UIDatePicker日期选取器

 //定义显示日期的格式
 NSDateFormatter *dateFormat = [[NSDateFormatter alloc]init];
 //NSDateFormatterMediumStyle的显示格式为:  Nov 23, 1937” or “3:30:32 PM
 dateFormat.dateStyle = NSDateFormatterMediumStyle;
 dateFormat.timeStyle = NSDateFormatterMediumStyle;

 //获取事件选取器的值
 NSDate *date = self.datePicker.date;
 //将date按dateFormat的格式转换成NSString对象显示并赋给message
 NSString *message = [dateFormat stringFromDate:date];

 UIAlertController *dateAlert = [UIAlertController alertControllerWithTitle:@"提示" message:message preferredStyle:UIAlertControllerStyleAlert];

 UIAlertAction *dateAction = [UIAlertAction actionWithTitle:@"Yes" style:UIAlertActionStyleDefault handler:nil];

 [dateAlert addAction:dateAction];

 [self presentViewController:dateAlert animated:YES completion:nil];