iphone - 对二维数组进行排序

Question

我有以下情况。我从 xml 提要和 facebook graph api 导入数据，在本例中是帖子。我想将这些数据合并到一个数组中，并根据包含的日期数据对其进行排序。

我现在有以下内容:

[containerArray addObject: [NSMutableArray arrayWithObjects: created_time, message, picture, fbSource, nil ]
                    ];

这将创建一个二维数组，但我想对 created_time 上的所有条目进行排序。

我怎样才能最好地解决这个问题？提前谢谢!!

Answer 1

创建一个包含必要实例变量而不是可变数组的数据类。然后你可以使用 NSArray 类的各种排序方法，例如 sortedArrayUsingDescriptors .

排序可能是这样的:

NSSortDescriptor *sortDescriptor = [[[NSSortDescriptor alloc] initWithKey:@"created_time" 
                                                                ascending:YES] autorelease];    

NSArray *sortedArray = [containerArray sortedArrayUsingDescriptors:[NSArray arrayWithObject:sortDescriptor]];

[sortDescriptor release];

编辑

引用 Fowler 先生的书 Refactoring: Improving the Design of Existing Code .

Replace Array with Object

You have an array in which certain elements mean different things.

Replace the array with an object that has a field for each element

...

Motivation

Arrays are a common structure for organizing data. However, they should be used only to contain a collection of similar objects in somre order.

这就是我们想要在这里做的。让我们创建一个简单的 Posts 类。您可以轻松添加接受四个值作为参数的自定义初始化程序，甚至可以添加一个方便的类方法来稍后返回一个自动释放的对象。这只是一个基本框架:

后.h

@interface Posts : NSObject 
{
    NSDate *created_time; 
    NSString *message;
    UIImage *picture;
    id fbSource; // Don't know what type :)
}

@property (nonatomic, retain) NSDate *created_time;
@property (nonatomic, copy) NSString *message;
@property (nonatomic, retain) UIImage *picture;
@property (nonatomic, retain) id fbSource;

@end

后.m

#import "Post.h"

@implementation Post

@synthesize created_time, message, picture, fbSource;

#pragma mark -
#pragma mark memory management

- (void)dealloc 
{
    [created_time release];
    [message release];
    [picture release];
    [fbSource release];
    [super dealloc];
}

#pragma mark -
#pragma mark initialization

- (id)init
{
    self = [super init];
    if (self) {
        // do your initialization here
    }
    return self;
}

编辑 2

将 Post 对象添加到您的数组:

Post *newPost = [[Post alloc] init];
newPost.reated_time = [Date date];
newPost.message = @"a message";
newPost.picture = [UIImage imageNamed:@"mypic.jpg"];
// newPost.fbSource = ???
[containerArray addObject:newPost];

[newPost release];