Question

所以我试图在DBManager对象中分离我的Parse调用。这是我的一个电话：

- (void)createMessageObject:(NSString*)text forConversation:(PFObject*)conversationObject withBlock:(PFBooleanResultBlock)block {

    /////////////////////////////////
    // First create the object
    PFObject* messageObject = [PFObject objectWithClassName:kWSMessageClassKey];
    [messageObject addObject:[PFUser currentUser] forKey:kWSMessageUserKey];
    [messageObject addObject:text forKey:kWSMessageTextKey];
    [messageObject addObject:[[WSWordlistManager shared] languageTarget] forKey:KWSMessageLanguageKey];


    [messageObject saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
        if (succeeded) {

            ///////////////////////////////
            // Now add it to the Conversation object
            [conversationObject addObject:messageObject forKey:kWSConversationMessagesKey];
            [conversationObject saveInBackgroundWithBlock:block];

        }
    }];
}

现在我正在开发应用内聊天/消息功能。因此，在上面的调用中，我想创建一个新的Message对象，如果它成功保存，则将其添加到现有的Conversation对象中。问题在于我在ViewController中的原始调用：

  [self createMessageObject:text forConversation:self.conversation withBlock:^(BOOL succeeded, NSError *error) {

        if (succeeded) {

            // PROBLEM HERE: HOW TO PASS BACK THE messageObject I CREATED IN THE DB CALL?
            [self.objects addObject:messageObject]; 

            [self.messages addObject:[[JSMessage alloc] initWithText:text sender:sender date:date]];
            [self finishSend];                
            [self sendMessagePushFromUser:[PFUser currentUser] toUsers:self.friends messageObject:messageObject];                
            [self scrollToBottomAnimated:YES];

        }

    }];

所以问题出在我评论的那一行。我需要访问我在Parse调用中创建的messageObject，但是如何将其传回去？

Answer 1

您可以使用回调。像这样：

- (void)createMessageObject:(NSString*)text forConversation:(PFObject*)conversationObject withCallback:(void(^)(PFObject *messageObject))callback {
    /////////////////////////////////
    // First create the object
    PFObject* messageObject = [PFObject objectWithClassName:kWSMessageClassKey];
    [messageObject addObject:[PFUser currentUser] forKey:kWSMessageUserKey];
    [messageObject addObject:text forKey:kWSMessageTextKey];
    [messageObject addObject:[[WSWordlistManager shared] languageTarget] forKey:KWSMessageLanguageKey];


    [messageObject saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
        if (succeeded) {
            if (callback) {
                callback(messageObject);
            }

        }
    }];
}

然后像这样称呼它：

[self createMessageObject:text forConversation:self.conversation withCallback:^(PFObject *messageObject) {
    NSLog(@"Text from message object: %@", [messageObject objectForKey:kWSMessageTextKey]);

    [self.objects addObject:messageObject];

    [self.messages addObject:[[JSMessage alloc] initWithText:text sender:sender date:date]];
    [self finishSend];
    [self sendMessagePushFromUser:[PFUser currentUser] toUsers:self.friends messageObject:messageObject];
    [self scrollToBottomAnimated:YES];
}];

通过传递块来分离DB逻辑

1 个答案: