在重新加載之前刪除表格行

Question

我想在重新加載數據之前刪除表格視圖中的所有行，但似乎無法使其工作。

在我的viewcontroller中，我從這個AFNetworking請求中獲得我的數組。

- (void)viewDidLoad 
    [[LocationApiClient sharedInstance] getPath:@"locations.json" 
            parameters:nil 
             success: 
       ^(AFHTTPRequestOperation *operation, id response) { 
        NSLog(@"Response: %@", response); 
        NSMutableArray *location_results = [NSMutableArray array]; 
        for (id locationDictionary in response) { 
         Location *location = [[Location alloc] initWithDictionary:locationDictionary]; 
         [location_results addObject:location]; 
        } 
        self.location_results = location_results; 
        [self.tableView reloadData]; 
        } 
            failure: 
       ^(AFHTTPRequestOperation *operation, NSError *error) { 
        NSLog(@"Error fetching locations!"); 
        NSLog(@"%@", error); 
       }]; 
} 

而且我想刪除的數據，然後通過這個按鈕

- (IBAction)locationPressed:(id)sender { 

    [[Location sharedSingleton].locationManager startUpdatingLocation]; 
    [self viewDidLoad]; 
    NSMutableArray *location_results = [NSMutableArray array]; 
    [location_results removeAllObjects]; 
    [self.tableView reloadData]; 

} 

重新加載它，但它不刪除行。我看到重載發生在已經存在的行的頂部。有什麼建議麼？

Answer 1

請千萬不要手動撥打viewDidLoad。

創建像

- (void)reloadDataWithCompletion:(void(^)(NSArray *locations))completion 
         failure:(void(^)(NSError *error))failure { 
    [[LocationApiClient sharedInstance] getPath:@"locations.json" 
            parameters:nil 
             success: 
      ^(AFHTTPRequestOperation *operation, id response) { 
       NSLog(@"Response: %@", response); 
       NSMutableArray *location_results = [NSMutableArray array]; 
       for (id locationDictionary in response) { 
        Location *location = [[Location alloc] initWithDictionary:locationDictionary]; 
        [location_results addObject:location]; 
       } 
        if(completion) 
         completion(location_results); 
       } 
           failure: 
      ^(AFHTTPRequestOperation *operation, NSError *error) { 
       if(failure) 
        failure(error); 
      }]; 
} 

的方法，並調用它時，你需要重新加載數據

- (void)viewDidLoad { 
    [super viewDidLoad]; // Don't forget the call to super! 

    [self reloadDataWithCompletion:^(NSArray *locations) { 
     self.location_results = locations; 
     [self.tableView reloadData]; 
    } failure:^(NSError *error) { 
     NSLog(@"Error fetching locations!"); 
     NSLog(@"%@", error); 
    }]; 
} 

- (IBAction)locationPressed:(id)sender { 
    [[Location sharedSingleton].locationManager startUpdatingLocation]; 
    [self reloadDataWithCompletion:^(NSArray *locations) { 
     self.location_results = locations; 
     [self.tableView reloadData]; 
    } failure:^(NSError *error) { 
     NSLog(@"Error fetching locations!"); 
     NSLog(@"%@", error); 
    }]; 
} 

爲了實現重載，你可以做表的圖形效果（假設你只有一個部分），替代品

[self.tableView reloadData]; 

與

[self.tableView reloadSections:[NSIndexSet indexSetWithIndex:0] withRowAnimation:UITableViewRowAnimationFade];