使用JSON的uitableview部分存在问题

Question

我正在创建一个用于演示的应用程序，并用JSON数据填充了一个uitableview，它运行良好。现在我想根据sessionDate在表中创建部分，但我的应用程序崩溃，错误如下：

由于未捕获异常"NSInvalidArgumentException"而终止应用程序，原因："-[Sessions objectForKey:]：无法识别的选择器发送到实例0xac2b460"

以下是解析JSON:的代码

-(void) retrieveData
{
    NSURL * url = [NSURL fileURLWithPath:[[NSBundle mainBundle]pathForResource:@"sessions-json.json" ofType:nil]];
    NSData * data = [NSData dataWithContentsOfURL:url];
    json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];
    //Set up our speakers array
    sessionsArray = [[NSMutableArray alloc] init];
    for (int i = 0; i < json.count; i++) {
    //create sessions object
    NSString * sID = [[json objectAtIndex:i] objectForKey:@"id"];
    NSString * sStatus = [[json objectAtIndex:i] objectForKey:@"sessionStatus"];
    NSString * sDay = [[json objectAtIndex:i] objectForKey:@"sessionDay"];
    NSString * sDate = [[json objectAtIndex:i] objectForKey:@"sessionDate"];
    NSString * sTime = [[json objectAtIndex:i] objectForKey:@"sessionTime"];
    NSString * sName = [[json objectAtIndex:i] objectForKey:@"sessionName"];
    NSString * sSpeaker1 = [[json objectAtIndex:i] objectForKey:@"sessionSpeaker1"];
    NSString * sSpeaker1Company = [[json objectAtIndex:i] objectForKey:@"speaker1Company"];
    NSString * sSpeaker2 = [[json objectAtIndex:i] objectForKey:@"sessionSpeaker2"];
    NSString * sSpeaker2Company = [[json objectAtIndex:i] objectForKey:@"speaker2Company"];
    NSString * sSpeaker3 = [[json objectAtIndex:i] objectForKey:@"sessionSpeaker3"];
    NSString * sSpeaker3Company = [[json objectAtIndex:i] objectForKey:@"speaker3Company"];
    NSString * sSpeaker4 = [[json objectAtIndex:i] objectForKey:@"sessionSpeaker4"];
    NSString * sSpeaker4Company = [[json objectAtIndex:i] objectForKey:@"speaker4Company"];
    NSString * sSpeaker5 = [[json objectAtIndex:i] objectForKey:@"sessionSpeaker5"];
    NSString * sSpeaker5Company = [[json objectAtIndex:i] objectForKey:@"speaker5Company"];
    NSString * sSpeaker6 = [[json objectAtIndex:i] objectForKey:@"sessionSpeaker6"];
    NSString * sSpeaker6Company = [[json objectAtIndex:i] objectForKey:@"speaker6Company"];
    NSString * sDesc = [[json objectAtIndex:i] objectForKey:@"sessionDesc"];
    NSString * sITSCECS = [[json objectAtIndex:i] objectForKey:@"ITSCECS"];
    NSString * sSessionID = [[json objectAtIndex:i] objectForKey:@"sessionID"];
    Sessions * mySessions = [[Sessions alloc] initWithID:sID andSessionStatus:sStatus andSessionDay:sDay andSessionDate:sDate andSessionTime:sTime andSessionName:sName andSessionSpeaker1:sSpeaker1 andSpeaker1Company:sSpeaker1Company andSessionSpeaker2:sSpeaker2 andSpeaker2Company:sSpeaker2Company andSessionSpeaker3:sSpeaker3 andSpeaker3Company:sSpeaker3Company andSessionSpeaker4:sSpeaker4 andSpeaker4Company:sSpeaker4Company andSessionSpeaker5:sSpeaker5 andSpeaker5Company:sSpeaker5Company andSessionSpeaker6:sSpeaker6 andSpeaker6Company:sSpeaker6Company andSessionDesc:sDesc andITSCECS:sITSCECS andSessionID:sSessionID];
    //Add our sessions object to our sessionsArray
    [sessionsArray addObject:mySessions];

    NSSortDescriptor *sort = [NSSortDescriptor sortDescriptorWithKey:@"sessionDate" ascending:YES];
    [sessionsArray sortUsingDescriptors:[NSArray arrayWithObject:sort]];

    }

[self.myTableView reloadData];
}

这是numberOfSectionsInTableView:中的代码

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    //#warning Potentially incomplete method implementation.
    // Return the number of sections.
    //return 1;
    if (tableView == self.myTableView) {
    return self.sessionsArray.count;
    }
    else
    {
        [self searchThroughData];
        return self.results.count;
    }

}

这是以行数为单位的代码部分：

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    // Return the number of rows in the section.
    //return sessionsArray.count;
    if (tableView == self.myTableView) {
    return self.sessionsArray.count;
    }
    else
    {
        [self searchThroughData];
        return self.results.count;
    }

}

这是标题ForHeaderInSection:中的代码

- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
    return [[sessionsArray objectAtIndex:section] objectForKey:@"sessionDate"];
}

我使用Objective C才几个月，所以我可能忽略了一些基本的东西。谢谢你的帮助。

Answer 1

sessionsArray包含Sessions对象，但当您使用它时，您将其视为包含字典。节计数和行计数也使用完全相同的代码。因此，看起来你打算拥有2组/级别的数据，但目前你只有1组，你正试图将其用于2件事。

您需要决定sessionsArray的实际用途并保持不变。各节表示什么，以及如何表示每个节中的行。将您的数据结构配置为与之匹配。