如何解析 JSON 数据对象内的数组内的数组？

Question

这是包含多个对象的 JSON 数据，我只想解析“continueWatching”对象，所以我只是分享了它：

{
            "message": {
                "continueWatching": [{
                                "id": "2",
                                "video": [{
                                        "videoName": "fsfdsf",
                                        "coverPicture": ""
                                    }
                                ],
                                "cursorPosition": "12:32:25",
                                "dateWatched": "2015-07-08 00:00:00",
                                "updated": "2015-07-15 12:12:34"
                            }, {
                                "id": "1",
                                "video": [{
                                        "videoName": "Hello",
                                        "coverPicture": ""
                                    }
                                ],
                                "cursorPosition": "15:42:41",
                                "dateWatched": "2015-07-02 00:00:00",
                                "updated": "2015-07-02 00:00:00"
                            }, {
                                "id": "3",
                                "video": [{
                                        "videoName": "adfafadf",
                                        "coverPicture": ""
                                    }
                                ],
                                "cursorPosition": "12:32:25",
                                "dateWatched": "2015-07-01 00:00:00",
                                "updated": "2015-07-02 00:00:00"
                            }]
}

我的代码现在，我打印了整个 JSON 数据和消息对象，我需要将所有“videoName”放在一个按其“id”数字排列的数组中，而且我还希望将所有“cursorPosition”放在一个按“id”排列的单个数组

NSString *myRequestString = [NSString stringWithFormat:@"getRecommendations=all&profileId=1"];
// Create Data from request
NSData *myRequestData = [NSData dataWithBytes: [myRequestString UTF8String] length: [myRequestString length]];
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL: [NSURL URLWithString: url];
// set Request Type
[request setHTTPMethod: @"POST"];
// Set content-type
[request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"content-type"];
// Set Request Body
[request setHTTPBody: myRequestData];
// Now send a request and get Response
NSData *returnData = [NSURLConnection sendSynchronousRequest: request returningResponse: nil error: nil];
// Log Response
NSString *response = [[NSString alloc] initWithBytes:[returnData bytes] length:[returnData length] encoding:NSUTF8StringEncoding];
NSLog(@"Response: %@",response);

NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:returnData options:NSJSONReadingMutableLeaves error:nil];
BOOL boolean=[[dict  objectForKey:@"boolean"]boolValue];

NSArray *message=[dict objectForKey:@"message"];
NSLog(@"kajhsdahfohofhoaehfpihjfpejwfp%@",message);

Answer 1

我没有得到任何非常优雅的方法，但这会解决你的问题

NSArray *continueWatching = [[dict objectForKey:@"message"] objectForKey:@"continueWatching"];

//sort all objects using id.
NSSortDescriptor *sortDesc = [NSSortDescriptor sortDescriptorWithKey:@"id" ascending:YES selector:@selector(localizedStandardCompare:)];
continueWatching = [continueWatching sortedArrayUsingDescriptors:@[sortDesc]];
NSMutableArray *cursorPosition = [NSMutableArray array];
NSMutableArray *videoNames = [NSMutableArray array];

[continueWatching enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
    //find all videos array and then again enumerate it and extract all video names
    NSArray *videos = [obj objectForKey:@"video"];
    [videos enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
        [videoNames addObject:[obj objectForKey:@"videoName"]];
    }];
    //extract all curser positions and save them
    [cursorPosition addObject:[obj objectForKey:@"cursorPosition"]];
}];



NSLog(@"%@",cursorPosition);
NSLog(@"%@",videoNames);

Answer 2

此解决方案使用valueForKeyPath 来提取请求的对象而无需循环。 数组continueWatchingArray 在获取属性之前进行排序。 因此，结果数组 videoNameArray 和 cursorPositionArray 也被排序

  NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:returnData options:NSJSONReadingMutableLeaves error:nil];
  NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"id" ascending:YES];
  NSArray *continueWatchingArray = [[dict valueForKeyPath:@"message.continueWatching"] sortedArrayUsingDescriptors:@[sortDescriptor]];
  NSArray *cursorPositionArray = [continueWatchingArray valueForKeyPath:@"cursorPosition"];
  NSArray *videoNameArray = [continueWatchingArray valueForKeyPath:@"video.videoName"];
  NSMutableArray *tempArray = [[NSMutableArray alloc] init];
  // repeat loop to flatten the array
  for (NSArray *subArray in videoNameArray) {
    [tempArray addObject:subArray[0]];
  }
  videoNameArray = tempArray;
  NSLog(@"%@", videoNameArray);
  NSLog(@"%@", cursorPositionArray);

Answer 3

你的代码会是这样的。

NSArray* continueWatching = [[dict objectForKey:@"message"] objectForKey:@"continueWatching"];
continueWatching = [continueWatching sortedArrayUsingDescriptors:@[[NSSortDescriptor sortDescriptorWithKey:@"id" ascending:YES]]];

NSMutableArray *arrayOfVideos = [[NSMutableArray alloc]init];
NSMutableArray *arrayOfCursors = [[NSMutableArray alloc]init];

for(NSDictionary *dicData in continueWatching){
    NSArray *videoArray = [dicData objectForKey:@"video"];
    [arrayOfVideos addObjectsFromArray:videoArray];

    [arrayOfCursors addObject:[dicData valueForKey:@"cursorPosition"]];
}

//now in the two arrays you will have the required result.

Answer 4

JSON 对象“消息”是字典而不是数组。

NSDictionary *messages = [dict objectForKey:@"message"];
NSArray *continue = [messages objectForKey:@"continueWatching"];

您现在拥有一组视频属性。

NSSortDescriptor *sortDesc = [NSSortDecriptor sortDescriptorWithKey:@"id" ascending:YES];
NSArray *sortedVideosById = [continue sortedArrayUsingDescriptors:@[sortDesc]];

您现在拥有一组按视频 ID 排序的视频属性。 解析它以在数组中收集视频名称和 cursorPosition，按 ids 排序。

NSMutableArray *videoNames = [NSMutableArray array];
NSMutableArray *cursorPositions = [NSMutableArray array];

for( NSDictionary *v in sortedVideosById )
{
    NSArray *videoArray = (NSArray *)(v[@"video"]);
    NSDictionary *firstVideo = videoArray[0];
    videoNames addObject:firstVideo[@"videoName"];
    [cursorPositions addObject:v[@"cursorPosition"];
}