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[英]AFNetworking tutorial of raywenderlich not displaying data on table cell
[英]AFNetworking 2.0 parsed data not displaying in table view
我的問題:表格中沒有數據。
以下是用於檢索json對象數組並使用AFNetworking 2.0對其進行解析的代碼。 我有一個UIViewController,在其中放置了帶有原型單元的表格視圖,原型單元具有重用標識符EventCell。 我想要的是在每個單元格中顯示標題和圖像。 我在運行時沒有錯誤。
的NSDictionary + events.h
#import <Foundation/Foundation.h>
@interface NSDictionary (events)
- (NSString *)eventImage;
- (NSString *)eventTitle;
- (NSDate *)eventDate;
- (NSNumber *)eventPrice;
- (NSNumber *)eventTicketsTotal;
@end
的NSDictionary + events.m
#import "NSDictionary+events.h"
@implementation NSDictionary (events)
- (NSString *)eventImage
{
return self[@"event_image"];
}
- (NSString *)eventTitle
{
return self[@"event_title"];
}
- (NSDate *)eventDate
{
// NSString *dateStr = self[@"date"]; // date = "2013-01-15";
return [NSDate date];
}
- (NSNumber *)eventPrice
{
NSString *cc = self[@"event_price"];
NSNumber *n = @([cc intValue]);
return n;
}
- (NSNumber *)eventTicketsTotal{
NSString *cc = self[@"event_tickets_total"];
NSNumber *n = @([cc intValue]);
return n;
}
@end
的NSDictionary + events_package.h
#import <Foundation/Foundation.h>
@interface NSDictionary (NSDictionary_events_package)
-(NSArray *)upcomingWeather;
@end
的NSDictionary + events_package.m
#import "NSDictionary+events_package.h"
@implementation NSDictionary (NSDictionary_events_package)
- (NSArray *)upcomingWeather
{
NSDictionary *dict = self[@"data"];
return dict[@"events"];
}
@end
TDViewController.h
#import <UIKit/UIKit.h>
#import "NSDictionary+events.h"
@interface TDViewController : UIViewController <UITableViewDataSource, UITableViewDelegate>
@property(nonatomic, retain) UITableView *tableView;
@end
TDViewController.m
#import "TDViewController.h"
#import "UIImageView+AFNetworking.h"
#import "TDSecondViewController.h"
#import "NSDictionary+events_package.h"
static NSString * const BaseURLString = @"http://xx.zzz.yy.xx/test/";
@interface TDViewController ()
@property(strong) NSDictionary *events;
@end
@implementation TDViewController
- (void)viewDidLoad
{
[super viewDidLoad];
// 1
NSString *string = [NSString stringWithFormat:@"%@event_json.php?format=json", BaseURLString];
NSLog(@"web service address: %@", string);
NSURL *url = [NSURL URLWithString:string];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
// 2
AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
operation.responseSerializer = [AFJSONResponseSerializer serializer];
[operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
// 3
self.events = (NSDictionary *)responseObject;
NSLog(@"%@", responseObject);
self.title = @"JSON Retrieved";
[self.tableView reloadData];
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
// 4
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Error Retrieving Events"
message:[error localizedDescription]
delegate:nil
cancelButtonTitle:@"Ok"
otherButtonTitles:nil];
[alertView show];
}];
// 5
[operation start];
}
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if([segue.identifier isEqualToString:@"WeatherDetailSegue"]){
UITableViewCell *cell = (UITableViewCell *)sender;
NSIndexPath *indexPath = [self.tableView indexPathForCell:cell];
TDSecondViewController *wac = (TDSecondViewController *)segue.destinationViewController;
NSDictionary *w;
if (indexPath.section == 0) {
{
w = [self.events upcomingWeather][indexPath.row];
//NSLog( @"this is w: %@", w );
}
wac.weatherDictionary = w;
}
}
}
#pragma mark - Table view data source
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if(!self.events)
return 0;
NSArray *upcomingWeather = [self.events upcomingWeather];
return [upcomingWeather count];
NSLog( @"the count is %lu", (long)[upcomingWeather count]);
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"EventCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
NSDictionary *daysWeather = nil;
NSArray *upcomingWeather = [self.events upcomingWeather];
daysWeather = upcomingWeather[indexPath.row];
NSLog( @"this is daysWeather: %@", daysWeather );
cell.textLabel.text = [daysWeather eventTitle];
NSLog(@"The content of arry is%@",daysWeather);
NSURL *url = [NSURL URLWithString:daysWeather.eventImage];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
UIImage *placeholderImage = [UIImage imageNamed:@"placeholder"];
__weak UITableViewCell *weakCell = cell;
[cell.imageView setImageWithURLRequest:request
placeholderImage:placeholderImage
success:^(NSURLRequest *request, NSHTTPURLResponse *response, UIImage *image) {
weakCell.imageView.image = image;
[weakCell setNeedsLayout];
} failure:nil];
return cell;
}
#pragma mark - Table view delegate
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
// Navigation logic may go here. Create and push another view controller.
}
@end
以下是我在模擬器上運行項目時獲得的nslog輸出(請注意,並非所有nslog語句都在顯示)。
2014-04-06 21:47:04.592 iCLUB[9198:60b] webservice address:
http://xx.zzz.yy.xx/test/event_json.php?format=json
2014-04-06 21:47:04.685 iCLUB[9198:60b] {
data = {
events = (
{
"event_date" = "7-5-2014";
"event_id" = 22;
"event_image" = "http://xx.zzz.yy.xx/...";
"event_price" = 150;
"event_tickets_total" = 200;
"event_title" = "New Event Title";
},
{
"event_date" = "3-2-2014";
"event_id" = 23;
"event_image" = "http://xx.zzz.yy.xx/...";
"event_price" = 150;
"event_tickets_total" = 200;
"event_title" = "New Event Title 2";
},
{
"event_date" = "9-25-2014";
"event_id" = 24;
"event_image" = "http://xx.zzz.yy.xx/...";
"event_price" = 150;
"event_tickets_total" = 200;
"event_title" = "New Event Title 33";
}
);
};
}
我只是不明白問題是什么,該應用程序在模擬器上構建並運行,但是單元格看上去完全是空的。 我將不勝感激任何幫助。 謝謝,JT。
該問題的可能原因包括:
未能為表視圖連接IBOutlet
。 如果未正確連接tableView
屬性,則它將為nil
,因此[self.tableView reloadData]
將不執行任何操作(因為向nil
對象發送消息不會執行任何操作)。
坦率地說,我不清楚如何設置此tableView
屬性,因為它缺乏在Interface Builder中連接控件時使用的典型IBOutlet
限定,而且我也看不到您以編程方式進行設置。
無法將視圖控制器指定為delegate
,更重要的是,未指定表視圖的dataSource
。 如果是這種情況,即使您成功調用了[self.tableView reloadData]
,也不會導致調用UITableViewDataSource
方法。
我建議檢查一下self.tableView
和self.tableView.dataSource
是否為nil
。
不會調用numberOfRowsInSection中的此NSLog語句,因為該方法在該語句之前返回!
return [upcomingWeather count]; NSLog( @"the count is %lu", (long)[upcomingWeather count]);
似乎沒有調用cellForRowAtIndexPath,這可能是由於多種原因造成的,包括未設置UITableView數據源和委托,numberOfRowsInSection返回0或TableView為零。 使用調試器將使您看到正在發生哪種情況。
查看蘋果的調試資源 。
當解析json數據時,請使用上面的代碼
NSDictionary *dict = (NSDictionary *)responseObject;
self.events = [dict objectForKey:@"data"];
您還記得為self.tableView設置委托和數據源嗎? 當您不繼承UITableViewController的子類時,它不會自動為您完成。
我認為您從API獲取的JSON無效。 events
數組應括在方括號[]
而不是括號中。 此外,JSON不使用分號。 請參閱JSON 規范 。
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