Fragment.java revision b31e84bc4513e46bac4be8f8d0513f78e360fb11
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.content.ComponentCallbacks; 20import android.content.Intent; 21import android.content.res.Configuration; 22import android.os.Bundle; 23import android.os.Parcel; 24import android.os.Parcelable; 25import android.util.AttributeSet; 26import android.util.SparseArray; 27import android.view.LayoutInflater; 28import android.view.Menu; 29import android.view.MenuInflater; 30import android.view.MenuItem; 31import android.view.View; 32import android.view.ViewGroup; 33import android.view.animation.Animation; 34 35import java.lang.reflect.InvocationTargetException; 36import java.util.HashMap; 37 38final class FragmentState implements Parcelable { 39 static final String VIEW_STATE_TAG = "android:view_state"; 40 41 final String mClassName; 42 final int mIndex; 43 final boolean mFromLayout; 44 final int mFragmentId; 45 final int mContainerId; 46 final String mTag; 47 final boolean mRetainInstance; 48 49 Bundle mSavedFragmentState; 50 51 Fragment mInstance; 52 53 public FragmentState(Fragment frag) { 54 mClassName = frag.getClass().getName(); 55 mIndex = frag.mIndex; 56 mFromLayout = frag.mFromLayout; 57 mFragmentId = frag.mFragmentId; 58 mContainerId = frag.mContainerId; 59 mTag = frag.mTag; 60 mRetainInstance = frag.mRetainInstance; 61 } 62 63 public FragmentState(Parcel in) { 64 mClassName = in.readString(); 65 mIndex = in.readInt(); 66 mFromLayout = in.readInt() != 0; 67 mFragmentId = in.readInt(); 68 mContainerId = in.readInt(); 69 mTag = in.readString(); 70 mRetainInstance = in.readInt() != 0; 71 mSavedFragmentState = in.readBundle(); 72 } 73 74 public Fragment instantiate(Activity activity) { 75 if (mInstance != null) { 76 return mInstance; 77 } 78 79 try { 80 mInstance = Fragment.instantiate(activity, mClassName); 81 } catch (Exception e) { 82 throw new RuntimeException("Unable to restore fragment " + mClassName, e); 83 } 84 85 if (mSavedFragmentState != null) { 86 mSavedFragmentState.setClassLoader(activity.getClassLoader()); 87 mInstance.mSavedFragmentState = mSavedFragmentState; 88 mInstance.mSavedViewState 89 = mSavedFragmentState.getSparseParcelableArray(VIEW_STATE_TAG); 90 } 91 mInstance.setIndex(mIndex); 92 mInstance.mFromLayout = mFromLayout; 93 mInstance.mFragmentId = mFragmentId; 94 mInstance.mContainerId = mContainerId; 95 mInstance.mTag = mTag; 96 mInstance.mRetainInstance = mRetainInstance; 97 98 return mInstance; 99 } 100 101 public int describeContents() { 102 return 0; 103 } 104 105 public void writeToParcel(Parcel dest, int flags) { 106 dest.writeString(mClassName); 107 dest.writeInt(mIndex); 108 dest.writeInt(mFromLayout ? 1 : 0); 109 dest.writeInt(mFragmentId); 110 dest.writeInt(mContainerId); 111 dest.writeString(mTag); 112 dest.writeInt(mRetainInstance ? 1 : 0); 113 dest.writeBundle(mSavedFragmentState); 114 } 115 116 public static final Parcelable.Creator<FragmentState> CREATOR 117 = new Parcelable.Creator<FragmentState>() { 118 public FragmentState createFromParcel(Parcel in) { 119 return new FragmentState(in); 120 } 121 122 public FragmentState[] newArray(int size) { 123 return new FragmentState[size]; 124 } 125 }; 126} 127 128/** 129 * A Fragment is a piece of an application's user interface or behavior 130 * that can be placed in an {@link Activity}. 131 */ 132public class Fragment implements ComponentCallbacks { 133 private static final HashMap<String, Class> sClassMap = 134 new HashMap<String, Class>(); 135 136 static final int INITIALIZING = 0; // Not yet created. 137 static final int CREATED = 1; // Created. 138 static final int CONTENT = 2; // View hierarchy content available. 139 static final int STARTED = 3; // Created and started, not resumed. 140 static final int RESUMED = 4; // Created started and resumed. 141 142 int mState = INITIALIZING; 143 144 // When instantiated from saved state, this is the saved state. 145 Bundle mSavedFragmentState; 146 SparseArray<Parcelable> mSavedViewState; 147 148 // Index into active fragment array. 149 int mIndex = -1; 150 151 // Internal unique name for this fragment; 152 String mWho; 153 154 // True if the fragment is in the list of added fragments. 155 boolean mAdded; 156 157 // Set to true if this fragment was instantiated from a layout file. 158 boolean mFromLayout; 159 160 // Number of active back stack entries this fragment is in. 161 int mBackStackNesting; 162 163 // Set as soon as a fragment is added to a transaction (or removed), 164 // to be able to do validation. 165 Activity mImmediateActivity; 166 167 // Activity this fragment is attached to. 168 Activity mActivity; 169 170 // The optional identifier for this fragment -- either the container ID if it 171 // was dynamically added to the view hierarchy, or the ID supplied in 172 // layout. 173 int mFragmentId; 174 175 // When a fragment is being dynamically added to the view hierarchy, this 176 // is the identifier of the parent container it is being added to. 177 int mContainerId; 178 179 // The optional named tag for this fragment -- usually used to find 180 // fragments that are not part of the layout. 181 String mTag; 182 183 // Set to true when the app has requested that this fragment be hidden 184 // from the user. 185 boolean mHidden; 186 187 // If set this fragment would like its instance retained across 188 // configuration changes. 189 boolean mRetainInstance; 190 191 // If set this fragment is being retained across the current config change. 192 boolean mRetaining; 193 194 // If set this fragment has menu items to contribute. 195 boolean mHasMenu; 196 197 // Used to verify that subclasses call through to super class. 198 boolean mCalled; 199 200 // If app has requested a specific animation, this is the one to use. 201 int mNextAnim; 202 203 // The parent container of the fragment after dynamically added to UI. 204 ViewGroup mContainer; 205 206 // The View generated for this fragment. 207 View mView; 208 209 public Fragment() { 210 } 211 212 static Fragment instantiate(Activity activity, String fname) 213 throws NoSuchMethodException, ClassNotFoundException, 214 IllegalArgumentException, InstantiationException, 215 IllegalAccessException, InvocationTargetException { 216 Class clazz = sClassMap.get(fname); 217 218 if (clazz == null) { 219 // Class not found in the cache, see if it's real, and try to add it 220 clazz = activity.getClassLoader().loadClass(fname); 221 sClassMap.put(fname, clazz); 222 } 223 return (Fragment)clazz.newInstance(); 224 } 225 226 void restoreViewState() { 227 if (mSavedViewState != null) { 228 mView.restoreHierarchyState(mSavedViewState); 229 mSavedViewState = null; 230 } 231 } 232 233 void setIndex(int index) { 234 mIndex = index; 235 mWho = "android:fragment:" + mIndex; 236 } 237 238 void clearIndex() { 239 mIndex = -1; 240 mWho = null; 241 } 242 243 /** 244 * Subclasses can not override equals(). 245 */ 246 @Override final public boolean equals(Object o) { 247 return super.equals(o); 248 } 249 250 /** 251 * Subclasses can not override hashCode(). 252 */ 253 @Override final public int hashCode() { 254 return super.hashCode(); 255 } 256 257 @Override 258 public String toString() { 259 StringBuilder sb = new StringBuilder(128); 260 sb.append("Fragment{"); 261 sb.append(Integer.toHexString(System.identityHashCode(this))); 262 if (mIndex >= 0) { 263 sb.append(" #"); 264 sb.append(mIndex); 265 } 266 if (mFragmentId != 0) { 267 sb.append(" id=0x"); 268 sb.append(Integer.toHexString(mFragmentId)); 269 } 270 if (mTag != null) { 271 sb.append(" "); 272 sb.append(mTag); 273 } 274 sb.append('}'); 275 return sb.toString(); 276 } 277 278 /** 279 * Return the identifier this fragment is known by. This is either 280 * the android:id value supplied in a layout or the container view ID 281 * supplied when adding the fragment. 282 */ 283 final public int getId() { 284 return mFragmentId; 285 } 286 287 /** 288 * Get the tag name of the fragment, if specified. 289 */ 290 final public String getTag() { 291 return mTag; 292 } 293 294 /** 295 * Return the Activity this fragment is currently associated with. 296 */ 297 final public Activity getActivity() { 298 return mActivity; 299 } 300 301 /** 302 * Return true if the fragment is currently added to its activity. 303 */ 304 final public boolean isAdded() { 305 return mActivity != null && mActivity.mFragments.mAdded.contains(this); 306 } 307 308 /** 309 * Return true if the fragment is currently visible to the user. This means 310 * it: (1) has been added, (2) has its view attached to the window, and 311 * (3) is not hidden. 312 */ 313 final public boolean isVisible() { 314 return isAdded() && !isHidden() && mView != null 315 && mView.getWindowToken() != null && mView.getVisibility() == View.VISIBLE; 316 } 317 318 /** 319 * Return true if the fragment has been hidden. By default fragments 320 * are shown. You can find out about changes to this state with 321 * {@link #onHiddenChanged}. Note that the hidden state is orthogonal 322 * to other states -- that is, to be visible to the user, a fragment 323 * must be both started and not hidden. 324 */ 325 final public boolean isHidden() { 326 return mHidden; 327 } 328 329 /** 330 * Called when the hidden state (as returned by {@link #isHidden()} of 331 * the fragment has changed. Fragments start out not hidden; this will 332 * be called whenever the fragment changes state from that. 333 * @param hidden True if the fragment is now hidden, false if it is not 334 * visible. 335 */ 336 public void onHiddenChanged(boolean hidden) { 337 } 338 339 /** 340 * Control whether a fragment instance is retained across Activity 341 * re-creation (such as from a configuration change). This can only 342 * be used with fragments not in the back stack. If set, the fragment 343 * lifecycle will be slightly different when an activity is recreated: 344 * <ul> 345 * <li> {@link #onDestroy()} will not be called (but {@link #onDetach()} still 346 * will be, because the fragment is being detached from its current activity). 347 * <li> {@link #onCreate(Bundle)} will not be called since the fragment 348 * is not being re-created. 349 * <li> {@link #onAttach(Activity)} and {@link #onReady(Bundle)} <b>will</b> 350 * still be called. 351 * </ul> 352 */ 353 public void setRetainInstance(boolean retain) { 354 mRetainInstance = retain; 355 } 356 357 final public boolean getRetainInstance() { 358 return mRetainInstance; 359 } 360 361 /** 362 * Report that this fragment would like to participate in populating 363 * the options menu by receiving a call to {@link #onCreateOptionsMenu(Menu)} 364 * and related methods. 365 * 366 * @param hasMenu If true, the fragment has menu items to contribute. 367 */ 368 public void setHasOptionsMenu(boolean hasMenu) { 369 if (mHasMenu != hasMenu) { 370 mHasMenu = hasMenu; 371 if (isAdded() && !isHidden()) { 372 mActivity.invalidateOptionsMenu(); 373 } 374 } 375 } 376 377 /** 378 * Call {@link Activity#startActivity(Intent)} on the fragment's 379 * containing Activity. 380 */ 381 public void startActivity(Intent intent) { 382 mActivity.startActivityFromFragment(this, intent, -1); 383 } 384 385 /** 386 * Call {@link Activity#startActivityForResult(Intent, int)} on the fragment's 387 * containing Activity. 388 */ 389 public void startActivityForResult(Intent intent, int requestCode) { 390 mActivity.startActivityFromFragment(this, intent, requestCode); 391 } 392 393 /** 394 * Receive the result from a previous call to 395 * {@link #startActivityForResult(Intent, int)}. This follows the 396 * related Activity API as described there in 397 * {@link Activity#onActivityResult(int, int, Intent)}. 398 * 399 * @param requestCode The integer request code originally supplied to 400 * startActivityForResult(), allowing you to identify who this 401 * result came from. 402 * @param resultCode The integer result code returned by the child activity 403 * through its setResult(). 404 * @param data An Intent, which can return result data to the caller 405 * (various data can be attached to Intent "extras"). 406 */ 407 public void onActivityResult(int requestCode, int resultCode, Intent data) { 408 } 409 410 /** 411 * Called when a fragment is being created as part of a view layout 412 * inflation, typically from setting the content view of an activity. This 413 * will be called both the first time the fragment is created, as well 414 * later when it is being re-created from its saved state (which is also 415 * given here). 416 * 417 * XXX This is kind-of yucky... maybe we could just supply the 418 * AttributeSet to onCreate()? 419 * 420 * @param activity The Activity that is inflating the fragment. 421 * @param attrs The attributes at the tag where the fragment is 422 * being created. 423 * @param savedInstanceState If the fragment is being re-created from 424 * a previous saved state, this is the state. 425 */ 426 public void onInflate(Activity activity, AttributeSet attrs, 427 Bundle savedInstanceState) { 428 mCalled = true; 429 } 430 431 /** 432 * Called when a fragment is first attached to its activity. 433 * {@link #onCreate(Bundle)} will be called after this. 434 */ 435 public void onAttach(Activity activity) { 436 mCalled = true; 437 } 438 439 public Animation onCreateAnimation(int transit, boolean enter, int nextAnim) { 440 return null; 441 } 442 443 /** 444 * Called to do initial creation of a fragment. This is called after 445 * {@link #onAttach(Activity)} and before {@link #onReady(Bundle)}. 446 * @param savedInstanceState If the fragment is being re-created from 447 * a previous saved state, this is the state. 448 */ 449 public void onCreate(Bundle savedInstanceState) { 450 mCalled = true; 451 } 452 453 /** 454 * Called to have the fragment instantiate its user interface view. 455 * This is optional, and non-graphical fragments can return null (which 456 * is the default implementation). This will be called between 457 * {@link #onCreate(Bundle)} and {@link #onReady(Bundle)}. 458 * 459 * @param inflater The LayoutInflater object that can be used to inflate 460 * any views in the fragment, 461 * @param container If non-null, this is the parent view that the fragment's 462 * UI should be attached to. The fragment should not add the view itself, 463 * but this can be used to generate the LayoutParams of the view. 464 * @param savedInstanceState If non-null, this fragment is being re-constructed 465 * from a previous saved state as given here. 466 * 467 * @return Return the View for the fragment's UI, or null. 468 */ 469 public View onCreateView(LayoutInflater inflater, ViewGroup container, 470 Bundle savedInstanceState) { 471 return null; 472 } 473 474 public View getView() { 475 return mView; 476 } 477 478 /** 479 * Called when the activity is ready for the fragment to run. This is 480 * most useful for fragments that use {@link #setRetainInstance(boolean)} 481 * instance, as this tells the fragment when it is fully associated with 482 * the new activity instance. This is called after {@link #onCreate(Bundle)} 483 * and before {@link #onStart()}. 484 * 485 * @param savedInstanceState If the fragment is being re-created from 486 * a previous saved state, this is the state. 487 */ 488 public void onReady(Bundle savedInstanceState) { 489 mCalled = true; 490 } 491 492 /** 493 * Called when the Fragment is visible to the user. This is generally 494 * tied to {@link Activity#onStart() Activity.onStart} of the containing 495 * Activity's lifecycle. 496 */ 497 public void onStart() { 498 mCalled = true; 499 } 500 501 /** 502 * Called when the fragment is visible to the user and actively running. 503 * This is generally 504 * tied to {@link Activity#onResume() Activity.onResume} of the containing 505 * Activity's lifecycle. 506 */ 507 public void onResume() { 508 mCalled = true; 509 } 510 511 public void onSaveInstanceState(Bundle outState) { 512 } 513 514 public void onConfigurationChanged(Configuration newConfig) { 515 mCalled = true; 516 } 517 518 /** 519 * Called when the Fragment is no longer resumed. This is generally 520 * tied to {@link Activity#onPause() Activity.onPause} of the containing 521 * Activity's lifecycle. 522 */ 523 public void onPause() { 524 mCalled = true; 525 } 526 527 /** 528 * Called when the Fragment is no longer started. This is generally 529 * tied to {@link Activity#onStop() Activity.onStop} of the containing 530 * Activity's lifecycle. 531 */ 532 public void onStop() { 533 mCalled = true; 534 } 535 536 public void onLowMemory() { 537 mCalled = true; 538 } 539 540 /** 541 * Called when the fragment is no longer in use. This is called 542 * after {@link #onStop()} and before {@link #onDetach()}. 543 */ 544 public void onDestroy() { 545 mCalled = true; 546 } 547 548 /** 549 * Called when the fragment is no longer attached to its activity. This 550 * is called after {@link #onDestroy()}. 551 */ 552 public void onDetach() { 553 mCalled = true; 554 } 555 556 /** 557 * Initialize the contents of the Activity's standard options menu. You 558 * should place your menu items in to <var>menu</var>. For this method 559 * to be called, you must have first called {@link #setHasMenu}. See 560 * {@link Activity#onCreateOptionsMenu(Menu) Activity.onCreateOptionsMenu} 561 * for more information. 562 * 563 * @param menu The options menu in which you place your items. 564 * 565 * @see #setHasMenu 566 * @see #onPrepareOptionsMenu 567 * @see #onOptionsItemSelected 568 */ 569 public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) { 570 } 571 572 /** 573 * Prepare the Screen's standard options menu to be displayed. This is 574 * called right before the menu is shown, every time it is shown. You can 575 * use this method to efficiently enable/disable items or otherwise 576 * dynamically modify the contents. See 577 * {@link Activity#onPrepareOptionsMenu(Menu) Activity.onPrepareOptionsMenu} 578 * for more information. 579 * 580 * @param menu The options menu as last shown or first initialized by 581 * onCreateOptionsMenu(). 582 * 583 * @see #setHasMenu 584 * @see #onCreateOptionsMenu 585 */ 586 public void onPrepareOptionsMenu(Menu menu) { 587 } 588 589 /** 590 * This hook is called whenever an item in your options menu is selected. 591 * The default implementation simply returns false to have the normal 592 * processing happen (calling the item's Runnable or sending a message to 593 * its Handler as appropriate). You can use this method for any items 594 * for which you would like to do processing without those other 595 * facilities. 596 * 597 * <p>Derived classes should call through to the base class for it to 598 * perform the default menu handling. 599 * 600 * @param item The menu item that was selected. 601 * 602 * @return boolean Return false to allow normal menu processing to 603 * proceed, true to consume it here. 604 * 605 * @see #onCreateOptionsMenu 606 */ 607 public boolean onOptionsItemSelected(MenuItem item) { 608 return false; 609 } 610 611 /** 612 * This hook is called whenever the options menu is being closed (either by the user canceling 613 * the menu with the back/menu button, or when an item is selected). 614 * 615 * @param menu The options menu as last shown or first initialized by 616 * onCreateOptionsMenu(). 617 */ 618 public void onOptionsMenuClosed(Menu menu) { 619 } 620} 621