iOS 进阶开发将来跳槽用

WKWebView

2018-07-26  本文已影响84人  Cooci_和谐学习_不急不躁

WKWebView是在Apple的WWDC 2014随iOS 8和OS X 10.10出来的,是为了解决UIWebView加载速度慢、占用内存大的问题。

WebKit中更新的WKWebView控件的新特性与使用方法,它很好的解决了UIWebView存在的内存、加载速度等诸多问题。

一、WKWebView新特性

将UIWebViewDelegate与UIWebView重构成了14类与3个协议查看苹果官方文档

二、WebKit框架概览

image

如上图所示,WebKit框架中最核心的类应该属于WKWebView了,这个类专门用来渲染网页视图,其他类和协议都将基于它和服务于它。

三、WKWebView的属性

/// webView的自定义配置
@property (nonatomic,readonly, copy) WKWebViewConfiguration *configuration;
/// 导航代理
@property (nullable, nonatomic, weak)id navigationDelegate;
/// UI代理
@property (nullable, nonatomic, weak)id UIDelegate;
/// 访问过网页历史列表
@property (nonatomic,readonly, strong) WKBackForwardList *backForwardList;

/// 自定义初始化
- (instancetype)initWithFrame:(CGRect)frame configuration:(WKWebViewConfiguration *)configuration NS_DESIGNATED_INITIALIZER;- (nullable instancetype)initWithCoder:(NSCoder *)coder NS_DESIGNATED_INITIALIZER;
/// url加载webView视图
- (nullable WKNavigation *)loadRequest:(NSURLRequest *)request;
/// 文件加载webView视图
- (nullable WKNavigation *)loadFileURL:(NSURL *)URL allowingReadAccessToURL:(NSURL *)readAccessURL API_AVAILABLE(macosx(10.11), ios(9.0));
/// HTMLString字符串加载webView视图
- (nullable WKNavigation *)loadHTMLString:(NSString *)stringbaseURL:(nullable NSURL *)baseURL;
/// NSData数据加载webView视图
- (nullable WKNavigation *)loadData:(NSData *)data MIMEType:(NSString *)MIMEType characterEncodingName:(NSString *)characterEncodingName baseURL:(NSURL *)baseURL API_AVAILABLE(macosx(10.11), ios(9.0));
/// 返回上一个网页节点
- (nullable WKNavigation *)goToBackForwardListItem:(WKBackForwardListItem *)item;

/// 网页的标题
@property (nullable, nonatomic,readonly, copy) NSString *title;
/// 网页的URL地址
@property (nullable, nonatomic,readonly, copy) NSURL *URL;
/// 网页是否正在加载
@property (nonatomic,readonly, getter=isLoading) BOOL loading;
/// 加载的进度 范围为[0, 1]
@property (nonatomic,readonly)double estimatedProgress;
/// 网页链接是否安全
@property (nonatomic,readonly) BOOL hasOnlySecureContent;
/// 证书服务
@property (nonatomic,readonly, nullable) SecTrustRef serverTrust API_AVAILABLE(macosx(10.12), ios(10.0));
/// 是否可以返回
@property (nonatomic,readonly) BOOL canGoBack;
/// 是否可以前进
@property (nonatomic,readonly) BOOL canGoForward;

/// 返回到上一个网页
- (nullable WKNavigation *)goBack;
/// 前进到下一个网页
- (nullable WKNavigation *)goForward;
/// 重新加载
- (nullable WKNavigation *)reload;
/// 忽略缓存 重新加载
- (nullable WKNavigation *)reloadFromOrigin;
/// 停止加载
- (void)stopLoading;
/// 执行JavaScript
- (void)evaluateJavaScript:(NSString *)javaScriptString completionHandler:(void(^ _Nullable)(_Nullableid, NSError * _Nullable error))completionHandler;

/// 是否允许左右滑动,返回-前进操作  默认是NO
@property (nonatomic) BOOL allowsBackForwardNavigationGestures;
/// 自定义代理字符串
@property (nullable, nonatomic, copy) NSString *customUserAgent API_AVAILABLE(macosx(10.11), ios(9.0));
/// 在iOS上默认为NO,标识不允许链接预览
@property (nonatomic) BOOL allowsLinkPreview API_AVAILABLE(macosx(10.11), ios(9.0));
/// 滚动视图
@property (nonatomic,readonly, strong) UIScrollView *scrollView;
/// 是否支持放大手势,默认为NO
@property (nonatomic) BOOL allowsMagnification;
/// 放大因子,默认为1
@property (nonatomic) CGFloat magnification;
/// 据设置的缩放因子来缩放页面,并居中显示结果在指定的点

- (void)setMagnification:(CGFloat)magnification centeredAtPoint:(CGPoint)point;/// 证书列表@property (nonatomic,readonly, copy) NSArray *certificateChain API_DEPRECATED_WITH_REPLACEMENT("serverTrust", macosx(10.11,10.12), ios(9.0,10.0));

四、WKWebView的使用

WKWebView *webView = [[WKWebView alloc] initWithFrame:self.view.bounds];
[webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"https://developer.apple.com/reference/webkit"]]];   
[self.view addSubview:webView];

再WKWebView里面注册供JS调用的方法,是通过WKUserContentController类下面的方法:

- (void)addScriptMessageHandler:(id )scriptMessageHandler name:(NSString *)name;

    // 创建配置
    WKWebViewConfiguration *config = [[WKWebViewConfiguration alloc] init];

    // 创建UserContentController(提供JavaScript向webView发送消息的方法)
    WKUserContentController* userContent = [[WKUserContentController alloc] init];

    // 添加消息处理,注意:self指代的对象需要遵守WKScriptMessageHandler协议,结束时需要移除
    [userContent addScriptMessageHandler:self name:@"NativeMethod"];

    // 将UserConttentController设置到配置文件
    config.userContentController = userContent;

    // 高端的自定义配置创建WKWebView
    WKWebView *webView = [[WKWebView alloc] initWithFrame:[UIScreen mainScreen].bounds configuration:config];
    // 设置访问的
    URLNSURL *url = [NSURL URLWithString:@"https://developer.apple.com/reference/webkit"];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    [webView loadRequest:request];
    [self.view addSubview:webView];

// 实现WKScriptMessageHandler协议方法

- (void)userContentController:(WKUserContentController *)userContentController didReceiveScriptMessage:(WKScriptMessage *)message {

  // 判断是否是调用原生的  
    if([@"NativeMethod" isEqualToString:message.name]) { 
        // 判断message的内容,然后做相应的操作   
        if([@"close" isEqualToString:message.body]) {
          }
     }
}

注意:上面将当前ViewController设置为MessageHandler之后需要在当前ViewController销毁前将其移除,否则会造成内存泄漏。

[self.webView.configuration.userContentController removeScriptMessageHandlerForName:@"NativeMethod"];

五、WKNavigationDelegate代理方法

如果实现了代理方法,一定要在decidePolicyForNavigationActiondecidePolicyForNavigationResponse方法中的回调设置允许跳转。

typedef NS_ENUM(NSInteger, WKNavigationActionPolicy) {

WKNavigationActionPolicyCancel, // 取消跳转

WKNavigationActionPolicyAllow, // 允许跳转

} API_AVAILABLE(macosx(10.10), ios(8.0));

- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void(^)(WKNavigationActionPolicy))decisionHandler {

    NSLog(@"1-------在发送请求之前,决定是否跳转  -->%@",navigationAction.request);

    decisionHandler(WKNavigationActionPolicyAllow);
}

- (void)webView:(WKWebView *)webView didStartProvisionalNavigation:(WKNavigation *)navigation {

    NSLog(@"2-------页面开始加载时调用");
}

- (void)webView:(WKWebView *)webView decidePolicyForNavigationResponse:(WKNavigationResponse *)navigationResponse decisionHandler:(void(^)(WKNavigationResponsePolicy))decisionHandler {

/// 在收到服务器的响应头,根据response相关信息,决定是否跳转。decisionHandler必须调用,来决定是否跳转,参数WKNavigationActionPolicyCancel取消跳转,WKNavigationActionPolicyAllow允许跳转    NSLog(@"3-------在收到响应后,决定是否跳转");

decisionHandler(WKNavigationResponsePolicyAllow);

}

- (void)webView:(WKWebView *)webView didCommitNavigation:(WKNavigation *)navigation {

    NSLog(@"4-------当内容开始返回时调用");
}

- (void)webView:(WKWebView *)webView didFinishNavigation:(WKNavigation *)navigation {

    NSLog(@"5-------页面加载完成之后调用");
}
- (void)webView:(WKWebView *)webView didFailProvisionalNavigation:(WKNavigation *)navigation {

    NSLog(@"6-------页面加载失败时调用");
}
- (void)webView:(WKWebView *)webView didReceiveServerRedirectForProvisionalNavigation:(WKNavigation *)navigation {

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

    NSLog(@"----数据加载发生错误时调用");
}
- (void)webView:(WKWebView *)webView didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge completionHandler:(void(^)(NSURLSessionAuthChallengeDisposition disposition, NSURLCredential * _Nullable credential))completionHandler {

    //用户身份信息    NSLog(@"----需要响应身份验证时调用 同样在block中需要传入用户身份凭证");

    NSURLCredential *newCred = [NSURLCredential credentialWithUser:@""                                                          password:@""                                                      persistence:NSURLCredentialPersistenceNone];

    // 为 challenge 的发送方提供 credential    [[challenge sender] useCredential:newCred forAuthenticationChallenge:challenge];
    completionHandler(NSURLSessionAuthChallengeUseCredential,newCred);

}

- (void)webViewWebContentProcessDidTerminate:(WKWebView *)webView {

    NSLog(@"----------进程被终止时调用");
}

六、WKUIDelegate代理方法

/**
*  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 completionHandler 警告框消失调用
*/

- (void)webView:(WKWebView *)webView runJavaScriptAlertPanelWithMessage:(NSString *)message initiatedByFrame:(void(^)())completionHandler {

    NSLog(@"-------web界面中有弹出警告框时调用");
}


* 创建新的webView时调用的方法

- (nullable WKWebView *)webView:(WKWebView *)webView createWebViewWithConfiguration:(WKWebViewConfiguration *)configuration forNavigationAction:(WKNavigationAction *)navigationAction windowFeatures:(WKWindowFeatures *)windowFeatures {

    NSLog(@"-----创建新的webView时调用的方法");

    return webView;

}

// 关闭webView时调用的方法

- (void)webViewDidClose:(WKWebView *)webView {

    NSLog(@"----关闭webView时调用的方法");

}

// 下面这些方法是交互JavaScript的方法

// JavaScript调用confirm方法后回调的方法 confirm是js中的确定框,需要在block中把用户选择的情况传递进去

-(void)webView:(WKWebView *)webView runJavaScriptConfirmPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void(^)(BOOL))completionHandler {

    NSLog(@"%@",message);

    completionHandler(YES);

}

// JavaScript调用prompt方法后回调的方法 prompt是js中的输入框 需要在block中把用户输入的信息传入

-(void)webView:(WKWebView *)webView runJavaScriptTextInputPanelWithPrompt:(NSString *)prompt defaultText:(NSString *)defaultText initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void(^)(NSString * _Nullable))completionHandler{

    NSLog(@"%@",prompt);

    completionHandler(@"123");

}

// 默认预览元素调用

- (BOOL)webView:(WKWebView *)webView shouldPreviewElement:(WKPreviewElementInfo *)elementInfo {

    NSLog(@"-----默认预览元素调用");

    return YES;

}

// 返回一个视图控制器将导致视图控制器被显示为一个预览。返回nil将WebKit的默认预览的行为。

- (nullable UIViewController *)webView:(WKWebView *)webView previewingViewControllerForElement:(WKPreviewElementInfo *)elementInfo defaultActions:(NSArray> *)previewActions {

    NSLog(@"----返回一个视图控制器将导致视图控制器被显示为一个预览。返回nil将WebKit的默认预览的行为。");

    return self;

}

// 允许应用程序向它创建的视图控制器弹出

- (void)webView:(WKWebView *)webView commitPreviewingViewController:(UIViewController *)previewingViewController {

    NSLog(@"----允许应用程序向它创建的视图控制器弹出");

}

// 显示一个文件上传面板。completionhandler完成处理程序调用后打开面板已被撤销。通过选择的网址,如果用户选择确定,否则为零。如果不实现此方法,Web视图将表现为如果用户选择了取消按钮。

- (void)webView:(WKWebView *)webView runOpenPanelWithParameters:(WKOpenPanelParameters *)parameters initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void(^)(NSArray * _Nullable URLs))completionHandler {

    NSLog(@"----显示一个文件上传面板");

}

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