iOS5替换

Question

iOS 5.0中不推荐使用didAnimateFirstHalfOfRotationToInterfaceOrientation。但是，我想在我的应用程序中使用此方法。我正在使用苹果在iOS开发人员中心提供的样例代码，项目名称为AlternateViews。我希望应用程序旋转portraitView，同时在landscapeView中淡入淡出。在iOS 5中可以做到这一点吗?或者这个特性会永远消失吗？

portraitView当前调用：

[self presentModalViewController:self.landscapeViewController animated:YES];

而landscapeView在init方法的代码中调用它：

self.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;

似乎所有动画都是在以下PortraitViewController.m中完成的：

#import "PortraitViewController.h"
#import "LandscapeViewController.h"

@implementation PortraitViewController

@synthesize landscapeViewController;

- (void)viewDidLoad
{
    self.view.backgroundColor = [UIColor colorWithRed:197.0/255.0 green:204.0/255.0 blue:211.0/255.0 alpha:1.0];

    LandscapeViewController *viewController = [[LandscapeViewController alloc]
                                                    initWithNibName:@"LandscapeView" bundle:nil];
    self.landscapeViewController = viewController;
    [viewController release];

    [[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(orientationChanged:)
                                                    name:UIDeviceOrientationDidChangeNotification object:nil];
}

- (void)viewDidUnload
{
    self.landscapeViewController = nil;
}

- (void)dealloc
{
    [[NSNotificationCenter defaultCenter] removeObserver:self];
    [[UIDevice currentDevice] endGeneratingDeviceOrientationNotifications];

    [landscapeViewController release];

    [super dealloc];
}

- (void)orientationChanged:(NSNotification *)notification
{
    // We must add a delay here, otherwise we'll swap in the new view
    // too quickly and we'll get an animation glitch
    [self performSelector:@selector(updateLandscapeView) withObject:nil afterDelay:0];
}

- (void)updateLandscapeView
{
    UIDeviceOrientation deviceOrientation = [UIDevice currentDevice].orientation;
    if (UIDeviceOrientationIsLandscape(deviceOrientation) && !isShowingLandscapeView)
    {
        [self presentModalViewController:self.landscapeViewController animated:YES];
        isShowingLandscapeView = YES;
    }
    else if (deviceOrientation == UIDeviceOrientationPortrait && isShowingLandscapeView)
    {
        [self dismissModalViewControllerAnimated:YES];
        isShowingLandscapeView = NO;
    }    
}

// override to allow orientations other than the default portrait orientation
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation == UIInterfaceOrientationPortrait); // support only portrait
}

@end

下面是我当前的实现文件，它们都失败得很糟糕。PortraitViewController.m：

#import "PortraitViewController.h"
#import "LandscapeViewController.h"

@implementation PortraitViewController

@synthesize landscapeViewController;

- (void)viewDidLoad
{   
    LandscapeViewController *viewController = [[LandscapeViewController alloc]
                                                    initWithNibName:@"LandscapeView" bundle:nil];
    self.landscapeViewController = viewController;
    [viewController release];
    NSLog(@"Portrait viewDidLoad");
}

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

    [[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleBlackTranslucent animated:NO];
}

- (void)viewDidUnload
{
    self.landscapeViewController = nil;
}

- (void)dealloc
{   
    [landscapeViewController release];

    [super dealloc];
}

- (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
    if (toInterfaceOrientation == UIInterfaceOrientationPortrait) {
        NSLog(@"Portrait-willAnimateRotationToInterfaceOrientation Portrait");
    } else if (toInterfaceOrientation == UIInterfaceOrientationLandscapeLeft || toInterfaceOrientation == UIInterfaceOrientationLandscapeRight) {
        NSLog(@"Portrait-willAnimateRotationToInterfaceOrientation Landscape");
    }
    [self performSelector:@selector(updateLandscapeView) withObject:nil afterDelay:0];

}

- (void)updateLandscapeView
{
    UIDeviceOrientation deviceOrientation = [UIDevice currentDevice].orientation;
    if (UIDeviceOrientationIsLandscape(deviceOrientation) && !isShowingLandscapeView)
    {
        NSLog(@"Portrait-present Landscape");
        [self presentModalViewController:self.landscapeViewController animated:YES];
        isShowingLandscapeView = YES;
    }
    else if (deviceOrientation == UIDeviceOrientationPortrait && isShowingLandscapeView)
    {
        NSLog(@"Portrait-dismiss Landscape");
        [self dismissModalViewControllerAnimated:YES];
        isShowingLandscapeView = NO;
    }    
}

// override to allow orientations other than the default portrait orientation
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    if (interfaceOrientation == UIInterfaceOrientationPortraitUpsideDown)
        return NO;
    else
        return YES;
}

@end

LandscapeViewController.m

#import "LandscapeViewController.h"

@implementation LandscapeViewController

// the designated initializer. Override to perform setup that is required before the view is loaded.
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil])
    {
        self.wantsFullScreenLayout = YES; // we want to overlap the status bar.

        // when presented, we want to display using a cross dissolve
        self.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
    }
    return self;
}

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

    oldStatusBarStyle = [[UIApplication sharedApplication] statusBarStyle];
    [[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleBlackTranslucent animated:NO];
    NSLog(@"Landscape viewWillAppear");
}

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

    [[UIApplication sharedApplication] setStatusBarStyle:oldStatusBarStyle animated:NO];    
}

// override to allow orientations other than the default portrait orientation
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    // return YES for supported orientations
    if (interfaceOrientation == UIInterfaceOrientationPortraitUpsideDown)
        return NO;
    else
        return YES;
    //return UIInterfaceOrientationIsLandscape(interfaceOrientation);
}

- (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
    if (toInterfaceOrientation == UIInterfaceOrientationPortrait) {
        NSLog(@"Landscape-willAnimateRotationToInterfaceOrientation Portrait");
        [self dismissModalViewControllerAnimated:YES];
    } else if (toInterfaceOrientation == UIInterfaceOrientationLandscapeLeft || toInterfaceOrientation == UIInterfaceOrientationLandscapeRight) {
        NSLog(@"Landscape-willAnimateRotationToInterfaceOrientation Landscape");

    }
}


@end

Answer 1

在苹果的UIViewController reference page中，你会在“处理视图旋转”一节中找到这个有用的段落：

如果要在方向更改期间执行自定义动画，可以通过以下两种方法之一执行此操作。方向更改通常分两步进行，通知发生在旋转的开始、中间和结束点。但是，在iOS 3.0中，添加了对在一个步骤中执行方向更改的支持。使用一步方向更改往往比旧的两步过程更快，并且通常推荐用于任何新代码。

若要为方向更改添加动画，请覆盖willAnimateRotationToInterfaceOrientation:duration:方法并在其中执行动画。

你能覆盖willAnimateRotationToInterfaceOrientation:方法来做你的动画吗？