iOS8以后，苹果推出了新框架Webkit，提供了替换UIWebView的组件WKWebView。其优点速度更快，占用内存更少，简而言之，WKWebView是App内部加载网页的最佳选择。

WKNavigationDelegate代理方法

#pragma mark -----WKNavigationDelegate---------
// 页面开始加载时调用
- (void)webView:(WKWebView *)webView didStartProvisionalNavigation:(WKNavigation *)navigation {
    NSLog(@"页面开始加载时调用");
}

// 当内容开始返回时调用
- (void)webView:(WKWebView *)webView didCommitNavigation:(WKNavigation *)navigation {
    NSLog(@"当内容开始返回时调用");
}

// 页面加载完成之后调用
- (void)webView:(WKWebView *)webView didFinishNavigation:(WKNavigation *)navigation {
    NSLog(@"页面加载完成之后调用");
}

// 页面加载失败时调用
- (void)webView:(WKWebView *)webView didFailProvisionalNavigation:(WKNavigation *)navigation {
    NSLog(@"页面加载失败时调用");
}

// 页面导航错误时调用
- (void)webView:(WKWebView *)webView didFailNavigation:(null_unspecified WKNavigation *)navigation withError:(nonnull NSError *)error {
    NSLog(@"页面导航错误时调用");
}

//页面终结时调用
- (void)webViewWebContentProcessDidTerminate:(WKWebView *)webView {
    
    NSLog(@"页面终结时调用");
}

// 接收到服务器跳转请求之后调用
- (void)webView:(WKWebView *)webView didReceiveServerRedirectForProvisionalNavigation:(WKNavigation *)navigation {
    
    NSLog(@"接收到服务器跳转请求之后调用");
}

// 在收到响应后，决定是否跳转
- (void)webView:(WKWebView *)webView decidePolicyForNavigationResponse:(WKNavigationResponse *)navigationResponse decisionHandler:(void (^)(WKNavigationResponsePolicy))decisionHandler {
    
    NSLog(@"在收到响应后，决定是否跳转");
    decisionHandler(WKNavigationResponsePolicyAllow);
}

// 在发送请求之前，决定是否跳转
- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler {
    
    NSLog(@"在发送请求之前，决定是否跳转");
    decisionHandler(WKNavigationActionPolicyAllow);
}

//证书验证处理
- (void)webView:(WKWebView *)webView didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge completionHandler:(nonnull void (^)(NSURLSessionAuthChallengeDisposition, NSURLCredential * _Nullable))completionHandler {

    NSLog(@"证书验证处理");
    // 判断服务器采用的验证方法
    if (challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodServerTrust) {
        // 如果没有错误的情况下 创建一个凭证，并使用证书
        if (challenge.previousFailureCount == 0) {
            NSURLCredential *credential = [NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust];
            completionHandler(NSURLSessionAuthChallengeUseCredential, credential);
        }else {
             //验证失败，取消本次验证
            completionHandler(NSURLSessionAuthChallengeCancelAuthenticationChallenge, nil);
        }
    }else {
        completionHandler(NSURLSessionAuthChallengeCancelAuthenticationChallenge, nil);
        
    }
}

WKUIDelegate代理方法

#pragma mark ----WKUIDelegate协议----

/**
 *  web界面中有弹出警告框时调用
 *
 *  @param webView           实现该代理的webview
 *  @param message           警告框中的内容
 *  @param frame             主窗口
 *  @param completionHandler 警告框消失调用
 */
- (void)webView:(WKWebView *)webView runJavaScriptAlertPanelWithMessage:(NSString *)message initiatedByFrame:(nonnull WKFrameInfo *)frame completionHandler:(nonnull void (^)(void))completionHandler {
    // js 里面的alert实现，如果不实现，网页的alert函数无效
    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"提示"
                                                                             message:message
                                                                      preferredStyle:UIAlertControllerStyleAlert];
    [alertController addAction:[UIAlertAction actionWithTitle:@"确定"
                                                        style:UIAlertActionStyleCancel
                                                      handler:^(UIAlertAction *action) {
                                                          completionHandler();
                                                      }]];
    
    [self presentViewController:alertController animated:YES completion:^{}];
    
}


/**
 web界面中有弹出选择框

 @param webView 实现该代理的webview
 @param message 警告框中的内容
 @param frame 主窗口
 @param completionHandler 警告框消失调用 得到选择结果
 */
- (void)webView:(WKWebView *)webView runJavaScriptConfirmPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(BOOL))completionHandler {
    //  js 里面的alert实现，如果不实现，网页的alert函数无效  ,
    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"提示"
                                                                             message:message
                                                                      preferredStyle:UIAlertControllerStyleAlert];
    [alertController addAction:[UIAlertAction actionWithTitle:@"确定"
                                                        style:UIAlertActionStyleDefault
                                                      handler:^(UIAlertAction *action) {
                                                          completionHandler(YES);
                                                      }]];
    [alertController addAction:[UIAlertAction actionWithTitle:@"取消"
                                                        style:UIAlertActionStyleCancel
                                                      handler:^(UIAlertAction *action){
                                                          completionHandler(NO);
                                                      }]];
    
    [self presentViewController:alertController animated:YES completion:^{}];
    
}


/**
 web界面中有弹出输入框

 @param webView 实现该代理的webview
 @param prompt 输入框的提示内容
 @param defaultText 默认的填写内容
 @param frame 主窗口
 @param completionHandler 警告框消失调用 得到输入内容
 */
- (void)webView:(WKWebView *)webView runJavaScriptTextInputPanelWithPrompt:(NSString *)prompt defaultText:(nullable NSString *)defaultText initiatedByFrame:(nonnull WKFrameInfo *)frame completionHandler:(nonnull void (^)(NSString * _Nullable))completionHandler {
    
    UIAlertController *alert = [UIAlertController alertControllerWithTitle:prompt message:nil preferredStyle:UIAlertControllerStyleAlert];
    
    [alert addTextFieldWithConfigurationHandler:^(UITextField * _Nonnull textField) {
        textField.textColor = [UIColor blackColor];
        textField.text = defaultText;
    }];
    
    [alert addAction:[UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        completionHandler([[alert.textFields lastObject] text]);
    }]];
    
    [self presentViewController:alert animated:YES completion:NULL];
}

添加进度条UIProgressView

需要通过KVO监听进行实现，初始化页面时添加监听事件

//初始化页面时添加监听事件
[_webView addObserver:self forKeyPath:@"estimatedProgress" options:NSKeyValueObservingOptionNew context:nil];
[_webView addObserver:self forKeyPath:@"loading" options:NSKeyValueObservingOptionNew context:nil];
[_webView addObserver:self forKeyPath:@"title" options:NSKeyValueObservingOptionNew context:nil];

// 计算wkWebView进度条
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
    
    if ([keyPath isEqualToString:@"estimatedProgress"]) {
        NSLog(@"estimatedProgress");
        CGFloat newprogress = [[change objectForKey:NSKeyValueChangeNewKey] doubleValue];
        if (newprogress == 1) {
            self.progressView.hidden = YES;
            [self.progressView setProgress:0 animated:NO];
        }else {
            self.progressView.hidden = NO;
            [self.progressView setProgress:newprogress animated:YES];
        }
    }else if ([keyPath isEqualToString:@"title"]) {
        NSLog(@"title");
        self.title = self.webView.title;
    }else if ([keyPath isEqualToString:@"loading"]) {
        
        NSLog(@"loading");
    }
}

页面代码示例 下载Demo

#import <WebViewController.h>
#import <WebKit/WebKit.h>

@interface WebViewController ()<WKNavigationDelegate, WKUIDelegate>

@property (nonatomic, strong) WKWebView *webView;
@property (strong, nonatomic) UIProgressView *progressView;

@end

@implementation WebViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    [self.webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:self.requestUrlStr]]];
    // Do any additional setup after loading the view.
}

#pragma mark -----WKNavigationDelegate---------
// 页面开始加载时调用
- (void)webView:(WKWebView *)webView didStartProvisionalNavigation:(WKNavigation *)navigation {
    NSLog(@"页面开始加载时调用");
}
// 当内容开始返回时调用
- (void)webView:(WKWebView *)webView didCommitNavigation:(WKNavigation *)navigation {
    NSLog(@"当内容开始返回时调用");
}
// 页面加载完成之后调用
- (void)webView:(WKWebView *)webView didFinishNavigation:(WKNavigation *)navigation {
    NSLog(@"页面加载完成之后调用");
}
// 页面加载失败时调用
- (void)webView:(WKWebView *)webView didFailProvisionalNavigation:(WKNavigation *)navigation {
    NSLog(@"页面加载失败时调用");
}
// 页面导航错误时调用
- (void)webView:(WKWebView *)webView didFailNavigation:(null_unspecified WKNavigation *)navigation withError:(nonnull NSError *)error {
    NSLog(@"页面导航错误时调用");
}
//页面终结时调用
- (void)webViewWebContentProcessDidTerminate:(WKWebView *)webView {
    
    NSLog(@"页面终结时调用");
}
// 接收到服务器跳转请求之后调用
- (void)webView:(WKWebView *)webView didReceiveServerRedirectForProvisionalNavigation:(WKNavigation *)navigation {
    
    NSLog(@"接收到服务器跳转请求之后调用");
}
//证书验证处理 基本上无需添加此代理方法
- (void)webView:(WKWebView *)webView didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge completionHandler:(nonnull void (^)(NSURLSessionAuthChallengeDisposition, NSURLCredential * _Nullable))completionHandler {

    NSLog(@"证书验证处理");
    // 判断服务器采用的验证方法
    if (challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodServerTrust) {
        // 如果没有错误的情况下 创建一个凭证，并使用证书
        if (challenge.previousFailureCount == 0) {
            NSURLCredential *credential = [NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust];
            completionHandler(NSURLSessionAuthChallengeUseCredential, credential);
        }else {
             //验证失败，取消本次验证
            completionHandler(NSURLSessionAuthChallengeCancelAuthenticationChallenge, nil);
        }
    }else {
        completionHandler(NSURLSessionAuthChallengeCancelAuthenticationChallenge, nil);
        
    }
}

// 在收到响应后，决定是否跳转
- (void)webView:(WKWebView *)webView decidePolicyForNavigationResponse:(WKNavigationResponse *)navigationResponse decisionHandler:(void (^)(WKNavigationResponsePolicy))decisionHandler {
    
    NSLog(@"在收到响应后，决定是否跳转");
    decisionHandler(WKNavigationResponsePolicyAllow);
}
// 在发送请求之前，决定是否跳转
- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler {
    
    NSLog(@"在发送请求之前，决定是否跳转");
    decisionHandler(WKNavigationActionPolicyAllow);
}
// 计算wkWebView进度条
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
    
    if ([keyPath isEqualToString:@"estimatedProgress"]) {
        NSLog(@"estimatedProgress");
        CGFloat newprogress = [[change objectForKey:NSKeyValueChangeNewKey] doubleValue];
        if (newprogress == 1) {
            self.progressView.hidden = YES;
            [self.progressView setProgress:0 animated:NO];
        }else {
            self.progressView.hidden = NO;
            [self.progressView setProgress:newprogress animated:YES];
        }
    }else if ([keyPath isEqualToString:@"title"]) {
        NSLog(@"title");
        self.title = self.webView.title;
    }else if ([keyPath isEqualToString:@"loading"]) {
        
        NSLog(@"loading");
    }
}

#pragma mark ----WKUIDelegate协议----

/**
 *  web界面中有弹出警告框时调用
 *
 *  @param webView           实现该代理的webview
 *  @param message           警告框中的内容
 *  @param frame             主窗口
 *  @param completionHandler 警告框消失调用
 */
- (void)webView:(WKWebView *)webView runJavaScriptAlertPanelWithMessage:(NSString *)message initiatedByFrame:(nonnull WKFrameInfo *)frame completionHandler:(nonnull void (^)(void))completionHandler {
    // js 里面的alert实现，如果不实现，网页的alert函数无效
    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"提示"
                                                                             message:message
                                                                      preferredStyle:UIAlertControllerStyleAlert];
    [alertController addAction:[UIAlertAction actionWithTitle:@"确定"
                                                        style:UIAlertActionStyleCancel
                                                      handler:^(UIAlertAction *action) {
                                                          completionHandler();
                                                      }]];
    
