Java tutorial
/* 50AH-code ========= 50 Android Hacks (http://manning.com/sessa/) book source code Copyright (c) 2012 Manning Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ /* * Copyright (C) 2011 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.actionbarsherlock.widget; import android.content.ComponentName; import android.content.Context; import android.content.Intent; import android.content.pm.ResolveInfo; import android.database.DataSetObservable; import android.os.Handler; import android.text.TextUtils; import android.util.Log; import android.util.Xml; import org.xmlpull.v1.XmlPullParser; import org.xmlpull.v1.XmlPullParserException; import org.xmlpull.v1.XmlSerializer; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.math.BigDecimal; import java.util.ArrayList; import java.util.Collections; import java.util.HashMap; import java.util.LinkedHashSet; import java.util.LinkedList; import java.util.List; import java.util.Map; import java.util.Set; import java.util.concurrent.Executor; /** * <p> * This class represents a data model for choosing a component for handing a * given {@link Intent}. The model is responsible for querying the system for * activities that can handle the given intent and order found activities * based on historical data of previous choices. The historical data is stored * in an application private file. If a client does not want to have persistent * choice history the file can be omitted, thus the activities will be ordered * based on historical usage for the current session. * <p> * </p> * For each backing history file there is a singleton instance of this class. Thus, * several clients that specify the same history file will share the same model. Note * that if multiple clients are sharing the same model they should implement semantically * equivalent functionality since setting the model intent will change the found * activities and they may be inconsistent with the functionality of some of the clients. * For example, choosing a share activity can be implemented by a single backing * model and two different views for performing the selection. If however, one of the * views is used for sharing but the other for importing, for example, then each * view should be backed by a separate model. * </p> * <p> * The way clients interact with this class is as follows: * </p> * <p> * <pre> * <code> * // Get a model and set it to a couple of clients with semantically similar function. * ActivityChooserModel dataModel = * ActivityChooserModel.get(context, "task_specific_history_file_name.xml"); * * ActivityChooserModelClient modelClient1 = getActivityChooserModelClient1(); * modelClient1.setActivityChooserModel(dataModel); * * ActivityChooserModelClient modelClient2 = getActivityChooserModelClient2(); * modelClient2.setActivityChooserModel(dataModel); * * // Set an intent to choose a an activity for. * dataModel.setIntent(intent); * <pre> * <code> * </p> * <p> * <strong>Note:</strong> This class is thread safe. * </p> * * @hide */ class ActivityChooserModel extends DataSetObservable { /** * Client that utilizes an {@link ActivityChooserModel}. */ public interface ActivityChooserModelClient { /** * Sets the {@link ActivityChooserModel}. * * @param dataModel The model. */ public void setActivityChooserModel(ActivityChooserModel dataModel); } /** * Defines a sorter that is responsible for sorting the activities * based on the provided historical choices and an intent. */ public interface ActivitySorter { /** * Sorts the <code>activities</code> in descending order of relevance * based on previous history and an intent. * * @param intent The {@link Intent}. * @param activities Activities to be sorted. * @param historicalRecords Historical records. */ // This cannot be done by a simple comparator since an Activity weight // is computed from history. Note that Activity implements Comparable. public void sort(Intent intent, List<ActivityResolveInfo> activities, List<HistoricalRecord> historicalRecords); } /** * Listener for choosing an activity. */ public interface OnChooseActivityListener { /** * Called when an activity has been chosen. The client can decide whether * an activity can be chosen and if so the caller of * {@link ActivityChooserModel#chooseActivity(int)} will receive and {@link Intent} * for launching it. * <p> * <strong>Note:</strong> Modifying the intent is not permitted and * any changes to the latter will be ignored. * </p> * * @param host The listener's host model. * @param intent The intent for launching the chosen activity. * @return Whether the intent is handled and should not be delivered to clients. * * @see ActivityChooserModel#chooseActivity(int) */ public boolean onChooseActivity(ActivityChooserModel host, Intent intent); } /** * Flag for selecting debug mode. */ private static final boolean DEBUG = false; /** * Tag used for logging. */ private static final String LOG_TAG = ActivityChooserModel.class.getSimpleName(); /** * The root tag in the history file. */ private static final String TAG_HISTORICAL_RECORDS = "historical-records"; /** * The tag for a record in the history file. */ private static final String TAG_HISTORICAL_RECORD = "historical-record"; /** * Attribute for the activity. */ private static final String ATTRIBUTE_ACTIVITY = "activity"; /** * Attribute for the choice time. */ private static final String ATTRIBUTE_TIME = "time"; /** * Attribute for the choice weight. */ private static final String ATTRIBUTE_WEIGHT = "weight"; /** * The default name of the choice history file. */ public static final String DEFAULT_HISTORY_FILE_NAME = "activity_choser_model_history.xml"; /** * The default maximal length of the choice history. */ public static final int DEFAULT_HISTORY_MAX_LENGTH = 50; /** * The amount with which to inflate a chosen activity when set as default. */ private static final int DEFAULT_ACTIVITY_INFLATION = 5; /** * Default weight for a choice record. */ private static final float DEFAULT_HISTORICAL_RECORD_WEIGHT = 1.0f; /** * The extension of the history file. */ private static final String HISTORY_FILE_EXTENSION = ".xml"; /** * An invalid item index. */ private static final int INVALID_INDEX = -1; /** * Lock to guard the model registry. */ private static final Object sRegistryLock = new Object(); /** * This the registry for data models. */ private static final Map<String, ActivityChooserModel> sDataModelRegistry = new HashMap<String, ActivityChooserModel>(); /** * Lock for synchronizing on this instance. */ private final Object mInstanceLock = new Object(); /** * List of activities that can handle the current intent. */ private final List<ActivityResolveInfo> mActivites = new ArrayList<ActivityResolveInfo>(); /** * List with historical choice records. */ private final List<HistoricalRecord> mHistoricalRecords = new ArrayList<HistoricalRecord>(); /** * Context for accessing resources. */ private final Context mContext; /** * The name of the history file that backs this model. */ private final String mHistoryFileName; /** * The intent for which a activity is being chosen. */ private Intent mIntent; /** * The sorter for ordering activities based on intent and past choices. */ private ActivitySorter mActivitySorter = new DefaultSorter(); /** * The maximal length of the choice history. */ private int mHistoryMaxSize = DEFAULT_HISTORY_MAX_LENGTH; /** * Flag whether choice history can be read. In general many clients can * share the same data model and {@link #readHistoricalData()} may be called * by arbitrary of them any number of times. Therefore, this class guarantees * that the very first read succeeds and subsequent reads can be performed * only after a call to {@link #persistHistoricalData()} followed by change * of the share records. */ private boolean mCanReadHistoricalData = true; /** * Flag whether the choice history was read. This is used to enforce that * before calling {@link #persistHistoricalData()} a call to * {@link #persistHistoricalData()} has been made. This aims to avoid a * scenario in which a choice history file exits, it is not read yet and * it is overwritten. Note that always all historical records are read in * full and the file is rewritten. This is necessary since we need to * purge old records that are outside of the sliding window of past choices. */ private boolean mReadShareHistoryCalled = false; /** * Flag whether the choice records have changed. In general many clients can * share the same data model and {@link #persistHistoricalData()} may be called * by arbitrary of them any number of times. Therefore, this class guarantees * that choice history will be persisted only if it has changed. */ private boolean mHistoricalRecordsChanged = true; /** * Hander for scheduling work on client tread. */ private final Handler mHandler = new Handler(); /** * Policy for controlling how the model handles chosen activities. */ private OnChooseActivityListener mActivityChoserModelPolicy; /** * Gets the data model backed by the contents of the provided file with historical data. * Note that only one data model is backed by a given file, thus multiple calls with * the same file name will return the same model instance. If no such instance is present * it is created. * <p> * <strong>Note:</strong> To use the default historical data file clients should explicitly * pass as file name {@link #DEFAULT_HISTORY_FILE_NAME}. If no persistence of the choice * history is desired clients should pass <code>null</code> for the file name. In such * case a new model is returned for each invocation. * </p> * * <p> * <strong>Always use difference historical data files for semantically different actions. * For example, sharing is different from importing.</strong> * </p> * * @param context Context for loading resources. * @param historyFileName File name with choice history, <code>null</code> * if the model should not be backed by a file. In this case the activities * will be ordered only by data from the current session. * * @return The model. */ public static ActivityChooserModel get(Context context, String historyFileName) { synchronized (sRegistryLock) { ActivityChooserModel dataModel = sDataModelRegistry.get(historyFileName); if (dataModel == null) { dataModel = new ActivityChooserModel(context, historyFileName); sDataModelRegistry.put(historyFileName, dataModel); } dataModel.readHistoricalData(); return dataModel; } } /** * Creates a new instance. * * @param context Context for loading resources. * @param historyFileName The history XML file. */ private ActivityChooserModel(Context context, String historyFileName) { mContext = context.getApplicationContext(); if (!TextUtils.isEmpty(historyFileName) && !historyFileName.endsWith(HISTORY_FILE_EXTENSION)) { mHistoryFileName = historyFileName + HISTORY_FILE_EXTENSION; } else { mHistoryFileName = historyFileName; } } /** * Sets an intent for which to choose a activity. * <p> * <strong>Note:</strong> Clients must set only semantically similar * intents for each data model. * <p> * * @param intent The intent. */ public void setIntent(Intent intent) { synchronized (mInstanceLock) { if (mIntent == intent) { return; } mIntent = intent; loadActivitiesLocked(); } } /** * Gets the intent for which a activity is being chosen. * * @return The intent. */ public Intent getIntent() { synchronized (mInstanceLock) { return mIntent; } } /** * Gets the number of activities that can handle the intent. * * @return The activity count. * * @see #setIntent(Intent) */ public int getActivityCount() { synchronized (mInstanceLock) { return mActivites.size(); } } /** * Gets an activity at a given index. * * @return The activity. * * @see ActivityResolveInfo * @see #setIntent(Intent) */ public ResolveInfo getActivity(int index) { synchronized (mInstanceLock) { return mActivites.get(index).resolveInfo; } } /** * Gets the index of a the given activity. * * @param activity The activity index. * * @return The index if found, -1 otherwise. */ public int getActivityIndex(ResolveInfo activity) { List<ActivityResolveInfo> activities = mActivites; final int activityCount = activities.size(); for (int i = 0; i < activityCount; i++) { ActivityResolveInfo currentActivity = activities.get(i); if (currentActivity.resolveInfo == activity) { return i; } } return INVALID_INDEX; } /** * Chooses a activity to handle the current intent. This will result in * adding a historical record for that action and construct intent with * its component name set such that it can be immediately started by the * client. * <p> * <strong>Note:</strong> By calling this method the client guarantees * that the returned intent will be started. This intent is returned to * the client solely to let additional customization before the start. * </p> * * @return An {@link Intent} for launching the activity or null if the * policy has consumed the intent. * * @see HistoricalRecord * @see OnChooseActivityListener */ public Intent chooseActivity(int index) { ActivityResolveInfo chosenActivity = mActivites.get(index); ComponentName chosenName = new ComponentName(chosenActivity.resolveInfo.activityInfo.packageName, chosenActivity.resolveInfo.activityInfo.name); Intent choiceIntent = new Intent(mIntent); choiceIntent.setComponent(chosenName); if (mActivityChoserModelPolicy != null) { // Do not allow the policy to change the intent. Intent choiceIntentCopy = new Intent(choiceIntent); final boolean handled = mActivityChoserModelPolicy.onChooseActivity(this, choiceIntentCopy); if (handled) { return null; } } HistoricalRecord historicalRecord = new HistoricalRecord(chosenName, System.currentTimeMillis(), DEFAULT_HISTORICAL_RECORD_WEIGHT); addHisoricalRecord(historicalRecord); return choiceIntent; } /** * Sets the listener for choosing an activity. * * @param listener The listener. */ public void setOnChooseActivityListener(OnChooseActivityListener listener) { mActivityChoserModelPolicy = listener; } /** * Gets the default activity, The default activity is defined as the one * with highest rank i.e. the first one in the list of activities that can * handle the intent. * * @return The default activity, <code>null</code> id not activities. * * @see #getActivity(int) */ public ResolveInfo getDefaultActivity() { synchronized (mInstanceLock) { if (!mActivites.isEmpty()) { return mActivites.get(0).resolveInfo; } } return null; } /** * Sets the default activity. The default activity is set by adding a * historical record with weight high enough that this activity will * become the highest ranked. Such a strategy guarantees that the default * will eventually change if not used. Also the weight of the record for * setting a default is inflated with a constant amount to guarantee that * it will stay as default for awhile. * * @param index The index of the activity to set as default. */ public void setDefaultActivity(int index) { ActivityResolveInfo newDefaultActivity = mActivites.get(index); ActivityResolveInfo oldDefaultActivity = mActivites.get(0); final float weight; if (oldDefaultActivity != null) { // Add a record with weight enough to boost the chosen at the top. weight = oldDefaultActivity.weight - newDefaultActivity.weight + DEFAULT_ACTIVITY_INFLATION; } else { weight = DEFAULT_HISTORICAL_RECORD_WEIGHT; } ComponentName defaultName = new ComponentName(newDefaultActivity.resolveInfo.activityInfo.packageName, newDefaultActivity.resolveInfo.activityInfo.name); HistoricalRecord historicalRecord = new HistoricalRecord(defaultName, System.currentTimeMillis(), weight); addHisoricalRecord(historicalRecord); } /** * Reads the history data from the backing file if the latter * was provided. Calling this method more than once before a call * to {@link #persistHistoricalData()} has been made has no effect. * <p> * <strong>Note:</strong> Historical data is read asynchronously and * as soon as the reading is completed any registered * {@link DataSetObserver}s will be notified. Also no historical * data is read until this method is invoked. * <p> */ private void readHistoricalData() { synchronized (mInstanceLock) { if (!mCanReadHistoricalData || !mHistoricalRecordsChanged) { return; } mCanReadHistoricalData = false; mReadShareHistoryCalled = true; if (!TextUtils.isEmpty(mHistoryFileName)) { /*AsyncTask.*/SERIAL_EXECUTOR.execute(new HistoryLoader()); } } } private static final SerialExecutor SERIAL_EXECUTOR = new SerialExecutor(); private static class SerialExecutor implements Executor { final LinkedList<Runnable> mTasks = new LinkedList<Runnable>(); Runnable mActive; public synchronized void execute(final Runnable r) { mTasks.offer(new Runnable() { public void run() { try { r.run(); } finally { scheduleNext(); } } }); if (mActive == null) { scheduleNext(); } } protected synchronized void scheduleNext() { if ((mActive = mTasks.poll()) != null) { mActive.run(); } } } /** * Persists the history data to the backing file if the latter * was provided. Calling this method before a call to {@link #readHistoricalData()} * throws an exception. Calling this method more than one without choosing an * activity has not effect. * * @throws IllegalStateException If this method is called before a call to * {@link #readHistoricalData()}. */ private void persistHistoricalData() { synchronized (mInstanceLock) { if (!mReadShareHistoryCalled) { throw new IllegalStateException("No preceding call to #readHistoricalData"); } if (!mHistoricalRecordsChanged) { return; } mHistoricalRecordsChanged = false; mCanReadHistoricalData = true; if (!TextUtils.isEmpty(mHistoryFileName)) { /*AsyncTask.*/SERIAL_EXECUTOR.execute(new HistoryPersister()); } } } /** * Sets the sorter for ordering activities based on historical data and an intent. * * @param activitySorter The sorter. * * @see ActivitySorter */ public void setActivitySorter(ActivitySorter activitySorter) { synchronized (mInstanceLock) { if (mActivitySorter == activitySorter) { return; } mActivitySorter = activitySorter; sortActivities(); } } /** * Sorts the activities based on history and an intent. If * a sorter is not specified this a default implementation is used. * * @see #setActivitySorter(ActivitySorter) */ private void sortActivities() { synchronized (mInstanceLock) { if (mActivitySorter != null && !mActivites.isEmpty()) { mActivitySorter.sort(mIntent, mActivites, Collections.unmodifiableList(mHistoricalRecords)); notifyChanged(); } } } /** * Sets the maximal size of the historical data. Defaults to * {@link #DEFAULT_HISTORY_MAX_LENGTH} * <p> * <strong>Note:</strong> Setting this property will immediately * enforce the specified max history size by dropping enough old * historical records to enforce the desired size. Thus, any * records that exceed the history size will be discarded and * irreversibly lost. * </p> * * @param historyMaxSize The max history size. */ public void setHistoryMaxSize(int historyMaxSize) { synchronized (mInstanceLock) { if (mHistoryMaxSize == historyMaxSize) { return; } mHistoryMaxSize = historyMaxSize; pruneExcessiveHistoricalRecordsLocked(); sortActivities(); } } /** * Gets the history max size. * * @return The history max size. */ public int getHistoryMaxSize() { synchronized (mInstanceLock) { return mHistoryMaxSize; } } /** * Gets the history size. * * @return The history size. */ public int getHistorySize() { synchronized (mInstanceLock) { return mHistoricalRecords.size(); } } /** * Adds a historical record. * * @param historicalRecord The record to add. * @return True if the record was added. */ private boolean addHisoricalRecord(HistoricalRecord historicalRecord) { synchronized (mInstanceLock) { final boolean added = mHistoricalRecords.add(historicalRecord); if (added) { mHistoricalRecordsChanged = true; pruneExcessiveHistoricalRecordsLocked(); persistHistoricalData(); sortActivities(); } return added; } } /** * Prunes older excessive records to guarantee {@link #mHistoryMaxSize}. */ private void pruneExcessiveHistoricalRecordsLocked() { List<HistoricalRecord> choiceRecords = mHistoricalRecords; final int pruneCount = choiceRecords.size() - mHistoryMaxSize; if (pruneCount <= 0) { return; } mHistoricalRecordsChanged = true; for (int i = 0; i < pruneCount; i++) { HistoricalRecord prunedRecord = choiceRecords.remove(0); if (DEBUG) { Log.i(LOG_TAG, "Pruned: " + prunedRecord); } } } /** * Loads the activities. */ private void loadActivitiesLocked() { mActivites.clear(); if (mIntent != null) { List<ResolveInfo> resolveInfos = mContext.getPackageManager().queryIntentActivities(mIntent, 0); final int resolveInfoCount = resolveInfos.size(); for (int i = 0; i < resolveInfoCount; i++) { ResolveInfo resolveInfo = resolveInfos.get(i); mActivites.add(new ActivityResolveInfo(resolveInfo)); } sortActivities(); } else { notifyChanged(); } } /** * Represents a record in the history. */ public final static class HistoricalRecord { /** * The activity name. */ public final ComponentName activity; /** * The choice time. */ public final long time; /** * The record weight. */ public final float weight; /** * Creates a new instance. * * @param activityName The activity component name flattened to string. * @param time The time the activity was chosen. * @param weight The weight of the record. */ public HistoricalRecord(String activityName, long time, float weight) { this(ComponentName.unflattenFromString(activityName), time, weight); } /** * Creates a new instance. * * @param activityName The activity name. * @param time The time the activity was chosen. * @param weight The weight of the record. */ public HistoricalRecord(ComponentName activityName, long time, float weight) { this.activity = activityName; this.time = time; this.weight = weight; } @Override public int hashCode() { final int prime = 31; int result = 1; result = prime * result + ((activity == null) ? 0 : activity.hashCode()); result = prime * result + (int) (time ^ (time >>> 32)); result = prime * result + Float.floatToIntBits(weight); return result; } @Override public boolean equals(Object obj) { if (this == obj) { return true; } if (obj == null) { return false; } if (getClass() != obj.getClass()) { return false; } HistoricalRecord other = (HistoricalRecord) obj; if (activity == null) { if (other.activity != null) { return false; } } else if (!activity.equals(other.activity)) { return false; } if (time != other.time) { return false; } if (Float.floatToIntBits(weight) != Float.floatToIntBits(other.weight)) { return false; } return true; } @Override public String toString() { StringBuilder builder = new StringBuilder(); builder.append("["); builder.append("; activity:").append(activity); builder.append("; time:").append(time); builder.append("; weight:").append(new BigDecimal(weight)); builder.append("]"); return builder.toString(); } } /** * Represents an activity. */ public final class ActivityResolveInfo implements Comparable<ActivityResolveInfo> { /** * The {@link ResolveInfo} of the activity. */ public final ResolveInfo resolveInfo; /** * Weight of the activity. Useful for sorting. */ public float weight; /** * Creates a new instance. * * @param resolveInfo activity {@link ResolveInfo}. */ public ActivityResolveInfo(ResolveInfo resolveInfo) { this.resolveInfo = resolveInfo; } @Override public int hashCode() { return 31 + Float.floatToIntBits(weight); } @Override public boolean equals(Object obj) { if (this == obj) { return true; } if (obj == null) { return false; } if (getClass() != obj.getClass()) { return false; } ActivityResolveInfo other = (ActivityResolveInfo) obj; if (Float.floatToIntBits(weight) != Float.floatToIntBits(other.weight)) { return false; } return true; } public int compareTo(ActivityResolveInfo another) { return Float.floatToIntBits(another.weight) - Float.floatToIntBits(weight); } @Override public String toString() { StringBuilder builder = new StringBuilder(); builder.append("["); builder.append("resolveInfo:").append(resolveInfo.toString()); builder.append("; weight:").append(new BigDecimal(weight)); builder.append("]"); return builder.toString(); } } /** * Default activity sorter implementation. */ private final class DefaultSorter implements ActivitySorter { private static final float WEIGHT_DECAY_COEFFICIENT = 0.95f; private final Map<String, ActivityResolveInfo> mPackageNameToActivityMap = new HashMap<String, ActivityResolveInfo>(); public void sort(Intent intent, List<ActivityResolveInfo> activities, List<HistoricalRecord> historicalRecords) { Map<String, ActivityResolveInfo> packageNameToActivityMap = mPackageNameToActivityMap; packageNameToActivityMap.clear(); final int activityCount = activities.size(); for (int i = 0; i < activityCount; i++) { ActivityResolveInfo activity = activities.get(i); activity.weight = 0.0f; String packageName = activity.resolveInfo.activityInfo.packageName; packageNameToActivityMap.put(packageName, activity); } final int lastShareIndex = historicalRecords.size() - 1; float nextRecordWeight = 1; for (int i = lastShareIndex; i >= 0; i--) { HistoricalRecord historicalRecord = historicalRecords.get(i); String packageName = historicalRecord.activity.getPackageName(); ActivityResolveInfo activity = packageNameToActivityMap.get(packageName); if (activity != null) { activity.weight += historicalRecord.weight * nextRecordWeight; nextRecordWeight = nextRecordWeight * WEIGHT_DECAY_COEFFICIENT; } } Collections.sort(activities); if (DEBUG) { for (int i = 0; i < activityCount; i++) { Log.i(LOG_TAG, "Sorted: " + activities.get(i)); } } } } /** * Command for reading the historical records from a file off the UI thread. */ private final class HistoryLoader implements Runnable { public void run() { FileInputStream fis = null; try { fis = mContext.openFileInput(mHistoryFileName); } catch (FileNotFoundException fnfe) { if (DEBUG) { Log.i(LOG_TAG, "Could not open historical records file: " + mHistoryFileName); } return; } try { XmlPullParser parser = Xml.newPullParser(); parser.setInput(fis, null); int type = XmlPullParser.START_DOCUMENT; while (type != XmlPullParser.END_DOCUMENT && type != XmlPullParser.START_TAG) { type = parser.next(); } if (!TAG_HISTORICAL_RECORDS.equals(parser.getName())) { throw new XmlPullParserException( "Share records file does not start with " + TAG_HISTORICAL_RECORDS + " tag."); } List<HistoricalRecord> readRecords = new ArrayList<HistoricalRecord>(); while (true) { type = parser.next(); if (type == XmlPullParser.END_DOCUMENT) { break; } if (type == XmlPullParser.END_TAG || type == XmlPullParser.TEXT) { continue; } String nodeName = parser.getName(); if (!TAG_HISTORICAL_RECORD.equals(nodeName)) { throw new XmlPullParserException("Share records file not well-formed."); } String activity = parser.getAttributeValue(null, ATTRIBUTE_ACTIVITY); final long time = Long.parseLong(parser.getAttributeValue(null, ATTRIBUTE_TIME)); final float weight = Float.parseFloat(parser.getAttributeValue(null, ATTRIBUTE_WEIGHT)); HistoricalRecord readRecord = new HistoricalRecord(activity, time, weight); readRecords.add(readRecord); if (DEBUG) { Log.i(LOG_TAG, "Read " + readRecord.toString()); } } if (DEBUG) { Log.i(LOG_TAG, "Read " + readRecords.size() + " historical records."); } synchronized (mInstanceLock) { Set<HistoricalRecord> uniqueShareRecords = new LinkedHashSet<HistoricalRecord>(readRecords); // Make sure no duplicates. Example: Read a file with // one record, add one record, persist the two records, // add a record, read the persisted records - the // read two records should not be added again. List<HistoricalRecord> historicalRecords = mHistoricalRecords; final int historicalRecordsCount = historicalRecords.size(); for (int i = historicalRecordsCount - 1; i >= 0; i--) { HistoricalRecord historicalRecord = historicalRecords.get(i); uniqueShareRecords.add(historicalRecord); } if (historicalRecords.size() == uniqueShareRecords.size()) { return; } // Make sure the oldest records go to the end. historicalRecords.clear(); historicalRecords.addAll(uniqueShareRecords); mHistoricalRecordsChanged = true; // Do this on the client thread since the client may be on the UI // thread, wait for data changes which happen during sorting, and // perform UI modification based on the data change. mHandler.post(new Runnable() { public void run() { pruneExcessiveHistoricalRecordsLocked(); sortActivities(); } }); } } catch (XmlPullParserException xppe) { Log.e(LOG_TAG, "Error reading historical recrod file: " + mHistoryFileName, xppe); } catch (IOException ioe) { Log.e(LOG_TAG, "Error reading historical recrod file: " + mHistoryFileName, ioe); } finally { if (fis != null) { try { fis.close(); } catch (IOException ioe) { /* ignore */ } } } } } /** * Command for persisting the historical records to a file off the UI thread. */ private final class HistoryPersister implements Runnable { public void run() { FileOutputStream fos = null; List<HistoricalRecord> records = null; synchronized (mInstanceLock) { records = new ArrayList<HistoricalRecord>(mHistoricalRecords); } try { fos = mContext.openFileOutput(mHistoryFileName, Context.MODE_PRIVATE); } catch (FileNotFoundException fnfe) { Log.e(LOG_TAG, "Error writing historical recrod file: " + mHistoryFileName, fnfe); return; } XmlSerializer serializer = Xml.newSerializer(); try { serializer.setOutput(fos, null); serializer.startDocument("UTF-8", true); serializer.startTag(null, TAG_HISTORICAL_RECORDS); final int recordCount = records.size(); for (int i = 0; i < recordCount; i++) { HistoricalRecord record = records.remove(0); serializer.startTag(null, TAG_HISTORICAL_RECORD); serializer.attribute(null, ATTRIBUTE_ACTIVITY, record.activity.flattenToString()); serializer.attribute(null, ATTRIBUTE_TIME, String.valueOf(record.time)); serializer.attribute(null, ATTRIBUTE_WEIGHT, String.valueOf(record.weight)); serializer.endTag(null, TAG_HISTORICAL_RECORD); if (DEBUG) { Log.i(LOG_TAG, "Wrote " + record.toString()); } } serializer.endTag(null, TAG_HISTORICAL_RECORDS); serializer.endDocument(); if (DEBUG) { Log.i(LOG_TAG, "Wrote " + recordCount + " historical records."); } } catch (IllegalArgumentException iae) { Log.e(LOG_TAG, "Error writing historical recrod file: " + mHistoryFileName, iae); } catch (IllegalStateException ise) { Log.e(LOG_TAG, "Error writing historical recrod file: " + mHistoryFileName, ise); } catch (IOException ioe) { Log.e(LOG_TAG, "Error writing historical recrod file: " + mHistoryFileName, ioe); } finally { if (fos != null) { try { fos.close(); } catch (IOException e) { /* ignore */ } } } } } }