我正在編寫一個應用程序,顯示一些基於一週中某天的變化的數據。該應用程序的上下文是即將舉行的會議。我想顯示當天的日曆條目。事件細節存儲在coredata中。iOS CoreData NSPredicate不清除
我用什麼來創建NSPredicate是:
NSDateFormatter *df = [[NSDateFormatter alloc] init];
[df setDateFormat:@"yyyy-MM-dd"];
NSDate *today = [NSDate date];
NSString *sunday = @"2011-12-04";
NSString *monday = @"2011-12-05";
NSString *tuesday = @"2011-12-06";
NSString *wednesday = @"2011-12-07";
NSInteger dayNumber = 1;
if ([[df stringFromDate:today] isEqualToString:sunday]) {
dayNumber = 2;
} else if ([[df stringFromDate:today] isEqualToString:monday]) {
dayNumber = 3;
} else if ([[df stringFromDate:today] isEqualToString:tuesday]) {
dayNumber = 4;
} else if ([[df stringFromDate:today] isEqualToString:wednesday]) {
dayNumber = 5;
}
NSExpression *lhs = [NSExpression expressionForKeyPath:@"day_number"];
NSExpression *rhs = [NSExpression expressionForConstantValue:[NSNumber numberWithInt:dayNumber]];
NSPredicate *equalToPredicat = [NSComparisonPredicate predicateWithLeftExpression:lhs
rightExpression:rhs
modifier:NSDirectPredicateModifier
type:NSEqualToPredicateOperatorType
options:0];
// Edit the sort key as appropriate.
NSSortDescriptor *sortDescriptorTime = [[NSSortDescriptor alloc] initWithKey:@"start_time" ascending:YES];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:/*sortDescriptorDayNumber,*/ sortDescriptorTime, nil];
[fetchRequest setSortDescriptors:sortDescriptors];
[fetchRequest setPredicate:equalToPredicat];
NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest
managedObjectContext:managedObjectContext
sectionNameKeyPath:@"day_number"
cacheName:@"TodayCache"]
我所看到的是,雖然當日期改變(即:週六至週日)的數據(在一個UITableView顯示)沒有按」 t得到更新。
謝謝, 馬特。
沒有你在你的問題有代碼的觸動的tableview在所有。你爲什麼期望tableview奇蹟般地改變? – deanWombourne