iphone - 从iphone sdk中的uiwebview下载文件

Question

有什么方法可以从 UIWebView 下载文件吗？我在 IBAction 事件中使用了这段代码

- (IBAction)saveFile:(id)sender {
// Get the URL of the loaded ressource
NSURL *theRessourcesURL = [[self.webDisplay request] URL];
NSString *fileExtension = [theRessourcesURL pathExtension];

if ([fileExtension isEqualToString:@"png"] || [fileExtension isEqualToString:@"jpg"] || 
    [fileExtension isEqualToString:@"pdf"] || [fileExtension isEqualToString:@"html"]) {
    // Get the filename of the loaded ressource form the UIWebView's request URL
    NSString *filename = [theRessourcesURL lastPathComponent];
    NSLog(@"Filename: %@", filename);
    // Get the path to the App's Documents directory
    NSString *docPath = [self documentsDirectoryPath];
    // Combine the filename and the path to the documents dir into the full path
    NSString *pathToDownloadTo = [NSString stringWithFormat:@"%@/%@", docPath, filename];


    // Load the file from the remote server
    NSData *tmp = [NSData dataWithContentsOfURL:theRessourcesURL];
    // Save the loaded data if loaded successfully
    if (tmp != nil) {
        NSError *error = nil;
        // Write the contents of our tmp object into a file
        [tmp writeToFile:pathToDownloadTo options:NSDataWritingAtomic error:&error];
        if (error != nil) {
            NSLog(@"Failed to save the file: %@", [error description]);
        } else {
            // Display an UIAlertView that shows the users we saved the file :)
            UIAlertView *filenameAlert = [[UIAlertView alloc] initWithTitle:@"File saved" message:[NSString stringWithFormat:@"The file %@ has been saved.", filename] delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
            [filenameAlert show];
            [filenameAlert release];
        }
    } else {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Warning" 
                                                        message:@"File could not be loaded" 
                                                       delegate:nil 
                                              cancelButtonTitle:@"Okay" 
                                              otherButtonTitles:nil];
        [alert show];
        [alert release];
        // File could notbe loaded -> handle errors
    }
} else {
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Warning" 
                                                    message:@"File type not supported" 
                                                   delegate:nil 
                                          cancelButtonTitle:@"Okay" 
                                          otherButtonTitles:nil];
    [alert show];
    [alert release];
    // File type not supported
}

}此代码在 UIWebView 中打开文件，我想下载该文件，当我按下按钮时，打开的文件将被保存。但我希望我的 UIWebView 表现得像普通浏览器一样，当下载链接出现在其中并且用户按下它时，UIWebView 显示带有选项的对话框，如果用户按下则打开它或保存它保存文件自动保存，如果用户按下打开它，文件应该在 UIWebView 中打开。

Answer 1

您可以在 UIWebViewDelegate 中提供 webView:shouldStartLoadWithRequest，这样每次用户要转到另一个网页时，您都有机会检查链接是什么看起来像:

 - (BOOL)webView:(UIWebView*)webView shouldStartLoadWithRequest:(NSURLRequest*)request navigationType:(UIWebViewNavigationType)navigationType {

     if ([[[request URL] scheme] isEqual:@"http"] && 
         [[[request URL] pathExtension]...])
            <your download/save code here>
            return NO;  //-- no need to follow the link
     }
     return YES; //-- otherwise, follow the link
  }