ios - parse.com ios中objectId的空输出

Question

我正在尝试获取 babyInfo 类的 objectId 并希望将其链接到 parse.com 的 User 类。但是在所有这些情况下都会返回 null objectId。

PFObject *babyInfo = [PFObject objectWithClassName:@"BabyInfo"];
babyInfo[@"babyname"] = babyname;
babyInfo[@"gender"] = gender;
babyInfo[@"dob"] = date;
  NSLog(@"Object ID: %@", babyInfo.objectId); //First method tried unsuccessfully
    [babyInfo saveInBackground];


  NSString *objectid=[babyInfo objectId];
    NSLog(@"%@",objectid);  // Second method tried unsuccessfully

    NSString *objectid= [babyInfo valueForKey:@"objectId"];
    NSLog(@"%@",objectid);  // Third method tried unsuccessfully

Answer 1

I think this is happening because you are using saveInBackground, so the log statements are logging null as the object hasn't saved yet. Also, your first log statement will definitely log null because it comes before the save statement. Try this:

PFObject *babyInfo = [PFObject objectWithClassName:@"BabyInfo"];
babyInfo[@"babyname"] = babyname;
babyInfo[@"gender"] = gender;
babyInfo[@"dob"] = date;

    [babyInfo save];


  NSString *objectid=[babyInfo objectId];
    NSLog(@"%@",objectid);