| /* |
| * Copyright (C) 2010 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package android.app; |
| |
| import android.content.Loader; |
| import android.os.Bundle; |
| import android.util.SparseArray; |
| |
| /** |
| * Interface associated with an {@link Activity} or {@link Fragment} for managing |
| * one or more {@link android.content.Loader} instances associated with it. |
| */ |
| public interface LoaderManager { |
| /** |
| * Callback interface for a client to interact with the manager. |
| */ |
| public interface LoaderCallbacks<D> { |
| /** |
| * Instantiate and return a new Loader for the given ID. |
| * |
| * @param id The ID whose loader is to be created. |
| * @param args Any arguments supplied by the caller. |
| * @return Return a new Loader instance that is ready to start loading. |
| */ |
| public Loader<D> onCreateLoader(int id, Bundle args); |
| |
| /** |
| * Called when a previously created loader has finished its load. |
| * @param loader The Loader that has finished. |
| * @param data The data generated by the Loader. |
| */ |
| public void onLoadFinished(Loader<D> loader, D data); |
| } |
| |
| /** |
| * Ensures a loader is initialized and active. If the loader doesn't |
| * already exist, one is created and (if the activity/fragment is currently |
| * started) starts the loader. Otherwise the last created |
| * loader is re-used. |
| * |
| * <p>In either case, the given callback is associated with the loader, and |
| * will be called as the loader state changes. If at the point of call |
| * the caller is in its started state, and the requested loader |
| * already exists and has generated its data, then |
| * callback. {@link LoaderCallbacks#onLoadFinished} will |
| * be called immediately (inside of this function), so you must be prepared |
| * for this to happen. |
| */ |
| public <D> Loader<D> initLoader(int id, Bundle args, |
| LoaderManager.LoaderCallbacks<D> callback); |
| |
| /** |
| * Creates a new loader in this manager, registers the callbacks to it, |
| * and (if the activity/fragment is currently started) starts loading it. |
| * If a loader with the same id has previously been |
| * started it will automatically be destroyed when the new loader completes |
| * its work. The callback will be delivered before the old loader |
| * is destroyed. |
| */ |
| public <D> Loader<D> restartLoader(int id, Bundle args, |
| LoaderManager.LoaderCallbacks<D> callback); |
| |
| /** |
| * Stops and removes the loader with the given ID. |
| */ |
| public void stopLoader(int id); |
| |
| /** |
| * Return the Loader with the given id or null if no matching Loader |
| * is found. |
| */ |
| public <D> Loader<D> getLoader(int id); |
| } |
| |
| class LoaderManagerImpl implements LoaderManager { |
| final SparseArray<LoaderInfo> mLoaders = new SparseArray<LoaderInfo>(); |
| final SparseArray<LoaderInfo> mInactiveLoaders = new SparseArray<LoaderInfo>(); |
| boolean mStarted; |
| boolean mRetaining; |
| boolean mRetainingStarted; |
| |
| final class LoaderInfo implements Loader.OnLoadCompleteListener<Object> { |
| final int mId; |
| final Bundle mArgs; |
| LoaderManager.LoaderCallbacks<Object> mCallbacks; |
| Loader<Object> mLoader; |
| Object mData; |
| boolean mStarted; |
| boolean mRetaining; |
| boolean mRetainingStarted; |
| boolean mDestroyed; |
| boolean mListenerRegistered; |
| |
| public LoaderInfo(int id, Bundle args, LoaderManager.LoaderCallbacks<Object> callbacks) { |
| mId = id; |
| mArgs = args; |
| mCallbacks = callbacks; |
| } |
| |
| void start() { |
| if (mRetaining && mRetainingStarted) { |
| // Our owner is started, but we were being retained from a |
| // previous instance in the started state... so there is really |
| // nothing to do here, since the loaders are still started. |
| mStarted = true; |
| return; |
| } |
| |
| if (mStarted) { |
| // If loader already started, don't restart. |
| return; |
| } |
| |
| if (mLoader == null && mCallbacks != null) { |
| mLoader = mCallbacks.onCreateLoader(mId, mArgs); |
| } |
| if (mLoader != null) { |
| if (!mListenerRegistered) { |
| mLoader.registerListener(mId, this); |
| mListenerRegistered = true; |
| } |
| mLoader.startLoading(); |
| mStarted = true; |
| } |
| } |
| |
| void retain() { |
| mRetaining = true; |
| mRetainingStarted = mStarted; |
| mStarted = false; |
| mCallbacks = null; |
| } |
| |
| void finishRetain() { |
| if (mRetaining) { |
| mRetaining = false; |
| if (mStarted != mRetainingStarted) { |
| if (!mStarted) { |
| // This loader was retained in a started state, but |
| // at the end of retaining everything our owner is |
| // no longer started... so make it stop. |
| stop(); |
| } |
| } |
| if (mStarted && mData != null && mCallbacks != null) { |
| // This loader was retained, and now at the point of |
| // finishing the retain we find we remain started, have |
| // our data, and the owner has a new callback... so |
| // let's deliver the data now. |
| mCallbacks.onLoadFinished(mLoader, mData); |
| } |
| } |
| } |
| |
| void stop() { |
| mStarted = false; |
| if (mLoader != null && mListenerRegistered) { |
| // Let the loader know we're done with it |
| mListenerRegistered = false; |
| mLoader.unregisterListener(this); |
| mLoader.stopLoading(); |
| } |
| } |
| |
| void destroy() { |
| mDestroyed = true; |
| mCallbacks = null; |
| if (mLoader != null) { |
| if (mListenerRegistered) { |
| mListenerRegistered = false; |
| mLoader.unregisterListener(this); |
| } |
| mLoader.destroy(); |
| } |
| } |
| |
| @Override public void onLoadComplete(Loader<Object> loader, Object data) { |
| if (mDestroyed) { |
| return; |
| } |
| |
| // Notify of the new data so the app can switch out the old data before |
| // we try to destroy it. |
| mData = data; |
| if (mCallbacks != null) { |
| mCallbacks.onLoadFinished(loader, data); |
| } |
| |
| // Look for an inactive loader and destroy it if found |
| LoaderInfo info = mInactiveLoaders.get(mId); |
| if (info != null) { |
| Loader<Object> oldLoader = info.mLoader; |
| if (oldLoader != null) { |
| if (info.mListenerRegistered) { |
| oldLoader.unregisterListener(info); |
| } |
| oldLoader.destroy(); |
| } |
| mInactiveLoaders.remove(mId); |
| } |
| } |
| } |
| |
| LoaderManagerImpl(boolean started) { |
| mStarted = started; |
| } |
| |
| private LoaderInfo createLoader(int id, Bundle args, |
| LoaderManager.LoaderCallbacks<Object> callback) { |
| LoaderInfo info = new LoaderInfo(id, args, (LoaderManager.LoaderCallbacks<Object>)callback); |
| mLoaders.put(id, info); |
| Loader<Object> loader = callback.onCreateLoader(id, args); |
| info.mLoader = (Loader<Object>)loader; |
| if (mStarted) { |
| // The activity will start all existing loaders in it's onStart(), |
| // so only start them here if we're past that point of the activitiy's |
| // life cycle |
| info.start(); |
| } |
| return info; |
| } |
| |
| @SuppressWarnings("unchecked") |
| public <D> Loader<D> initLoader(int id, Bundle args, LoaderManager.LoaderCallbacks<D> callback) { |
| LoaderInfo info = mLoaders.get(id); |
| |
| if (info == null) { |
| // Loader doesn't already exist; create. |
| info = createLoader(id, args, (LoaderManager.LoaderCallbacks<Object>)callback); |
| } else { |
| info.mCallbacks = (LoaderManager.LoaderCallbacks<Object>)callback; |
| } |
| |
| if (info.mData != null && mStarted) { |
| // If the loader has already generated its data, report it now. |
| info.mCallbacks.onLoadFinished(info.mLoader, info.mData); |
| } |
| |
| return (Loader<D>)info.mLoader; |
| } |
| |
| @SuppressWarnings("unchecked") |
| public <D> Loader<D> restartLoader(int id, Bundle args, LoaderManager.LoaderCallbacks<D> callback) { |
| LoaderInfo info = mLoaders.get(id); |
| if (info != null) { |
| if (mInactiveLoaders.get(id) != null) { |
| // We already have an inactive loader for this ID that we are |
| // waiting for! Now we have three active loaders... let's just |
| // drop the one in the middle, since we are still waiting for |
| // its result but that result is already out of date. |
| info.destroy(); |
| } else { |
| // Keep track of the previous instance of this loader so we can destroy |
| // it when the new one completes. |
| mInactiveLoaders.put(id, info); |
| } |
| } |
| |
| info = createLoader(id, args, (LoaderManager.LoaderCallbacks<Object>)callback); |
| return (Loader<D>)info.mLoader; |
| } |
| |
| public void stopLoader(int id) { |
| int idx = mLoaders.indexOfKey(id); |
| if (idx >= 0) { |
| LoaderInfo info = mLoaders.valueAt(idx); |
| mLoaders.removeAt(idx); |
| info.destroy(); |
| } |
| } |
| |
| @SuppressWarnings("unchecked") |
| public <D> Loader<D> getLoader(int id) { |
| LoaderInfo loaderInfo = mLoaders.get(id); |
| if (loaderInfo != null) { |
| return (Loader<D>)mLoaders.get(id).mLoader; |
| } |
| return null; |
| } |
| |
| void doStart() { |
| // Call out to sub classes so they can start their loaders |
| // Let the existing loaders know that we want to be notified when a load is complete |
| for (int i = mLoaders.size()-1; i >= 0; i--) { |
| mLoaders.valueAt(i).start(); |
| } |
| mStarted = true; |
| } |
| |
| void doStop() { |
| for (int i = mLoaders.size()-1; i >= 0; i--) { |
| mLoaders.valueAt(i).stop(); |
| } |
| mStarted = false; |
| } |
| |
| void doRetain() { |
| mRetaining = true; |
| mStarted = false; |
| for (int i = mLoaders.size()-1; i >= 0; i--) { |
| mLoaders.valueAt(i).retain(); |
| } |
| } |
| |
| void finishRetain() { |
| mRetaining = false; |
| for (int i = mLoaders.size()-1; i >= 0; i--) { |
| mLoaders.valueAt(i).finishRetain(); |
| } |
| } |
| |
| void doDestroy() { |
| if (!mRetaining) { |
| for (int i = mLoaders.size()-1; i >= 0; i--) { |
| mLoaders.valueAt(i).destroy(); |
| } |
| } |
| |
| for (int i = mInactiveLoaders.size()-1; i >= 0; i--) { |
| mInactiveLoaders.valueAt(i).destroy(); |
| } |
| mInactiveLoaders.clear(); |
| } |
| } |