基本用法示例

- (void)viewDidLoad{  [super viewDidLoad];  // Do any additional setup after loading the view.  UIWebView * webView = [[UIWebView alloc]initWithFrame:CGRectMake(0, 20, ScreenWidth, ScreenHeight-20)];  // 自动队页面进行缩放以适应屏幕  webView.scalesPageToFit = YES;  webView.userInteractionEnabled = YES;  webView.opaque = YES;  [self.view addSubview:webView];  NSURL * url = [NSURL URLWithString:@"http://www.youku.com"];  NSURLRequest * request = [NSURLRequest requestWithURL:url];  [webView loadRequest:request];//  NSString * myHT = @"优酷";//  [webView loadHTMLString:myHT baseURL:url];/*  [webView goBack];    // 返回  [webView goForward];   // 前往  [webView reload];  [webView stopLoading]; */  webView.delegate = self;  //移除滚动后的外边阴影  UIScrollView *scrollView = webView.scrollView;  for (int i = 0; i < scrollView.subviews.count ; i++) {    UIView *view = [scrollView.subviews objectAtIndex:i];    if ([view isKindOfClass:[UIImageView class]]) {      view.hidden = YES ;    }  }}#pragma mark - UIWebViewDelegate- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType{  /**   * typedef NS_ENUM(NSInteger, UIWebViewNavigationType) {   * UIWebViewNavigationTypeLinkClicked,   * UIWebViewNavigationTypeFormSubmitted,   * UIWebViewNavigationTypeBackForward,   * UIWebViewNavigationTypeReload,   * UIWebViewNavigationTypeFormResubmitted,   * UIWebViewNavigationTypeOther   };   */  NSLOG_FUNCTION;  return YES;}// 开始加载- (void)webViewDidStartLoad:(UIWebView *)webView{  NSLOG_FUNCTION;}// 完成加载- (void)webViewDidFinishLoad:(UIWebView *)webView{  NSLOG_FUNCTION;}// 加载失败,弹出错误提示- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error{  UIAlertView *alterview = [[UIAlertView alloc] initWithTitle:@"" message:[error localizedDescription]                            delegate:nil cancelButtonTitle:nil otherButtonTitles:@"OK", nil];  [alterview show];  [alterview release];  NSLOG_FUNCTION;}

以下是关于它的一些使用技巧：

1.让网页适应手机屏幕宽度

如果用UIWebView显示一些pc站的网页，会发现网页会超出屏幕，显得很不好看，这时可以在webViewDidFinishLoad这个代理里面通过js添加一个meta：

- (void)webViewDidFinishLoad:(UIWebView *)webView{  NSString *meta = [NSString stringWithFormat:@"document.getElementsByName(/"viewport/")[0].content = /"width=%f, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no/"", IPHONE_WIDTH];  [webView stringByEvaluatingJavaScriptFromString:meta];}

注意：使用这个方法时要把UIWebView的scalesPageToFit设成NO

webView.scalesPageToFit = NO;

2.为网页中的图片添加点击事件，当点击图片时放大查看

思路是给每一个img标签添加onclick事件，在事件中把img的src属性封装成一个特殊的url，然后进行拦截

如果是通过loadHTMLString去加载网页的话，可以执行下面一句进行替换：

代码如下：

    html = [html stringByReplacingOccurrencesOfString:@"<img " withString:@"<img onclick=/"window.location.href=('http://src.'+this.src);/" "];

如果是通过loadRequest，那就要再webViewDidFinishLoad中执行以下JS：

  NSString *js = @"var imgs = document.getElementsByTagName(/"img/");"  "for(var i=0;i<imgs.length;i++){"  "  var img = imgs[i];"  "  img.onclick=function(){window.location.href=('http://src.'+this.src);}"  "}";  [webView stringByEvaluatingJavaScriptFromString:js];

然后通过webview的代理方法去拦截，拿到图片的url，之后就可以做各种处理了

- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType{  NSString *url = request.URL.absoluteString;  if ([url hasPrefix:@"http://src."])  {    url = [url stringByReplacingOccurrencesOfString:@"http://src." withString:@""];    // Do something..    return NO;  }  return YES;}

3.为UIWebView添加一个跟随网页滚动的页头

UIWebView里包含一个scrollview，可以向scrollview里添加一个页头以达到跟随网页滚动的效果

CGFloat headerHeight = 36.0f;// 注意：y坐标必须是负数，IPHONE_WIDTH是屏幕宽度UIView *headerView = [[UIView alloc] initWithFrame:CGRectMake(0, -headerHeight, IPHONE_WIDTH, headerHeight)];[_webView.scrollView addSubview:_headerView];// 修改webView的scrollView的contentInset，让顶部留出一点空间UIEdgeInsets edgeInset = _webView.scrollView.contentInset;_webView.scrollView.contentInset = UIEdgeInsetsMake(headerView.frameHeight, edgeInset.left, edgeInset.bottom, edgeInset.right);