Question

这是JSON，按降序显示，id_no

 {"users":[
{"id_no":"501",
 "type":"User",
   "country":"United Kingdom",
   "city":"London"
 }    
 {"id_no":"500",
 "type":"Admin",
   "country":"United States",
   "city":"San Fransisco"}
 ]

这是我的代码：

 - (void)viewDidLoad
{
[super viewDidLoad];
NSURL *jsonURL = [NSURL URLWithString:@"http://example.com/sohw.php"];
NSData *jsonData = [NSData dataWithContentsOfURL:jsonURL];
NSError *error = nil;
NSDictionary *dataDictionary = [NSJSONSerialization JSONObjectWithData:jsonData options:0 error:&error];
self.reports = [dataDictionary objectForKey:@"users"];
}

我想要做的是按照JSON文件在tableView上显示时按降序排序users。

我已经得到了如下答案： Best way to sort an NSArray of NSDictionary objects?

或：

  NSSortDescriptor *descriptor = [[NSSortDescriptor alloc] initWithKey:@"interest"  ascending:YES];
   stories=[stories sortedArrayUsingDescriptors:[NSArray arrayWithObjects:descriptor,nil]];
   recent = [stories copy];

但是当我尝试实现它时，根据我目前的代码结构，它对我不起作用。

根据我提供的代码，您能指导我如何解决它吗？

Answer 1

您需要使用要排序的字段的键路径：

-(void)viewDidLoad
{
    [super viewDidLoad];
    NSURL *jsonURL = [NSURL URLWithString:@"http://example.com/sohw.php"];
    NSData *jsonData = [NSData dataWithContentsOfURL:jsonURL];
    NSError *error = nil;
    NSDictionary *dataDictionary = [NSJSONSerialization JSONObjectWithData:jsonData options:0 error:&error];

    NSSortDescriptor *sorter = [NSSortDescriptor sortDescriptorWithKey:@"id_no" ascending:NO];
    self.reports = [[dataDictionary objectForKey:@"users"] sortedArrayUsingDescriptors:@[sorter]];
}

Answer 2

将id_no用作key到dictionary这里的sort

NSSortDescriptor *descriptor = [[NSSortDescriptor alloc] initWithKey:@"id_no"  ascending:NO];
NSArray *users=[self.reports sortedArrayUsingDescriptors:[NSArray arrayWithObjects:descriptor,nil]];

self.reports = [users mutableCopy];

Mistake您完成的是used interest not key dictionary

编辑：对于descending order设置ascending:NO

iOS - tableView，按降序排序JSON数组

2 个答案: