Question

我正在使用

学习AFNetworking

https://www.raywenderlich.com/59255/afnetworking-2-0-tutorial

但是，对于json部分，我没有在本教程中显示的单元格上显示数据。

我收到了json格式的响应，但之后没有在单元格中显示任何内容。

    static NSString * const BaseURLString = @"http://www.raywenderlich.com/demos/weather_sample/";

    @interface WTTableViewController ()
    @property(strong) NSDictionary *weather;
    @end

    @implementation WTTableViewController

    - (id)initWithStyle:(UITableViewStyle)style
    {
        self = [super initWithStyle:style];
        if (self) {
            // Custom initialization
        }
        return self;
    }

    - (void)viewDidLoad
    {
        [super viewDidLoad];
        self.navigationController.toolbarHidden = NO;

        [self.tableView setDelegate:self];
        self.tableView.dataSource=self;
        // Uncomment the following line to preserve selection between presentations.
        // self.clearsSelectionOnViewWillAppear = NO;

        // Uncomment the following line to display an Edit button in the navigation bar for this view controller.
        // self.navigationItem.rightBarButtonItem = self.editButtonItem;
    }

    - (void)didReceiveMemoryWarning
    {
        [super didReceiveMemoryWarning];
        // Dispose of any resources that can be recreated.
    }

    - (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
    {
        if([segue.identifier isEqualToString:@"WeatherDetailSegue"]){
            UITableViewCell *cell = (UITableViewCell *)sender;
            NSIndexPath *indexPath = [self.tableView indexPathForCell:cell];

            WeatherAnimationViewController *wac = (WeatherAnimationViewController *)segue.destinationViewController;

            NSDictionary *w;
            switch (indexPath.section) {
                case 0: {
                    w = self.weather.currentCondition;
                    break;
                }
                case 1: {
                    w = [self.weather upcomingWeather][indexPath.row];
                    break;
                }
                default: {
                    break;
                }
            }
            wac.weatherDictionary = w;
        }
    }

    #pragma mark - Actions

    - (IBAction)clear:(id)sender
    {
        self.title = @"";
        self.weather = nil;
        [self.tableView reloadData];
    }

    - (IBAction)jsonTapped:(id)sender
    {
        NSString *string = [NSString stringWithFormat:@"%@weather.php?format=json", BaseURLString];
        NSURL *url = [NSURL URLWithString:string];
        //NSURLRequest *request = [NSURLRequest requestWithURL:url];

        AFHTTPSessionManager *manager = [AFHTTPSessionManager manager];
        [manager GET:string parameters:nil progress:nil success:^(NSURLSessionTask *task, id responseObject) {
            NSLog(@"JSON: %@", responseObject);
        } failure:^(NSURLSessionTask *operation, NSError *error) {
            NSLog(@"Error: %@", error);

            UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Error Retrieving Weather"
                                                                message:[error localizedDescription]
                                                               delegate:nil
                                                      cancelButtonTitle:@"Ok"
                                                      otherButtonTitles:nil];
            [alertView show];

        }];

    }
#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    return 2;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    if(!self.weather)
        return 1;

    switch (section) {
        case 0: {
            NSLog(@"return 1");
            return 1;
        }
        case 1: {
            NSArray *upcomingWeather = [self.weather upcomingWeather];
            NSLog(@"return upcomingWeather");
            return [upcomingWeather count];
        }
        default:
            return 0;
    }
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{NSLog(@"tableView");
    static NSString *CellIdentifier = @"WeatherCell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];


    NSDictionary *daysWeather = nil;

    switch (indexPath.section) {
        case 0: {
            daysWeather = [self.weather currentCondition];
            NSLog(@"currentCondition");
            break;
        }

        case 1: {
            NSArray *upcomingWeather = [self.weather upcomingWeather];
            daysWeather = upcomingWeather[indexPath.row];
            NSLog(@"upcomingWeather");
            break;
        }

        default:
            break;
    }

    cell.textLabel.text = [daysWeather weatherDescription];
    NSLog(@"textLabel = %@", cell.textLabel.text);
    // Configure the cell...


    return cell;
}

我的表视图控制器中有这个代码。

此方法用于上述代码中的委托方法：

- (NSDictionary *)currentCondition
{
    NSDictionary *dict = self[@"data"];
    NSArray *ar = dict[@"current_condition"];
    return ar[0];
}

- (NSArray *)upcomingWeather
{
    NSDictionary *dict = self[@"data"];
    return dict[@"weather"];
}

我在json甲酸盐中得到了反应，但细胞是空的。如果此处缺少任何内容，请参阅教程。

谢谢。

Answer 1

收到数据后，您只需打印数据。你必须将这些数据存储在字典中并重新加载tableview。

使用以下代码：

    AFHTTPSessionManager *manager = [AFHTTPSessionManager manager];
    [manager GET:string parameters:nil progress:nil 
    success:^(NSURLSessionTask *task, id responseObject) {

        self.weather = (NSDictionary *)responseObject; //add this line
        [self.tableView reloadData];                   //add this line

    } failure:^(NSURLSessionTask *operation, NSError *error) {
        NSLog(@"Error: %@", error);

        UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Error Retrieving Weather"
                                                            message:[error localizedDescription]
                                                           delegate:nil
                                                  cancelButtonTitle:@"Ok"
                                                  otherButtonTitles:nil];
        [alertView show];

    }];

Answer 2

您缺少来自成功阻止的代码

    self.weather = (NSDictionary *)responseObject;
    self.title = @"JSON Retrieved";
    [self.tableView reloadData];

Answer 3

只需在加载到dict之前检查天气tableview内的数据是否存在，并且在完成从服务器获取数据后，只需调用reloadData的{{1}}方法即可加载您的代码稍后收到的数据。

raywenderlic的AFNetworking教程不在表格单元格上显示数据

3 个答案: