Question

我想在显示新视图之前，当用户按下uinavigationcontroler上的按钮时，将整个屏幕（包括导航栏）淡化为黑色。（出于各种原因，我不想推动这种新观点）。我怎么做到这一点？

修改

感谢Mac和Eiko，我已经弄明白了。这是我使用的代码。不确定它是否是最佳的，但它可以解决问题。

// this is called from a programmatically constructed button. 
// change (void) to (IBAction) if linking from IB.

- (void)fadeAndShow:(id)sender
{
    // blackView is a @property which has been @synthesize-d
    // do I really need to alloc and init this?
    blackView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];
    blackView.alpha = 0.0;
    [blackView setBackgroundColor:[UIColor blackColor]];
    [self.navigationController.navigationBar.superview addSubview:blackView];
    [UIView beginAnimations:@"fadeAway" context:NULL]; 
    [UIView setAnimationDelegate:self];
    [UIView setAnimationDuration:0.75];
    [UIView setAnimationDidStopSelector:@selector(showNewScreen:finished:context:)];
    blackView.alpha = 1.0;
    [UIView commitAnimations];
}


-(void)showNewScreen:(NSString *)animationID finished:(BOOL)finished context:(void *)context
{
    // I guess you could fade in somewhere in the new view controller. 
    // don't know how to fade back in this view tho... viewDidAppear?
    NewViewController *controller = [[NewViewController alloc] initWithNibName:@"NewView" bundle:nil];
    [self.navigationController setNavigationBarHidden:YES];
    controller.hidesBottomBarWhenPushed = YES;
    [[self navigationController] pushViewController:controller animated:NO];
    [blackView removeFromSuperview];
    [controller release];
}

Answer 1

您可以在当前视图的顶部添加屏幕尺寸的黑色UIView，并将其alpha设置为0到1的动画。动画完成后，添加新视图。然后你可以删除黑色的。从1到0的动画效果相反 - 从黑色到内容。

Answer 2

脱离我的头顶（我实际上没有测试过以下内容）：

-(IBAction) buttonClicked:(id) sender  
{  
    [UIView beginAnimations:@"myAnimation" context:nil];  
    [UIView setAnimationDuration:ANIMATION_DURATION];

    blackView.alpha = 1.0;

    [UIView commitAnimations];
}

在导航栏的超级视图中创建一个UIView（我假设它是窗口大小的），与窗口大小相同。
将该视图的backgroundColor设置为[UIColor blackColor]，将alpha设置为0.0。
在您的按钮处理程序中执行上述操作（假设您的新UIView为blackView，ANIMATION_DURATION是您所需的动画时间（以秒为单位）。
然后，在顶部添加新视图。

在uinavigationcontroller中淡化为黑色？

2 个答案: