View Controller:如何以编程方式在视图之间切换？

Question

简而言之:我希望有两个全屏视图,我可以在视图A和视图B之间切换.我知道我可以使用标签栏控制器,但我不想这样做.我想看看这是如何手工完成的,以了解幕后发生的事情.

我有一个充当根控制器的UIViewController:

@interface MyRootController : UIViewController {
    IBOutlet UIView *contentView;
}
@property(nonatomic, retain) UIView *contentView;

@end

contentView连接到UIView,我将其作为子视图添加到Nib的"视图"中.这有绿色,我看到它全屏.工作良好.

然后,我以几乎相同的方式创建了另外两个View Controller.ViewControllerA和ViewControllerB.ViewControllerA有蓝色背景,ViewControllerB有黑色背景.只是看看哪一个是活跃的.

所以,在myRootController的实现中,我这样做:

// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
    [super viewDidLoad];

    ViewControllerA *vcA = [[ViewControllerA alloc] initWithNib];
    [self.contentView addSubview:vcA.view];

    [cvA release];
}

顺便说一句,-initWithNib方法如下所示:

- (id)initWithNib { // Load the view nib
    if (self = [super initWithNibName:@"ViewA" bundle:nil]) {
        // do ivar initialization here, if needed
    }
    return self;
}

这样可行.当我启动应用程序时,我会看到ViewControllerA中的视图.但现在最大的问题是:View Controller通常具有以下所有方法:

• (空隙)viewWillAppear中:(BOOL)动画;
• (空隙)viewDidDisappear:(BOOL)动画;
• (无效)viewDidLoad中;

...等等.如果我在没有标签栏控制器的情况下以"我的"方式进行操作,那么这些方法是谁或者是什么？我的意思是:如果我分配了ViewController的类并且视图得到可见,我是否需要注意调用这些方法？它是如何知道viewWillAppear,viewDidDisappear或viewDidLoad的？我相信标签栏控制器具有所有这些"聪明"的内幕.还是我错了？

更新:我已经测试过了.如果我释放视图控制器(例如:ViewControllerA),我将在viewDidDisappear上没有日志消息.只有在分配和初始化ViewControllerA时,我才会得到一个viewDidLoad.但就是这样.所以所有迹象都代表着UITabBarController的聪明才智;)我必须弄清楚如何复制它,对吧？

Answer 1

在Beginning iPhone Development的第6章中有一个很好的切换视图的例子.你可以在这里看到它的源代码:http: //iphonedevbook.com/

SwitchViewController具有以编程方式更改视图的代码.

- (IBAction)switchViews:(id)sender
{

    if (self.yellowViewController == nil)
    {
        YellowViewController *yellowController = [[YellowViewController alloc]
                initWithNibName:@"YellowView" bundle:nil];
        self.yellowViewController = yellowController;
        [yellowController release];
    }

    [UIView beginAnimations:@"View Flip" context:nil];
    [UIView setAnimationDuration:1.25];
    [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];

    UIViewController *coming = nil;
    UIViewController *going = nil;
    UIViewAnimationTransition transition;

    if (self.blueViewController.view.superview == nil) 
    {   
        coming = blueViewController;
        going = yellowViewController;
        transition = UIViewAnimationTransitionFlipFromLeft;
    }
    else
    {
        coming = yellowViewController;
        going = blueViewController;
        transition = UIViewAnimationTransitionFlipFromRight;
    }

    [UIView setAnimationTransition: transition forView:self.view cache:YES];
    [coming viewWillAppear:YES];
    [going viewWillDisappear:YES];
    [going.view removeFromSuperview];
    [self.view insertSubview: coming.view atIndex:0];
    [going viewDidDisappear:YES];
    [coming viewDidAppear:YES];

    [UIView commitAnimations];

}

Answer 2

您可以从最简单的removeFromSuperview/insertSubview开始,一点一点地添加代码.

//SwitchViewController.h
#import 
@class BlueViewController;
@class YellowViewController;

@interface SwitchViewController : UIViewController {
    IBOutlet BlueViewController *blueViewController;
    IBOutlet YellowViewController *yellowViewController;
}
- (IBAction)switchViews:(id)sender;
@property (nonatomic, retain) BlueViewController *blueViewController;
@property (nonatomic, retain) YellowViewController *yellowViewController;
@end

//1. remove yellow view and insert blue view
- (IBAction)switchViews:(id)sender {
    if(self.blueViewController.view.superview == nil)
    {
        [yellowViewController.view removeFromSuperview];
        [self.view insertSubview:blueViewController.view atIndex:0];
    }
}

//2. appear=insert, disappear=remove
if(blueViewController.view.superview == nil)
{
    [blueViewController viewWillAppear:YES];
    [yellowViewController viewWillDisappear:YES];

    [yellowViewController.view removeFromSuperview];
    [self.view insertSubview:self.blueViewController.view atIndex:0];

    [yellowViewController viewDidDisappear:YES];
    [blueViewController viewDidAppear:YES];
}

//3. now add animation
[UIView beginAnimations:@"View Flip" context:nil];
[UIView setAnimationDuration:1.25];
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
//blue view will appear by flipping from right
if(blueViewController.view.superview == nil)
{
    [UIView setAnimationTransition: UIViewAnimationTransitionFlipFromRight 
                            forView:self.view cache:YES];

    [blueViewController viewWillAppear:YES];
    [yellowViewController viewWillDisappear:YES];

    [yellowViewController.view removeFromSuperview];
    [self.view insertSubview:self.blueViewController.view atIndex:0];

    [yellowViewController viewDidDisappear:YES];
    [blueViewController viewDidAppear:YES];
}
[UIView commitAnimations];

Answer 3

如果我理解正确,你想要完成的事情非常简单.

只需在应用程序委托上添加UINavigationController,然后执行以下操作:

[navigationController pushView:vcA];

代表们将被召集:

• (空隙)viewWillAppear中:(BOOL)动画;
• (空隙)viewDidDisappear:(BOOL)动画;
• (无效)viewDidLoad中;

当你想要弹出视图并推送另一个视图时:

[navigationController popViewControllerAnimated:true];
[navigationController pushView:vcB];

如果你不希望导航控件显示只是使用:

[navigationBar setHidden:YES];

其中navigationBar是与您的UINavigationController对应的UINavigationBar.