使用fetchedresultcontroller爲每個月設置一個不同的部分

我想將我的tableview分成每個月的部分。我開始使用DateSectionTitles蘋果的例子。首先，我在覈心數據庫中添加了一個屬性'sectionIdentifier'。然後在我的managedobject子類中添加了這個方法。使用fetchedresultcontroller爲每個月設置一個不同的部分

- (NSString *)sectionIdentifier { 

    // Create and cache the section identifier on demand. 

    [self willAccessValueForKey:@"sectionIdentifier"]; 
    NSString *tmp = [self primitiveSectionIdentifier]; 
    [self didAccessValueForKey:@"sectionIdentifier"]; 

    if (!tmp) { 
     /* 
     Sections are organized by month and year. Create the section identifier as a string representing the number (year * 1000) + month; this way they will be correctly ordered chronologically regardless of the actual name of the month. 
     */ 
     NSCalendar *calendar = [NSCalendar currentCalendar]; 

     NSDateComponents *components = [calendar components:(NSYearCalendarUnit | NSMonthCalendarUnit) fromDate:[self date]]; 
     tmp = [NSString stringWithFormat:@"%d", ([components year] * 1000) + [components month]]; 
      [self setPrimitiveSectionIdentifier:tmp]; 
    } 
    NSLog(@"tmp: %@",tmp); 
    return tmp; 
}

這是我在titleForHeaderSection

- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section { 
     id <NSFetchedResultsSectionInfo> theSection = [[self.fetchedResultsController sections] objectAtIndex:section]; 


    /* 
    Section information derives from an event's sectionIdentifier, which is a string representing the number (year * 1000) + month. 
    To display the section title, convert the year and month components to a string representation. 
    */ 
    static NSArray *monthSymbols = nil; 

    if (!monthSymbols) { 
     NSDateFormatter *formatter = [[NSDateFormatter alloc] init]; 
     [formatter setCalendar:[NSCalendar currentCalendar]]; 
     monthSymbols = [formatter monthSymbols]; 
    } 

    NSInteger numericSection = [[theSection name] integerValue]; 

    NSInteger year = numericSection/1000; 
    NSInteger month = numericSection - (year * 1000); 

    NSString *titleString = [NSString stringWithFormat:@"%@ %d", [monthSymbols objectAtIndex:month-1], year]; 
    NSLog(@"titelstring is: %@",titleString); 
    return titleString; 
}

做我的電話號碼rowsInSection我做到這一點。

id <NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:section]; 

     NSInteger count = [sectionInfo numberOfObjects]; 
     return count;

這對我NumberOfSectionsInTableview

NSInteger count = [[self.fetchedResultsController sections] count]; 
     return count;

任何人可以幫助？

在此先感謝！

到底哪裏出問題了

首先關閉所有它不打印我的日誌中的NSLog（@ 「TMP：％@」，TMP）; 同時，我得到以下錯誤：

CoreData: error: (NSFetchedResultsController) A section returned nil value for section name key path 'sectionIdentifier'. Objects will be placed in unnamed section 
2012-10-10 10:41:17.475 RacingGenk[15785:c07] *** Terminating app due to uncaught exception 'NSRangeException', reason: '-[__NSCFArray objectAtIndex:]: index (-1 (or possibly larger)) beyond bounds (12)'

來源

2012-10-10 Steaphann

NSPostWhenidle，你編輯了什麼？ – Steaphann

您是否在創建抓取的結果控制器時設置了'sectionNameKeyPath：@「sectionIdentifier」'？ - （這個問題很古老，但是因爲某種原因關閉了並重新打開，以致它再次顯示爲「主動」。也許問題已經解決了嗎？） –

一個常見的錯誤通常編碼瞬時屬性nsmanagedobject，是人們忘了還「使能」的數據模型文件（xcdatamodeld）瞬態特性。

來源

2013-12-22 02:53:16 netliner

這是一個主要答案！我有第二個解決這個 –

使用fetchedresultcontroller爲每個月設置一個不同的部分

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