Cocoa Touch 中的协调控制器设计模式

Question

我正在创建一个带有大量自定义视图的 iOS 应用程序，因此，使用默认的 Cocoa 视图不是一个选项。然后，我决定采用 Coordinating / Mediator Controller 设计模式（在 Apress - Pro Objective-C Design Patterns for iOS 中学习）。

从委托中，我创建了一个 rootViewController 指向我的协调控制器中的视图：

self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
coordinatingController = [C6CoordinatingController sharedInstance];
self.window.rootViewController = coordinatingController.activeVC;
[self.window makeKeyAndVisible];
return YES;

然后，在协调控制器中，我有单例创建方法：

+ (C6CoordinatingController *) sharedInstance{
if (sharedCoordinator == nil){
    C6Log(@"New Shared Coordinator");
    sharedCoordinator = [[super allocWithZone:NULL] init];
    [sharedCoordinator initialize];
}
else {
    C6Log(@"Return Singleton Shared Coordinator");
}
return sharedCoordinator;
}



+ (id) allocWithZone:(NSZone *)zone{
return [self sharedInstance];
}



- (void) initialize{
C6Log(@"");
[self checkDevice];

_mainVC = [C6MainViewController initWithDevice:device];
_activeVC = _mainVC;
[self checkLanguage];
[self chooseFirstView];
}

我还有一个选择器可以选择第一个视图（我目前只有两个）：

-(void) chooseFirstView{
// If a language was not setted, go to language settings view
if (!language) {
    C6Log(@"Going to Language Settings");
    C6LanguageSettingsViewController *languageVC = [C6LanguageSettingsViewController initWithDevice:device];
    [_mainVC.view addSubview:languageVC.view];
}
else {
    C6Log(@"Going to User Settings", language);
    C6AccountSettingsViewController *accountVC = [C6AccountSettingsViewController initWithDevice:device];
    [_mainVC.view addSubview:accountVC.view];
}
}

然后，我有一个 IBAction 供我的视图使用：

- (IBAction) requestViewChangeByObject:(id)object {
int buttonTag = [object tag]; // dividend
int viewTag = buttonTag / divisor; // quotient
int actionTag = buttonTag - (divisor * viewTag); // remainder
C6Log(@"viewTag: %d | actionTag %d", viewTag, actionTag);
switch (viewTag) {
    case LanguageTags:
        C6Log(@"LanguageTags");
        break;
    case AccountTags:
        C6Log(@"AccountTags");
        break;
    default:
        break;
}

在 NIB 中，我创建了一个 Obect（协调控制器）并从那里调用 IBAction。它工作得很好，我可以改变我的观点（它仍然需要实现）…………

但是……我也想更改语言，但是，因为这不是导航问题，所以我想从 C6LanguageSettingsViewController 而不是从 C6CoodinatingController 进行。

所以，我在 C6LanguageSettingsViewController 中创建了另一个 IBAction：

- (IBAction)chooseLang:(id)sender{
UIImage *bt;
[self resetImagesToNormalState];
C6Log(@""); 
C6Log(@"%@", [sender tag]);
C6Log(@"%@", sender);
.
.
.

当我将按钮连接到此 IBAction（通过 File's Owner 或通过 LanguageSettingsViewController 对象）时，应用程序中断，有时它没有显示错误，有时它显示 Unrecognized selector sent to instance 或EXC_BAD_ACCESS (Code=1, address = 0x……) 在 UIApplicationMain 中。

我认为问题是 NIB 找不到文件的所有者……但我不知道如何解决它。

Answer 1

好吧……这似乎很荒谬，但我正在回答自己：P

我设法让它工作（终于！），我发现我正在以 BAAAAD 方式管理视图控制器，所以，我更改了协调控制器中的一些代码：

首先，我没有一个“真正的”mainViewController，不再有 NIB 和 stuf……

旧初始化

- (void) initialize{
    C6Log(@"");
    [self checkDevice];
    _mainVC = [C6MainViewController initWithDevice:device];
    _activeVC = _mainVC;
    [self checkLanguage];
    [self chooseFirstView];
}

新初始化

- (void) initialize{
    C6Log(@"");
    [self checkDevice];
    [self checkLanguage];
    [self chooseFirstView];
}

checkDevice 验证它是 iPhone 还是 iPad，所以我可以选择正确的 NIB。

checkLanguage 检查语言的 [NSUserDefaults standardUserDefaults]

最后，我调用了 chooseFirstView：

OLD 选择FirstView

-(void) chooseFirstView{
    // If a language was not setted, go to language settings view
    if (!language) {
        C6Log(@"Going to Language Settings");
        C6LanguageSettingsViewController *languageVC = [C6LanguageSettingsViewController initWithDevice:device];
        [_mainVC.view addSubview:languageVC.view];
    }
    else {
        C6Log(@"Going to User Settings", language);
        C6AccountSettingsViewController *accountVC = [C6AccountSettingsViewController initWithDevice:device];
        [_mainVC.view addSubview:accountVC.view];
    }
}

新选择第一视图

-(void) chooseFirstView{
    // If a language was not setted, go to language settings view
    _activeVC = [[UIViewController alloc] init];
    UIImage *bgImage = [UIImage imageNamed:@"bg.png"];
    UIImageView *bgView = [[UIImageView alloc] initWithImage:bgImage];
    [_activeVC.view addSubview:bgView];

    if (!language) {
        C6Log(@"Going to Language Settings");
        languageVC = [C6LanguageSettingsViewController initWithDevice:device];
        [_activeVC.view addSubview:languageVC.view];
    }
    else {
        C6Log(@"Going to User Settings", language);
        accountVC = [C6AccountSettingsViewController initWithDevice:device];
        [_activeVC.view addSubview:accountVC.view];
    }
}

最大的变化是我何时以及如何启动 _activeVC……以及 _languageVC 和 _accountVC 现在都是全局变量这一事实。

嗯，在此更改之后，NIB 按钮调用两个 IBAction 方法：它是文件的所有者和协调控制器。

使用这种模式的另一件大事是如何在不爆炸 iOS 设备内存的情况下从一个视图更改为另一个视图……这是我在协调控制器中的操作方式：

- (IBAction) requestViewChangeByObject:(id)object {
    int buttonTag = [object tag]; // dividend
    int viewTag = buttonTag / divisor; // quotient
    int actionTag = buttonTag - (divisor * viewTag); // remainder
    C6Log(@"ViewTag: %d", viewTag);
    switch (viewTag) {
        case LanguageTags:{
            C6Log(@"LanguageTags - button %d", actionTag);
            accountVC = [C6AccountSettingsViewController initWithDevice:device];
            UIView *fromView = languageVC.view;
            UIView *toView = accountVC.view;
            [self switchFrom:fromView To:toView usingAnimation:AnimationPushFromRigh];
        }
            break;
        case AccountTags:{
            C6Log(@"AccountTags - button %d", actionTag);
            switch (actionTag) {
                case 0:{
                    C6Log(@"Go back");
                    languageVC = [C6LanguageSettingsViewController initWithDevice:device];
                    UIView *fromView = accountVC.view;
                    UIView *toView = languageVC.view;
                    [self switchFrom:fromView To:toView usingAnimation:AnimationPushFromLeft];
                }
                    break;

                default:
                    break;
            }
        }
            break;
        default:
            break;
    }
}

在方法的开始，我做了很多数学运算……我“创建”了一个模式，其中每个 NIB 的标签都应该以 100 倍数开头……所以，语言以 0 开头，帐户以 100 开头…………

#define divisor         100
#define LanguageTags    0
#define AccountTags     1

然后，我从一种视图切换到另一种视图的方式就在那里：

-(void) switchFrom:(UIView*) fromView To:(UIView*) toView usingAnimation:(int) animation{
    C6Log(@"");
    /*************** SET ALL DEFAULT TRANSITION SETTINGS ***************/
    // Get the current view frame, width and height
    CGRect pageFrame = fromView.frame;
    CGFloat pageWidth = pageFrame.size.width;
    // Create the animation
    [UIView beginAnimations:nil context:nil];
    // Create the delegate, so the "fromView" is removed after the transition
    [UIView setAnimationDelegate: fromView];
    [UIView setAnimationDidStopSelector:@selector(removeFromSuperview)];
    // Set the transition duration
    [UIView setAnimationDuration: 0.4];

    // Add the "toView" as subview of "fromView" superview
    [fromView.superview addSubview:toView];

    switch (animation) {
        case AnimationPushFromRigh:{
            // Position the "toView" to the right corner of the page            
            toView.frame = CGRectOffset(pageFrame, pageWidth,0);
            // Animate the "fromView" to the left corner of the page
            fromView.frame = CGRectOffset(pageFrame, -pageWidth,0);
            // Animate the "toView" to the center of the page
            toView.frame = pageFrame;
            // Animate the "fromView" alpha
            fromView.alpha = 0;
            // Set and animate the "toView" alpha
            toView.alpha = 0;
            toView.alpha = 1;

            // Commit the animation
            [UIView commitAnimations];
        }
            break;
        case AnimationPushFromLeft:{
            // Position the "toView" to the left corner of the page         
            toView.frame = CGRectOffset(pageFrame, -pageWidth,0);
            // Animate the "fromView" to the right corner of the page
            fromView.frame = CGRectOffset(pageFrame, pageWidth,0);
            // Animate the "toView" to the center of the page
            toView.frame = pageFrame;
            // Animate the "fromView" alpha
            fromView.alpha = 0;
            // Set and animate the "toView" alpha
            toView.alpha = 0;
            toView.alpha = 1;

            // Commit the animation
            [UIView commitAnimations];
        }
            break;
        default:
            break;
    }
}

我真的希望这对尝试使用这种协调控制器模式的人有所帮助：P