I am trying out some code to use NSMetaDataQuery to get an application path based on bundle Identifier. I was following hte sample code found in the apple dev site: Static Spotlight search implementation.
I wrote the following files for it
//AppPath.h
void GetAppPath();
@interface SearchQuery: NSObject
{
}
@property (copy) NSMetaDataQuery *metaData;
-(void) initiateSearch;
-(void) queryDidUpdate:sender;
-(void) initalGatherComplete:sender;
@end
Definitions where as follows:
void GetAppPath()
{
SearchQuery *query = [[SearchQuery alloc] init];
[query initiateSearch];
}
@Implementation SearchQuery
// Initialize Search Method
- (void)initiateSearch
{
// Create the metadata query instance. The metadataSearch @property is
// declared as retain
self.metadataSearch=[[[NSMetadataQuery alloc] init] autorelease];
// Register the notifications for batch and completion updates
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(queryDidUpdate:)
name:NSMetadataQueryDidUpdateNotification
object:self.metadataSearch];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(initalGatherComplete:)
name:NSMetadataQueryDidFinishGatheringNotification
object:self.metadataSearch];
// Configure the search predicate to find all application with the given
//Bundle Id
NSPredicate *searchPredicate;
searchPredicate=[NSPredicate predicateWithFormat:@"NSApplicationBundleIdentifier == 'com.myapp.app'"];
[self.metadataSearch setPredicate:searchPredicate];
// Begin the asynchronous query
[self.metadataSearch startQuery];
}
// Method invoked when notifications of content batches have been received
- (void)queryDidUpdate:sender;
{
NSLog(@"A data batch has been received");
}
// Method invoked when the initial query gathering is completed
- (void)initalGatherComplete:sender;
{
// Stop the query, the single pass is completed.
[self.metadataSearch stopQuery];
// Process the content.
NSUInteger i=0;
for (i=0; i < [self.metadataSearch resultCount]; i++) {
//Do Something with the result
}
// Remove the notifications to clean up after ourselves.
// Also release the metadataQuery.
// When the Query is removed the query results are also lost.
[[NSNotificationCenter defaultCenter] removeObserver:self
name:NSMetadataQueryDidUpdateNotification
object:self.metadataSearch];
[[NSNotificationCenter defaultCenter] removeObserver:self
name:NSMetadataQueryDidFinishGatheringNotification
object:self.metadataSearch];
self.metadataSearch=nil;
}
@end
I am calling the GetAppPAth method in main. I had added the necessary header files. The code compiles and run, but I don't get any notification to the two observers.
I had put breakpoints in the two methods, queryDidUpdate & initalGatherComplete. But they are never hit. I thought the failure was because my main code was not
waiting for the search to complete. But it was not working even when I had put some wait in main. I had also tried the code in the following question: Not quite understanding NSMetadataQuery
But it ended in an infinite while loop.
