Ios XMPP,CoreData-如何仅加载自身和目标用户消息?
我保存到核心数据并用下面的代码加载所有消息,但是我如何才能只加载2个用户的消息,对于自我用户和目标用户,我希望基于用户JIDIos XMPP,CoreData-如何仅加载自身和目标用户消息?,ios,iphone,xcode,core-data,xmpp,Ios,Iphone,Xcode,Core Data,Xmpp,我保存到核心数据并用下面的代码加载所有消息,但是我如何才能只加载2个用户的消息,对于自我用户和目标用户,我希望基于用户JID NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init]; NSManagedObjectContext *context = [[self appDelegate].xmppMessageArchivingCoreDataStorage mainThreadManagedObjectContext]; N
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSManagedObjectContext *context = [[self appDelegate].xmppMessageArchivingCoreDataStorage mainThreadManagedObjectContext];
NSEntityDescription *messageEntity = [NSEntityDescription entityForName:@"XMPPMessageArchiving_Message_CoreDataObject" inManagedObjectContext:context];
fetchRequest.entity = messageEntity;
NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"timestamp" ascending:YES];
fetchRequest.sortDescriptors = [NSArray arrayWithObject:sortDescriptor];
NSError *error = nil;
NSArray *results = [context executeFetchRequest:fetchRequest error:&error];
//Now you get the NSArray with element type of "XMPPMessageArchiving_Message_CoreDataObject"
假设您的消息对象具有从到用户实体的
关系。
只需添加(在执行请求之前):
其中selfUser
和otherUser
是User
核心数据管理对象或用户的管理对象ID。
如果使用字段标识符(高度不推荐):
您可能想阅读您可以这样使用的
-(void)testMessageArchiving {
NSString *strmyid = @"myid";
NSString *strBuddy ="toid";
NSLog(@"my id and buddy is is %@ and %@",strmyid,strBuddy);
XMPPMessageArchivingCoreDataStorage *storage = [XMPPMessageArchivingCoreDataStorage sharedInstance];
NSManagedObjectContext *moc = [storage mainThreadManagedObjectContext];
NSEntityDescription *entityDescription = [NSEntityDescription entityForName:@"XMPPMessageArchiving_Message_CoreDataObject"
inManagedObjectContext:moc];
NSFetchRequest *request = [[NSFetchRequest alloc]init];
request.predicate = [NSPredicate predicateWithFormat:@"bareJidStr = %@ OR bareJidStr = %@", strmyid, strBuddy];
NSError *error;
NSArray *messages = [moc executeFetchRequest:request error:&error];
// NSLog(@"the history of messages is %@",messages);
[self print:[[NSMutableArray alloc]initWithArray:messages]];
我使用了以下方法,并且工作正常:)
我使用fetchRequest.predicate=[NSPredicate predicateWithFormat:@“bareJidStr=%@或bareJidStr=%@”、self.sourceUser.uJid、self.destinationUser.uJid];但是我仍然有来自所有用户的消息,在消息条目中,我没有从该用户id中获得消息,它是有问题的添加输出。我不太确定出了什么问题,并且您的输出没有说明太多,也没有使用谓词。您需要在执行请求之前设置谓词。问题可能出在from=”168@kotikiwebcrew.com/ms MacBook Air”和[NSPredicate predicateWithFormat:@“from=%@或from=%@”,是否可以在没有详细信息的情况下从字段中获取?
fetchRequest.predicate = [NSPredicate predicateWithFormat:@"bareJID.bare = %@ OR bareJID.bare = %@",selfUser.jid,otherUser.jid];
-(void)testMessageArchiving {
NSString *strmyid = @"myid";
NSString *strBuddy ="toid";
NSLog(@"my id and buddy is is %@ and %@",strmyid,strBuddy);
XMPPMessageArchivingCoreDataStorage *storage = [XMPPMessageArchivingCoreDataStorage sharedInstance];
NSManagedObjectContext *moc = [storage mainThreadManagedObjectContext];
NSEntityDescription *entityDescription = [NSEntityDescription entityForName:@"XMPPMessageArchiving_Message_CoreDataObject"
inManagedObjectContext:moc];
NSFetchRequest *request = [[NSFetchRequest alloc]init];
request.predicate = [NSPredicate predicateWithFormat:@"bareJidStr = %@ OR bareJidStr = %@", strmyid, strBuddy];
NSError *error;
NSArray *messages = [moc executeFetchRequest:request error:&error];
// NSLog(@"the history of messages is %@",messages);
[self print:[[NSMutableArray alloc]initWithArray:messages]];
-(void)checkForPastMessageAndDisplayIt
{
NSString *strmyid = @"user1@domain";
NSString *strBuddy = @"user2@domain";
NSManagedObjectContext *moc = [[self appDelegate] managedObjectContext_message_achiving];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"XMPPMessageArchiving_Message_CoreDataObject"
inManagedObjectContext:moc];
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
fetchRequest.predicate = [NSPredicate predicateWithFormat:@"bareJidStr = %@ OR bareJidStr = %@", strmyid, strBuddy];
[fetchRequest setEntity:entity];
NSError *error;
NSArray *messagesArray = [moc executeFetchRequest:fetchRequest error:&error];
[messagesArray enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
id messageObject = [messagesArray objectAtIndex:idx];
if ([messageObject isKindOfClass:[XMPPMessageArchiving_Message_CoreDataObject class]]) {
XMPPMessageArchiving_Message_CoreDataObject *currentMessageCoreDataObject = (XMPPMessageArchiving_Message_CoreDataObject*)messageObject;
XMPPMessage *message = currentMessageCoreDataObject.message;
if (message!=nil) {
[messages addObject:message];
}
}
}];
}