关于设置滚动条的默认值

如何在每次应用返回背景时设置滚动条的默认值？

滚动条如下：

- (IBAction)slider1:(id)sender
{
    UISlider *slider = (UISlider *)sender;  //declare slider
    NSLog(@"%f",slider.value;
}

如何设置？

添加 observer 到 UIApplicationWillEnterForegroundNotification

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(willEnterForeground:) name:UIApplicationWillEnterForegroundNotification object:nil];


- (void)willEnterForeground:(NSNotification *)n {
    self.slider.value = 0.0f;
}