Question

我在Application Delegate中使用了两个UIViewController，并使用presentmodalviewcontroller导航到UIViewController。但问题是presentmodalviewcontroller第一次工作UIViewController，当我想使用presentmodalviewcontroller导航到第二个UIViewController然后它显示第一个UIViewController。以下是代码： -

-(void)removeTabBar:(NSString *)str
{
    HelpViewController *hvc =[[HelpViewController alloc] initWithNibName:@"HelpViewController" bundle:[NSBundle mainBundle]];
    VideoPlaylistViewController *vpvc =[[VideoPlaylistViewController alloc] initWithNibName:@"VideoPlaylistViewController" bundle:[NSBundle mainBundle]];
    if ([str isEqualToString:@"Help"])
    {
        [tabBarController.view removeFromSuperview];
        [vpvc dismissModalViewControllerAnimated:YES];
        [viewController presentModalViewController:hvc animated:YES];
        [hvc release];
    }
    if ([str isEqualToString:@"VideoPlaylist"])
    {
        [hvc dismissModalViewControllerAnimated:YES];
        [viewController presentModalViewController:vpvc animated:YES];
        [vpvc release];
    }
}

有人可以帮我解决问题吗？

Answer 1

每次运行此功能时，您都会创建一个新的hvc和vpvc。

第一次，我假设您致电removeTabBar:@"Help"，它会生成hvc和vpvc，然后会显示正确的。{/ p>

第二次调用removeTabBar:@"VideoPlayList"时，您正在制作新的hvc和vpvc。这意味着，当您致电hvc dismissModalViewController:YES];时，您没有删除之前添加的那个，那么您将删除刚刚创建的新内容，而这个内容根本没有显示！

要解决此问题，您需要将两个控制器作为应用委托中的属性委托，并使用applicationDidFinishLaunching方法创建它们。

将这些添加到您的app delegate的.h文件中：

@class MyAppDelegate {
    HelpViewController *hvc;
    VideoPlaylistViewController *vpvc;
}

@property (nonatomic, retain) HelpViewController *hvc;
@property (nonatomic, retain) VideoPlaylistViewController *vpvc;

@end

并在您的app delegate的.m文件中：

- (void)applicationDidFinishLaunching:(UIApplication *)application {
    ...
    self.hvc = [[[HelpViewController alloc] initWithNibName:@"HelpViewController" bundle:nil] autorelease];
    self.vpvc = [[[VideoPlaylistViewController alloc] initWithNibName:@"VideoPlaylistViewController" bundle:nil] autorelease];
    ...
}

并删除removeTabBar

中的前两行

presentmodalviewcontroller在iPhone中的Application Delegate中无法正常工作

1 个答案: