Using the same UIWebView across different viewControllers

Question

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];
}

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.

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.

Answer 1

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