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Add AsyncQueryHandler helper for queryEntities().

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Recently we added queryEntities() to the ContentProvider
interface to read out Entity objects atomically.  This
change adds a helper to AsyncQueryHandler to perform these
queries on a background thread, returning the result when
finished.
This commit is contained in:
Jeff Sharkey
2009-08-12 09:53:48 -07:00
parent e7037b6c9e
commit a5f743f1fc
2 changed files with 112 additions and 7 deletions
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40
api/current.xml
View File

@ -27892,6 +27892,23 @@
<parameter name="cursor" type="android.database.Cursor">
</parameter>
</method>
<method name="onQueryEntitiesComplete"
return="void"
abstract="false"
native="false"
synchronized="false"
static="false"
final="false"
deprecated="not deprecated"
visibility="protected"
>
<parameter name="token" type="int">
</parameter>
<parameter name="cookie" type="java.lang.Object">
</parameter>
<parameter name="iterator" type="android.content.EntityIterator">
</parameter>
</method>
<method name="onUpdateComplete"
return="void"
abstract="false"
@ -27974,6 +27991,29 @@
<parameter name="orderBy" type="java.lang.String">
</parameter>
</method>
<method name="startQueryEntities"
return="void"
abstract="false"
native="false"
synchronized="false"
static="false"
final="false"
deprecated="not deprecated"
visibility="public"
>
<parameter name="token" type="int">
</parameter>
<parameter name="cookie" type="java.lang.Object">
</parameter>
<parameter name="uri" type="android.net.Uri">
</parameter>
<parameter name="selection" type="java.lang.String">
</parameter>
<parameter name="selectionArgs" type="java.lang.String[]">
</parameter>
<parameter name="orderBy" type="java.lang.String">
</parameter>
</method>
<method name="startUpdate"
return="void"
abstract="false"

79
core/java/android/content/AsyncQueryHandler.java
View File

@ -38,7 +38,8 @@ public abstract class AsyncQueryHandler extends Handler {
private static final int EVENT_ARG_INSERT = 2;
private static final int EVENT_ARG_UPDATE = 3;
private static final int EVENT_ARG_DELETE = 4;
private static final int EVENT_ARG_QUERY_ENTITIES = 5;
/* package */ final WeakReference<ContentResolver> mResolver;
private static Looper sLooper = null;
@ -85,13 +86,25 @@ public abstract class AsyncQueryHandler extends Handler {
cursor.getCount();
}
} catch (Exception e) {
Log.d(TAG, e.toString());
Log.w(TAG, e.toString());
cursor = null;
}
args.result = cursor;
break;
case EVENT_ARG_QUERY_ENTITIES:
EntityIterator iterator = null;
try {
iterator = resolver.queryEntities(args.uri, args.selection,
args.selectionArgs, args.orderBy);
} catch (Exception e) {
Log.w(TAG, e.toString());
}
args.result = iterator;
break;
case EVENT_ARG_INSERT:
args.result = resolver.insert(args.uri, args.values);
break;
@ -104,7 +117,6 @@ public abstract class AsyncQueryHandler extends Handler {
case EVENT_ARG_DELETE:
args.result = resolver.delete(args.uri, args.selection, args.selectionArgs);
break;
}
// passing the original token value back to the caller
@ -129,7 +141,7 @@ public abstract class AsyncQueryHandler extends Handler {
if (sLooper == null) {
HandlerThread thread = new HandlerThread("AsyncQueryWorker");
thread.start();
sLooper = thread.getLooper();
}
}
@ -182,6 +194,44 @@ public abstract class AsyncQueryHandler extends Handler {
mWorkerThreadHandler.sendMessage(msg);
}
/**
* This method begins an asynchronous query for an {@link EntityIterator}.
* When the query is done {@link #onQueryEntitiesComplete} is called.
*
* @param token A token passed into {@link #onQueryComplete} to identify the
* query.
* @param cookie An object that gets passed into {@link #onQueryComplete}
* @param uri The URI, using the content:// scheme, for the content to
* retrieve.
* @param selection A filter declaring which rows to return, formatted as an
* SQL WHERE clause (excluding the WHERE itself). Passing null
* will return all rows for the given URI.
* @param selectionArgs You may include ?s in selection, which will be
* replaced by the values from selectionArgs, in the order that
* they appear in the selection. The values will be bound as
* Strings.
* @param orderBy How to order the rows, formatted as an SQL ORDER BY clause
* (excluding the ORDER BY itself). Passing null will use the
* default sort order, which may be unordered.
*/
public void startQueryEntities(int token, Object cookie, Uri uri, String selection,
String[] selectionArgs, String orderBy) {
// Use the token as what so cancelOperations works properly
Message msg = mWorkerThreadHandler.obtainMessage(token);
msg.arg1 = EVENT_ARG_QUERY_ENTITIES;
WorkerArgs args = new WorkerArgs();
args.handler = this;
args.uri = uri;
args.selection = selection;
args.selectionArgs = selectionArgs;
args.orderBy = orderBy;
args.cookie = cookie;
msg.obj = args;
mWorkerThreadHandler.sendMessage(msg);
}
/**
* Attempts to cancel operation that has not already started. Note that
* there is no guarantee that the operation will be canceled. They still may
@ -280,14 +330,25 @@ public abstract class AsyncQueryHandler extends Handler {
* Called when an asynchronous query is completed.
*
* @param token the token to identify the query, passed in from
* {@link #startQuery}.
* @param cookie the cookie object that's passed in from {@link #startQuery}.
* {@link #startQuery}.
* @param cookie the cookie object passed in from {@link #startQuery}.
* @param cursor The cursor holding the results from the query.
*/
protected void onQueryComplete(int token, Object cookie, Cursor cursor) {
// Empty
}
/**
* Called when an asynchronous query is completed.
*
* @param token The token to identify the query.
* @param cookie The cookie object.
* @param iterator The iterator holding the query results.
*/
protected void onQueryEntitiesComplete(int token, Object cookie, EntityIterator iterator) {
// Empty
}
/**
* Called when an asynchronous insert is completed.
*
@ -338,13 +399,17 @@ public abstract class AsyncQueryHandler extends Handler {
int token = msg.what;
int event = msg.arg1;
// pass token back to caller on each callback.
switch (event) {
case EVENT_ARG_QUERY:
onQueryComplete(token, args.cookie, (Cursor) args.result);
break;
case EVENT_ARG_QUERY_ENTITIES:
onQueryEntitiesComplete(token, args.cookie, (EntityIterator)args.result);
break;
case EVENT_ARG_INSERT:
onInsertComplete(token, args.cookie, (Uri) args.result);
break;