详见在Android 2.2源码 packages/apps/Phone/tests/src/com/android/phone/NotificationMgr.java 模块中异步查询机制：
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(1)开始查询
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??// instantiate query handler
?? ? ? ?mQueryHandler = new QueryHandler(mContext.getContentResolver());
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?? ? ? ?// setup query spec, look for all Missed calls that are new.
?? ? ? ?StringBuilder where = new StringBuilder("type=");
?? ? ? ?where.append(Calls.MISSED_TYPE);
?? ? ? ?where.append(" AND new=1");
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?? ? ? ?// start the query
?? ? ? ?mQueryHandler.startQuery(CALL_LOG_TOKEN, null, Calls.CONTENT_URI, ?CALL_LOG_PROJECTION,
?? ? ? ? ? ? ? ?where.toString(), null, Calls.DEFAULT_SORT_ORDER);
(2)异步查询类
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/**
???? * Class used to run asynchronous queries to re-populate
???? * the notifications we care about.
???? */
??? private class QueryHandler extends AsyncQueryHandler {
??????? /**
???????? * Used to store relevant fields for the Missed Call
???????? * notifications.
???????? */
??????? private class NotificationInfo {?? //Modle
??????????? public String name;
??????????? public String number;
??????????? public String label;
??????????? public long date;
??????????? public int subscription;
??????? }
??????? public QueryHandler(ContentResolver cr) {
??????????? super(cr);
??????? }
??????? /**
???????? * Handles the query results.? There are really 2 steps to this,
???????? * similar to what happens in RecentCallsListActivity.
???????? *? 1. Find the list of missed calls
???????? *? 2. For each call, run a query to retrieve the caller's name.
???????? */
??????? @Override
??????? protected void onQueryComplete(int token, Object cookie, Cursor cursor) {
??????????? // TODO: it would be faster to use a join here, but for the purposes
??????????? // of this small record set, it should be ok.
??????????? // Note that CursorJoiner is not useable here because the number
??????????? // comparisons are not strictly equals; the comparisons happen in
??????????? // the SQL function PHONE_NUMBERS_EQUAL, which is not available for
??????????? // the CursorJoiner.
??????????? // Executing our own query is also feasible (with a join), but that
??????????? // will require some work (possibly destabilizing) in Contacts
??????????? // Provider.
??????????? // At this point, we will execute subqueries on each row just as
??????????? // RecentCallsListActivity.java does.
??????????? switch (token) {
??????????????? case CALL_LOG_TOKEN:
??????????????????? if (DBG) log("call log query complete.");
??????????????????? // initial call to retrieve the call list.
??????????????????? if (cursor != null) {
??????????????????????? while (cursor.moveToNext()) {
??????????????????????????? // for each call in the call log list, create
??????????????????????????? // the notification object and query contacts
??????????????????????????? NotificationInfo n = getNotificationInfo (cursor);
??????????????????????????? if (DBG) log("query contacts for number: " + n.number); ?//从号码中查询联系人
??????????????????????????? mQueryHandler.startQuery(CONTACT_TOKEN, n,
??????????????????????????????????? Uri.withAppendedPath(PhoneLookup.CONTENT_FILTER_URI, n.number),
??????????????????????????????????? PHONES_PROJECTION, null, null, PhoneLookup.NUMBER);
??????????????????????? }
??????????????????????? if (DBG) log("closing call log cursor.");
??????????????????????? cursor.close();
??????????????????? }
??????????????????? break;
??????????????? case CONTACT_TOKEN:
??????????????????? if (DBG) log("contact query complete.");
??????????????????? // subqueries to get the caller name.
??????????????????? if ((cursor != null) && (cookie != null)){
??????????????????????? NotificationInfo n = (NotificationInfo) cookie;
??????????????????????? if (cursor.moveToFirst()) {
??????????????????????????? // we have contacts data, get the name.
??????????????????????????? if (DBG) log("contact :" + n.name + " found for phone: " + n.number);
??????????????????????????? n.name = cursor.getString(
??????????????????????????????????? cursor.getColumnIndexOrThrow(PhoneLookup.DISPLAY_NAME));
??????????????????????? }
??????????????????????? // send the notification
??????????????????????? if (DBG) log("sending notification.");
??????????????????????? if (TelephonyManager.isDsdsEnabled()) {
??????????????????????????? notifyMissedCall(n.name, n.number, n.label, n.date, n.subscription);
??????????????????????? } else {
??????????????????????????? notifyMissedCall(n.name, n.number, n.label, n.date);
??????????????????????? }
??????????????????????? if (DBG) log("closing contact cursor.");
??????????????????????? cursor.close();
??????????????????? }
??????????????????? break;
??????????????? default:
??????????? }
??????? }
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/**
?? ? ? ? * Factory method to generate a NotificationInfo object given a
?? ? ? ? * cursor from the call log table.
?? ? ? ? */
?? ? ? ?private final NotificationInfo getNotificationInfo(Cursor cursor) {
?? ? ? ? ? ?NotificationInfo n = new NotificationInfo();
?? ? ? ? ? ?n.name = null;
?? ? ? ? ? ?n.number = cursor.getString(cursor.getColumnIndexOrThrow(Calls.NUMBER));
?? ? ? ? ? ?n.label = cursor.getString(cursor.getColumnIndexOrThrow(Calls.TYPE));
?? ? ? ? ? ?n.date = cursor.getLong(cursor.getColumnIndexOrThrow(Calls.DATE));
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?? ? ? ? ? ?// make sure we update the number depending upon saved values in
?? ? ? ? ? ?// CallLog.addCall(). ?If either special values for unknown or
?? ? ? ? ? ?// private number are detected, we need to hand off the message
?? ? ? ? ? ?// to the missed call notification.
?? ? ? ? ? ?if ( (n.number.equals(CallerInfo.UNKNOWN_NUMBER)) ||
?? ? ? ? ? ? ? ? (n.number.equals(CallerInfo.PRIVATE_NUMBER)) ||
?? ? ? ? ? ? ? ? (n.number.equals(CallerInfo.PAYPHONE_NUMBER)) ) {
?? ? ? ? ? ? ? ?n.number = null;
?? ? ? ? ? ?}
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?? ? ? ? ? ?if (DBG) log("NotificationInfo constructed for number: " + n.number);
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?? ? ? ? ? ?return n;
?? ? ? ?}
?? ?}
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