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/*
* 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 java.util.HashMap;
/**
* A Fragment that has utility methods for managing {@link Loader}s.
*
* @param <D> The type of data returned by the Loader. If you're using multiple Loaders with
* different return types use Object and case the results.
*
* @deprecated This was an old design, it will be removed before Honeycomb ships.
*/
@Deprecated
public abstract class LoaderManagingFragment<D> extends Fragment
implements Loader.OnLoadCompleteListener<D> {
private boolean mStarted = false;
static final class LoaderInfo<D> {
public Bundle args;
public Loader<D> loader;
}
private HashMap<Integer, LoaderInfo<D>> mLoaders;
private HashMap<Integer, LoaderInfo<D>> mInactiveLoaders;
/**
* Registers a loader with this activity, registers the callbacks on it, and starts it loading.
* If a loader with the same id has previously been started it will automatically be destroyed
* when the new loader completes it's work. The callback will be delivered before the old loader
* is destroyed.
*/
public Loader<D> startLoading(int id, Bundle args) {
LoaderInfo<D> info = mLoaders.get(id);
if (info != null) {
// Keep track of the previous instance of this loader so we can destroy
// it when the new one completes.
mInactiveLoaders.put(id, info);
}
info = new LoaderInfo<D>();
info.args = args;
mLoaders.put(id, info);
Loader<D> loader = onCreateLoader(id, args);
info.loader = 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
loader.registerListener(id, this);
loader.startLoading();
}
return loader;
}
protected abstract Loader<D> onCreateLoader(int id, Bundle args);
protected abstract void onInitializeLoaders();
protected abstract void onLoadFinished(Loader<D> loader, D data);
public final void onLoadComplete(Loader<D> loader, D data) {
// Notify of the new data so the app can switch out the old data before
// we try to destroy it.
onLoadFinished(loader, data);
// Look for an inactive loader and destroy it if found
int id = loader.getId();
LoaderInfo<D> info = mInactiveLoaders.get(id);
if (info != null) {
Loader<D> oldLoader = info.loader;
if (oldLoader != null) {
oldLoader.destroy();
}
mInactiveLoaders.remove(id);
}
}
@Override
public void onCreate(Bundle savedState) {
super.onCreate(savedState);
if (mLoaders == null) {
// Look for a passed along loader and create a new one if it's not there
// TODO: uncomment once getLastNonConfigurationInstance method is available
// mLoaders = (HashMap<Integer, LoaderInfo>) getLastNonConfigurationInstance();
if (mLoaders == null) {
mLoaders = new HashMap<Integer, LoaderInfo<D>>();
onInitializeLoaders();
}
}
if (mInactiveLoaders == null) {
mInactiveLoaders = new HashMap<Integer, LoaderInfo<D>>();
}
}
@Override
public void onStart() {
super.onStart();
// 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 (HashMap.Entry<Integer, LoaderInfo<D>> entry : mLoaders.entrySet()) {
LoaderInfo<D> info = entry.getValue();
Loader<D> loader = info.loader;
int id = entry.getKey();
if (loader == null) {
loader = onCreateLoader(id, info.args);
info.loader = loader;
}
loader.registerListener(id, this);
loader.startLoading();
}
mStarted = true;
}
@Override
public void onStop() {
super.onStop();
for (HashMap.Entry<Integer, LoaderInfo<D>> entry : mLoaders.entrySet()) {
LoaderInfo<D> info = entry.getValue();
Loader<D> loader = info.loader;
if (loader == null) {
continue;
}
// Let the loader know we're done with it
loader.unregisterListener(this);
// The loader isn't getting passed along to the next instance so ask it to stop loading
if (!getActivity().isChangingConfigurations()) {
loader.stopLoading();
}
}
mStarted = false;
}
/* TO DO: This needs to be turned into a retained fragment.
@Override
public Object onRetainNonConfigurationInstance() {
// Pass the loader along to the next guy
Object result = mLoaders;
mLoaders = null;
return result;
}
**/
@Override
public void onDestroy() {
super.onDestroy();
if (mLoaders != null) {
for (HashMap.Entry<Integer, LoaderInfo<D>> entry : mLoaders.entrySet()) {
LoaderInfo<D> info = entry.getValue();
Loader<D> loader = info.loader;
if (loader == null) {
continue;
}
loader.destroy();
}
}
}
/**
* Stops and removes the loader with the given ID.
*/
public void stopLoading(int id) {
if (mLoaders != null) {
LoaderInfo<D> info = mLoaders.remove(id);
if (info != null) {
Loader<D> loader = info.loader;
if (loader != null) {
loader.unregisterListener(this);
loader.destroy();
}
}
}
}
/**
* @return the Loader with the given id or null if no matching Loader
* is found.
*/
public Loader<D> getLoader(int id) {
LoaderInfo<D> loaderInfo = mLoaders.get(id);
if (loaderInfo != null) {
return mLoaders.get(id).loader;
}
return null;
}
}
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