UIDatePickerModeCountDownTimer模式下的UIDatePicker:如何通过代码获取/设置小时和分钟? [英] UIDatePicker in UIDatePickerModeCountDownTimer mode: how to get/set the hours and minutes via code?

问题描述

如何通过代码从UIDatePickerModeCountDownTimer模式下的UIDatePicker获取/设置小时和分钟?

How to get/set the hours and minutes via code from a UIDatePicker in UIDatePickerModeCountDownTimer mode?

情况:

• 我有一个界面，用户可以选择几个小时和几分钟.然后，他保存了信息(因此，我必须通过代码从UIDatePicker中获取小时和分钟，以保存到数据库中.)

• I have an interface in that a user selects just hours and minutes. Then, he saves the information (so, I have to get the hours and minutes from UIDatePicker via code to save in a DB).

当用户编辑以前保存的信息时，我想使用保存的小时/分钟启动界面(因此，我必须通过代码和DB中的值来设置UIDatePicker的小时和分钟).

When the user is editing the information saved previously, I want to start the interface with the saved hours/minutes (so, I have to set the UIDatePicker hours and minutes via code with values from DB).

在UIDatePickerModeCountDownTimer模式下如何使用UIDatePicker进行操作?

How do I do that with the UIDatePicker in UIDatePickerModeCountDownTimer mode?

谢谢.

推荐答案

当日期选择器模式设置为UIDatePickerModeCountDownTimer时，必须在UIDatePicker中使用countDownDuration属性.

You have to use the countDownDuration property in UIDatePicker when the date picker mode is set to UIDatePickerModeCountDownTimer.

倒计时持续时间以秒为单位，因此您可以按照以下方式从NSDate计算该时间(要进行测试，只需将其放入任何UIViewController的viewDidLoad中):

The countdown duration is in seconds, so you can calculate that from a NSDate as follows (to test it just drop it into the viewDidLoad of any UIViewController):

// Create a new date with the current time
NSDate *date = [NSDate new];
// Split up the date components
NSDateComponents *time = [[NSCalendar currentCalendar] 
                            components:NSHourCalendarUnit | NSMinuteCalendarUnit 
                            fromDate:date];
NSInteger seconds = ([time hour] * 60 * 60) + ([time minute] * 60);

UIDatePicker *picker = [UIDatePicker new];
[picker setDatePickerMode:UIDatePickerModeCountDownTimer];
[picker setCountDownDuration:seconds];
[[self view] addSubview:picker];

因此，如果当前时间是17:28，则UIDatePicker将显示"17小时28分钟".将NSDate替换为从数据库中获得的NSDate，应该对它进行排序:)

So if the current time is 17:28, the UIDatePicker will show "17 hours 28 mins". Simly replace the NSDate with the one you get from the DB and you should be sorted :)

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