在不同的viewControllers中使用相同的UIWebView [英] Using the same UIWebView across different viewControllers

问题描述

TL; DR：我需要实现一个在多个ViewControllers之间共享的单例UIWebVIew。这个问题包含到目前为止的所有方法。

TL;DR: I need to implement a singleton UIWebVIew that's shared across multiple ViewControllers. The question contains all of my approaches so far.

appDelegate：

@property (strong, nonatomic) UIWebView *singleWebView;

firstViewController：

@property (weak, nonatomic) IBOutlet UIWebView *webView;

- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear: animated];
    NSLog(@"Removing webview from the first VC");

    [self.webView removeFromSuperview];
    self.webView.delegate = nil;

    AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
    appDelegate.singleWebView = self.webView;

    self.webView = nil;
}

- (BOOL)webView:(UIWebView*)webView shouldStartLoadWithRequest:(NSURLRequest*)request navigationType:(UIWebViewNavigationType)navigationType {
    NSURL *URL = [request URL];

    if ([[URL absoluteString] isEqualToString:@"myapp://postsShow"]) {
        [self performSegueWithIdentifier:@"postsShowSegue" sender:self];
        return false;
    }
    return true;
}

PostsShowViewController

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

    AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
    [self.viewContainer addSubview: appDelegate.singleWebView];
}

在第一个视图控制器中，我加载了我的单页应用，显示了首先列出帖子。然后，用户查看其中一个帖子，他将被重定向到第二个视图控制器。我想重用第二个ViewController中第一个ViewController中使用的UIWebView，所以我不必重新加载网页。

In the first view controller, I load my single page app, which shows a list of posts first. Then, the user views one of the posts and he will be redirected to the second View Controller. I want to reuse the UIWebView that was used in the first ViewController in the second ViewController so I don't have to reload the webpage.

问题是，在 addSubview 之后，似乎没有加载UIWebView。我只看到我用作容器的 UIView 。如果你能给我一些调试点，那将非常有帮助。

The problem is that, after addSubview the UIWebView doesn't seem to be loaded. I only see a UIView that I use as a container. It would be really helpful if you could give me some debugging points.

推荐答案

我终于想通了。即使我从 FirstViewController 中删除​​ UIWebView 实例后，保留计数始终为2。我从故事板中删除了 UIWebView ，并在加载 firstViewController 时以编程方式创建它。我把其他一切都保留了下来。最后我可以开始重用 webView 。

I finally figured out. The retain count was always 2, even after I removed the UIWebView instance from the FirstViewController. I removed the UIWebView from the storyboard and created it programmatically when the firstViewController was loaded. I left everything else the same. Finally I could start reusing the webView.

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