ios - 如何在 iOS 中使用 PFQuery 获取表中的所有数据？

Question

我是 iOS 和 Parse Framework 的新手，我想从 PFQuery 的 Parse 表中获取数据，就像

NSUInteger limit = 1500;
PFQuery *query = [PFQuery queryWithClassName:@"MapInfo"];
[query setLimit: limit];
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error)
{
    if (!error) {
        NSLog(@"Successfully retrieved: %@", objects);
    } else {
        NSString *errorString = [[error userInfo] objectForKey:@"error"];
        NSLog(@"Error: %@", errorString);
    }
}];

它按我想要的方式工作，但它只给我 1000 个我想要的对象，以获取它包含的所有表数据到 2000 个对象，它会随着时间的推移而增加，请帮助我。

为此，现在我写了这样的代码，但它只给我 1000 个对象

 NSMutableArray *allObjects = [NSMutableArray array];
NSUInteger limit = 0;
__block NSUInteger skip = 0;
PFQuery *query = [PFQuery queryWithClassName:@"MapInfo"];
[query setLimit: limit];
[query setSkip: skip];
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
    if (!error) {
        [allObjects addObjectsFromArray:objects];
        if (objects.count == limit) {

            skip += limit;
            [query setSkip: skip];
            [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
                NSLog(@"Array %@",objects);
            }];
             }

             } else {
                 NSLog(@"Error: %@ %@", error, [error userInfo]);
             }
             }];

谢谢。

Answer 1

我认为可以获取的对象数量存在查询限制。我会做的是查询对同一件事进行两次查询，但对于第二个查询，做这样的事情

[查询 setSkip1000];

您可以跳过第一个查询中的前 1000 个对象并获取接下来的 1000 个对象。将您的数组设为 NSMutableArray 并在每个 block 内执行此操作

[self.myArray addObjects:objects]; 而不是 self.myArray = objects; 这样你就覆盖了数组中的对象。

编辑

您也可以这样做，而不是 2 个单独的查询

NSMutableArray *allObjectsArray = [NSMutableArray array];
//Set this to the amount of objects you want. Has to be be 1000 or less
NSUInteger limit = 0;

//Set this to the amount you want to skip (Usually 0)
NSUInteger skip = 0;
PFQuery *query = [PFQuery queryWithClassName:@"tempClass"];
[query setLimit: limit];
[query setSkip: skip];
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
  if (!error) {
    // The find succeeded. Add the returned objects to allObjects
    [allObjectsArray addObjectsFromArray:objects];
    if (objects.count == limit) {
      // There could be more objects in your database. Update the skip number and perform the same query.
      skip = skip + limit;
      [query setSkip: skip];
      [query findObject...// Exactly the same way as you did before to get the rest of your objects in the database
    }

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