Question

我需要解析一个Coulomb中的所有对象。比方说比如我在课堂上用coulombs解析：City，StreetCode，Suburb。现在我希望City下的所有对象都在一个数组中。

数组应该添加City下的所有对象：

应该返回Array：City1，City2，City3，City4等。

我发现这段代码可以获取Class中的所有对象：

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

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

        NSLog(@"%@",allObjects);
        // The find succeeded. The first 100 objects are available in objects
    } else
    {
        // Log details of the failure
        NSLog(@"Error: %@ %@", error, [error userInfo]);
    }
}];

但是此代码返回：

<StreetCodes: 0x7c1d76e0, objectId: dpFuJgeRnB, localId: (null)> {\n    City = KWANOBUHLE;\n    StreetCode = 6242;\n    Suburb = \"10TH AVENUE\";\n}",
    "<StreetCodes: 0x7c638020, objectId: OE9MtOGpVd, localId: (null)> {\n    City = KWANOBUHLE;\n    StreetCode = 6242;\n    Suburb = \"1ST AVENUE\";\n}",
    "<StreetCodes: 0x7c1cf970, objectId: 16TMG5V3jS, localId: (null)> {\n    City = DURBAN;\n    StreetCode = 4091;\n    Suburb = \"45TH CUTTING\";\n}",
    "<StreetCodes: 0x7c1c1dd0, objectId: 0Vk6oav0Zt, localId: (null)> {\n    City = RIVERSDALE;\n    StreetCode = 6670;\n    Suburb = AALWYNFLEUR;\n}",
    "<StreetCodes: 0x7c1db4e0, objectId: EVYUUWzTB7, localId: (null)> {\n    City = BLOEMFONTEIN;\n    StreetCode = 9301;\n    Suburb = AANDRUS;

这将返回添加到数组中的类中的所有对象。我该如何使用它？因为我只想要City Coulomb对象。

请帮助或提供一些示例代码

Answer 1

使用PFQuery的selectKeys会将查询限制为仅检索您的城市数据：

[query selectKeys:@[@"City"]];

我认为这不是你想要的。您需要运行从它们中取出City的返回对象数组：

if (!error)
{
    NSMutableArray* array = [NSMutableArray arrayWithCapacity:objects.count]; // make an array to hold the cities
    for(PFObject* obj in objects) {
        [array addObject:[obj objectForKey:"@City"]];
    }
// etc.

获取一列Parse IOS 8下的所有对象

1 个答案: