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/*
* Copyright (C) 2013 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 com.android.camera.data;
import android.content.Context;
import android.net.Uri;
import com.android.gallery3d.util.LightCycleHelper;
import com.android.gallery3d.util.LightCycleHelper.PanoramaMetadata;
import java.util.ArrayList;
/**
* This class breaks out the off-thread panorama support.
*/
public class PanoramaMetadataLoader {
/**
* Classes implementing this interface can get information about loaded
* photo sphere metadata.
*/
public static interface PanoramaMetadataCallback {
/**
* Called with the loaded metadata or <code>null</code>.
*/
public void onPanoramaMetadataLoaded(PanoramaMetadata metadata);
}
private PanoramaMetadata mPanoramaMetadata;
private ArrayList<PanoramaMetadataCallback> mCallbacksWaiting;
private Uri mMediaUri;
/**
* Instantiated the meta data loader for the image resource with the given
* URI.
*/
public PanoramaMetadataLoader(Uri uri) {
mMediaUri = uri;
}
/**
* Asynchronously extract and return panorama metadata from the item with
* the given URI.
* <p>
* NOTE: This call is backed by a cache to speed up successive calls, which
* will return immediately. Use {@link #clearCachedValues()} is called.
*/
public synchronized void getPanoramaMetadata(final Context context,
PanoramaMetadataCallback callback) {
if (mPanoramaMetadata != null) {
// Return the cached data right away, no need to fetch it again.
callback.onPanoramaMetadataLoaded(mPanoramaMetadata);
} else {
if (mCallbacksWaiting == null) {
mCallbacksWaiting = new ArrayList<PanoramaMetadataCallback>();
// TODO: Don't create a new thread each time, use a pool or
// single instance.
(new Thread() {
@Override
public void run() {
onLoadingDone(LightCycleHelper.getPanoramaMetadata(context,
mMediaUri));
}
}).start();
}
mCallbacksWaiting.add(callback);
}
}
/**
* Clear cached value and stop all running loading threads.
*/
public synchronized void clearCachedValues() {
if (mPanoramaMetadata != null) {
mPanoramaMetadata = null;
}
// TODO: Cancel running loading thread if active.
}
private synchronized void onLoadingDone(PanoramaMetadata metadata) {
mPanoramaMetadata = metadata;
if (mPanoramaMetadata == null) {
// Error getting panorama data from file. Treat as not panorama.
mPanoramaMetadata = LightCycleHelper.NOT_PANORAMA;
}
for (PanoramaMetadataCallback cb : mCallbacksWaiting) {
cb.onPanoramaMetadataLoaded(mPanoramaMetadata);
}
mCallbacksWaiting = null;
}
}
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