以修改日期的顺序获取目录内容 [英] Get directory contents in date modified order

问题描述

是否有按特定顺序获取文件夹内容的方法?我想要按修改日期排序的文件属性字典(或只是文件名)的数组.

Is there an method to get the contents of a folder in a particular order? I'd like an array of file attribute dictionaries (or just file names) ordered by date modified.

现在，我这样做是这样的:

Right now, I'm doing it this way:

• 获取具有文件名的数组
• 获取每个文件的属性
• 将文件的路径和修改的日期存储在以日期为键的字典中

接下来，我必须按日期顺序输出字典，但是我想知道是否有更简单的方法?如果没有，那么某个地方是否有代码片段可以为我做到这一点?

Next I have to output the dictionary in date order, but I wondered if there's an easier way? If not, is there a code snippet somewhere which will do this for me?

谢谢.

推荐答案

上面的nall代码为我指明了正确的方向，但是我认为上面发布的代码中存在一些错误.例如:

nall's code above pointed me in the right direction, but I think there are some mistakes in the code as posted above. For instance:

1. 为什么使用NMutableDictonary而不是NSMutableArray分配filesAndProperties?

1. Why is filesAndProperties allocated using NMutableDictonary rather than an NSMutableArray?

NSDictionary* properties = [[NSFileManager defaultManager]
                                        attributesOfItemAtPath:NSFileModificationDate
                                        error:&error];

上面的代码为attributesOfItemAtPath传递了错误的参数-应该为attributesOfItemAtPath:path

您正在对files数组进行排序，但是您应该正在对filesAndProperties进行排序.

The code above is passing the wrong parameter for attributesOfItemAtPath - it should be attributesOfItemAtPath:path

Your are sorting the files array, but you should be sorting filesAndProperties.

我已经实现了相同的功能，并进行了更正，并使用了块，并在下面发布:

I have implemented the same, with corrections, and using blocks and posted below:

    NSArray *searchPaths = NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES);
    NSString* documentsPath = [searchPaths objectAtIndex: 0]; 

    NSError* error = nil;
    NSArray* filesArray = [[NSFileManager defaultManager] contentsOfDirectoryAtPath:documentsPath error:&error];
    if(error != nil) {
        NSLog(@"Error in reading files: %@", [error localizedDescription]);
        return;
    }

    // sort by creation date
    NSMutableArray* filesAndProperties = [NSMutableArray arrayWithCapacity:[filesArray count]];
    for(NSString* file in filesArray) {
        NSString* filePath = [iMgr.documentsPath stringByAppendingPathComponent:file];
        NSDictionary* properties = [[NSFileManager defaultManager]
                                    attributesOfItemAtPath:filePath
                                    error:&error];
        NSDate* modDate = [properties objectForKey:NSFileModificationDate];

        if(error == nil)
        {
            [filesAndProperties addObject:[NSDictionary dictionaryWithObjectsAndKeys:
                                           file, @"path",
                                           modDate, @"lastModDate",
                                           nil]];                 
        }
    }

        // sort using a block
        // order inverted as we want latest date first
    NSArray* sortedFiles = [filesAndProperties sortedArrayUsingComparator:
                            ^(id path1, id path2)
                            {                               
                                // compare 
                                NSComparisonResult comp = [[path1 objectForKey:@"lastModDate"] compare:
                                                           [path2 objectForKey:@"lastModDate"]];
                                // invert ordering
                                if (comp == NSOrderedDescending) {
                                    comp = NSOrderedAscending;
                                }
                                else if(comp == NSOrderedAscending){
                                    comp = NSOrderedDescending;
                                }
                                return comp;                                
                            }];

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