【iOS开发】WKWebView学习笔记(2)-WKNavigationDelegate

UIWebViewDelegate有以下几个代理方法。相对于WKWebView的delegate来说很少。相信小伙伴们通过字面意思都可以知道下面方法是做什么的。UIWebViewDelegate是用来监控页面加载进度和结果的。

UIWebViewNavigationType{
UIWebViewNavigationTypeLinkClicked,点击链接
UIWebViewNavigationTypeFormSubmitted,提交表单
UIWebViewNavigationTypeBackForward,点击前进或返回按钮
UIWebViewNavigationTypeReload,点击重新加载按钮
UIWebViewNavigationTypeFormResubmitted,重复提交表单
UIWebViewNavigationTypeOther,发生其它行为
}
  __TVOS_PROHIBITED @protocol UIWebViewDelegate <NSObject>
    @optional
//询问是否允许加载页面请求。UIWebViewNavigationType是个枚举。 可以通过判断不同的枚举值拿到事件,进行操作。
    - (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType;
//页面开始加载
    - (void)webViewDidStartLoad:(UIWebView *)webView;
//页面加载完成
    - (void)webViewDidFinishLoad:(UIWebView *)webView;
//页面加载失败
    - (void)webView:(UIWebView *)webView didFailLoadWithError:(nullable NSError *)error;

    @end

接下来看看WKNavigationDelegate,它将UIWebViewDelegate细化,可以监控加载进度,服务器跳转、身份认证等。

@protocol WKNavigationDelegate <NSObject>

@optional
//请求之前,决定是否要跳转:用户点击网页上的链接,需要打开新页面时,将先调用这个方法。
- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler;
//接收到相应数据后,决定是否跳转
- (void)webView:(WKWebView *)webView decidePolicyForNavigationResponse:(WKNavigationResponse *)navigationResponse decisionHandler:(void (^)(WKNavigationResponsePolicy))decisionHandler;
//页面开始加载时调用
- (void)webView:(WKWebView *)webView didStartProvisionalNavigation:(null_unspecified WKNavigation *)navigation;
// 主机地址被重定向时调用
- (void)webView:(WKWebView *)webView didReceiveServerRedirectForProvisionalNavigation:(null_unspecified WKNavigation *)navigation;
// 页面加载失败时调用
- (void)webView:(WKWebView *)webView didFailProvisionalNavigation:(null_unspecified WKNavigation *)navigation withError:(NSError *)error;
// 当内容开始返回时调用
- (void)webView:(WKWebView *)webView didCommitNavigation:(null_unspecified WKNavigation *)navigation;
// 页面加载完毕时调用
- (void)webView:(WKWebView *)webView didFinishNavigation:(null_unspecified WKNavigation *)navigation;
//跳转失败时调用
- (void)webView:(WKWebView *)webView didFailNavigation:(null_unspecified WKNavigation *)navigation withError:(NSError *)error;
// 如果需要证书验证,与使用AFN进行HTTPS证书验证是一样的
- (void)webView:(WKWebView *)webView didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disposition, NSURLCredential *__nullable credential))completionHandler;
//9.0才能使用,web内容处理中断时会触发
- (void)webViewWebContentProcessDidTerminate:(WKWebView *)webView NS_AVAILABLE(10_11, 9_0);

@end

按照上面代理方法的顺序,每个内部都打印数字.第一个打印1,第二个打印2,第三个打印3等等。

     WKWebView *web = [[WKWebView alloc] initWithFrame:self.view.bounds];
     [self.view addSubview:web];
      web.navigationDelegate = self;
    [web loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.baidu.com"]]];

界面加载出来,其打印结果:

Snip20160902_6.png

这两个回调要这么写。

- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler{
    
//    WKNavigationActionPolicyCancel,
//    WKNavigationActionPolicyAllow,
//    navigationAction.sourceFrame;
//    navigationAction.targetFrame;
//        navigationAction.request;
    if (navigationAction.navigationType == WKNavigationTypeLinkActivated){
        decisionHandler(WKNavigationActionPolicyCancel);
    }else{
        decisionHandler(WKNavigationActionPolicyAllow);
    }
  NSLog(@"1");
//接收到相应后,决定是否跳转
- (void)webView:(WKWebView *)webView decidePolicyForNavigationResponse:(WKNavigationResponse *)navigationResponse decisionHandler:(void (^)(WKNavigationResponsePolicy))decisionHandler{
    if (!navigationResponse.isForMainFrame){
        decisionHandler(WKNavigationResponsePolicyCancel);
    }else{
        decisionHandler(WKNavigationResponsePolicyAllow);
    }
    NSLog(@"2");

}
}

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