iphone - 如何在 iOS 上旋转自定义启动画面？

Question

我的启动画面正常，但我的应用程序在横向模式下运行，启动画面以默认的纵向模式显示。

如何启动应用程序，以便启动画面像我的应用程序一样在横屏模式之间旋转？

我正在使用以下代码:

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
// Overriden to allow any orientation.
if (interfaceOrientation == UIInterfaceOrientationLandscapeLeft ||
    interfaceOrientation == UIInterfaceOrientationLandscapeRight)
    return YES;
else {
    return NO;  }
}

和启动画面

-(void)displayScreen { 
UIViewController *displayViewController=[[UIViewController alloc] init];
displayViewController.view = displaySplashScreen;
[self presentModalViewController:displayViewController animated:NO];
[self performSelector:@selector(removeScreen) withObject:nil afterDelay:3.0];
} 
 -(void)removeScreen
{   [[self modalViewController] dismissModalViewControllerAnimated:YES];
}

但是我怎样才能把旋转放在显示屏幕内呢？

Answer 1

啊哈。如果你想显示你自己的启动画面，你应该为此创建一个特殊的 View Controller ，你已经这样做了。我认为你可以简化自动旋转查询代码:

- (BOOL) shouldAutorotateToInterfaceOrientation: (UIInterfaceOrientation) foo
{
    return YES; // all interface orientations supported
}

现在您必须考虑不同方向的启动画面。您是否有单独的横向和纵向启动图像？如果是，你可以这样做:

- (UIView*) startupImageWithOrientation: (UIInterfaceOrientation) io
{
    UIImage *img = [UIImage imageNamed:[NSString
        stringWithFormat:@"Default-%@.png", UIInterfaceOrientationName(io)]];
    UIView *view = [[UIImageView alloc] initWithImage:img];
    [view setFrame:[[UIScreen mainScreen] applicationFrame]];
    return [view autorelease];
}

- (void) loadView
{
    self.view = [self startupImageWithOrientation:self.interfaceOrientation];
}

- (void) willRotateToInterfaceOrientation: (UIInterfaceOrientation) io
    duration: (NSTimeInterval) duration
{
    self.view = [self startupImageWithOrientation:io];
    self.view.transform = CGAffineTransformFromUIOrientation(io);
}

调用了两个实用函数，你可以把它们塞进一个单独的文件中:

NSString *UIInterfaceOrientationName(UIInterfaceOrientation io)
{
    return UIInterfaceOrientationIsPortrait(io) ? @"Portrait" : @"Landscape";
}

CGAffineTransform CGAffineTransformFromUIOrientation(UIInterfaceOrientation io)
{
    assert(io <= 4);
    // unknown, portrait, portrait u/d, landscape L, landscape R
    static float angles[] = {0, 0, M_PI, M_PI/2, -M_PI/2};
    return CGAffineTransformMakeRotation(angles[io]);
}

有点乱，我自己对更简单的解决方案很感兴趣。