Java tutorial
/* * 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 lewa.support.v7.internal.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.AsyncTask; import android.os.Build; import android.support.v4.os.AsyncTaskCompat; 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.List; import java.util.Map; /** * <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 */ public 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> mActivities = 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 #readHistoricalDataIfNeeded()} 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 #persistHistoricalDataIfNeeded()} 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 #persistHistoricalDataIfNeeded()} a call to * {@link #persistHistoricalDataIfNeeded()} 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 #persistHistoricalDataIfNeeded()} 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; /** * Flag whether to reload the activities for the current intent. */ private boolean mReloadActivities = false; /** * 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); } 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; mReloadActivities = true; ensureConsistentState(); } } /** * 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) { ensureConsistentState(); return mActivities.size(); } } /** * Gets an activity at a given index. * * @return The activity. * * @see ActivityResolveInfo * @see #setIntent(Intent) */ public ResolveInfo getActivity(int index) { synchronized (mInstanceLock) { ensureConsistentState(); return mActivities.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) { synchronized (mInstanceLock) { ensureConsistentState(); List<ActivityResolveInfo> activities = mActivities; 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 or there is not current intent * set via {@link #setIntent(Intent)}. * * @see HistoricalRecord * @see OnChooseActivityListener */ public Intent chooseActivity(int index) { synchronized (mInstanceLock) { if (mIntent == null) { return null; } ensureConsistentState(); ActivityResolveInfo chosenActivity = mActivities.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) { synchronized (mInstanceLock) { 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) { ensureConsistentState(); if (!mActivities.isEmpty()) { return mActivities.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) { synchronized (mInstanceLock) { ensureConsistentState(); ActivityResolveInfo newDefaultActivity = mActivities.get(index); ActivityResolveInfo oldDefaultActivity = mActivities.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); } } /** * Persists the history data to the backing file if the latter * was provided. Calling this method before a call to {@link #readHistoricalDataIfNeeded()} * 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 #readHistoricalDataIfNeeded()}. */ private void persistHistoricalDataIfNeeded() { if (!mReadShareHistoryCalled) { throw new IllegalStateException("No preceding call to #readHistoricalData"); } if (!mHistoricalRecordsChanged) { return; } mHistoricalRecordsChanged = false; if (!TextUtils.isEmpty(mHistoryFileName)) { AsyncTaskCompat.executeParallel(new PersistHistoryAsyncTask(), mHistoricalRecords, mHistoryFileName); } } /** * 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; if (sortActivitiesIfNeeded()) { 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; pruneExcessiveHistoricalRecordsIfNeeded(); if (sortActivitiesIfNeeded()) { notifyChanged(); } } } /** * 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) { ensureConsistentState(); return mHistoricalRecords.size(); } } /** * Ensures the model is in a consistent state which is the * activities for the current intent have been loaded, the * most recent history has been read, and the activities * are sorted. */ private void ensureConsistentState() { boolean stateChanged = loadActivitiesIfNeeded(); stateChanged |= readHistoricalDataIfNeeded(); pruneExcessiveHistoricalRecordsIfNeeded(); if (stateChanged) { sortActivitiesIfNeeded(); notifyChanged(); } } /** * Sorts the activities if necessary which is if there is a * sorter, there are some activities to sort, and there is some * historical data. * * @return Whether sorting was performed. */ private boolean sortActivitiesIfNeeded() { if (mActivitySorter != null && mIntent != null && !mActivities.isEmpty() && !mHistoricalRecords.isEmpty()) { mActivitySorter.sort(mIntent, mActivities, Collections.unmodifiableList(mHistoricalRecords)); return true; } return false; } /** * Loads the activities for the current intent if needed which is * if they are not already loaded for the current intent. * * @return Whether loading was performed. */ private boolean loadActivitiesIfNeeded() { if (mReloadActivities && mIntent != null) { mReloadActivities = false; mActivities.clear(); 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); mActivities.add(new ActivityResolveInfo(resolveInfo)); } return true; } return false; } /** * Reads the historical data if necessary which is it has * changed, there is a history file, and there is not persist * in progress. * * @return Whether reading was performed. */ private boolean readHistoricalDataIfNeeded() { if (mCanReadHistoricalData && mHistoricalRecordsChanged && !TextUtils.isEmpty(mHistoryFileName)) { mCanReadHistoricalData = false; mReadShareHistoryCalled = true; readHistoricalDataImpl(); return true; } return false; } /** * Adds a historical record. * * @param historicalRecord The record to add. * @return True if the record was added. */ private boolean addHisoricalRecord(HistoricalRecord historicalRecord) { final boolean added = mHistoricalRecords.add(historicalRecord); if (added) { mHistoricalRecordsChanged = true; pruneExcessiveHistoricalRecordsIfNeeded(); persistHistoricalDataIfNeeded(); sortActivitiesIfNeeded(); notifyChanged(); } return added; } /** * Prunes older excessive records to guarantee maxHistorySize. */ private void pruneExcessiveHistoricalRecordsIfNeeded() { final int pruneCount = mHistoricalRecords.size() - mHistoryMaxSize; if (pruneCount <= 0) { return; } mHistoricalRecordsChanged = true; for (int i = 0; i < pruneCount; i++) { HistoricalRecord prunedRecord = mHistoricalRecords.remove(0); if (DEBUG) { Log.i(LOG_TAG, "Pruned: " + prunedRecord); } } } /** * 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 void readHistoricalDataImpl() { 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> historicalRecords = mHistoricalRecords; historicalRecords.clear(); 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); historicalRecords.add(readRecord); if (DEBUG) { Log.i(LOG_TAG, "Read " + readRecord.toString()); } } if (DEBUG) { Log.i(LOG_TAG, "Read " + historicalRecords.size() + " historical records."); } } 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 PersistHistoryAsyncTask extends AsyncTask<Object, Void, Void> { @Override @SuppressWarnings("unchecked") public Void doInBackground(Object... args) { List<HistoricalRecord> historicalRecords = (List<HistoricalRecord>) args[0]; String hostoryFileName = (String) args[1]; FileOutputStream fos = null; try { fos = mContext.openFileOutput(hostoryFileName, Context.MODE_PRIVATE); } catch (FileNotFoundException fnfe) { Log.e(LOG_TAG, "Error writing historical recrod file: " + hostoryFileName, fnfe); return null; } XmlSerializer serializer = Xml.newSerializer(); try { serializer.setOutput(fos, null); serializer.startDocument("UTF-8", true); serializer.startTag(null, TAG_HISTORICAL_RECORDS); final int recordCount = historicalRecords.size(); for (int i = 0; i < recordCount; i++) { HistoricalRecord record = historicalRecords.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 { mCanReadHistoricalData = true; if (fos != null) { try { fos.close(); } catch (IOException e) { /* ignore */ } } } return null; } } }