iphone - 每周触发 UILocalNotification

Question

我似乎无法弄清楚为什么这个通知没有安排在星期六......我已经尝试过NSGregorianCalendar和autoupdatingCurrentCalendar。我正在设置[dateComps setWeekday:7];，但它一直在星期天返回。

//NSCalendar *calendar = [NSCalendar autoupdatingCurrentCalendar];
 NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *timeComponent = [calendar components:( NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit ) fromDate:reminderTime];
 // Set up the fire time
 NSDateComponents *dateComps = [[NSDateComponents alloc] init];
 [dateComps setYear: 2012];;
 [dateComps setHour: timeComponent.hour];
 [dateComps setMinute: timeComponent.minute];
 [dateComps setSecond:0];
 // Set day of the week
 [dateComps setWeekday:7];
 NSDate *itemDate = [calendar dateFromComponents:dateComps];

 UILocalNotification *notification = [[UILocalNotification alloc] init];
 if (notification == nil)
     return;
 notification.fireDate = itemDate;
 notification.repeatInterval = NSWeekCalendarUnit;

Answer 1

dateComps正如您计算的那样，它不包含一天或一个月，因此它setWeekday只是被忽略并且itemDate是 2012 年 1 月的第一个日期（这是一个星期日）。

要计算下一个星期六，您可以按照“日期和时间编程指南”的将组件添加到日期中的说明进行操作：

NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

// Weekday of "reminderTime":
NSDateComponents *weekdayComponents = [calendar components:NSWeekdayCalendarUnit fromDate:reminderTime];

// Number of weekdays until next Saturday:
NSDateComponents *componentsToAdd = [[NSDateComponents alloc] init];
[componentsToAdd setDay: 7 - [weekdayComponents weekday]];

NSDate *itemDate = [calendar dateByAddingComponents:componentsToAdd toDate:reminderTime options:0];