Question

我尝试使用MWFeedParser库。我认为问题是我想使用带有表视图的视图控制器来显示新闻。现在，在启动应用程序时，我的表视图中没有任何内容。新闻视图控制器的代码如下所示：

·H：

#import "MWFeedItem.h"
#import "MWFeedParser.h"

@interface NewsViewController : UIViewController <MWFeedParserDelegate> {
    IBOutlet UILabel *label;
    // Parsing
    MWFeedParser *feedParser;
    NSMutableArray *parsedItems;

    // Displaying
    NSArray *itemsToDisplay;
    NSDateFormatter *formatter;
    IBOutlet UITableView *tableView;

}


// Properties
@property (nonatomic, retain) NSArray *itemsToDisplay;
@property (nonatomic, retain) IBOutlet UITableView *tableView;

@end

.M：

#import "NSString+HTML.h"
#import "MWFeedParser.h"
#import "DetailTableViewController.h"

@implementation NewsViewController

@synthesize itemsToDisplay, tableView;


#pragma mark -
#pragma mark View lifecycle

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        self.title = NSLocalizedString(@"News", @"News");
        self.tabBarItem.image = [UIImage imageNamed:@"icon_news"];    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
    // Date
    // Setup
    self.title = @"News";
    formatter = [[NSDateFormatter alloc] init];
    [formatter setDateStyle:NSDateFormatterShortStyle];
    [formatter setTimeStyle:NSDateFormatterShortStyle];
    parsedItems = [[NSMutableArray alloc] init];
    self.itemsToDisplay = [NSArray array];

    // Refresh button
    self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemRefresh
                                                                                            target:self
                                                                                            action:@selector(refresh)];
    // Parse
    NSURL *feedURL = [NSURL URLWithString:@"http://www.website.com/feed/"];
    feedParser = [[MWFeedParser alloc] initWithFeedURL:feedURL];
    feedParser.delegate = self;
    feedParser.feedParseType = ParseTypeFull; // Parse feed info and all items
    feedParser.connectionType = ConnectionTypeAsynchronously;
    [feedParser parse];

    UIImage *someImage = [UIImage imageNamed:@"back_active1@2x.png"];
    [button setBackgroundImage:someImage forState:UIControlStateHighlighted];
}

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

- (void)viewDidAppear:(BOOL)animated {
    static BOOL first = YES;
    if (first) {
        UIViewController *popup = [[Home1ViewController alloc] initWithNibName:@"Home1ViewController" bundle:nil];

        [self presentViewController:popup animated:NO completion:nil];
        first = NO;
    }
}

#pragma mark -
#pragma mark Parsing

// Reset and reparse
- (void)refresh {
    self.title = @"Refreshing...";
    [parsedItems removeAllObjects];
    [feedParser stopParsing];
    [feedParser parse];
    /*
    self.tableView.userInteractionEnabled = NO;
    self.tableView.alpha = 0.3;
     */
}

- (void)updateTableWithParsedItems {
    self.itemsToDisplay = [parsedItems sortedArrayUsingDescriptors:
                           [NSArray arrayWithObject:[[NSSortDescriptor alloc] initWithKey:@"date"
                                                                             ascending:NO]]];
    /*  self.tableView.userInteractionEnabled = YES;
    self.tableView.alpha = 1;
    [self.tableView reloadData];
                 */
}

#pragma mark -
#pragma mark MWFeedParserDelegate

- (void)feedParserDidStart:(MWFeedParser *)parser {
    NSLog(@"Started Parsing: %@", parser.url);
}

- (void)feedParser:(MWFeedParser *)parser didParseFeedInfo:(MWFeedInfo *)info {
    NSLog(@"Parsed Feed Info: “%@”", info.title);
    self.title = info.title;
}

- (void)feedParser:(MWFeedParser *)parser didParseFeedItem:(MWFeedItem *)item {
    NSLog(@"Parsed Feed Item: “%@”", item.title);
    if (item) [parsedItems addObject:item];
}

- (void)feedParserDidFinish:(MWFeedParser *)parser {
    NSLog(@"Finished Parsing%@", (parser.stopped ? @" (Stopped)" : @""));
    [self updateTableWithParsedItems];
}

- (void)feedParser:(MWFeedParser *)parser didFailWithError:(NSError *)error {
    NSLog(@"Finished Parsing With Error: %@", error);
    if (parsedItems.count == 0) {
        self.title = @"Failed"; // Show failed message in title
    } else {
        // Failed but some items parsed, so show and inform of error
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Parsing Incomplete"
                                                         message:@"There was an error during the parsing of this feed. Not all of the feed items could parsed."
                                                        delegate:nil
                                               cancelButtonTitle:@"Dismiss"
                                               otherButtonTitles:nil];
        [alert show];
    }
    [self updateTableWithParsedItems];
}

#pragma mark -
#pragma mark Table view data source

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

// Customize the number of rows in the table view.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return itemsToDisplay.count;
}

// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
        cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
    }

    // Configure the cell.
    MWFeedItem *item = [itemsToDisplay objectAtIndex:indexPath.row];
    if (item) {

        // Process
        NSString *itemTitle = item.title ? [item.title stringByConvertingHTMLToPlainText] : @"[No Title]";
        NSString *itemSummary = item.summary ? [item.summary stringByConvertingHTMLToPlainText] : @"[No Summary]";

        // Set
        cell.textLabel.font = [UIFont boldSystemFontOfSize:15];
        cell.textLabel.text = itemTitle;
        NSMutableString *subtitle = [NSMutableString string];
        if (item.date) [subtitle appendFormat:@"%@: ", [formatter stringFromDate:item.date]];
        [subtitle appendString:itemSummary];
        cell.detailTextLabel.text = subtitle;

    }
    return cell;
}

#pragma mark -
#pragma mark Table view delegate

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {

    // Show detail
    DetailTableViewController *detail = [[DetailTableViewController alloc] initWithStyle:UITableViewStyleGrouped];
    detail.item = (MWFeedItem *)[itemsToDisplay objectAtIndex:indexPath.row];
    [self.navigationController pushViewController:detail animated:YES];

    // Deselect
    [self->tableView deselectRowAtIndexPath:indexPath animated:YES];

}

@end

在IB中，我将表视图拖到视图上并将其链接到dataSource和delegate。但是在表视图中没有显示任何内容。非常感谢一些答案/想法！

感谢。

Answer 1

我认为您应该在“updateTableWithParsedItems”方法中取消注释以下行：

[self.tableView reloadData];

实施MWFeedParser时出错

1 个答案: