使用Webview，我想找到此頁面中的鏈接。DOM何時準備好以及如何枚舉其元素？
-(void)webView:(WebView *)sender didFinishLoadForFrame:(WebFrame *)frame {
DOMDocument *myDOMDocument = [[self.webview mainFrame] DOMDocument];
看起來像一個很好的起點，但我發現WebScriptObject類參考有點神祕。顯然，我不想評估一些Javascript來獲得鏈接。我想直接閱讀DOM。
我怎麼才能找到DOM中的哪些節點是鏈接，並獲取他們指向的地址？
查找圖像
看到walkNodeTree @http://cocoadev.com/wiki/DOMCore
的DOMNodes - 完整的樣品找到圖像節點，得到他們的src和使nsimages
@implementation DDAppDelegate
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification {
[self.webview.mainFrame loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://dominik.pich.info/Home.html"]]];
}
-(void)webView:(WebView *)sender didFinishLoadForFrame:(WebFrame *)frame {
DOMDocument *myDOMDocument = [[self.webview mainFrame] DOMDocument];
NSMutableArray *imgs = [NSMutableArray array];
[self walkNodeTree:myDOMDocument imgsCollected:imgs];
//bad code, demo
NSMutableArray *nsImages = [NSMutableArray array];
for (DOMNode *img in imgs) {
for(int i = 0; i < img.attributes.length; i++) {
DOMNode *attr = [img.attributes item:i];
NSLog(@"%@", attr.nodeName);
if([attr.nodeName.lowercaseString isEqualToString:@"src"]) {
NSString *urlstring = [attr nodeValue];
NSURL *url = [NSURL URLWithString:urlstring relativeToURL:[NSURL URLWithString:@"http://dominik.pich.info/"]];
NSImage *nsimg = [[NSImage alloc] initWithContentsOfURL:url];
if(nsimg)
[nsImages addObject:nsimg];
}
}
}
NSLog(@"%@", nsImages);
}
- (void)walkNodeTree:(DOMNode*)parent imgsCollected:(NSMutableArray*)imgs {
DOMNodeList *nodeList = [parent childNodes];
unsigned i, length = [nodeList length];
for (i = 0; i < length; i++) {
DOMNode *node = [nodeList item:i];
NSLog(@"%@", node.nodeName);
if([node.nodeName.lowercaseString isEqualToString:@"img"]) {
[imgs addObject:node];
}
else {
//recurse
[self walkNodeTree:node imgsCollected:imgs];
}
}
}
@end
我一直在使用xpath規範XPath Introduction
通過將HTML從URL傳遞到NSXMLDocument和t母雞得到我想要的值NSXMLNode'snodesForXPath:error:
在這種情況下，我使用大型機的URL。但任何有效的網址都應該可以。
兩個NSXML類似乎沒有問題解析HTML就像他們做XML
有大量的XPath查詢字符串語法例子，你可以搜索，我發現它是非常容易深入到DOM樹一旦你知道HTML標籤和類語法是什麼。
我已經使用了一個非常簡單的a href在這裏查詢整個頁面。
但我已經加入了一個註釋掉的例子來顯示更多。上述
-(void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
[theWebView setFrameLoadDelegate:self];
NSURL* fileURL = [NSURL URLWithString:@"http://example.com"];
NSURLRequest* request = [NSURLRequest requestWithURL:fileURL];
[[theWebView mainFrame] loadRequest:request];
}
-(void)webView:(WebView *)sender didFinishLoadForFrame:(WebFrame *)frame {
NSError *err_p = nil;
NSXMLDocument * xmlDoc = [[NSXMLDocument alloc] initWithContentsOfURL:[NSURL URLWithString:[theWebView mainFrameURL]]
options:(NSXMLNodePreserveWhitespace|
NSXMLNodePreserveCDATA)
error:&err_p];
if (xmlDoc == nil) {
xmlDoc = [[NSXMLDocument alloc] initWithContentsOfURL:[NSURL URLWithString:[theWebView mainFrameURL]]
options:NSXMLDocumentTidyXML
error:&err_p];
}
NSError * error2;
NSString *xpathQueryTRTest [email protected]"//a";//--query string for all <a href tags
//-- for example 2 --NSString *xpathQueryTRTest [email protected]"//div/p[1]";//--query string for all <a href tags
NSArray *newItemsNodesTRTEST = [xmlDoc nodesForXPath:xpathQueryTRTest error:&error2];//--xpath node results returned in an array
[xmlDoc release];
if (error2)
{
[[NSAlert alertWithError:error2] runModal];
return ;
}
for (NSXMLElement *node in newItemsNodesTRTEST)//--parse the nodes in the array
{
NSLog(@"\nThe Node = %@\nThe node href value = %@", node, [[node attributeForName:@"href"]stringValue]);
//--for example 2 -- NSLog(@"\nThe Node value = %@\n", [node stringValue]);
}
}