LazyTableImages for iPhone 示例代码重新加载问题

Question

我正在使用 LazyTableImages 示例代码从 RSS 提要异步加载表格视图中的图像。我想知道的是，添加新项目后如何在此表中重新加载（重新启动解析操作），具体到此示例？

http://developer.apple.com/library/ios/#samplecode/LazyTableImages/Introduction/Intro.html

非常感谢。

Answer 1

我认为您需要重新请求下载。您可能希望向 LazyTableAppDelegate 添加一个新方法来执行此操作，因为这是执行初始下载的类：

- (void)reloadAppList
{
    NSURLRequest *urlRequest = [NSURLRequest requestWithURL:[NSURL URLWithString:TopPaidAppsFeed]];
    self.appListFeedConnection = [[[NSURLConnection alloc] initWithRequest:urlRequest delegate:self] autorelease];
}

另外，修改-[LazyTableAppDelegate handleLoadedApps:] 清除旧数据，如下：

- (void)handleLoadedApps:(NSArray *)loadedApps
{
    [self.appRecords removeAllObjects];
    rootViewController.entries = [NSArray array];
    [self.appRecords addObjectsFromArray:loadedApps];

    // tell our table view to reload its data, now that parsing has completed
    [rootViewController.tableView reloadData];
}

我自己没有尝试过，但这是基本的想法。

Answer 2

（找不到评论的方法...）

我在这里遇到了同样的问题并尝试了这种方法。使用 removeAllObjects 清除了 appRecords，但第二次，所有文章都适用，但图标没有加载。

您可以通过这种方式更改原始示例代码来重现该问题：

- (void)applicationDidFinishLaunching:(UIApplication *)application

{ // 配置并显示窗口 [窗口 addSubview:[self.navigationController 视图]]; [窗口 makeKeyAndVisible];

// Initialize the array of app records and pass a reference to that list to our root view controller
self.appRecords = [NSMutableArray array];
rootViewController.entries = self.appRecords;

// NSURLRequest *urlRequest = [NSURLRequest requestWithURL:[NSURL URLWithString:TopPaidAppsFeed]]; //self.appListFeedConnection = [[[NSURLConnection alloc] initWithRequest:urlRequest delegate:self] autorelease];

// Test the validity of the connection object. The most likely reason for the connection object
// to be nil is a malformed URL, which is a programmatic error easily detected during development
// If the URL is more dynamic, then you should implement a more flexible validation technique, and
// be able to both recover from errors and communicate problems to the user in an unobtrusive manner.
//
//NSAssert(self.appListFeedConnection != nil, @"Failure to create URL connection.");

// show in the status bar that network activity is starting
// [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
[self reloadData];

}

• （IBAction）重新加载：（id）发件人{ [自我重载数据]; }

-(void)reloadData { NSLog(@"更新条目"); [self.appRecords removeAllObjects]; //[[myTableViewController imageDownloadsInProgress] removeAllObjects];

NSURLRequest *urlRequest = [NSURLRequest requestWithURL:[NSURL URLWithString:TopPaidAppsFeed]];
self.appListFeedConnection = [[[NSURLConnection alloc] initWithRequest:urlRequest delegate:self] autorelease];

// Test the validity of the connection object. The most likely reason for the connection object
// to be nil is a malformed URL, which is a programmatic error easily detected during development
// If the URL is more dynamic, then you should implement a more flexible validation technique, and
// be able to both recover from errors and communicate problems to the user in an unobtrusive manner.
//
NSAssert(self.appListFeedConnection != nil, @"Failure to create URL connection.");

// show in the status bar that network activity is starting
[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;

}