Question

只要应用程序处于打开状态，我希望每天都在上午9:00 执行UILocalNotification。我发现的最接近的是：

UILocalNotification *notification = [[UILocalNotification alloc] init];
notification.fireDate = [[NSDate date] dateByAddingTimeInterval:60*60*24];
notification.alertBody = @"It's been 24 hours.";
[[UIApplication sharedApplication] scheduleLocalNotification:notification];

但是，此代码仅在24小时内执行一次UILocalNotification，而不是在指定时间执行。我一直在考虑以某种方式使用NSDate，但一直没有。

代码将在AppDelegate方法的application didFinishLaunchingWithOptions中执行。如果有人打开应用程序并将其置于上午8:59 的后台，则UILocalNotification仍将在上午9:00 执行。

NSDateComponent无法使用此功能，因为我必须声明一年，一月和一天，但我想每天执行此UILocalNotification而无需编辑代码

Answer 1

您需要找到9am发生的NEXT时间，然后将当地通知设置为当时：

NSDate *now = [NSDate date];
NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit fromDate:now];
[components setHour:9];
// Gives us today's date but at 9am
NSDate *next9am = [calendar dateFromComponents:components];
if ([next9am timeIntervalSinceNow] < 0) {
    // If today's 9am already occurred, add 24hours to get to tomorrow's
    next9am = [next9am dateByAddingTimeInterval:60*60*24];
}

UILocalNotification *notification = [[UILocalNotification alloc] init];
notification.fireDate = next9am;
notification.alertBody = @"It's been 24 hours.";
// Set a repeat interval to daily
notification.repeatInterval = NSDayCalendarUnit;
[[UIApplication sharedApplication] scheduleLocalNotification:notification];

Answer 2

您的问题有两个问题：

获取下一个开火日期的正确NSDate。
设置本地通知，以便每24小时触发一次

这是一个片段：

// 1st: find next fire date, using NSDateComponents

NSDate * date = [NSDate date];
NSDateComponents * components = [[NSCalendar currentCalendar] components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit|NSHourCalendarUnit|NSMinuteCalendarUnit fromDate:date];

// Components will now contain information about current hour and minute, day, month and year.

// Do your calculation in order to setup the right date. Note that components reflect user timezone.
// For example, skip to the next day if current time is after 9:00:
if (components.hour >= 9) {
    components.day += 1;
}

// Now fix the components for firing time, for example 9:00.
components.hour = 9;
components.minute = 0;

NSDate * fireDate = [[NSCalendar currentCalendar] dateFromComponents:components];

NSLog(@"Notification will fire at: %@", fireDate);


// 2nd: Schedule local notification with repetitions:

UILocalNotification * notification = [[UILocalNotification alloc] init];
notification.fireDate = fireDate;
notification.repeatInterval = NSDayCalendarUnit; // Here is the trick

notification.alertBody = @"It's been 24 hours.";
[[UIApplication sharedApplication] scheduleLocalNotification:notification];

Answer 3

在安排通知之前设置repeatInterval

localNotification.repeatInterval = NSCalendarUnitDay;

iOS每日本地推送通知

3 个答案: