我正在编写一个应用程序,显示一些基于一周中某天的变化的数据。该应用程序的上下文是即将举行的会议。我想显示当天的日历条目。事件细节存储在coredata中。iOS CoreData NSPredicate不清除
我用什么来创建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,虽然当日期改变(即:周六至周日)的数据(在一个UITableView显示)没有按” t得到更新。
谢谢, 马特。
没有你在你的问题有代码的触动的tableview在所有。你为什么期望tableview奇迹般地改变? – deanWombourne