Question

以字符串格式存储时间HH：MM：来自json的SS响应。我想将其转换为NSDate以进行本地通知。试着 NSString * datestr = @＆＃34; 21：00：00＆＃34 ;;

NSDateFormatter *dateformat = [[NSDateFormatter alloc]init];

[dateformat setDateFormat:@"hh:mm:ss"];
NSDate *date = [dateformat dateFromString:datestr];



NSLog(@"time is %@",date);

获得空闲时间。我有时间格式从json是在21:00:00格式只有没有日期。我想每天为本地通知设置这个时间。

Answer 1

如果字符串的小时部分范围为0到23，则需要使用HH。This site has a convenient list of date formatter codes.

然后，您希望将日期转换为NSDateComponents，以便创建UNCalendarNotificationTrigger。

@implementation ViewController {
    NSDateFormatter *parser;
}

- (void)viewDidLoad {
    [super viewDidLoad];
    parser = [[NSDateFormatter alloc] init];
    parser.dateFormat = @"HH:mm:ss";
    parser.calendar = [NSCalendar autoupdatingCurrentCalendar];
}

- (void)createRepeatingNotificationAtTimeOfDay:(NSString *)timeOfDay {
    NSDate *date = [parser dateFromString:timeOfDay];
    if (date == nil) {
        // Couldn't parse the string.
        return;
    }

    NSDateComponents *components = [parser.calendar components:NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond fromDate:date];
    if (components == nil) {
        // Couldn't extract components.
        return;
    }

    UNCalendarNotificationTrigger *trigger = [UNCalendarNotificationTrigger triggerWithDateMatchingComponents:components repeats:YES];
    UNMutableNotificationContent *content = [[UNMutableNotificationContent alloc] init];
    content.title = @"Daily alarm";
    UNNotificationRequest *request = [UNNotificationRequest requestWithIdentifier:@"dailyalarm" content:content trigger:trigger];
    [[UNUserNotificationCenter currentNotificationCenter] addNotificationRequest:request withCompletionHandler:nil];
}

如何将格式为HH：MM：SS的字符串转换为NSDate？

1 个答案: