ios - 使按钮在按下时填充 UITableView

Question

我创建了一个简单的 rss 阅读器，可以毫无问题地填充 viewdidLoad 上的 tableviewcell。我的问题是每当我单击我的按钮时，tableview 都不会改变。我尝试用里面的按钮修饰重新加载，但仍然没有任何反应。 Xcode 和 iOS 编程的新手，所以任何帮助都很棒。

.m 文件

#import "ViewController.h"
#import "KMXMLParser.h"
#import "WebViewController.h"
#import "SportsViewController.h"

@interface ViewController ()
@end

@implementation ViewController
{
    NSArray *loadData;
    NSURL *thumbnails;
}

@synthesize parseResults=_parseResults;

- (void)viewDidLoad
{
    [super viewDidLoad];
    KMXMLParser *parser = [[KMXMLParser alloc]  initWithURL:@"http://www.daytonastate.edu/rss/it.xml" delegate:nil];

    _parseResults = [parser posts];
   [self refreshFeed];
        // Do any additional setup after loading the view, typically from a nib.
}

-(void) refreshInvoked:(id)sender forState:(UIControlState)state
{
    [self refreshFeed];
}

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

-(void)refreshFeed
{
    KMXMLParser *parser = [[KMXMLParser alloc]  initWithURL:@"http://www.daytonastate.edu/rss/it.xml" delegate:nil];

    _parseResults = [parser posts];
}

- (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.parseResults.count;
}

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

    if (cell == nil)
    {

        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle  reuseIdentifier:CellIdentifier];
    }// Configure the cell...
        cell.textLabel.text = (self.parseResults)[indexPath.row][@"title"];

    cell.detailTextLabel.text = (self.parseResults)[indexPath.row][@"summary"];

    [self reloadData];

    return cell;
} 
#pragma mark - Table view delegate

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    WebViewController *vc = [[WebViewController alloc] init];

    vc.url = [NSURL URLWithString:(self.parseResults)[indexPath.row][@"link"] ];

    [self.navigationController pushViewController:vc animated:YES];

    //Makes sure function clicks to reader feed.

    // Navigation logic may go here. Create and push another view controller.
}

-(IBAction)pressBtn:(id)sender
{
    UIButton *button= [UIButton buttonWithType:UIButtonTypeRoundedRect];

    if (button.tag==1)
    {
        NSLog(@"Press button 1");
        KMXMLParser *parser = [[KMXMLParser alloc]  initWithURL:@"http://www.daytonastate.edu/rss/cea.xml" delegate:nil];

        _parseResults = [parser posts];

        [self reloadData];
    }
    if (button.tag==2)
    {
        NSLog(@"Press button 2");
        [self EventsBtn:nil];
    }
}

- (IBAction)NewsBtn:(id)sender
{
      KMXMLParser *parser = [[KMXMLParser alloc]  initWithURL:@"http://rss.cnn.com/rss/cnn_topstories.rss" delegate:nil];

        _parseResults = [parser posts];
    NSLog(@"reload happened");
   // self.printMessage = [[PrintHello alloc] init]; // EDIT: THIS LINE WAS MISSING NOW IT WORKS
    //[self.printMessage Print];

    NSLog(@"NewsBtn Pressed");
}

- (IBAction)SportsBtn:(id)sender
    {
       KMXMLParser *parser = [[KMXMLParser alloc]  initWithURL:@"http://www.daytonastate.edu/rss/it.xml" delegate:nil];

        _parseResults = [parser posts];
    }

- (IBAction)EventsBtn:(id)sender
{
    KMXMLParser *parser = [[KMXMLParser alloc]  initWithURL:@"http://www.daytonastate.edu/rss/events.xml" delegate:nil];
    _parseResults = [parser posts];
    NSLog(@"eventsBtn Pressed");
}

- (IBAction)WeatherBtn:(id)sender
    {
        KMXMLParser *parser = [[KMXMLParser alloc]  initWithURL:@"http://w1.weather.gov/xml/current_obs/KDAB.rss" delegate:nil];

        _parseResults = [parser posts];
    }
@end

Answer 1

在您的 pressBtn: 方法中，替换此行:

UIButton *button= [UIButton buttonWithType:UIButtonTypeRoundedRect];

与:

UIButton *button = (UIButton *)sender;

这假设在 IB 中您已经将 pressBtn: 方法连接到适当的按钮。当您的 pressBtn: 操作被调用时，您拥有的代码正在创建一个新按钮。由于这个新按钮的 tag 值为 0，因此什么也没有发生。我建议的代码实际上使用了用户点击的按钮。