * <li> {@link #onStart} makes the fragment visible to the user (based on its 186 * containing activity being started). 187 * <li> {@link #onResume} makes the fragment interacting with the user (based on its 188 * containing activity being resumed). 189 * </ol> 190 * 191 * <p>As a fragment is no longer being used, it goes through a reverse 192 * series of callbacks: 193 * 194 * <ol> 195 * <li> {@link #onPause} fragment is no longer interacting with the user either 196 * because its activity is being paused or a fragment operation is modifying it 197 * in the activity. 198 * <li> {@link #onStop} fragment is no longer visible to the user either 199 * because its activity is being stopped or a fragment operation is modifying it 200 * in the activity. 201 * <li> {@link #onDestroyView} allows the fragment to clean up resources 202 * associated with its View. 203 * <li> {@link #onDestroy} called to do final cleanup of the fragment's state. 204 * <li> {@link #onDetach} called immediately prior to the fragment no longer 205 * being associated with its activity. 206 * </ol> 207 * 208 * <a name="Layout"></a> 209 * <h3>Layout</h3> 210 * 211 * <p>Fragments can be used as part of your application's layout, allowing 212 * you to better modularize your code and more easily adjust your user 213 * interface to the screen it is running on. As an example, we can look 214 * at a simple program consisting of a list of items, and display of the 215 * details of each item.</p> 216 * 217 * <p>An activity's layout XML can include <code><fragment></code> tags 218 * to embed fragment instances inside of the layout. For example, here is 219 * a simple layout that embeds one fragment:</p> 220 * 221 * {@sample development/samples/ApiDemos/res/layout/fragment_layout.xml layout} 222 * 223 * <p>The layout is installed in the activity in the normal way:</p> 224 * 225 * {@sample development/samples/ApiDemos/src/com/example/android/apis/app/FragmentLayout.java 226 * main} 227 * 228 * <p>The titles fragment, showing a list of titles, is fairly simple, relying 229 * on {@link ListFragment} for most of its work. Note the implementation of 230 * clicking an item: depending on the current activity's layout, it can either 231 * create and display a new fragment to show the details in-place (more about 232 * this later), or start a new activity show the details.</p> 233 * 234 * {@sample development/samples/ApiDemos/src/com/example/android/apis/app/FragmentLayout.java 235 * titles} 236 * 237 * <p>The details fragment showing the contents of selected item here just 238 * displays a string of text based on an index of a string array built in to 239 * the app:</p> 240 * 241 * {@sample development/samples/ApiDemos/src/com/example/android/apis/app/FragmentLayout.java 242 * details} 243 * 244 * <p>In this case when the user clicks on a title, there is no details 245 * container in the current activity, so the title title fragment's click code will 246 * launch a new activity to display the details fragment:</p> 247 * 248 * {@sample development/samples/ApiDemos/src/com/example/android/apis/app/FragmentLayout.java 249 * details_activity} 250 * 251 * <p>However the screen may be large enough to show both the list of titles 252 * and details about the currently selected title. To use such a layout on 253 * a landscape screen, this alternative layout can be placed under layout-land:</p> 254 * 255 * {@sample development/samples/ApiDemos/res/layout-land/fragment_layout.xml layout} 256 * 257 * <p>Note how the prior code will adjust to this alternative UI flow: the titles 258 * fragment will now embed the details fragment inside of this activity, and the 259 * details activity will finish itself if it is running in a configuration 260 * where the details can be shown in-place. 261 * 262 * <p>When a configuration change causes the activity hosting these fragments 263 * to restart, its new instance may use a different layout that doesn't 264 * include the same fragments as the previous layout. In this case all of 265 * the previous fragments will still be instantiated and running in the new 266 * instance. However, any that are no longer associated with a <fragment> 267 * tag in the view hierarchy will not have their content view created 268 * and will return false from {@link #isInLayout}. (The code here also shows 269 * how you can determine if a fragment placed in a container is no longer 270 * running in a layout with that container and avoid creating its view hierarchy 271 * in that case.) 272 * 273 * <p>The attributes of the <fragment> tag are used to control the 274 * LayoutParams provided when attaching the fragment's view to the parent 275 * container. They can also be parsed by the fragment in {@link #onInflate} 276 * as parameters. 277 * 278 * <p>The fragment being instantiated must have some kind of unique identifier 279 * so that it can be re-associated with a previous instance if the parent 280 * activity needs to be destroyed and recreated. This can be provided these 281 * ways: 282 * 283 * <ul> 284 * <li>If nothing is explicitly supplied, the view ID of the container will 285 * be used. 286 * <li><code>android:tag</code> can be used in <fragment> to provide 287 * a specific tag name for the fragment. 288 * <li><code>android:id</code> can be used in <fragment> to provide 289 * a specific identifier for the fragment. 290 * </ul> 291 * 292 * <a name="BackStack"></a> 293 * <h3>Back Stack</h3> 294 * 295 * <p>The transaction in which fragments are modified can be placed on an 296 * internal back-stack of the owning activity. When the user presses back 297 * in the activity, any transactions on the back stack are popped off before 298 * the activity itself is finished. 299 * 300 * <p>For example, consider this simple fragment that is instantiated with 301 * an integer argument and displays that in a TextView in its UI:</p> 302 * 303 * {@sample development/samples/ApiDemos/src/com/example/android/apis/app/FragmentStack.java 304 * fragment} 305 * 306 * <p>A function that creates a new instance of the fragment, replacing 307 * whatever current fragment instance is being shown and pushing that change 308 * on to the back stack could be written as: 309 * 310 * {@sample development/samples/ApiDemos/src/com/example/android/apis/app/FragmentStack.java 311 * add_stack} 312 * 313 * <p>After each call to this function, a new entry is on the stack, and 314 * pressing back will pop it to return the user to whatever previous state 315 * the activity UI was in. 316 */ 317public class Fragment implements ComponentCallbacks, OnCreateContextMenuListener { 318 private static final HashMap<String, Class<?>> sClassMap = 319 new HashMap<String, Class<?>>(); 320 321 static final int INITIALIZING = 0; // Not yet created. 322 static final int CREATED = 1; // Created. 323 static final int ACTIVITY_CREATED = 2; // The activity has finished its creation. 324 static final int STARTED = 3; // Created and started, not resumed. 325 static final int RESUMED = 4; // Created started and resumed. 326 327 int mState = INITIALIZING; 328 329 // Non-null if the fragment's view hierarchy is currently animating away, 330 // meaning we need to wait a bit on completely destroying it. This is the 331 // animation that is running. 332 Animator mAnimatingAway; 333 334 // If mAnimatingAway != null, this is the state we should move to once the 335 // animation is done. 336 int mStateAfterAnimating; 337 338 // When instantiated from saved state, this is the saved state. 339 Bundle mSavedFragmentState; 340 SparseArray<Parcelable> mSavedViewState; 341 342 // Index into active fragment array. 343 int mIndex = -1; 344 345 // Internal unique name for this fragment; 346 String mWho; 347 348 // Construction arguments; 349 Bundle mArguments; 350 351 // Target fragment. 352 Fragment mTarget; 353 354 // Target request code. 355 int mTargetRequestCode; 356 357 // True if the fragment is in the list of added fragments. 358 boolean mAdded; 359 360 // True if the fragment is in the resumed state. 361 boolean mResumed; 362 363 // Set to true if this fragment was instantiated from a layout file. 364 boolean mFromLayout; 365 366 // Set to true when the view has actually been inflated in its layout. 367 boolean mInLayout; 368 369 // True if this fragment has been restored from previously saved state. 370 boolean mRestored; 371 372 // Number of active back stack entries this fragment is in. 373 int mBackStackNesting; 374 375 // The fragment manager we are associated with. Set as soon as the 376 // fragment is used in a transaction; cleared after it has been removed 377 // from all transactions. 378 FragmentManager mFragmentManager; 379 380 // Set as soon as a fragment is added to a transaction (or removed), 381 // to be able to do validation. 382 Activity mImmediateActivity; 383 384 // Activity this fragment is attached to. 385 Activity mActivity; 386 387 // The optional identifier for this fragment -- either the container ID if it 388 // was dynamically added to the view hierarchy, or the ID supplied in 389 // layout. 390 int mFragmentId; 391 392 // When a fragment is being dynamically added to the view hierarchy, this 393 // is the identifier of the parent container it is being added to. 394 int mContainerId; 395 396 // The optional named tag for this fragment -- usually used to find 397 // fragments that are not part of the layout. 398 String mTag; 399 400 // Set to true when the app has requested that this fragment be hidden 401 // from the user. 402 boolean mHidden; 403 404 // If set this fragment would like its instance retained across 405 // configuration changes. 406 boolean mRetainInstance; 407 408 // If set this fragment is being retained across the current config change. 409 boolean mRetaining; 410 411 // If set this fragment has menu items to contribute. 412 boolean mHasMenu; 413 414 // Used to verify that subclasses call through to super class. 415 boolean mCalled; 416 417 // If app has requested a specific animation, this is the one to use. 418 int mNextAnim; 419 420 // The parent container of the fragment after dynamically added to UI. 421 ViewGroup mContainer; 422 423 // The View generated for this fragment. 424 View mView; 425 426 LoaderManagerImpl mLoaderManager; 427 boolean mLoadersStarted; 428 boolean mCheckedForLoaderManager; 429 430 /** 431 * Thrown by {@link Fragment#instantiate(Context, String, Bundle)} when 432 * there is an instantiation failure. 433 */ 434 static public class InstantiationException extends AndroidRuntimeException { 435 public InstantiationException(String msg, Exception cause) { 436 super(msg, cause); 437 } 438 } 439 440 /** 441 * Default constructor. <strong>Every</strong> fragment must have an 442 * empty constructor, so it can be instantiated when restoring its 443 * activity's state. It is strongly recommended that subclasses do not 444 * have other constructors with parameters, since these constructors 445 * will not be called when the fragment is re-instantiated; instead, 446 * arguments can be supplied by the caller with {@link #setArguments} 447 * and later retrieved by the Fragment with {@link #getArguments}. 448 * 449 * <p>Applications should generally not implement a constructor. The 450 * first place application code an run where the fragment is ready to 451 * be used is in {@link #onAttach(Activity)}, the point where the fragment 452 * is actually associated with its activity. Some applications may also 453 * want to implement {@link #onInflate} to retrieve attributes from a 454 * layout resource, though should take care here because this happens for 455 * the fragment is attached to its activity. 456 */ 457 public Fragment() { 458 } 459 460 /** 461 * Like {@link #instantiate(Context, String, Bundle)} but with a null 462 * argument Bundle. 463 */ 464 public static Fragment instantiate(Context context, String fname) { 465 return instantiate(context, fname, null); 466 } 467 468 /** 469 * Create a new instance of a Fragment with the given class name. This is 470 * the same as calling its empty constructor. 471 * 472 * @param context The calling context being used to instantiate the fragment. 473 * This is currently just used to get its ClassLoader. 474 * @param fname The class name of the fragment to instantiate. 475 * @param args Bundle of arguments to supply to the fragment, which it 476 * can retrieve with {@link #getArguments()}. May be null. 477 * @return Returns a new fragment instance. 478 * @throws InstantiationException If there is a failure in instantiating 479 * the given fragment class. This is a runtime exception; it is not 480 * normally expected to happen. 481 */ 482 public static Fragment instantiate(Context context, String fname, Bundle args) { 483 try { 484 Class<?> clazz = sClassMap.get(fname); 485 if (clazz == null) { 486 // Class not found in the cache, see if it's real, and try to add it 487 clazz = context.getClassLoader().loadClass(fname); 488 sClassMap.put(fname, clazz); 489 } 490 Fragment f = (Fragment)clazz.newInstance(); 491 if (args != null) { 492 args.setClassLoader(f.getClass().getClassLoader()); 493 f.mArguments = args; 494 } 495 return f; 496 } catch (ClassNotFoundException e) { 497 throw new InstantiationException("Unable to instantiate fragment " + fname 498 + ": make sure class name exists, is public, and has an" 499 + " empty constructor that is public", e); 500 } catch (java.lang.InstantiationException e) { 501 throw new InstantiationException("Unable to instantiate fragment " + fname 502 + ": make sure class name exists, is public, and has an" 503 + " empty constructor that is public", e); 504 } catch (IllegalAccessException e) { 505 throw new InstantiationException("Unable to instantiate fragment " + fname 506 + ": make sure class name exists, is public, and has an" 507 + " empty constructor that is public", e); 508 } 509 } 510 511 void restoreViewState() { 512 if (mSavedViewState != null) { 513 mView.restoreHierarchyState(mSavedViewState); 514 mSavedViewState = null; 515 } 516 } 517 518 void setIndex(int index) { 519 mIndex = index; 520 mWho = "android:fragment:" + mIndex; 521 } 522 523 void clearIndex() { 524 mIndex = -1; 525 mWho = null; 526 } 527 528 /** 529 * Subclasses can not override equals(). 530 */ 531 @Override final public boolean equals(Object o) { 532 return super.equals(o); 533 } 534 535 /** 536 * Subclasses can not override hashCode(). 537 */ 538 @Override final public int hashCode() { 539 return super.hashCode(); 540 } 541 542 @Override 543 public String toString() { 544 StringBuilder sb = new StringBuilder(128); 545 DebugUtils.buildShortClassTag(this, sb); 546 if (mIndex >= 0) { 547 sb.append(" #"); 548 sb.append(mIndex); 549 } 550 if (mFragmentId != 0) { 551 sb.append(" id=0x"); 552 sb.append(Integer.toHexString(mFragmentId)); 553 } 554 if (mTag != null) { 555 sb.append(" "); 556 sb.append(mTag); 557 } 558 sb.append('}'); 559 return sb.toString(); 560 } 561 562 /** 563 * Return the identifier this fragment is known by. This is either 564 * the android:id value supplied in a layout or the container view ID 565 * supplied when adding the fragment. 566 */ 567 final public int getId() { 568 return mFragmentId; 569 } 570 571 /** 572 * Get the tag name of the fragment, if specified. 573 */ 574 final public String getTag() { 575 return mTag; 576 } 577 578 /** 579 * Supply the construction arguments for this fragment. This can only 580 * be called before the fragment has been attached to its activity; that 581 * is, you should call it immediately after constructing the fragment. The 582 * arguments supplied here will be retained across fragment destroy and 583 * creation. 584 */ 585 public void setArguments(Bundle args) { 586 if (mIndex >= 0) { 587 throw new IllegalStateException("Fragment already active"); 588 } 589 mArguments = args; 590 } 591 592 /** 593 * Return the arguments supplied when the fragment was instantiated, 594 * if any. 595 */ 596 final public Bundle getArguments() { 597 return mArguments; 598 } 599 600 /** 601 * Optional target for this fragment. This may be used, for example, 602 * if this fragment is being started by another, and when done wants to 603 * give a result back to the first. The target set here is retained 604 * across instances via {@link FragmentManager#putFragment 605 * FragmentManager.putFragment()}. 606 * 607 * @param fragment The fragment that is the target of this one. 608 * @param requestCode Optional request code, for convenience if you 609 * are going to call back with {@link #onActivityResult(int, int, Intent)}. 610 */ 611 public void setTargetFragment(Fragment fragment, int requestCode) { 612 mTarget = fragment; 613 mTargetRequestCode = requestCode; 614 } 615 616 /** 617 * Return the target fragment set by {@link #setTargetFragment}. 618 */ 619 final public Fragment getTargetFragment() { 620 return mTarget; 621 } 622 623 /** 624 * Return the target request code set by {@link #setTargetFragment}. 625 */ 626 final public int getTargetRequestCode() { 627 return mTargetRequestCode; 628 } 629 630 /** 631 * Return the Activity this fragment is currently associated with. 632 */ 633 final public Activity getActivity() { 634 return mActivity; 635 } 636 637 /** 638 * Return <code>getActivity().getResources()</code>. 639 */ 640 final public Resources getResources() { 641 return mActivity.getResources(); 642 } 643 644 /** 645 * Return a localized, styled CharSequence from the application's package's 646 * default string table. 647 * 648 * @param resId Resource id for the CharSequence text 649 */ 650 public final CharSequence getText(int resId) { 651 return getResources().getText(resId); 652 } 653 654 /** 655 * Return a localized string from the application's package's 656 * default string table. 657 * 658 * @param resId Resource id for the string 659 */ 660 public final String getString(int resId) { 661 return getResources().getString(resId); 662 } 663 664 /** 665 * Return a localized formatted string from the application's package's 666 * default string table, substituting the format arguments as defined in 667 * {@link java.util.Formatter} and {@link java.lang.String#format}. 668 * 669 * @param resId Resource id for the format string 670 * @param formatArgs The format arguments that will be used for substitution. 671 */ 672 673 public final String getString(int resId, Object... formatArgs) { 674 return getResources().getString(resId, formatArgs); 675 } 676 677 /** 678 * Return the FragmentManager for interacting with fragments associated 679 * with this fragment's activity. Note that this will be non-null slightly 680 * before {@link #getActivity()}, during the time from when the fragment is 681 * placed in a {@link FragmentTransaction} until it is committed and 682 * attached to its activity. 683 */ 684 final public FragmentManager getFragmentManager() { 685 return mFragmentManager; 686 } 687 688 /** 689 * Return true if the fragment is currently added to its activity. 690 */ 691 final public boolean isAdded() { 692 return mActivity != null && mActivity.mFragments.mAdded.contains(this); 693 } 694 695 /** 696 * Return true if the layout is included as part of an activity view 697 * hierarchy via the <fragment> tag. This will always be true when 698 * fragments are created through the <fragment> tag, <em>except</em> 699 * in the case where an old fragment is restored from a previous state and 700 * it does not appear in the layout of the current state. 701 */ 702 final public boolean isInLayout() { 703 return mInLayout; 704 } 705 706 /** 707 * Return true if the fragment is in the resumed state. This is true 708 * for the duration of {@link #onResume()} and {@link #onPause()} as well. 709 */ 710 final public boolean isResumed() { 711 return mResumed; 712 } 713 714 /** 715 * Return true if the fragment is currently visible to the user. This means 716 * it: (1) has been added, (2) has its view attached to the window, and 717 * (3) is not hidden. 718 */ 719 final public boolean isVisible() { 720 return isAdded() && !isHidden() && mView != null 721 && mView.getWindowToken() != null && mView.getVisibility() == View.VISIBLE; 722 } 723 724 /** 725 * Return true if the fragment has been hidden. By default fragments 726 * are shown. You can find out about changes to this state with 727 * {@link #onHiddenChanged}. Note that the hidden state is orthogonal 728 * to other states -- that is, to be visible to the user, a fragment 729 * must be both started and not hidden. 730 */ 731 final public boolean isHidden() { 732 return mHidden; 733 } 734 735 /** 736 * Called when the hidden state (as returned by {@link #isHidden()} of 737 * the fragment has changed. Fragments start out not hidden; this will 738 * be called whenever the fragment changes state from that. 739 * @param hidden True if the fragment is now hidden, false if it is not 740 * visible. 741 */ 742 public void onHiddenChanged(boolean hidden) { 743 } 744 745 /** 746 * Control whether a fragment instance is retained across Activity 747 * re-creation (such as from a configuration change). This can only 748 * be used with fragments not in the back stack. If set, the fragment 749 * lifecycle will be slightly different when an activity is recreated: 750 * <ul> 751 * <li> {@link #onDestroy()} will not be called (but {@link #onDetach()} still 752 * will be, because the fragment is being detached from its current activity). 753 * <li> {@link #onCreate(Bundle)} will not be called since the fragment 754 * is not being re-created. 755 * <li> {@link #onAttach(Activity)} and {@link #onActivityCreated(Bundle)} <b>will</b> 756 * still be called. 757 * </ul> 758 */ 759 public void setRetainInstance(boolean retain) { 760 mRetainInstance = retain; 761 } 762 763 final public boolean getRetainInstance() { 764 return mRetainInstance; 765 } 766 767 /** 768 * Report that this fragment would like to participate in populating 769 * the options menu by receiving a call to {@link #onCreateOptionsMenu} 770 * and related methods. 771 * 772 * @param hasMenu If true, the fragment has menu items to contribute. 773 */ 774 public void setHasOptionsMenu(boolean hasMenu) { 775 if (mHasMenu != hasMenu) { 776 mHasMenu = hasMenu; 777 if (isAdded() && !isHidden()) { 778 mActivity.invalidateOptionsMenu(); 779 } 780 } 781 } 782 783 /** 784 * Return the LoaderManager for this fragment, creating it if needed. 785 */ 786 public LoaderManager getLoaderManager() { 787 if (mLoaderManager != null) { 788 return mLoaderManager; 789 } 790 mCheckedForLoaderManager = true; 791 mLoaderManager = mActivity.getLoaderManager(mIndex, mLoadersStarted, true); 792 return mLoaderManager; 793 } 794 795 /** 796 * Call {@link Activity#startActivity(Intent)} on the fragment's 797 * containing Activity. 798 */ 799 public void startActivity(Intent intent) { 800 mActivity.startActivityFromFragment(this, intent, -1); 801 } 802 803 /** 804 * Call {@link Activity#startActivityForResult(Intent, int)} on the fragment's 805 * containing Activity. 806 */ 807 public void startActivityForResult(Intent intent, int requestCode) { 808 mActivity.startActivityFromFragment(this, intent, requestCode); 809 } 810 811 /** 812 * Receive the result from a previous call to 813 * {@link #startActivityForResult(Intent, int)}. This follows the 814 * related Activity API as described there in 815 * {@link Activity#onActivityResult(int, int, Intent)}. 816 * 817 * @param requestCode The integer request code originally supplied to 818 * startActivityForResult(), allowing you to identify who this 819 * result came from. 820 * @param resultCode The integer result code returned by the child activity 821 * through its setResult(). 822 * @param data An Intent, which can return result data to the caller 823 * (various data can be attached to Intent "extras"). 824 */ 825 public void onActivityResult(int requestCode, int resultCode, Intent data) { 826 } 827 828 /** 829 * Called when a fragment is being created as part of a view layout 830 * inflation, typically from setting the content view of an activity. This 831 * will be called immediately after the fragment is created from a <fragment> 832 * tag in a layout file. Note this is <em>before</em> the fragment's 833 * {@link #onAttach(Activity)} has been called; all you should do here is 834 * parse the attributes and save them away. A convenient thing to do is 835 * simply copy them into a Bundle that is given to {@link #setArguments(Bundle)}. 836 * 837 * <p>This is called every time the fragment is inflated, even if it is 838 * being inflated into a new instance with saved state. Because a fragment's 839 * arguments are retained across instances, it may make no sense to re-parse 840 * the attributes into new arguments. You may want to first check 841 * {@link #getArguments()} and only parse the attributes if it returns null, 842 * the assumption being that if it is non-null those are the same arguments 843 * from the first time the fragment was inflated. (That said, you may want 844 * to have layouts change for different configurations such as landscape 845 * and portrait, which can have different attributes. If so, you will need 846 * to re-parse the attributes each time this is called to generate new 847 * arguments.)</p> 848 * 849 * @param attrs The attributes at the tag where the fragment is 850 * being created. 851 * @param savedInstanceState If the fragment is being re-created from 852 * a previous saved state, this is the state. 853 */ 854 public void onInflate(AttributeSet attrs, Bundle savedInstanceState) { 855 mCalled = true; 856 } 857 858 /** 859 * Called when a fragment is first attached to its activity. 860 * {@link #onCreate(Bundle)} will be called after this. 861 */ 862 public void onAttach(Activity activity) { 863 mCalled = true; 864 } 865 866 /** 867 * Called when a fragment loads an animation. 868 */ 869 public Animator onCreateAnimator(int transit, boolean enter, int nextAnim) { 870 return null; 871 } 872 873 /** 874 * Called to do initial creation of a fragment. This is called after 875 * {@link #onAttach(Activity)} and before 876 * {@link #onCreateView(LayoutInflater, ViewGroup, Bundle)}. 877 * 878 * <p>Note that this can be called while the fragment's activity is 879 * still in the process of being created. As such, you can not rely 880 * on things like the activity's content view hierarchy being initialized 881 * at this point. If you want to do work once the activity itself is 882 * created, see {@link #onActivityCreated(Bundle)}. 883 * 884 * @param savedInstanceState If the fragment is being re-created from 885 * a previous saved state, this is the state. 886 */ 887 public void onCreate(Bundle savedInstanceState) { 888 mCalled = true; 889 } 890 891 /** 892 * Called to have the fragment instantiate its user interface view. 893 * This is optional, and non-graphical fragments can return null (which 894 * is the default implementation). This will be called between 895 * {@link #onCreate(Bundle)} and {@link #onActivityCreated(Bundle)}. 896 * 897 * <p>If you return a View from here, you will later be called in 898 * {@link #onDestroyView} when the view is being released. 899 * 900 * @param inflater The LayoutInflater object that can be used to inflate 901 * any views in the fragment, 902 * @param container If non-null, this is the parent view that the fragment's 903 * UI should be attached to. The fragment should not add the view itself, 904 * but this can be used to generate the LayoutParams of the view. 905 * @param savedInstanceState If non-null, this fragment is being re-constructed 906 * from a previous saved state as given here. 907 * 908 * @return Return the View for the fragment's UI, or null. 909 */ 910 public View onCreateView(LayoutInflater inflater, ViewGroup container, 911 Bundle savedInstanceState) { 912 return null; 913 } 914 915 public View getView() { 916 return mView; 917 } 918 919 /** 920 * Called when the fragment's activity has been created and this 921 * fragment's view hierarchy instantiated. It can be used to do final 922 * initialization once these pieces are in place, such as retrieving 923 * views or restoring state. It is also useful for fragments that use 924 * {@link #setRetainInstance(boolean)} to retain their instance, 925 * as this callback tells the fragment when it is fully associated with 926 * the new activity instance. This is called after {@link #onCreateView} 927 * and before {@link #onStart()}. 928 * 929 * @param savedInstanceState If the fragment is being re-created from 930 * a previous saved state, this is the state. 931 */ 932 public void onActivityCreated(Bundle savedInstanceState) { 933 mCalled = true; 934 } 935 936 /** 937 * Called when the Fragment is visible to the user. This is generally 938 * tied to {@link Activity#onStart() Activity.onStart} of the containing 939 * Activity's lifecycle. 940 */ 941 public void onStart() { 942 mCalled = true; 943 944 if (!mLoadersStarted) { 945 mLoadersStarted = true; 946 if (!mCheckedForLoaderManager) { 947 mCheckedForLoaderManager = true; 948 mLoaderManager = mActivity.getLoaderManager(mIndex, mLoadersStarted, false); 949 } 950 if (mLoaderManager != null) { 951 mLoaderManager.doStart(); 952 } 953 } 954 } 955 956 /** 957 * Called when the fragment is visible to the user and actively running. 958 * This is generally 959 * tied to {@link Activity#onResume() Activity.onResume} of the containing 960 * Activity's lifecycle. 961 */ 962 public void onResume() { 963 mCalled = true; 964 } 965 966 /** 967 * Called to ask the fragment to save its current dynamic state, so it 968 * can later be reconstructed in a new instance of its process is 969 * restarted. If a new instance of the fragment later needs to be 970 * created, the data you place in the Bundle here will be available 971 * in the Bundle given to {@link #onCreate(Bundle)}, 972 * {@link #onCreateView(LayoutInflater, ViewGroup, Bundle)}, and 973 * {@link #onActivityCreated(Bundle)}. 974 * 975 * <p>This corresponds to {@link Activity#onSaveInstanceState(Bundle) 976 * Activity.onSaveInstanceState(Bundle)} and most of the discussion there 977 * applies here as well. Note however: <em>this method may be called 978 * at any time before {@link #onDestroy()}</em>. There are many situations 979 * where a fragment may be mostly torn down (such as when placed on the 980 * back stack with no UI showing), but its state will not be saved until 981 * its owning activity actually needs to save its state. 982 * 983 * @param outState Bundle in which to place your saved state. 984 */ 985 public void onSaveInstanceState(Bundle outState) { 986 } 987 988 public void onConfigurationChanged(Configuration newConfig) { 989 mCalled = true; 990 } 991 992 /** 993 * Called when the Fragment is no longer resumed. This is generally 994 * tied to {@link Activity#onPause() Activity.onPause} of the containing 995 * Activity's lifecycle. 996 */ 997 public void onPause() { 998 mCalled = true; 999 } 1000 1001 /** 1002 * Called when the Fragment is no longer started. This is generally 1003 * tied to {@link Activity#onStop() Activity.onStop} of the containing 1004 * Activity's lifecycle. 1005 */ 1006 public void onStop() { 1007 mCalled = true; 1008 } 1009 1010 public void onLowMemory() { 1011 mCalled = true; 1012 } 1013 1014 /** 1015 * Called when the view previously created by {@link #onCreateView} has 1016 * been detached from the fragment. The next time the fragment needs 1017 * to be displayed, a new view will be created. This is called 1018 * after {@link #onStop()} and before {@link #onDestroy()}. It is called 1019 * <em>regardless</em> of whether {@link #onCreateView} returned a 1020 * non-null view. Internally it is called after the view's state has 1021 * been saved but before it has been removed from its parent. 1022 */ 1023 public void onDestroyView() { 1024 mCalled = true; 1025 } 1026 1027 /** 1028 * Called when the fragment is no longer in use. This is called 1029 * after {@link #onStop()} and before {@link #onDetach()}. 1030 */ 1031 public void onDestroy() { 1032 mCalled = true; 1033 //Log.v("foo", "onDestroy: mCheckedForLoaderManager=" + mCheckedForLoaderManager 1034 // + " mLoaderManager=" + mLoaderManager); 1035 if (!mCheckedForLoaderManager) { 1036 mCheckedForLoaderManager = true; 1037 mLoaderManager = mActivity.getLoaderManager(mIndex, mLoadersStarted, false); 1038 } 1039 if (mLoaderManager != null) { 1040 mLoaderManager.doDestroy(); 1041 } 1042 } 1043 1044 /** 1045 * Called when the fragment is no longer attached to its activity. This 1046 * is called after {@link #onDestroy()}. 1047 */ 1048 public void onDetach() { 1049 mCalled = true; 1050 } 1051 1052 /** 1053 * Initialize the contents of the Activity's standard options menu. You 1054 * should place your menu items in to <var>menu</var>. For this method 1055 * to be called, you must have first called {@link #setHasOptionsMenu}. See 1056 * {@link Activity#onCreateOptionsMenu(Menu) Activity.onCreateOptionsMenu} 1057 * for more information. 1058 * 1059 * @param menu The options menu in which you place your items. 1060 * 1061 * @see #setHasOptionsMenu 1062 * @see #onPrepareOptionsMenu 1063 * @see #onOptionsItemSelected 1064 */ 1065 public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) { 1066 } 1067 1068 /** 1069 * Prepare the Screen's standard options menu to be displayed. This is 1070 * called right before the menu is shown, every time it is shown. You can 1071 * use this method to efficiently enable/disable items or otherwise 1072 * dynamically modify the contents. See 1073 * {@link Activity#onPrepareOptionsMenu(Menu) Activity.onPrepareOptionsMenu} 1074 * for more information. 1075 * 1076 * @param menu The options menu as last shown or first initialized by 1077 * onCreateOptionsMenu(). 1078 * 1079 * @see #setHasOptionsMenu 1080 * @see #onCreateOptionsMenu 1081 */ 1082 public void onPrepareOptionsMenu(Menu menu) { 1083 } 1084 1085 /** 1086 * Called when this fragment's option menu items are no longer being 1087 * included in the overall options menu. Receiving this call means that 1088 * the menu needed to be rebuilt, but this fragment's items were not 1089 * included in the newly built menu (its {@link #onCreateOptionsMenu(Menu, MenuInflater)} 1090 * was not called). 1091 */ 1092 public void onDestroyOptionsMenu() { 1093 } 1094 1095 /** 1096 * This hook is called whenever an item in your options menu is selected. 1097 * The default implementation simply returns false to have the normal 1098 * processing happen (calling the item's Runnable or sending a message to 1099 * its Handler as appropriate). You can use this method for any items 1100 * for which you would like to do processing without those other 1101 * facilities. 1102 * 1103 * <p>Derived classes should call through to the base class for it to 1104 * perform the default menu handling. 1105 * 1106 * @param item The menu item that was selected. 1107 * 1108 * @return boolean Return false to allow normal menu processing to 1109 * proceed, true to consume it here. 1110 * 1111 * @see #onCreateOptionsMenu 1112 */ 1113 public boolean onOptionsItemSelected(MenuItem item) { 1114 return false; 1115 } 1116 1117 /** 1118 * This hook is called whenever the options menu is being closed (either by the user canceling 1119 * the menu with the back/menu button, or when an item is selected). 1120 * 1121 * @param menu The options menu as last shown or first initialized by 1122 * onCreateOptionsMenu(). 1123 */ 1124 public void onOptionsMenuClosed(Menu menu) { 1125 } 1126 1127 /** 1128 * Called when a context menu for the {@code view} is about to be shown. 1129 * Unlike {@link #onCreateOptionsMenu}, this will be called every 1130 * time the context menu is about to be shown and should be populated for 1131 * the view (or item inside the view for {@link AdapterView} subclasses, 1132 * this can be found in the {@code menuInfo})). 1133 * <p> 1134 * Use {@link #onContextItemSelected(android.view.MenuItem)} to know when an 1135 * item has been selected. 1136 * <p> 1137 * The default implementation calls up to 1138 * {@link Activity#onCreateContextMenu Activity.onCreateContextMenu}, though 1139 * you can not call this implementation if you don't want that behavior. 1140 * <p> 1141 * It is not safe to hold onto the context menu after this method returns. 1142 * {@inheritDoc} 1143 */ 1144 public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) { 1145 getActivity().onCreateContextMenu(menu, v, menuInfo); 1146 } 1147 1148 /** 1149 * Registers a context menu to be shown for the given view (multiple views 1150 * can show the context menu). This method will set the 1151 * {@link OnCreateContextMenuListener} on the view to this fragment, so 1152 * {@link #onCreateContextMenu(ContextMenu, View, ContextMenuInfo)} will be 1153 * called when it is time to show the context menu. 1154 * 1155 * @see #unregisterForContextMenu(View) 1156 * @param view The view that should show a context menu. 1157 */ 1158 public void registerForContextMenu(View view) { 1159 view.setOnCreateContextMenuListener(this); 1160 } 1161 1162 /** 1163 * Prevents a context menu to be shown for the given view. This method will 1164 * remove the {@link OnCreateContextMenuListener} on the view. 1165 * 1166 * @see #registerForContextMenu(View) 1167 * @param view The view that should stop showing a context menu. 1168 */ 1169 public void unregisterForContextMenu(View view) { 1170 view.setOnCreateContextMenuListener(null); 1171 } 1172 1173 /** 1174 * This hook is called whenever an item in a context menu is selected. The 1175 * default implementation simply returns false to have the normal processing 1176 * happen (calling the item's Runnable or sending a message to its Handler 1177 * as appropriate). You can use this method for any items for which you 1178 * would like to do processing without those other facilities. 1179 * <p> 1180 * Use {@link MenuItem#getMenuInfo()} to get extra information set by the 1181 * View that added this menu item. 1182 * <p> 1183 * Derived classes should call through to the base class for it to perform 1184 * the default menu handling. 1185 * 1186 * @param item The context menu item that was selected. 1187 * @return boolean Return false to allow normal context menu processing to 1188 * proceed, true to consume it here. 1189 */ 1190 public boolean onContextItemSelected(MenuItem item) { 1191 return false; 1192 } 1193 1194 /** 1195 * Print the Fragments's state into the given stream. 1196 * 1197 * @param prefix Text to print at the front of each line. 1198 * @param fd The raw file descriptor that the dump is being sent to. 1199 * @param writer The PrintWriter to which you should dump your state. This will be 1200 * closed for you after you return. 1201 * @param args additional arguments to the dump request. 1202 */ 1203 public void dump(String prefix, FileDescriptor fd, PrintWriter writer, String[] args) { 1204 writer.print(prefix); writer.print("mFragmentId=#"); 1205 writer.print(Integer.toHexString(mFragmentId)); 1206 writer.print(" mContainerId#="); 1207 writer.print(Integer.toHexString(mContainerId)); 1208 writer.print(" mTag="); writer.println(mTag); 1209 writer.print(prefix); writer.print("mState="); writer.print(mState); 1210 writer.print(" mIndex="); writer.print(mIndex); 1211 writer.print(" mWho="); writer.print(mWho); 1212 writer.print(" mBackStackNesting="); writer.println(mBackStackNesting); 1213 writer.print(prefix); writer.print("mAdded="); writer.print(mAdded); 1214 writer.print(" mResumed="); writer.print(mResumed); 1215 writer.print(" mFromLayout="); writer.print(mFromLayout); 1216 writer.print(" mInLayout="); writer.println(mInLayout); 1217 writer.print(prefix); writer.print("mHidden="); writer.print(mHidden); 1218 writer.print(" mRetainInstance="); writer.print(mRetainInstance); 1219 writer.print(" mRetaining="); writer.print(mRetaining); 1220 writer.print(" mHasMenu="); writer.println(mHasMenu); 1221 if (mFragmentManager != null) { 1222 writer.print(prefix); writer.print("mFragmentManager="); 1223 writer.println(mFragmentManager); 1224 } 1225 if (mImmediateActivity != null) { 1226 writer.print(prefix); writer.print("mImmediateActivity="); 1227 writer.println(mImmediateActivity); 1228 } 1229 if (mActivity != null) { 1230 writer.print(prefix); writer.print("mActivity="); 1231 writer.println(mActivity); 1232 } 1233 if (mArguments != null) { 1234 writer.print(prefix); writer.print("mArguments="); writer.println(mArguments); 1235 } 1236 if (mSavedFragmentState != null) { 1237 writer.print(prefix); writer.print("mSavedFragmentState="); 1238 writer.println(mSavedFragmentState); 1239 } 1240 if (mSavedViewState != null) { 1241 writer.print(prefix); writer.print("mSavedViewState="); 1242 writer.println(mSavedViewState); 1243 } 1244 if (mTarget != null) { 1245 writer.print(prefix); writer.print("mTarget="); writer.print(mTarget); 1246 writer.print(" mTargetRequestCode="); 1247 writer.println(mTargetRequestCode); 1248 } 1249 if (mNextAnim != 0) { 1250 writer.print(prefix); writer.print("mNextAnim="); writer.println(mNextAnim); 1251 } 1252 if (mContainer != null) { 1253 writer.print(prefix); writer.print("mContainer="); writer.println(mContainer); 1254 } 1255 if (mView != null) { 1256 writer.print(prefix); writer.print("mView="); writer.println(mView); 1257 } 1258 if (mAnimatingAway != null) { 1259 writer.print(prefix); writer.print("mAnimatingAway="); writer.println(mAnimatingAway); 1260 writer.print(prefix); writer.print("mStateAfterAnimating="); 1261 writer.println(mStateAfterAnimating); 1262 } 1263 if (mLoaderManager != null) { 1264 writer.print(prefix); writer.println("Loader Manager:"); 1265 mLoaderManager.dump(prefix + " ", fd, writer, args); 1266 } 1267 } 1268 1269 void performStop() { 1270 onStop(); 1271 1272 if (mLoadersStarted) { 1273 mLoadersStarted = false; 1274 if (!mCheckedForLoaderManager) { 1275 mCheckedForLoaderManager = true; 1276 mLoaderManager = mActivity.getLoaderManager(mIndex, mLoadersStarted, false); 1277 } 1278 if (mLoaderManager != null) { 1279 if (mActivity == null || !mActivity.mChangingConfigurations) { 1280 mLoaderManager.doStop(); 1281 } else { 1282 mLoaderManager.doRetain(); 1283 } 1284 } 1285 } 1286 } 1287} 1288