UIDatePicker不会动画

我有一个视图包含一个分段控制器和一个只显示24小时的UIDatePicker . 我希望能够根据分段控件所说的设置不同的时间 . 因此，“星期一”将对应一次，“星期二”对应于另一次，依此类推 . 我有这个工作 . 但是，当用户更改分段控制器上的按钮时，我还想为选取器设置动画 . 截至目前，我已将我的动作方法链接到分段控制器：

[timePicker setDate:date animate:YES];

其中date是NSDate格式如下：HH：mm

正如我所说，它将更改为日期，但它不会为操作设置动画 . 任何人都知道为什么它没有动画？

顺便说一句，虽然我已经将格式化程序设置为“HH：mm”，如果我使用NSLog打印它，我仍然会打印整个1970-01-01 02:00:00字符串 . 我假设唯一的HH：mm无论如何被发送到datepicker并且它只是打印整个东西的NSLog？

编辑：这是实际视图控制器的代码，这是运行SDK4

#import "FlipsideViewController.h"

@implementation FlipsideViewController

@synthesize delegate, times, weatherImage, condition, timePicker;


- (void)viewDidLoad {

    [super viewDidLoad];
    self.view.backgroundColor = [UIColor viewFlipsideBackgroundColor];

    UIImage *image = [UIImage imageNamed:@"sunny.png"];
    weatherImage.image = image;

    WeatherClockAppDelegate *appDelegate = (WeatherClockAppDelegate *)[[UIApplication sharedApplication] delegate];

    times = appDelegate.times;

    [timePicker addTarget:self action:@selector(timePickerAction:) forControlEvents:UIControlEventValueChanged];

    NSDateFormatter *df = [[NSDateFormatter alloc] init];
    [df setDateFormat:@"HH:mm"];
    NSDate *sunnyDate = [df dateFromString: [times objectAtIndex:0]];
    [df release];

    [timePicker setDate:sunnyDate animated:NO];


}

- (IBAction)done:(id)sender {

    if (!busy) {

        [self.parentViewController dismissModalViewControllerAnimated:YES];

        for (NSString *s in times) {
            NSLog(@"Set times: %@", s);
        }
    }

}

- (IBAction)segmentedAction {

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

    switch (self.condition.selectedSegmentIndex) {

        case 0:

            self.weatherImage.image = [UIImage imageNamed:@"sunny.png"];

            NSDate *sunnyDate = [df dateFromString: [times objectAtIndex:0]];

            [timePicker setDate:sunnyDate animated:YES];

            break;

        case 1:

            self.weatherImage.image = [UIImage imageNamed:@"cloudy.png"];

            NSDate *cloudyDate = [df dateFromString: [times objectAtIndex:1]];

            NSLog(@"Cloudydate: %@", cloudyDate);

            [timePicker setDate:cloudyDate animated:YES];

            break;

        case 2:

            self.weatherImage.image = [UIImage imageNamed:@"rain.png"];

            NSDate *rainyDate = [df dateFromString: [times objectAtIndex:2]];

            [timePicker setDate:rainyDate animated:YES];

            break;

        case 3:

            self.weatherImage.image = [UIImage imageNamed:@"final.png"];

            NSDate *finalDate = [df dateFromString: [times objectAtIndex:3]];

            [timePicker setDate:finalDate animated:YES];

            break;

    }

    [df release];
}


- (IBAction)timePickerAction:(id)sender {

    NSDateFormatter *df = [[NSDateFormatter alloc] init];
    [df setDateFormat:@"HH:mm"];
    NSString *date = [NSString stringWithFormat:@"%@", [df stringFromDate:timePicker.date]];
    NSLog(@"%@", date);
    [df release];

    switch (self.condition.selectedSegmentIndex) {

        case 0:

            [times replaceObjectAtIndex:0 withObject:date];

            break;

        case 1:

            [times replaceObjectAtIndex:1 withObject:date];

            break;

        case 2:

            [times replaceObjectAtIndex:2 withObject:date];         

            break;

        case 3:

            [times replaceObjectAtIndex:3 withObject:date];

            break;

    }

}


- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use.
}


- (void)viewDidUnload {
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}


/*
 // Override to allow orientations other than the default portrait orientation.
 - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
 // Return YES for supported orientations
 return (interfaceOrientation == UIInterfaceOrientationPortrait);
 }
 */


- (void)dealloc {

    [times release];
    [weatherImage release];
    [condition release];
    [timePicker release];
    [super dealloc];
}


@end