我正在尝试使用iCloud来存储我的应用程序的用户设置,这是我的保存和加载代码:,它通常做得很好,但有时会崩溃并显示如下消息:尝试打开或恢复已经在飞行中打开或恢复操作的文档,或发送到dealloc实例,所以我添加文件状态日志befere openWithCompletionHandler它总是显示状态= UIDocumentStateClosed无论是否会崩溃, 我在苹果时保存数据DidEnterBackground,并在应用程序DidBecom变得活跃时加载。
救:
-(void)storeToiCloud{
NSURL *baseURL = [[NSFileManager defaultManager] URLForUbiquityContainerIdentifier:nil];
if (baseURL) {
NSURL *documentsURL = [baseURL URLByAppendingPathComponent:@"Documents"];
NSURL *documentURL = [documentsURL URLByAppendingPathComponent:[NSString stringWithFormat:@"userSetting"]];
if (!loadDocument) {
self.loadDocument = [[MyUserDefaultsDocument alloc] initWithFileURL:documentURL];
}
loadDocument.myUserDefault = [MyUserDefaults standardUserDefaults];
[loadDocument saveToURL:documentURL forSaveOperation:UIDocumentSaveForCreating completionHandler:^(BOOL success) {
}];
}
}
负荷:
-(BOOL)shouldSynciCloud{
if (![Utility iCloudEnable]) {
return NO;
}
NSURL *baseURL = [[NSFileManager defaultManager] URLForUbiquityContainerIdentifier:nil];
if (baseURL) {
self.query = [[[NSMetadataQuery alloc] init] autorelease];
[self.query setSearchScopes:[NSArray arrayWithObject:NSMetadataQueryUbiquitousDocumentsScope]];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"%K == 'userSetting'", NSMetadataItemFSNameKey];
[self.query setPredicate:predicate];
NSNotificationCenter *nc = [NSNotificationCenter defaultCenter];
[nc addObserver:self selector:@selector(queryDidFinish:) name:NSMetadataQueryDidFinishGatheringNotification object:self.query];
[self.query startQuery];
[Utility showSpinner];
return YES;
}
return NO;
}
- (void)queryDidFinish:(NSNotification *)notification {
NSMetadataQuery *query = [notification object];
// Stop Updates
[query disableUpdates];
// Stop Query
[query stopQuery];
[query.results enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
NSURL *documentURL = [(NSMetadataItem *)obj valueForAttribute:NSMetadataItemURLKey];
if([[documentURL lastPathComponent] hasPrefix:@"userSetting"]){
self.document = [[MyUserDefaultsDocument alloc] initWithFileURL:documentURL];
NSString* message;
if (document.documentState == UIDocumentStateNormal){
message = @"UIDocumentStateNormal";
}else if (document.documentState == UIDocumentStateClosed) {
message = @"UIDocumentStateClosed";
}else if(document.documentState == UIDocumentStateEditingDisabled){
message = @"UIDocumentStateEditingDisabled";
}else if(document.documentState == UIDocumentStateInConflict){
message = @"UIDocumentStateInConflict";
}else if(document.documentState == UIDocumentStateSavingError){
message = @"UIDocumentStateSavingError";
}
NSLog(@"state = %@",message);
[document openWithCompletionHandler:^(BOOL success) {
if (success) {
MyUserDefaults *prefs = [MyUserDefaults standardUserDefaults];
NSData *book =[document.myUserDefault.realDict objectForKey:@"realbook"];
NSData *readSetting = [document.myUserDefault.realDict objectForKey:@"epubRS"];
if (book&&[[NSUserDefaults standardUserDefaults] boolForKey:@"iCloudBook"]) {
[prefs setObject:book forKey:@"realbook"];
[Utility reloadRealBooks];
}
if (readSetting&&[[NSUserDefaults standardUserDefaults] boolForKey:@"iCloudSetting"]) {
[prefs setObject:readSetting forKey:@"epubRS"];
[Utility setEpubReadSettingFromData:readSetting];
}
[prefs save];
[[NSNotificationCenter defaultCenter]postNotificationName:@"iCloudSynced" object:nil];
[Utility removeSpinner];
}
else{
[[NSNotificationCenter defaultCenter]postNotificationName:@"iCloudSyncfailed" object:nil];
[Utility removeSpinner];
}
}];
}
}];
if ([query.results count]==0) {
[[NSNotificationCenter defaultCenter]postNotificationName:@"iCloudSyncfailed" object:nil];
[Utility removeSpinner];
}
[[NSNotificationCenter defaultCenter] removeObserver:self name:NSMetadataQueryDidFinishGatheringNotification object:nil];
}
如此问题中所述,如果您的应用尝试连续两次调用 [文档打开与完成处理程序:] 方法,则会发生此错误。
由于 openWithCompletionHandler: 异步打开文档,因此在再次调用该方法时,文档可能仍在打开。
如果发生这种情况,你的应用最终会尝试打开文档两次(因为文档状态将保持 UIDocumentStateClosed 直到完成),这会导致引发异常。