UIActinSheet和UIActionSheetDelegate

这个是就那个UIActionSheet对象  一般用来选择类型或者改变界面。。。还有更多应用

定义如下：
UIActionSheet *styleAlert = [[UIActionSheet alloc] initWithTitle:@"Choose a UIBarStyle:"
                                                delegate:self cancelButtonTitle:@"Cancel"
                                               destructiveButtonTitle:nil
                                               otherButtonTitles:  @"Default",
                                                                   @"BlackOpaque",
                                                                   @"BlackTranslucent",
                                                                   nil,
                                                                   nil];
   
    // use the same style as the nav bar
    styleAlert.actionSheetStyle = self.navigationController.navigationBar.barStyle;
    //styleAlert.actionSheetStyle =UIActionSheetStyleAutomatic;
    [styleAlert showInView:self.view];
    [styleAlert release];

在委托里的操作代码如下：
- (void)actionSheet:(UIActionSheet *)modalView clickedButtonAtIndex:(NSInteger)buttonIndex
{
    // Change the navigation bar style, also make the status bar match with it
    switch (buttonIndex)
    {
        case 0:
        {
            [UIApplication sharedApplication].statusBarStyle = UIStatusBarStyleDefault;
            self.navigationController.navigationBar.barStyle = UIBarStyleDefault;
            break;
        }
        case 1:
        {
            [UIApplication sharedApplication].statusBarStyle = UIStatusBarStyleBlackOpaque;
            self.navigationController.navigationBar.barStyle = UIBarStyleBlackOpaque;
            break;
        }
        case 2:
        {
            [UIApplication sharedApplication].statusBarStyle = UIStatusBarStyleBlackTranslucent;
            self.navigationController.navigationBar.barStyle = UIBarStyleBlackTranslucent;
            break;
        }
    }
}