使用网络视图下载文件

Downloading a file using web view

在一个项目中,我想在 Web 视图中加载的 http 页面中下载 mp3 文件。下载的文件可以通过 phone 驱动器或保管箱等应用程序打开。

当用户在 Web 视图中单击 link 时,它应该将其下载到 iphone。

在服务器端,mp3 文件位于 webroot 之外。所以,下载的 link 类似于 "download.php?id=554"

有人可以帮我解决这个问题吗? 我想知道有没有办法实现这一目标。谢谢

编辑

我添加了这个代表

func webView(webView: UIWebView!, shouldStartLoadWithRequest request: NSURLRequest!, navigationType: UIWebViewNavigationType) -> Bool {

        var urlm = request.URL.absoluteURL?.absoluteString

        if urlm?.rangeOfString("filename") != nil{

            print(urlm)

            //code to download (I NEED IT TOO) 

            return false
        }


    return true
    }

但是还是不知道怎么下载?

我没有得到你的实际要求,但你可以使用下面的代码从 URL 下载文件。

NSString *stringURL = @"http://www.somewhere.com/Untitled.mp3";
NSURL  *url = [NSURL URLWithString:stringURL];
NSData *urlData = [NSData dataWithContentsOfURL:url];

当您在网页上按 links 时,您可以从 UIWebView 委托方法

获取 mp3 文件 url(从 NSURLRequest 对象读取)
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
{
    return NO;
}

在 Swift、

中创建 UIWebView
override func viewDidLoad() {
    super.viewDidLoad()
    let webV:UIWebView = UIWebView(frame: CGRectMake(0, 0, UIScreen.mainScreen().bounds.width, UIScreen.mainScreen().bounds.height))
    webV.loadRequest(NSURLRequest(URL: NSURL(string: "http://www.somewhere.com")))
    webV.delegate = self;
    self.view.addSubview(webV)
}

当用户点击网页中的link时,UIWebView会自动调用"shouldStartLoadWithRequest"方法,使用下面的代码下载文件

func webView(webView: UIWebView!,
shouldStartLoadWithRequest request: NSURLRequest!,
navigationType navigationType: UIWebViewNavigationType) -> Bool {
    println("Redirecting URL = \(request.URL)")

    //check if this is a mp3 file url and download
    if(mp3 file)
    {
        let request:NSURLRequest = NSURLRequest(request.URL)
        let queue:NSOperationQueue = NSOperationQueue()
        NSURLConnection.sendAsynchronousRequest(request, queue: queue, completionHandler:{ (response: NSURLResponse!, mp3Data: NSData!, error: NSError!) -> Void in
            let documentsPath : AnyObject = NSSearchPathForDirectoriesInDomains(.DocumentDirectory,.UserDomainMask,true)[0]
            let destinationPath:NSString = documentsPath.stringByAppendingString("/Untitled.mp3")
            mp3Data.writeToFile(destinationPath, atomically: true)

            return false
    })
    return true
}

希望对您有所帮助

为了能够检测来自 link 的下载,您需要首先检查 shouldStartLoadWithRequest 中的请求和导航类型。

您需要检查一些内容,请求 HTTPMethod 将是 POST,导航类型也将是 UIWebViewNavigationTypeFormSubmittedUIWebViewNavigationTypeFormResubmittedUIWebViewNavigationTypeLinkClicked。您还需要解析请求 URL 的查询字符串,它将有一个 response-content-dispositionattachmentdl 键,如果有,则它是文件下载。然后您需要为请求创建一个 NSURLConnection 并启动它,然后在 Web 视图委托中 return NO

以下是我在我的应用程序中检查下载的方式。 (进入 shouldStartLoadWithRequest

NSDictionary *dict = [url parseQueryString];

    if (([[request.HTTPMethod uppercaseString] isEqualToString:@"POST"] &&
        (navigationType == UIWebViewNavigationTypeFormSubmitted ||
         navigationType == UIWebViewNavigationTypeFormResubmitted ||
         navigationType == UIWebViewNavigationTypeLinkClicked)) || [[dict objectForKey:@"response-content-disposition"] isEqualToString:@"attachment"] || [[dict objectForKey:@"dl"] boolValue] == YES) {
        NSURLConnection *connection = [NSURLConnection connectionWithRequest:request delegate:self];
        [connection start];
        return NO;
    }

然后您需要添加 NSURLConnection 委托方法 didReceiveResponse。我检查 header 字段中的一些键,然后如果它们通过,您可以开始下载,或者如果结果不是下载,则让 Web 视图继续加载。 (进入 didReceiveResponse

    if (urlResponse.allHeaderFields[@"Content-Disposition"] ||
                 ([[urlResponse.allHeaderFields[@"Content-Type"] lowercaseString] containsString:@"text/html;"] == NO &&
                  [[urlResponse.allHeaderFields[@"Content-Type"] lowercaseString] containsString:@"charset=utf-8"] == NO )) {
                      // Start a download with NSURLSession with response.URL and connection.currentRequest
            }
            else {
                [self.webView loadRequest:connection.currentRequest];
                [connection cancel];
            }

SwiftHTTP (https://github.com/daltoniam/swiftHTTP) 让我成为可能!

就是这么简单我的朋友,

NSString *stringURL = @"http://www.somewhere.com/thefile.png";
NSURL  *url = [NSURL URLWithString:stringURL];
NSData *urlData = [NSData dataWithContentsOfURL:url];
if ( urlData )
{
  NSArray       *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
  NSString  *documentsDirectory = [paths objectAtIndex:0];  

  NSString  *filePath = [NSString stringWithFormat:@"%@/%@", documentsDirectory,@"filename.png"];
  [urlData writeToFile:filePath atomically:YES];
}

建议在单独的线程中执行代码。

对于大量下载:

-(IBAction) downloadButtonPressed:(id)sender;{
    //download the file in a seperate thread.
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        NSLog(@"Downloading Started");
        NSString *urlToDownload = @"http://www.somewhere.com/thefile.png";
        NSURL  *url = [NSURL URLWithString:urlToDownload];
        NSData *urlData = [NSData dataWithContentsOfURL:url];
        if ( urlData )
        {
            NSArray       *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
            NSString  *documentsDirectory = [paths objectAtIndex:0];

            NSString  *filePath = [NSString stringWithFormat:@"%@/%@", documentsDirectory,@"filename.png"];

            //saving is done on main thread
            dispatch_async(dispatch_get_main_queue(), ^{
                [urlData writeToFile:filePath atomically:YES];
                NSLog(@"File Saved !");
            });
        }

    });

}