Question

为了执行操作，获取用户当前时间（中午12:00等）的最佳方法是什么？我有一个游戏，如果用户当前的时间是晚上8点到早上5点，我想显示夜间图像。

Answer 1

NSDate *currentTime = [NSDate date];

NSDateFormatter *timeFormatter = [[NSDateFormatter alloc] init];
[timeFormatter setDateFormat:@"HH"];

NSString *hourCountString = [timeFormatter stringFromDate:currentTime];

int hourCountInt = [hourCountString intValue];

//time between 8PM - 5AM.
if(hourCountInt > 20 || hourCountInt < 5)
{
    NSLog(@"display night-time images");
}

Answer 2

NSDate *currentTime = [NSDate date];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"hh-mm"];
NSString *resultString = [dateFormatter stringFromDate: currentTime];

Answer 3

直道将是：

NSCalendar *calendar= [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSCalendarUnit unitFlags = NSHourCalendarUnit | NSMinuteCalendarUnit;
NSDate *date = [NSDate date];
NSDateComponents *dateComponents = [calendar components:unitFlags fromDate:date];

NSInteger hour = [dateComponents hour];
NSInteger minute = [dateComponents minute];

我喜欢helperfunctions，所以你可以这样，如果你需要更频繁的这个功能，并希望保持你的代码清洁：

- (void) getHour:(NSInteger *)hour andMinute:(NSInteger *)minute fromDate:(NSDate *)date
{
    NSCalendar *calendar= [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
    NSCalendarUnit unitFlags = NSHourCalendarUnit | NSMinuteCalendarUnit;
    NSDateComponents *dateComponents = [calendar components:unitFlags fromDate:date];

    *hour = [dateComponents hour];
    *minute = [dateComponents minute];
}

然后调用这样的函数，其中小时和分钟可以是常见的类变量：

NSInteger hour, minute;
NSDate *date = [NSDate date];
[self getHour:&hour andMinute:&minute fromDate:date];

iOS：如何获取设备的当前时间来执行操作？

3 个答案: