WatchOS：在基于页面的导航中插入页面

Question

我正在使用 -[WKInterfaceController presentControllerWithNames:contexts:] 以模态方式呈现一组动态创建的页面。有时我想在页面集中插入可见的页面。这是可能的，还是一旦可见就固定了一组页面？

Answer 1

我设计了一个方法来实现这个，但是很麻烦。更好的解决方案将是一个相当大的改进。

1. 页面组中的每个 WKInterfaceController 都有一个 UUID 属性，它使用其上下文分配并存储在 awakeWithContext:
期间
2. 显示页面组的 WKInterfaceController 在显示之前保留 WKInterfaceController 名称和上下文的数组
3. 当其中一个页面需要 insert/delete 个页面时，它会向当前 WKInterfaceController
发回通知
4. 呈现 WKInterfaceController 在其保留的 WKInterfaceController 名称和上下文数组中进行所需的更改
5. 呈现 WKInterfaceController 关闭当前页面组，然后使用更新的 name/context 数组重新呈现它们
6. 呈现 WKInterfaceController 发布一个通知，所有页面都会观察到该通知，包括新页面的 UUID 作为通知对象。通知会触发页面根据通知对象中发送的页面检查自己的 UUID。如果通知匹配，则该接口控制器调用 becomeCurrentPage

我还没有实际测试过，但这是我能想到的唯一可行的方法。但这会很丑陋，因为您会看到当前页面消失，然后第一页出现，然后新页面以动画形式出现。从用户体验的角度来看不是很好，但我想不出任何其他方法，因为 Apple 没有给我们任何插入页面的方法。

Answer 2

这是我为此设计的解决方案。

/*
MyInterfaceController - class within the set of pages
*/
- (void)awakeWithContext:(id)context {
    [super awakeWithContext:context];
    NSDictionary *dict = (NSDictionary*)context;
    self.uuid = [dict valueForKey:@"uuid"];
    self.jumpuuid = [dict valueForKey:@"jumpuuid"];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(checkBecomeCurrentPage:) name:@"checkBecomeCurrentPage" object:nil];
}

- (void)checkBecomeCurrentPage:(NSNotification*)notification {
    NSString *checkUUID = (NSString*)notification.object;

    if ([self.uuid isEqualToString:checkUUID]) {
        [self becomeCurrentPage];
    }
}

- (void)didAppear {
    [super didAppear];

    if (self.jumpuuid) {
        [[NSNotificationCenter defaultCenter] postNotificationName:@"checkBecomeCurrentPage" object:self.jumpuuid];
    }
}

- (IBAction)addPageButtonAction {
    [[NSNotificationCenter defaultCenter] postNotificationName:@"addPageNotification" object:self];
}

#warning Populate this with the names and contexts for the set of pages when initially displaying them. It is used for inserting pages later
+ (NSMutableDictionary*)namesAndContextsForCurrentlyDisplayedPage {
    static NSMutableDictionary *dict = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        dict = [NSMutableDictionary dictionary];
    });
    return dict;
}

+ (void)addPageWithPresentingController:(WKInterfaceController *)presentingController requestingInterfaceController:(MyInterfaceController *)requestingInterfaceController {
    NSMutableArray *contexts = [[[MyInterfaceController namesAndContextsForCurrentlyDisplayedPages] objectForKey:@"contexts"] mutableCopy];

    NSInteger requestingInterfaceControllerIndex = -1;

    for (NSDictionary *dict in contexts) {
        if ([[dict valueForKey:@"uuid"] isEqualToString:requestingInterfaceController.uuid]) {
            requestingInterfaceControllerIndex = [contexts indexOfObject:dict];
        }
    }

    if (requestingSetInterfaceControllerIndex == -1) {
        #warning Display an error that the position of the current page could not be established
    }
    else {
        NSInteger insertIndex = requestingInterfaceControllerIndex + 1;

        NSMutableArray *names = [[[MyInterfaceController namesAndContextsForCurrentlyDisplayedPages] objectForKey:@"names"] mutableCopy];
        [names insertObject:@"MyInterfaceController" atIndex:insertIndex];

        NSString *newUUID = [[NSUUID UUID] UUIDString];
        NSDictionary *newDict = @{@"uuid": newUUID};

        [contexts insertObject:newdict atIndex:insertIndex];

        NSMutableDictionary *firstDict = [contexts.firstObject mutableCopy];
        [firstDict setValue:newUUID forKey:@"jumpuuid"];
        [contexts replaceObjectAtIndex:0 withObject:firstDict];

        [[MyInterfaceController namesAndContextsForCurrentlyDisplayedPages] setValue:names forKey:@"names"];
        [[MyInterfaceController namesAndContextsForCurrentlyDisplayedPages] setValue:contexts forKey:@"contexts"];

        [presentingController dismissController];
        [presentingController presentControllerWithNames:names contexts:contexts];
    }
}

-

/*
MyParentInterfaceController - the controller which originally presented the set of pages
*/

- (void)awakeWithContext:(id)context {
    [super awakeWithContext:context];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(addPage:) name:@"addPageNotification" object:nil];
}

- (void)addPage:(NSNotification*)notification {
    [MyInterfaceController addPageWithPresentingController:self requestingInterfaceController:notification.object];
}