Question

我正在构建一个将用作日常阅读指南的应用程序。数据全部存储在XML中，存储在app中，并根据pubDate进行排序。关于每个部分代码中的行数，如果我只输入一个数字，我会得到错误，但如果我放入

[array count];

它显示每一项。我能否就如何实现目标获得一些建议？

编辑：这是我的应用程序的更多代码。我使用ASIHTTPRequest和GDataXML来解析XML并将每个项目存储在一个数组中。我想要做的是只显示最早的第1天，第二天添加2，依此类推。如果我在numberOfRowsInSection中输入除数组计数之外的任何其他数字，它会崩溃。我相信这是由于用于按日期对数组条目进行排序的代码。

- (void)requestFinished:(ASIHTTPRequest *)request {

    [_queue addOperationWithBlock:^{

        NSError *error;
        GDataXMLDocument *doc = [[GDataXMLDocument alloc] initWithData:[request responseData] 
                                                               options:0 error:&error];
        if (doc == nil) { 
            NSLog(@"Failed to parse %@", request.url);
        } else {

            NSMutableArray *entries = [NSMutableArray array];
            [self parseFeed:doc.rootElement entries:entries];                

            [[NSOperationQueue mainQueue] addOperationWithBlock:^{

                for (RSSEntry *entry in entries) {

                    int insertIdx = [_allEntries indexForInsertingObject:entry sortedUsingBlock:^(id a, id b) {
                        RSSEntry *entry1 = (RSSEntry *) a;
                        RSSEntry *entry2 = (RSSEntry *) b;
                        return [entry1.articleDate compare:entry2.articleDate];
                    }];

                    [_allEntries insertObject:entry atIndex:insertIdx];
                    [self.tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:[NSIndexPath indexPathForRow:insertIdx inSection:0]]
                                          withRowAnimation:UITableViewRowAnimationRight];

                }                            

            }];

        }        
    }];
    [self.refreshControl endRefreshing];

}

如何更改此选项以按日期排序，在第一天显示最早的一个，并每天添加一个？

Answer 1

我会将一个日期值存储到您的NSUserDefaults中，并使用它来比较并查看当天是否已更改，然后使用它来修改该部分中的行数。我对此代码进行了大量评论，希望能更好地解释。

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {

    NSCalendar *calendar = [NSCalendar autoupdatingCurrentCalendar];

    int numberOfDays = 0;   //initialize integer variable    

    //get the current date from the user's device
    NSDate *now = [NSDate date];

    //create a dateformatter to handle string conversion
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateStyle:NSDateFormatterMediumStyle];

    // String to store in defaults.
    NSString *todaysDateString = [dateFormatter stringFromDate:now];

    // get access to the user defaults
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];

    if (![defaults valueForKey:@"date_last_opened"]) {

        // if there is no value for the key, save today's date as the string we formatted
        [defaults setValue:todaysDateString forKey:@"date_last_opened"];

    } else {

        // there is already a value for date-last-opened, so pull it from the defaults, and convert it from a string back into a date.
        NSDate *dateLastOpened = [dateFormatter dateFromString:[defaults valueForKey:@"date_last_opened"]];

        if ([dateLastOpened compare:now] == NSOrderedAscending) {

            // if the date_last_opened is before todays date, get the number of days difference.

            unsigned int unitFlags = NSDayCalendarUnit;
            NSDateComponents *comps = [calendar components:unitFlags fromDate:dateLastOpened  toDate:now options:0];

            numberOfDays = [defaults integerForKey:@"totalDays"] + [comps day];
        [defaults setInteger:numberOfDays forKey:@"totalDays"];
        }
    }

return numberOfDays;

}

编辑：此代码假定，您已在应用首次启动时为类似于@“totalDays”的键设置NSUserDefault值为1，例如在viewDidLoad中可能：

if (![defaults integerForKey:@"totalDays"]) {

        // if there is no value for the key, set it to 1
        [defaults setInteger:1 forKey:@"totalDays"];

    }

Answer 2

在你的AppDelegate.m课程中你可以这样做：

//Application did launch
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
  int count = [[NSUserDefaults standardUserDefaults] integerForKey:@"LaunchCount"];
  if(count < 0) count = 0;
  [[NSUserDefaults standardUserDefaults] setInteger:count+1 forKey:@"LaunchCount"];
}

//The application was in background and become active
- (void)applicationWillEnterForeground:(UIApplication *)application
{
  int count = [[NSUserDefaults standardUserDefaults] integerForKey:@"LaunchCount"];
  if(count < 0) count = 0;
  [[NSUserDefaults standardUserDefaults] setInteger:count+1 forKey:@"LaunchCount"];
}

然后使用NSUserDefault Key @“LaunchCount”，您可以添加一个表行。

Answer 3

听起来你想要一个带[array count]行的部分，而现在你要返回[array count]部分和[array count]行。

Answer 4

如24小时的NSTimeInterval之类的东西。

每天使用的应用程序向TableView添加一行

4 个答案: