Question

我正在尝试从JSON文件加载数据。我已将此文件添加到Xcode 4.6中的Project Files中，但每次运行我的代码时，我都会在TableView中得到空单元格，根本没有数据，即使我已经为每个标签声明了正确的文件并分配了一个来自JSON文件的值。

我创建了两个类：events.h和.m，jsonloader.h和.m，并将它们导入我的主视图控制器。

以下是我的JSON数据示例：

{
"Events": [
    {
        "id": "1",
        "title": "parr jazz presents zoe chiotis",
        "performingArtists": "Zoe Chiotis",
        "day": "Tuesday",
        "date": "2013-12-03",
        "lastUpdated": "2013-12-03",
        "startingTime": "8:00:00 PM",
        "endingTime": "1:00:00 AM",
        "venue": "STUDIO2",
        "location": {
            "streetAddress": "33-45 Parr Street",
            "postCode": "L1 4JN"
        },
        "music genre": "Jazz",
        "information": "ZOE CHIOTIS is a singer/songwriter/guitarist based in Manchester. ",
        "image": "http://bandonthewall.org/images/content/large/zoe-chiotis-1764.jpg",
        "thumb": "http://swingbands.co.uk/wp-content/zoechiotis.jpg"
    },
...

]}

这是event.m：

@implementation JSONLoader

- (NSArray *)eventsFromJSONFile:(NSURL *)url {
    // Create a NSURLRequest with the given URL
    NSURLRequest *request = [NSURLRequest requestWithURL:url
                                                  cachePolicy:NSURLRequestReloadIgnoringLocalAndRemoteCacheData
                                         timeoutInterval:30.0];

    // Get the data
    NSURLResponse *response;
    NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:nil];

    // Now create a NSDictionary from the JSON data
    NSDictionary *jsonDictionary = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil];

    // Create a new array to hold the locations
    NSMutableArray *events = [[NSMutableArray alloc] init];

    // Get an array of dictionaries with the key "Events"
    NSArray *array = [jsonDictionary objectForKey:@"Events"];
    // Iterate through the array of dictionaries
    for(NSDictionary *dict in array) {
        // Create a new event object for each one and initialise it with information in the dictionary
        Events *dataevents = [[Events alloc] initWithJSONDictionary:dict];
        // Add the Location object to the array
        [events addObject:dataevents];
    }

    // Return the array of Location objects
    return events;
}

在我的mainViewController.m中我加入了这个：

@implementation MV_HomeViewController {
    NSArray *_events;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    // Create a new JSONLoader with a local file URL
    JSONLoader *jsonLoader = [[JSONLoader alloc] init];
    NSURL *url = [[NSBundle mainBundle] URLForResource:@"EventsData" withExtension:@"json"];

    // Load the data on a background queue...
    // As we are using a local file it's not really necessary, but if we were connecting to an online URL then we'd need it
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        _events = [jsonLoader eventsFromJSONFile:url];
        // Now that we have the data, reload the table data on the main UI thread
        [self.myTableView performSelectorOnMainThread:@selector(reloadData) withObject:nil waitUntilDone:YES];
    });       
}

#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    // Return the number of sections.
    return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    // Return the number of rows in the section.
    return [_events count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{

    static NSString *CellIdentifier = @"eventCell";
    MV_CustomCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier
                                                        forIndexPath:indexPath];

    if (cell == nil) {
        cell = [[MV_CustomCell alloc] initWithStyle:UITableViewCellStyleDefault
                                    reuseIdentifier:CellIdentifier];
    }

    // Configure the cell...

    //[[cell textLabel] setText:_eventType];
    Events *event = [_events objectAtIndex:indexPath.row];

    cell.TitleLabel.text = event.title;
    cell.GenreLabel.text = event.musicGenre;

    return cell;

}

有人知道这里的问题是什么吗？

使用Xcode 4.6将JSON数据加载到表视图中

0 个答案: