XCode webview 连接/服务器错误处理

XCode webview connection/server error handling

提问by Dave

All,

全部，

I am fairly new to XCode and am trying to get a handle on how to best deal with connection issues when trying to use a WebView. I know there are related questions on SO, but none seem to offer complete solutions. I have the following code, but it seems a little inefficient. Hopefully, someone can help me refactor it down to a point where it can be usable anywhere that a UIWebView is called.

我对 XCode 相当陌生，并且正在尝试了解如何在尝试使用 WebView 时最好地处理连接问题。我知道有关于 SO 的相关问题，但似乎没有一个提供完整的解决方案。我有以下代码，但它似乎有点低效。希望有人可以帮助我将其重构到可以在调用 UIWebView 的任何地方使用的程度。

NOTE: Please ignore memory issues for now. I realize that has to be added as well.

注意：请暂时忽略内存问题。我意识到也必须添加。

- (void)viewDidLoad {
    [webView setDelegate:self];

    NSString *urlAddress = @"http://www.somesite.com/somepage";
    NSURL *url = [NSURL URLWithString:urlAddress];
    NSURLRequest *urlRequest = [NSURLRequest requestWithURL:url];

    NSURLConnection *urlConnection = [[NSURLConnection alloc] initWithRequest:urlRequest delegate:self];

    [super viewDidLoad];
}

// Check for URLConnection failure
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
    UIAlertView *connectionError = [[UIAlertView alloc] initWithTitle:@"Connection error" message:@"Error connecting to page.  Please check your 3G and/or Wifi settings." delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil]; 
    [connectionError show];
    webView.hidden = true;
}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {

    NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;

    //Check for server error
    if ([httpResponse statusCode] >= 400) {
        UIAlertView *serverError = [[UIAlertView alloc] initWithTitle:@"Server error" message:@"Error connecting to page.  If error persists, please contact support." delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil]; 
        [serverError show];
        webView.hidden = true;

    //Otherwise load webView
    } else {
        // Redundant code
        NSString *urlAddress = @"http://somesite.com/somepage";
        NSURL *url = [NSURL URLWithString:urlAddress];
        NSURLRequest *urlRequest = [NSURLRequest requestWithURL:url];

        [webView loadRequest:urlRequest];
        webView.hidden = false;
    }
}

// Seems redundant since we are already checking the URLConnection
- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error {

    UIAlertView *connectionError = [[UIAlertView alloc] initWithTitle:@"Connection error" message:@"Error connecting to page.  Please check your 3G and/or Wifi settings." delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil]; 
    [connectionError show];
}

I guess what I'm wondering is, are there any shortcuts to achieve the desired functionality? Can I somehow access the URLResponse via the WebView directly? Does a nil value for the URLConnection or UIWebView imply connection errors without having to explicitly check for them? Is there an easier way to pass the URLRequest down into the delegate methods so it doesn't have be recreated twice?

我想我想知道的是，是否有任何捷径可以实现所需的功能？我可以以某种方式直接通过 WebView 访问 URLResponse 吗？URLConnection 或 UIWebView 的 nil 值是否意味着连接错误而无需明确检查它们？有没有更简单的方法将 URLRequest 传递给委托方法，这样它就不会被重新创建两次？

Thanks in advance!

提前致谢！

回答by Bart Schoon

- (void)viewDidLoad {
    webView = [[UIWebView alloc]init];
    [webView setDelegate:self];
    [webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://yourUrl.com"]]]
    [super viewDidLoad];
}

#pragma mark UIWebView delegate methods
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType{
    //read your request here
    //before the webview will load your request
    return YES;
}
- (void)webViewDidStartLoad:(UIWebView *)webView{
    //access your request
    webView.request;
}
- (void)webViewDidFinishLoad:(UIWebView *)webView{
    //access your request 
    webView.request;    
}
- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error{
    NSLog(@"could not load the website caused by error: %@", error);
}
-(void)dealloc{
[webView release];
[super dealloc];
}

You can load the webpage with NSURLRequest directly into your webview. With the delegate callback methods you can change the behavior of your webview.

您可以将带有 NSURLRequest 的网页直接加载到您的 webview 中。使用委托回调方法，您可以更改 web 视图的行为。

With this piece of code you should get it done.

使用这段代码，您应该可以完成。