iOS每日本地推送通知 [英] iOS Daily Local Push Notifications

问题描述

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

I want to execute a UILocalNotification at 9:00 AM every day, forever, as long as the app is open. The closest thing I've found is this:

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，此代码只执行 UILocalNotification 一次在24小时内，而不是在指定时间。我一直在考虑以某种方式利用 NSDate ，但一直没有。

However, this code only executes a UILocalNotification once in 24 hours, not at a specified time. I've been looking into utilizing NSDate somehow, but have been getting no where.

代码将执行在应用程序中的 AppDelegate 中的didFinishLaunchingWithOptions 方法。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 9处执行： 00 AM 。

The code will be executing in the AppDelegate in the application didFinishLaunchingWithOptions method. If someone were to open the application and place it in the background at 8:59 AM, the UILocalNotification would still execute at 9:00 AM.

NSDateComponent 将无法使用此功能，因为我必须申报年，月和日，但我想每天执行此 UILocalNotification 而无需编辑代码。

An NSDateComponent won't work with this because I would have to declare a year, month, and day, but I want to execute this UILocalNotification every day without having to edit the code.

推荐答案

您需要找到9点发生的NEXT时间，并在当时设置当地通知：

You need to find the NEXT time that 9am occurs, and set the local notification to fire at that time:

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];

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