iCloud Document Storage with UIDocument - Beginning iOS Cloud and Database Development - page 107

Now, let's go to the two spots that we have TODO #1 and change them to read:
[self moveLocalToiCloud];
And change our TODO #2s to read:
[self copyiCloudToLocal];
And let's change our TODO #3 to read:
[self queryiCloud];
Finally let's add the following two lines at the beginning of our reload method.
_iCloudIsReady = NO;
[_iCloudURLs removeAllObjects];
Now we need to modify our getDocumentFilename:forLocal method so that we are handling a value
of NO for the last parameter. Currently we only check to see whether the value isLocal is YES . We
need to add an else to that statement so we can check to see whether the name exists in our iCloud
container. The if statement should now look like this:
if(isLocal){
nameExists = [self documentNameExistsInObjects:newDocName];
} else {
nameExists = [self documentNameExistsIniCloudURLs:newDocName];
}
We are calling a new method here documentNameExistsIniCloudURLs: . Let's write that now.
-(BOOL)documentNameExistsIniCloudURLs:(NSString *)documentName {
__block BOOL nameExists = NO;
[_iCloudURLs enumerateObjectsUsingBlock:^(NSURL *fileURL, NSUInteger idx, BOOL *stop) {
if([[fileURL lastPathComponent] isEqualToString:documentName]){
nameExists = YES;
*stop = YES;
}
}];
return nameExists;
}
This is an identical method to documentNameExistsInObjects: except here we are enumerating
through the iCloudURLs array.
The last thing we want to do is to add our self as an observer to the
UIApplicationDidBecomeActiveNotification . We do this in the viewWillAppear: method. We add an
enableUpdates call on our NSMetadataQuery object as well.