Question

在呈现模态视图控制器后，我得到一个白色屏幕。我就是这样做的：

SomeViewController *controller = [[[SomeViewController alloc] initWithManagedObjectContext:managedObjectContext] autorelease];
UINavigationController *navController = [[[UINavigationController alloc] initWithRootViewController:controller] autorelease];
[navController setModalTransitionStyle:UIModalTransitionStyleCoverVertical];
[self presentModalViewController:navController animated:YES];

导航栏工作正常，因为我在SomeViewController中设置它，但视图的内容不可见，我看到的只是根窗口的白色背景颜色。

奇怪的是，这曾经起作用，但现在却不是出于某种原因。可能是什么问题？

修改

这就是我创建SomeViewController的方法：

- (void)viewDidLoad
{
    [super viewDidLoad];

    [self setTitle:@"Some View"];

    UIBarButtonItem *sortButton = [[[UIBarButtonItem alloc] initWithTitle:@"Sort" style:UIBarButtonItemStylePlain target:self action:@selector(sortButtonClicked:)] autorelease];
    [[self navigationItem] setRightBarButtonItems:[NSArray arrayWithObjects:sortButton, [self editButtonItem], nil] animated:YES];

    UIBarButtonItem *backButton = [[[UIBarButtonItem alloc] initWithTitle:@"Back" style:UIBarButtonItemStylePlain target:self action:@selector(dismissModalViewControllerAnimated:)] autorelease];
    [[self navigationItem] setLeftBarButtonItem:backButton];

    // Hack to force landscape orientation
    UIViewController *controller = [[UIViewController alloc] init];
    [self presentModalViewController:controller animated:NO];
    [self dismissModalViewControllerAnimated:NO];
    [controller release];
}

- (void)viewDidUnload
{
    [super viewDidUnload];
}

- (void) viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return UIInterfaceOrientationIsLandscape(interfaceOrientation);
}

Answer 1

白屏是由控制器的xib file不属于target（其目标成员资格复选框未选中）引起的。

Answer 2

您是否碰巧在SomeViewController类中还有其他一些初始化？请发布整个.m文件。如果是这样，您可以尝试删除initWithNibName方法并检查它是否显示内容。

编辑：另一个奇怪的点是您在viewController实例上使用的initWithManagedObjectContext方法。你能解释一下吗？

Answer 3

尝试

SomeViewController *controller = [[[SomeViewController alloc] init] autorelease];

它应该可以正常工作。

呈现模态视图控制器后的白色屏幕

3 个答案: