| 1 | /* |
| 2 | * Copyright (C) 2011 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 | |
| 17 | package android.support.v2.app; |
| 18 | |
| 19 | import android.app.Activity; |
| 20 | import android.os.Bundle; |
| 21 | import android.support.v2.content.Loader; |
| 22 | import android.support.v2.util.DebugUtils; |
| 23 | import android.util.Log; |
| 24 | |
| 25 | import java.io.FileDescriptor; |
| 26 | import java.io.PrintWriter; |
| 27 | import java.lang.reflect.Modifier; |
| 28 | |
| 29 | /** |
| 30 | * Static library support version of the framework's {@link android.app.LoaderManager}. |
| 31 | * Used to write apps that run on platforms prior to Android 3.0. When running |
| 32 | * on Android 3.0 or above, this implementation is still used; it does not try |
| 33 | * to switch to the framework's implementation. See the framework SDK |
| 34 | * documentation for a class overview. |
| 35 | * |
| 36 | * <p>Your activity must derive from {@link FragmentActivity} to use this. |
| 37 | */ |
| 38 | public abstract class LoaderManager { |
| 39 | /** |
| 40 | * Callback interface for a client to interact with the manager. |
| 41 | */ |
| 42 | public interface LoaderCallbacks<D> { |
| 43 | /** |
| 44 | * Instantiate and return a new Loader for the given ID. |
| 45 | * |
| 46 | * @param id The ID whose loader is to be created. |
| 47 | * @param args Any arguments supplied by the caller. |
| 48 | * @return Return a new Loader instance that is ready to start loading. |
| 49 | */ |
| 50 | public Loader<D> onCreateLoader(int id, Bundle args); |
| 51 | |
| 52 | /** |
| 53 | * Called when a previously created loader has finished its load. Note |
| 54 | * that normally an application is <em>not</em> allowed to commit fragment |
| 55 | * transactions while in this call, since it can happen after an |
| 56 | * activity's state is saved. See {@link FragmentManager#beginTransaction() |
| 57 | * FragmentManager.openTransaction()} for further discussion on this. |
| 58 | * |
| 59 | * <p>This function is guaranteed to be called prior to the release of |
| 60 | * the last data that was supplied for this Loader. At this point |
| 61 | * you should remove all use of the old data (since it will be released |
| 62 | * soon), but should not do your own release of the data since its Loader |
| 63 | * owns it and will take care of that. The Loader will take care of |
| 64 | * management of its data so you don't have to. In particular: |
| 65 | * |
| 66 | * <ul> |
| 67 | * <li> <p>The Loader will monitor for changes to the data, and report |
| 68 | * them to you through new calls here. You should not monitor the |
| 69 | * data yourself. For example, if the data is a {@link android.database.Cursor} |
| 70 | * and you place it in a {@link android.widget.CursorAdapter}, use |
| 71 | * the {@link android.widget.CursorAdapter#CursorAdapter(android.content.Context, |
| 72 | * android.database.Cursor, int)} constructor <em>without</em> passing |
| 73 | * in either {@link android.widget.CursorAdapter#FLAG_AUTO_REQUERY} |
| 74 | * or {@link android.widget.CursorAdapter#FLAG_REGISTER_CONTENT_OBSERVER} |
| 75 | * (that is, use 0 for the flags argument). This prevents the CursorAdapter |
| 76 | * from doing its own observing of the Cursor, which is not needed since |
| 77 | * when a change happens you will get a new Cursor throw another call |
| 78 | * here. |
| 79 | * <li> The Loader will release the data once it knows the application |
| 80 | * is no longer using it. For example, if the data is |
| 81 | * a {@link android.database.Cursor} from a {@link android.content.CursorLoader}, |
| 82 | * you should not call close() on it yourself. If the Cursor is being placed in a |
| 83 | * {@link android.widget.CursorAdapter}, you should use the |
| 84 | * {@link android.widget.CursorAdapter#swapCursor(android.database.Cursor)} |
| 85 | * method so that the old Cursor is not closed. |
| 86 | * </ul> |
| 87 | * |
| 88 | * @param loader The Loader that has finished. |
| 89 | * @param data The data generated by the Loader. |
| 90 | */ |
| 91 | public void onLoadFinished(Loader<D> loader, D data); |
| 92 | |
| 93 | /** |
| 94 | * Called when a previously created loader is being reset, and thus |
| 95 | * making its data unavailable. The application should at this point |
| 96 | * remove any references it has to the Loader's data. |
| 97 | * |
| 98 | * @param loader The Loader that is being reset. |
| 99 | */ |
| 100 | public void onLoaderReset(Loader<D> loader); |
| 101 | } |
| 102 | |
| 103 | /** |
| 104 | * Ensures a loader is initialized and active. If the loader doesn't |
| 105 | * already exist, one is created and (if the activity/fragment is currently |
| 106 | * started) starts the loader. Otherwise the last created |
| 107 | * loader is re-used. |
| 108 | * |
| 109 | * <p>In either case, the given callback is associated with the loader, and |
| 110 | * will be called as the loader state changes. If at the point of call |
| 111 | * the caller is in its started state, and the requested loader |
| 112 | * already exists and has generated its data, then |
| 113 | * callback {@link LoaderCallbacks#onLoadFinished} will |
| 114 | * be called immediately (inside of this function), so you must be prepared |
| 115 | * for this to happen. |
| 116 | * |
| 117 | * @param id A unique identifier for this loader. Can be whatever you want. |
| 118 | * Identifiers are scoped to a particular LoaderManager instance. |
| 119 | * @param args Optional arguments to supply to the loader at construction. |
| 120 | * If a loader already exists (a new one does not need to be created), this |
| 121 | * parameter will be ignored and the last arguments continue to be used. |
| 122 | * @param callback Interface the LoaderManager will call to report about |
| 123 | * changes in the state of the loader. Required. |
| 124 | */ |
| 125 | public abstract <D> Loader<D> initLoader(int id, Bundle args, |
| 126 | LoaderManager.LoaderCallbacks<D> callback); |
| 127 | |
| 128 | /** |
| 129 | * Starts a new or restarts an existing {@link android.content.Loader} in |
| 130 | * this manager, registers the callbacks to it, |
| 131 | * and (if the activity/fragment is currently started) starts loading it. |
| 132 | * If a loader with the same id has previously been |
| 133 | * started it will automatically be destroyed when the new loader completes |
| 134 | * its work. The callback will be delivered before the old loader |
| 135 | * is destroyed. |
| 136 | * |
| 137 | * @param id A unique identifier for this loader. Can be whatever you want. |
| 138 | * Identifiers are scoped to a particular LoaderManager instance. |
| 139 | * @param args Optional arguments to supply to the loader at construction. |
| 140 | * @param callback Interface the LoaderManager will call to report about |
| 141 | * changes in the state of the loader. Required. |
| 142 | */ |
| 143 | public abstract <D> Loader<D> restartLoader(int id, Bundle args, |
| 144 | LoaderManager.LoaderCallbacks<D> callback); |
| 145 | |
| 146 | /** |
| 147 | * Stops and removes the loader with the given ID. If this loader |
| 148 | * had previously reported data to the client through |
| 149 | * {@link LoaderCallbacks#onLoadFinished(Loader, Object)}, a call |
| 150 | * will be made to {@link LoaderCallbacks#onLoaderReset(Loader)}. |
| 151 | */ |
| 152 | public abstract void destroyLoader(int id); |
| 153 | |
| 154 | /** |
| 155 | * Return the Loader with the given id or null if no matching Loader |
| 156 | * is found. |
| 157 | */ |
| 158 | public abstract <D> Loader<D> getLoader(int id); |
| 159 | |
| 160 | /** |
| 161 | * Print the LoaderManager's state into the given stream. |
| 162 | * |
| 163 | * @param prefix Text to print at the front of each line. |
| 164 | * @param fd The raw file descriptor that the dump is being sent to. |
| 165 | * @param writer A PrintWriter to which the dump is to be set. |
| 166 | * @param args Additional arguments to the dump request. |
| 167 | */ |
| 168 | public abstract void dump(String prefix, FileDescriptor fd, PrintWriter writer, String[] args); |
| 169 | |
| 170 | /** |
| 171 | * Control whether the framework's internal loader manager debugging |
| 172 | * logs are turned on. If enabled, you will see output in logcat as |
| 173 | * the framework performs loader operations. |
| 174 | */ |
| 175 | public static void enableDebugLogging(boolean enabled) { |
| 176 | LoaderManagerImpl.DEBUG = enabled; |
| 177 | } |
| 178 | } |
| 179 | |
| 180 | class LoaderManagerImpl extends LoaderManager { |
| 181 | static final String TAG = "LoaderManager"; |
| 182 | static boolean DEBUG = false; |
| 183 | |
| 184 | // These are the currently active loaders. A loader is here |
| 185 | // from the time its load is started until it has been explicitly |
| 186 | // stopped or restarted by the application. |
| 187 | final HCSparseArray<LoaderInfo> mLoaders = new HCSparseArray<LoaderInfo>(); |
| 188 | |
| 189 | // These are previously run loaders. This list is maintained internally |
| 190 | // to avoid destroying a loader while an application is still using it. |
| 191 | // It allows an application to restart a loader, but continue using its |
| 192 | // previously run loader until the new loader's data is available. |
| 193 | final HCSparseArray<LoaderInfo> mInactiveLoaders = new HCSparseArray<LoaderInfo>(); |
| 194 | |
| 195 | FragmentActivity mActivity; |
| 196 | boolean mStarted; |
| 197 | boolean mRetaining; |
| 198 | boolean mRetainingStarted; |
| 199 | |
| 200 | boolean mCreatingLoader; |
| 201 | |
| 202 | final class LoaderInfo implements Loader.OnLoadCompleteListener<Object> { |
| 203 | final int mId; |
| 204 | final Bundle mArgs; |
| 205 | LoaderManager.LoaderCallbacks<Object> mCallbacks; |
| 206 | Loader<Object> mLoader; |
| 207 | boolean mHaveData; |
| 208 | boolean mDeliveredData; |
| 209 | Object mData; |
| 210 | boolean mStarted; |
| 211 | boolean mRetaining; |
| 212 | boolean mRetainingStarted; |
| 213 | boolean mDestroyed; |
| 214 | boolean mListenerRegistered; |
| 215 | |
| 216 | LoaderInfo mPendingLoader; |
| 217 | |
| 218 | public LoaderInfo(int id, Bundle args, LoaderManager.LoaderCallbacks<Object> callbacks) { |
| 219 | mId = id; |
| 220 | mArgs = args; |
| 221 | mCallbacks = callbacks; |
| 222 | } |
| 223 | |
| 224 | void start() { |
| 225 | if (mRetaining && mRetainingStarted) { |
| 226 | // Our owner is started, but we were being retained from a |
| 227 | // previous instance in the started state... so there is really |
| 228 | // nothing to do here, since the loaders are still started. |
| 229 | mStarted = true; |
| 230 | return; |
| 231 | } |
| 232 | |
| 233 | if (mStarted) { |
| 234 | // If loader already started, don't restart. |
| 235 | return; |
| 236 | } |
| 237 | |
| 238 | mStarted = true; |
| 239 | |
| 240 | if (DEBUG) Log.v(TAG, " Starting: " + this); |
| 241 | if (mLoader == null && mCallbacks != null) { |
| 242 | mLoader = mCallbacks.onCreateLoader(mId, mArgs); |
| 243 | } |
| 244 | if (mLoader != null) { |
| 245 | if (mLoader.getClass().isMemberClass() |
| 246 | && !Modifier.isStatic(mLoader.getClass().getModifiers())) { |
| 247 | throw new IllegalArgumentException( |
| 248 | "Object returned from onCreateLoader must not be a non-static inner member class: " |
| 249 | + mLoader); |
| 250 | } |
| 251 | if (!mListenerRegistered) { |
| 252 | mLoader.registerListener(mId, this); |
| 253 | mListenerRegistered = true; |
| 254 | } |
| 255 | mLoader.startLoading(); |
| 256 | } |
| 257 | } |
| 258 | |
| 259 | void retain() { |
| 260 | if (DEBUG) Log.v(TAG, " Retaining: " + this); |
| 261 | mRetaining = true; |
| 262 | mRetainingStarted = mStarted; |
| 263 | mStarted = false; |
| 264 | mCallbacks = null; |
| 265 | } |
| 266 | |
| 267 | void finishRetain() { |
| 268 | if (mRetaining) { |
| 269 | if (DEBUG) Log.v(TAG, " Finished Retaining: " + this); |
| 270 | mRetaining = false; |
| 271 | if (mStarted != mRetainingStarted) { |
| 272 | if (!mStarted) { |
| 273 | // This loader was retained in a started state, but |
| 274 | // at the end of retaining everything our owner is |
| 275 | // no longer started... so make it stop. |
| 276 | stop(); |
| 277 | } |
| 278 | } |
| 279 | } |
| 280 | |
| 281 | if (mStarted && mHaveData) { |
| 282 | // This loader has retained its data, either completely across |
| 283 | // a configuration change or just whatever the last data set |
| 284 | // was after being restarted from a stop, and now at the point of |
| 285 | // finishing the retain we find we remain started, have |
| 286 | // our data, and the owner has a new callback... so |
| 287 | // let's deliver the data now. |
| 288 | callOnLoadFinished(mLoader, mData); |
| 289 | } |
| 290 | } |
| 291 | |
| 292 | void stop() { |
| 293 | if (DEBUG) Log.v(TAG, " Stopping: " + this); |
| 294 | mStarted = false; |
| 295 | if (!mRetaining) { |
| 296 | if (mLoader != null && mListenerRegistered) { |
| 297 | // Let the loader know we're done with it |
| 298 | mListenerRegistered = false; |
| 299 | mLoader.unregisterListener(this); |
| 300 | mLoader.stopLoading(); |
| 301 | } |
| 302 | } |
| 303 | } |
| 304 | |
| 305 | void destroy() { |
| 306 | if (DEBUG) Log.v(TAG, " Destroying: " + this); |
| 307 | mDestroyed = true; |
| 308 | boolean needReset = mDeliveredData; |
| 309 | mDeliveredData = false; |
| 310 | if (mCallbacks != null && mLoader != null && mHaveData && needReset) { |
| 311 | if (DEBUG) Log.v(TAG, " Reseting: " + this); |
| 312 | String lastBecause = null; |
| 313 | if (mActivity != null) { |
| 314 | lastBecause = mActivity.mFragments.mNoTransactionsBecause; |
| 315 | mActivity.mFragments.mNoTransactionsBecause = "onLoaderReset"; |
| 316 | } |
| 317 | try { |
| 318 | mCallbacks.onLoaderReset(mLoader); |
| 319 | } finally { |
| 320 | if (mActivity != null) { |
| 321 | mActivity.mFragments.mNoTransactionsBecause = lastBecause; |
| 322 | } |
| 323 | } |
| 324 | } |
| 325 | mCallbacks = null; |
| 326 | mData = null; |
| 327 | mHaveData = false; |
| 328 | if (mLoader != null) { |
| 329 | if (mListenerRegistered) { |
| 330 | mListenerRegistered = false; |
| 331 | mLoader.unregisterListener(this); |
| 332 | } |
| 333 | mLoader.reset(); |
| 334 | } |
| 335 | if (mPendingLoader != null) { |
| 336 | mPendingLoader.destroy(); |
| 337 | } |
| 338 | } |
| 339 | |
| 340 | @Override public void onLoadComplete(Loader<Object> loader, Object data) { |
| 341 | if (DEBUG) Log.v(TAG, "onLoadComplete: " + this); |
| 342 | |
| 343 | if (mDestroyed) { |
| 344 | if (DEBUG) Log.v(TAG, " Ignoring load complete -- destroyed"); |
| 345 | return; |
| 346 | } |
| 347 | |
| 348 | if (mLoaders.get(mId) != this) { |
| 349 | // This data is not coming from the current active loader. |
| 350 | // We don't care about it. |
| 351 | if (DEBUG) Log.v(TAG, " Ignoring load complete -- not active"); |
| 352 | return; |
| 353 | } |
| 354 | |
| 355 | LoaderInfo pending = mPendingLoader; |
| 356 | if (pending != null) { |
| 357 | // There is a new request pending and we were just |
| 358 | // waiting for the old one to complete before starting |
| 359 | // it. So now it is time, switch over to the new loader. |
| 360 | if (DEBUG) Log.v(TAG, " Switching to pending loader: " + pending); |
| 361 | mPendingLoader = null; |
| 362 | mLoaders.put(mId, null); |
| 363 | destroy(); |
| 364 | installLoader(pending); |
| 365 | return; |
| 366 | } |
| 367 | |
| 368 | // Notify of the new data so the app can switch out the old data before |
| 369 | // we try to destroy it. |
| 370 | if (mData != data || !mHaveData) { |
| 371 | mData = data; |
| 372 | mHaveData = true; |
| 373 | if (mStarted) { |
| 374 | callOnLoadFinished(loader, data); |
| 375 | } |
| 376 | } |
| 377 | |
| 378 | //if (DEBUG) Log.v(TAG, " onLoadFinished returned: " + this); |
| 379 | |
| 380 | // We have now given the application the new loader with its |
| 381 | // loaded data, so it should have stopped using the previous |
| 382 | // loader. If there is a previous loader on the inactive list, |
| 383 | // clean it up. |
| 384 | LoaderInfo info = mInactiveLoaders.get(mId); |
| 385 | if (info != null && info != this) { |
| 386 | info.mDeliveredData = false; |
| 387 | info.destroy(); |
| 388 | mInactiveLoaders.remove(mId); |
| 389 | } |
| 390 | } |
| 391 | |
| 392 | void callOnLoadFinished(Loader<Object> loader, Object data) { |
| 393 | if (mCallbacks != null) { |
| 394 | String lastBecause = null; |
| 395 | if (mActivity != null) { |
| 396 | lastBecause = mActivity.mFragments.mNoTransactionsBecause; |
| 397 | mActivity.mFragments.mNoTransactionsBecause = "onLoadFinished"; |
| 398 | } |
| 399 | try { |
| 400 | if (DEBUG) Log.v(TAG, " onLoadFinished in " + loader + ": " |
| 401 | + loader.dataToString(data)); |
| 402 | mCallbacks.onLoadFinished(loader, data); |
| 403 | } finally { |
| 404 | if (mActivity != null) { |
| 405 | mActivity.mFragments.mNoTransactionsBecause = lastBecause; |
| 406 | } |
| 407 | } |
| 408 | mDeliveredData = true; |
| 409 | } |
| 410 | } |
| 411 | |
| 412 | @Override |
| 413 | public String toString() { |
| 414 | StringBuilder sb = new StringBuilder(64); |
| 415 | sb.append("LoaderInfo{"); |
| 416 | sb.append(Integer.toHexString(System.identityHashCode(this))); |
| 417 | sb.append(" #"); |
| 418 | sb.append(mId); |
| 419 | sb.append(" : "); |
| 420 | DebugUtils.buildShortClassTag(mLoader, sb); |
| 421 | sb.append("}}"); |
| 422 | return sb.toString(); |
| 423 | } |
| 424 | |
| 425 | public void dump(String prefix, FileDescriptor fd, PrintWriter writer, String[] args) { |
| 426 | writer.print(prefix); writer.print("mId="); writer.print(mId); |
| 427 | writer.print(" mArgs="); writer.println(mArgs); |
| 428 | writer.print(prefix); writer.print("mCallbacks="); writer.println(mCallbacks); |
| 429 | writer.print(prefix); writer.print("mLoader="); writer.println(mLoader); |
| 430 | if (mLoader != null) { |
| 431 | mLoader.dump(prefix + " ", fd, writer, args); |
| 432 | } |
| 433 | if (mHaveData || mDeliveredData) { |
| 434 | writer.print(prefix); writer.print("mHaveData="); writer.print(mHaveData); |
| 435 | writer.print(" mDeliveredData="); writer.println(mDeliveredData); |
| 436 | writer.print(prefix); writer.print("mData="); writer.println(mData); |
| 437 | } |
| 438 | writer.print(prefix); writer.print("mStarted="); writer.print(mStarted); |
| 439 | writer.print(" mRetaining="); writer.print(mRetaining); |
| 440 | writer.print(" mDestroyed="); writer.println(mDestroyed); |
| 441 | writer.print(prefix); writer.print("mListenerRegistered="); |
| 442 | writer.println(mListenerRegistered); |
| 443 | if (mPendingLoader != null) { |
| 444 | writer.print(prefix); writer.println("Pending Loader "); |
| 445 | writer.print(mPendingLoader); writer.println(":"); |
| 446 | mPendingLoader.dump(prefix + " ", fd, writer, args); |
| 447 | } |
| 448 | } |
| 449 | } |
| 450 | |
| 451 | LoaderManagerImpl(FragmentActivity activity, boolean started) { |
| 452 | mActivity = activity; |
| 453 | mStarted = started; |
| 454 | } |
| 455 | |
| 456 | void updateActivity(FragmentActivity activity) { |
| 457 | mActivity = activity; |
| 458 | } |
| 459 | |
| 460 | private LoaderInfo createLoader(int id, Bundle args, |
| 461 | LoaderManager.LoaderCallbacks<Object> callback) { |
| 462 | LoaderInfo info = new LoaderInfo(id, args, (LoaderManager.LoaderCallbacks<Object>)callback); |
| 463 | Loader<Object> loader = callback.onCreateLoader(id, args); |
| 464 | info.mLoader = (Loader<Object>)loader; |
| 465 | return info; |
| 466 | } |
| 467 | |
| 468 | private LoaderInfo createAndInstallLoader(int id, Bundle args, |
| 469 | LoaderManager.LoaderCallbacks<Object> callback) { |
| 470 | try { |
| 471 | mCreatingLoader = true; |
| 472 | LoaderInfo info = createLoader(id, args, callback); |
| 473 | installLoader(info); |
| 474 | return info; |
| 475 | } finally { |
| 476 | mCreatingLoader = false; |
| 477 | } |
| 478 | } |
| 479 | |
| 480 | void installLoader(LoaderInfo info) { |
| 481 | mLoaders.put(info.mId, info); |
| 482 | if (mStarted) { |
| 483 | // The activity will start all existing loaders in it's onStart(), |
| 484 | // so only start them here if we're past that point of the activitiy's |
| 485 | // life cycle |
| 486 | info.start(); |
| 487 | } |
| 488 | } |
| 489 | |
| 490 | /** |
| 491 | * Call to initialize a particular ID with a Loader. If this ID already |
| 492 | * has a Loader associated with it, it is left unchanged and any previous |
| 493 | * callbacks replaced with the newly provided ones. If there is not currently |
| 494 | * a Loader for the ID, a new one is created and started. |
| 495 | * |
| 496 | * <p>This function should generally be used when a component is initializing, |
| 497 | * to ensure that a Loader it relies on is created. This allows it to re-use |
| 498 | * an existing Loader's data if there already is one, so that for example |
| 499 | * when an {@link Activity} is re-created after a configuration change it |
| 500 | * does not need to re-create its loaders. |
| 501 | * |
| 502 | * <p>Note that in the case where an existing Loader is re-used, the |
| 503 | * <var>args</var> given here <em>will be ignored</em> because you will |
| 504 | * continue using the previous Loader. |
| 505 | * |
| 506 | * @param id A unique (to this LoaderManager instance) identifier under |
| 507 | * which to manage the new Loader. |
| 508 | * @param args Optional arguments that will be propagated to |
| 509 | * {@link LoaderCallbacks#onCreateLoader(int, Bundle) LoaderCallbacks.onCreateLoader()}. |
| 510 | * @param callback Interface implementing management of this Loader. Required. |
| 511 | * Its onCreateLoader() method will be called while inside of the function to |
| 512 | * instantiate the Loader object. |
| 513 | */ |
| 514 | @SuppressWarnings("unchecked") |
| 515 | public <D> Loader<D> initLoader(int id, Bundle args, LoaderManager.LoaderCallbacks<D> callback) { |
| 516 | if (mCreatingLoader) { |
| 517 | throw new IllegalStateException("Called while creating a loader"); |
| 518 | } |
| 519 | |
| 520 | LoaderInfo info = mLoaders.get(id); |
| 521 | |
| 522 | if (DEBUG) Log.v(TAG, "initLoader in " + this + ": args=" + args); |
| 523 | |
| 524 | if (info == null) { |
| 525 | // Loader doesn't already exist; create. |
| 526 | info = createAndInstallLoader(id, args, (LoaderManager.LoaderCallbacks<Object>)callback); |
| 527 | if (DEBUG) Log.v(TAG, " Created new loader " + info); |
| 528 | } else { |
| 529 | if (DEBUG) Log.v(TAG, " Re-using existing loader " + info); |
| 530 | info.mCallbacks = (LoaderManager.LoaderCallbacks<Object>)callback; |
| 531 | } |
| 532 | |
| 533 | if (info.mHaveData && mStarted) { |
| 534 | // If the loader has already generated its data, report it now. |
| 535 | info.callOnLoadFinished(info.mLoader, info.mData); |
| 536 | } |
| 537 | |
| 538 | return (Loader<D>)info.mLoader; |
| 539 | } |
| 540 | |
| 541 | /** |
| 542 | * Call to re-create the Loader associated with a particular ID. If there |
| 543 | * is currently a Loader associated with this ID, it will be |
| 544 | * canceled/stopped/destroyed as appropriate. A new Loader with the given |
| 545 | * arguments will be created and its data delivered to you once available. |
| 546 | * |
| 547 | * <p>This function does some throttling of Loaders. If too many Loaders |
| 548 | * have been created for the given ID but not yet generated their data, |
| 549 | * new calls to this function will create and return a new Loader but not |
| 550 | * actually start it until some previous loaders have completed. |
| 551 | * |
| 552 | * <p>After calling this function, any previous Loaders associated with |
| 553 | * this ID will be considered invalid, and you will receive no further |
| 554 | * data updates from them. |
| 555 | * |
| 556 | * @param id A unique (to this LoaderManager instance) identifier under |
| 557 | * which to manage the new Loader. |
| 558 | * @param args Optional arguments that will be propagated to |
| 559 | * {@link LoaderCallbacks#onCreateLoader(int, Bundle) LoaderCallbacks.onCreateLoader()}. |
| 560 | * @param callback Interface implementing management of this Loader. Required. |
| 561 | * Its onCreateLoader() method will be called while inside of the function to |
| 562 | * instantiate the Loader object. |
| 563 | */ |
| 564 | @SuppressWarnings("unchecked") |
| 565 | public <D> Loader<D> restartLoader(int id, Bundle args, LoaderManager.LoaderCallbacks<D> callback) { |
| 566 | if (mCreatingLoader) { |
| 567 | throw new IllegalStateException("Called while creating a loader"); |
| 568 | } |
| 569 | |
| 570 | LoaderInfo info = mLoaders.get(id); |
| 571 | if (DEBUG) Log.v(TAG, "restartLoader in " + this + ": args=" + args); |
| 572 | if (info != null) { |
| 573 | LoaderInfo inactive = mInactiveLoaders.get(id); |
| 574 | if (inactive != null) { |
| 575 | if (info.mHaveData) { |
| 576 | // This loader now has data... we are probably being |
| 577 | // called from within onLoadComplete, where we haven't |
| 578 | // yet destroyed the last inactive loader. So just do |
| 579 | // that now. |
| 580 | if (DEBUG) Log.v(TAG, " Removing last inactive loader: " + info); |
| 581 | inactive.mDeliveredData = false; |
| 582 | inactive.destroy(); |
| 583 | info.mLoader.abandon(); |
| 584 | mInactiveLoaders.put(id, info); |
| 585 | } else { |
| 586 | // We already have an inactive loader for this ID that we are |
| 587 | // waiting for! What to do, what to do... |
| 588 | if (!info.mStarted) { |
| 589 | // The current Loader has not been started... we thus |
| 590 | // have no reason to keep it around, so bam, slam, |
| 591 | // thank-you-ma'am. |
| 592 | if (DEBUG) Log.v(TAG, " Current loader is stopped; replacing"); |
| 593 | mLoaders.put(id, null); |
| 594 | info.destroy(); |
| 595 | } else { |
| 596 | // Now we have three active loaders... we'll queue |
| 597 | // up this request to be processed once one of the other loaders |
| 598 | // finishes. |
| 599 | if (info.mPendingLoader != null) { |
| 600 | if (DEBUG) Log.v(TAG, " Removing pending loader: " + info.mPendingLoader); |
| 601 | info.mPendingLoader.destroy(); |
| 602 | info.mPendingLoader = null; |
| 603 | } |
| 604 | if (DEBUG) Log.v(TAG, " Enqueuing as new pending loader"); |
| 605 | info.mPendingLoader = createLoader(id, args, |
| 606 | (LoaderManager.LoaderCallbacks<Object>)callback); |
| 607 | return (Loader<D>)info.mPendingLoader.mLoader; |
| 608 | } |
| 609 | } |
| 610 | } else { |
| 611 | // Keep track of the previous instance of this loader so we can destroy |
| 612 | // it when the new one completes. |
| 613 | if (DEBUG) Log.v(TAG, " Making last loader inactive: " + info); |
| 614 | info.mLoader.abandon(); |
| 615 | mInactiveLoaders.put(id, info); |
| 616 | } |
| 617 | } |
| 618 | |
| 619 | info = createAndInstallLoader(id, args, (LoaderManager.LoaderCallbacks<Object>)callback); |
| 620 | return (Loader<D>)info.mLoader; |
| 621 | } |
| 622 | |
| 623 | /** |
| 624 | * Rip down, tear apart, shred to pieces a current Loader ID. After returning |
| 625 | * from this function, any Loader objects associated with this ID are |
| 626 | * destroyed. Any data associated with them is destroyed. You better not |
| 627 | * be using it when you do this. |
| 628 | * @param id Identifier of the Loader to be destroyed. |
| 629 | */ |
| 630 | public void destroyLoader(int id) { |
| 631 | if (mCreatingLoader) { |
| 632 | throw new IllegalStateException("Called while creating a loader"); |
| 633 | } |
| 634 | |
| 635 | if (DEBUG) Log.v(TAG, "destroyLoader in " + this + " of " + id); |
| 636 | int idx = mLoaders.indexOfKey(id); |
| 637 | if (idx >= 0) { |
| 638 | LoaderInfo info = mLoaders.valueAt(idx); |
| 639 | mLoaders.removeAt(idx); |
| 640 | info.destroy(); |
| 641 | } |
| 642 | idx = mInactiveLoaders.indexOfKey(id); |
| 643 | if (idx >= 0) { |
| 644 | LoaderInfo info = mInactiveLoaders.valueAt(idx); |
| 645 | mInactiveLoaders.removeAt(idx); |
| 646 | info.destroy(); |
| 647 | } |
| 648 | } |
| 649 | |
| 650 | /** |
| 651 | * Return the most recent Loader object associated with the |
| 652 | * given ID. |
| 653 | */ |
| 654 | @SuppressWarnings("unchecked") |
| 655 | public <D> Loader<D> getLoader(int id) { |
| 656 | if (mCreatingLoader) { |
| 657 | throw new IllegalStateException("Called while creating a loader"); |
| 658 | } |
| 659 | |
| 660 | LoaderInfo loaderInfo = mLoaders.get(id); |
| 661 | if (loaderInfo != null) { |
| 662 | if (loaderInfo.mPendingLoader != null) { |
| 663 | return (Loader<D>)loaderInfo.mPendingLoader.mLoader; |
| 664 | } |
| 665 | return (Loader<D>)loaderInfo.mLoader; |
| 666 | } |
| 667 | return null; |
| 668 | } |
| 669 | |
| 670 | void doStart() { |
| 671 | if (DEBUG) Log.v(TAG, "Starting in " + this); |
| 672 | if (mStarted) { |
| 673 | RuntimeException e = new RuntimeException("here"); |
| 674 | e.fillInStackTrace(); |
| 675 | Log.w(TAG, "Called doStart when already started: " + this, e); |
| 676 | return; |
| 677 | } |
| 678 | |
| 679 | mStarted = true; |
| 680 | |
| 681 | // Call out to sub classes so they can start their loaders |
| 682 | // Let the existing loaders know that we want to be notified when a load is complete |
| 683 | for (int i = mLoaders.size()-1; i >= 0; i--) { |
| 684 | mLoaders.valueAt(i).start(); |
| 685 | } |
| 686 | } |
| 687 | |
| 688 | void doStop() { |
| 689 | if (DEBUG) Log.v(TAG, "Stopping in " + this); |
| 690 | if (!mStarted) { |
| 691 | RuntimeException e = new RuntimeException("here"); |
| 692 | e.fillInStackTrace(); |
| 693 | Log.w(TAG, "Called doStop when not started: " + this, e); |
| 694 | return; |
| 695 | } |
| 696 | |
| 697 | for (int i = mLoaders.size()-1; i >= 0; i--) { |
| 698 | mLoaders.valueAt(i).stop(); |
| 699 | } |
| 700 | mStarted = false; |
| 701 | } |
| 702 | |
| 703 | void doRetain() { |
| 704 | if (DEBUG) Log.v(TAG, "Retaining in " + this); |
| 705 | if (!mStarted) { |
| 706 | RuntimeException e = new RuntimeException("here"); |
| 707 | e.fillInStackTrace(); |
| 708 | Log.w(TAG, "Called doRetain when not started: " + this, e); |
| 709 | return; |
| 710 | } |
| 711 | |
| 712 | mRetaining = true; |
| 713 | mStarted = false; |
| 714 | for (int i = mLoaders.size()-1; i >= 0; i--) { |
| 715 | mLoaders.valueAt(i).retain(); |
| 716 | } |
| 717 | } |
| 718 | |
| 719 | void finishRetain() { |
| 720 | if (mRetaining) { |
| 721 | if (DEBUG) Log.v(TAG, "Finished Retaining in " + this); |
| 722 | |
| 723 | mRetaining = false; |
| 724 | for (int i = mLoaders.size()-1; i >= 0; i--) { |
| 725 | mLoaders.valueAt(i).finishRetain(); |
| 726 | } |
| 727 | } |
| 728 | } |
| 729 | |
| 730 | void doDestroy() { |
| 731 | if (!mRetaining) { |
| 732 | if (DEBUG) Log.v(TAG, "Destroying Active in " + this); |
| 733 | for (int i = mLoaders.size()-1; i >= 0; i--) { |
| 734 | mLoaders.valueAt(i).destroy(); |
| 735 | } |
| 736 | } |
| 737 | |
| 738 | if (DEBUG) Log.v(TAG, "Destroying Inactive in " + this); |
| 739 | for (int i = mInactiveLoaders.size()-1; i >= 0; i--) { |
| 740 | mInactiveLoaders.valueAt(i).destroy(); |
| 741 | } |
| 742 | mInactiveLoaders.clear(); |
| 743 | } |
| 744 | |
| 745 | @Override |
| 746 | public String toString() { |
| 747 | StringBuilder sb = new StringBuilder(128); |
| 748 | sb.append("LoaderManager{"); |
| 749 | sb.append(Integer.toHexString(System.identityHashCode(this))); |
| 750 | sb.append(" in "); |
| 751 | DebugUtils.buildShortClassTag(mActivity, sb); |
| 752 | sb.append("}}"); |
| 753 | return sb.toString(); |
| 754 | } |
| 755 | |
| 756 | @Override |
| 757 | public void dump(String prefix, FileDescriptor fd, PrintWriter writer, String[] args) { |
| 758 | if (mLoaders.size() > 0) { |
| 759 | writer.print(prefix); writer.println("Active Loaders:"); |
| 760 | String innerPrefix = prefix + " "; |
| 761 | for (int i=0; i < mLoaders.size(); i++) { |
| 762 | LoaderInfo li = mLoaders.valueAt(i); |
| 763 | writer.print(prefix); writer.print(" #"); writer.print(mLoaders.keyAt(i)); |
| 764 | writer.print(": "); writer.println(li.toString()); |
| 765 | li.dump(innerPrefix, fd, writer, args); |
| 766 | } |
| 767 | } |
| 768 | if (mInactiveLoaders.size() > 0) { |
| 769 | writer.print(prefix); writer.println("Inactive Loaders:"); |
| 770 | String innerPrefix = prefix + " "; |
| 771 | for (int i=0; i < mInactiveLoaders.size(); i++) { |
| 772 | LoaderInfo li = mInactiveLoaders.valueAt(i); |
| 773 | writer.print(prefix); writer.print(" #"); writer.print(mInactiveLoaders.keyAt(i)); |
| 774 | writer.print(": "); writer.println(li.toString()); |
| 775 | li.dump(innerPrefix, fd, writer, args); |
| 776 | } |
| 777 | } |
| 778 | } |
| 779 | } |