    [self presentViewController:alertController animated:YES completion:^{}];
    
}


/**
 web界面中有弹出选择框

 @param webView 实现该代理的webview
 @param message 警告框中的内容
 @param frame 主窗口
 @param completionHandler 警告框消失调用 得到选择结果
 */
- (void)webView:(WKWebView *)webView runJavaScriptConfirmPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(BOOL))completionHandler {
    //  js 里面的alert实现，如果不实现，网页的alert函数无效  ,
    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"提示"
                                                                             message:message
                                                                      preferredStyle:UIAlertControllerStyleAlert];
    [alertController addAction:[UIAlertAction actionWithTitle:@"确定"
                                                        style:UIAlertActionStyleDefault
                                                      handler:^(UIAlertAction *action) {
                                                          completionHandler(YES);
                                                      }]];
    [alertController addAction:[UIAlertAction actionWithTitle:@"取消"
                                                        style:UIAlertActionStyleCancel
                                                      handler:^(UIAlertAction *action){
                                                          completionHandler(NO);
                                                      }]];
    
    [self presentViewController:alertController animated:YES completion:^{}];
    
}


/**
 web界面中有弹出输入框

 @param webView 实现该代理的webview
 @param prompt 输入框的提示内容
 @param defaultText 默认的填写内容
 @param frame 主窗口
 @param completionHandler 警告框消失调用 得到输入内容
 */
- (void)webView:(WKWebView *)webView runJavaScriptTextInputPanelWithPrompt:(NSString *)prompt defaultText:(nullable NSString *)defaultText initiatedByFrame:(nonnull WKFrameInfo *)frame completionHandler:(nonnull void (^)(NSString * _Nullable))completionHandler {
    
    UIAlertController *alert = [UIAlertController alertControllerWithTitle:prompt message:nil preferredStyle:UIAlertControllerStyleAlert];
    
    [alert addTextFieldWithConfigurationHandler:^(UITextField * _Nonnull textField) {
        textField.textColor = [UIColor blackColor];
        textField.text = defaultText;
    }];
    
    [alert addAction:[UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        completionHandler([[alert.textFields lastObject] text]);
    }]];
    
    [self presentViewController:alert animated:YES completion:NULL];
}


// 记得取消监听
- (void)dealloc {
    [self.webView removeObserver:self forKeyPath:@"estimatedProgress"];
    [self.webView removeObserver:self forKeyPath:@"loading"];//移除kvo
    [self.webView removeObserver:self forKeyPath:@"title"];
}

/**
 清理缓存
 */
- (void)clearWbCache {
    
    [[NSURLCache sharedURLCache] removeAllCachedResponses];
    [[NSURLCache sharedURLCache] setDiskCapacity:0];
    [[NSURLCache sharedURLCache] setMemoryCapacity:0];
}

- (WKWebView *)webView {
    
    if (!_webView) {
        _webView = [[WKWebView alloc] initWithFrame:self.view.frame];
        _webView.navigationDelegate = self;
        _webView.UIDelegate = self;
        [_webView addObserver:self forKeyPath:@"estimatedProgress" options:NSKeyValueObservingOptionNew context:nil];
        [_webView addObserver:self forKeyPath:@"loading" options:NSKeyValueObservingOptionNew context:nil];
        [_webView addObserver:self forKeyPath:@"title" options:NSKeyValueObservingOptionNew context:nil];
        [self.view insertSubview:_webView belowSubview:self.progressView];
    }
    return _webView;
}

- (UIProgressView *)progressView {
    
    if (!_progressView) {
        
        _progressView = [[UIProgressView alloc] initWithFrame:CGRectMake(0, 64, self.view.frame.size.width, 0)];
        self.progressView.tintColor = [UIColor orangeColor];
        self.progressView.trackTintColor = [UIColor clearColor];
        [self.view addSubview:self.progressView];
    }
    return _progressView;
}