UITableView方法被調用之前ViewDidLoad

我試圖創建一個簡單的天氣應用程序，它使用JSON從OpenweatherMap獲取數據並在UITableView中打印出來。但是，當我在下面執行此代碼並在numberOfRowsInSection方法中設置斷點時，它將返回0行。不知怎的，viewDidLoad方法在numberOfRowsInSection方法之後被調用，這就是threeHoursForecast數組爲空的原因。任何人都可以幫助我嗎？UITableView方法被調用之前ViewDidLoad

static NSString * const BaseURLString = @"http://api.openweathermap.org/data/2.5/forecast?q=Houston"; 

@interface HPViewController() 

@end 

@implementation HPViewController 

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil 
{ 
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]; 
    if (self) { 
     // Custom initialization 
    } 
    return self; 
} 

- (void)viewDidLoad 
{ 
    [super viewDidLoad]; 

    self.threeHoursForecast = [[NSMutableArray alloc] init]; 
    self.tableView.dataSource = self; 
    self.tableView.delegate = self; 

    AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager]; 

    [manager POST:BaseURLString parameters:nil 
      success:^(AFHTTPRequestOperation *operation, id responseObject) { 

       NSArray *data = [responseObject objectForKey:@"list"]; 

       for (NSDictionary *forecastPerThreeHours in data) 
        [self.threeHoursForecast addObject:[[forecastPerThreeHours valueForKey:@"main"] valueForKey:@"temp"]]; 
      } 

      failure:^(AFHTTPRequestOperation *operation, NSError *error) { 

       NSLog(@"Error: %@", error); 
      }]; 

} 

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

- (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 [self.threeHoursForecast count]; 
}

來源

2014-10-02 Harry

您可以在調用完成處理程序後重新載入數據，這將解決問題。

[manager POST:BaseURLString parameters:nil 
      success:^(AFHTTPRequestOperation *operation, id responseObject) { 

       NSArray *data = [responseObject objectForKey:@"list"]; 

       for (NSDictionary *forecastPerThreeHours in data) 
        [self.threeHoursForecast addObject:[[forecastPerThreeHours valueForKey:@"main"] valueForKey:@"temp"]]; 

       //Add this line 
       [self.TableView reloadData]; 
      } 

      failure:^(AFHTTPRequestOperation *operation, NSError *error) { 

       NSLog(@"Error: %@", error); 
      }];

來源

2014-10-02 07:38:27

謝謝。它現在有效。我曾嘗試重新加載數據，但我把它放在請求的成功塊之外，所以它不起作用 – Harry 2014-10-02 16:10:10

post方法是異步的。您需要在連續的請求中添加[self.tableView reloadData];。

來源

2014-10-02 07:37:08

謝謝。它現在有效。我曾嘗試重新加載數據，但我把它放在請求的成功塊之外，所以它不起作用 – Harry 2014-10-02 16:10:31

manager POST:是異步調用，因此您需要在獲取JSON後重新載入數據。

[manager POST:BaseURLString parameters:nil 
       success:^(AFHTTPRequestOperation *operation, id responseObject) { 

        NSArray *data = [responseObject objectForKey:@"list"]; 

        for (NSDictionary *forecastPerThreeHours in data) 
         [self.threeHoursForecast addObject:[[forecastPerThreeHours valueForKey:@"main"] valueForKey:@"temp"]]; 

        // [NOTE] 
        [self.tableView reloadData]; 
       } 

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

來源

2014-10-02 07:54:43 l0gg3r

UITableView方法被調用之前ViewDidLoad

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