Question

我对Objective-C相当新，所以请原谅我可能很难看的代码，但是目前我有以下函数从parse中检索对象，然后我打算用它来填充Xcode中的列表视图。

- （void）retrieveEventsFromParse {

PFQuery *query = [PFQuery queryWithClassName:@"events"];

//retrieve all columns (will be fixed once a userId value is added)
[query whereKey:@"location" notEqualTo:@""];

[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
    if (!error) {

        // The find succeeded.

        NSLog(@"Successfully retrieved %lu locations.", (unsigned long)objects.count);
        // Do something with the found objects
        for (PFObject *object in objects) {

            NSLog(@"%@", object.objectId);
        }
    } else {
        // Log details of the failure
        NSLog(@"Error: %@ %@", error, [error userInfo]);
    }
}];

}

但是我似乎只能检索objectId，而是想要检索一个名为'location'的值，该值存储为字符串。我该怎么做呢？

抱歉，我对此非常陌生，所以如果你能在具体的例子中具体说明，那么谢谢。

Answer 1

代码看起来还不错。要开始使用，请跳过whereKey限定以确保您可以获得一些对象。使用objectForKey:上的PFObject方法访问列的值...

PFQuery *query = [PFQuery queryWithClassName:@"events"];
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
    if (!error) {
        NSLog(@"Successfully retrieved %lu locations.", (unsigned long)objects.count);
        // Do something with the found objects
        for (PFObject *object in objects) {
            // assuming location is a string, change the type if it isn't
            NSString *location = [object objectForKey:@"location"];
            NSLog(@"object with id has location %@ %@", object.objectId, location);
        }
    } else {
        // Log details of the failure
        NSLog(@"Error: %@ %@", error, [error userInfo]);
    }
}];

Objective-C PFQuery检索字符串

1 个答案: