如何将PFUser与PFInstallations动态关联以发送推送通知？

Question

基于使用高级定位推送通知的解析指南,我理解为了PFInstallations与当前用户关联,应该通过以下方式:

PFInstallation *installation = [PFInstallation currentInstallation];
installation[@"user"] = [PFUser currentUser];
[installation saveInBackground];

我的问题是,如何能够"在运行中"为其他用户(即不是当前用户)做到这一点.例如,我有一个Message对象,我想发送给用户Sally,Alex和Ben:如何能够根据用户objectIds获得这些用户的PFInstallations,然后设置他们的PFInstallation,以便

//Sally, Alex and Ben's PFInstallations:
[installation setObject:YES forKey:message.objectId];

...所以当我发出消息时,只有Sally,Alex和Ben会收到推送通知他们收到了我的消息？

谢谢!

Answer 1

这是我设法做到的方式.请注意,这recipientIDs是我发送推送通知的用户列表(确切地说是用户objectIds).

if (recipientIDs.count > 0){

        //Find the users that were just sent the message
        PFQuery *userQuery = [PFUser query];
        [userQuery whereKey:@"objectId" containedIn:recipientIDs];

        //Find the devices associated with these users
        PFQuery *pushQuery = [PFInstallation query];
        [pushQuery whereKey:@"user" matchesQuery:userQuery];

        //Send push to these users
        PFPush *push = [[PFPush alloc] init];
        NSDictionary *data = [NSDictionary dictionaryWithObjectsAndKeys:
                              [NSString stringWithFormat:@"New message from %@", [PFUser currentUser].username], @"alert",
                              @"Increment", @"badge",
                              nil];
        [push setQuery:pushQuery]; // Set our Installation query
        [push setData:data];
        [push sendPushInBackground];
    }