UIWebView废弃，迁移WKWebView
WWDC 2018中 ，在安全方面，Session上来就宣布了一件重量级的大事，UIWebView正式被官方宣布废弃，建议开发者迁移适配到WKWebView。
在XCode9中UIWebView还是 NS_CLASS_AVAILABLE_IOS(2_0)，而我们从最新的Xcode10再看UIWebView就已经是这个样子了
UIKIT_EXTERN API_DEPRECATED("No longer supported; please adopt WKWebView.", ios(2.0, 12.0)) API_PROHIBITED(tvos, macos) @interface UIWebView : UIView <NSCoding, UIScrollViewDelegate>
WKWebView从诞生之初相比UIWebView有太多的优势，无论是内存泄露还是网页性能，并且WKWebView可以同时支持macOS与iOS。由于WKWebView的独特设计，网页运行在独立的进程，如果网页遇到Crash，不会影响App的正常运行。
但是WKWebView不支持JSContext，不支持NSURLProtocol，Cookie管理蛋疼等问题确实给让不少开发者不想丢弃UIWebView，但最后通牒来了还是准备着手替换吧。
下面的一些方法均是看了许多大神的博客后总结到一起的，自己并未一一验证，后续发现错误会去纠正。
WKWebView的特点
- 性能高，稳定性好，占用的内存比较小，
- 支持JS交互
- 支持HTML5 新特性
- 可以添加进度条（然并卵，不好用，还是习惯第三方的）。
- 支持内建手势，
- 据说高达60fps的刷新频率（不卡）
初始化WKWebView
一、先导入头文件 #import <WebKit/WebKit.h>
二、WKWebView创建
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WKWebViewConfiguration *config = [[WKWebViewConfiguration alloc] init];
config.selectionGranularity = WKSelectionGranularityDynamic;
config.allowsInlineMediaPlayback = YES;
WKPreferences *preferences = [WKPreferences new];
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- WKWebViewConfiguration 用于配置WKWebView的一些属性
- WKPreferences 用于配置WKWebView视图的一些属性
- 加上
<WKNavigationDelegate, WKUIDelegate>两个代理
三、WKNavigationDelegate代理事件
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四、WKUIDelegate代理事件,主要实现与js的交互
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五、JS调用OC方法
window.webkit.messageHandlers.方法名.postMessage(参数);
- 在WKScriptMessageHandler中：
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- (void)userContentController:(WKUserContentController *)userContentController didReceiveScriptMessage:(WKScriptMessage *)message{
if ([message.name isEqualToString:@"takePicturesByNative"]) {
[self takePicturesByNativeWithBody:message.body];
}
}
- (void)takePicturesByNativeWithBody:(NSString *)body {
NSLog(@"调用了takePicturesByNative方法");
UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"提示" message:body preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction *a1 = [UIAlertAction actionWithTitle:@"确认" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
}];
[alert addAction:a1];
[self presentViewController:alert animated:YES completion:nil];
}
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在使用上述方法中发现，addScriptMessageHandler:self中发生了循环引用，造成webview不会被释放掉，故经测试有以下两种解决方案：
1.新建个WeakScriptMessageDelegate类
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#import <Foundation/Foundation.h>
#import <WebKit/WebKit.h>
@interface WeakScriptMessageDelegate : NSObject <WKScriptMessageHandler>
@property (nonatomic, assign) id<WKScriptMessageHandler> scriptDelegate;
+ (instancetype)scriptWithDelegate:(id<WKScriptMessageHandler>)delegate;
@end
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@implementation WeakScriptMessageDelegate
- (instancetype)initWithDelegate:(id<WKScriptMessageHandler>)scriptDelegate {
self = [super init];
if (self) {
_scriptDelegate = scriptDelegate;
}
return self;
}
+ (instancetype)scriptWithDelegate:(id<WKScriptMessageHandler>)delegate {
return [[WeakScriptMessageDelegate alloc]initWithDelegate:delegate];
}
- (void)userContentController:(WKUserContentController *)userContentController didReceiveScriptMessage:(WKScriptMessage *)message {
[self.scriptDelegate userContentController:userContentController didReceiveScriptMessage:message];
}
@end
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设置addScriptMessageHandler方法更换为：
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[[_webView configuration].userContentController addScriptMessageHandler:[WeakScriptMessageDelegate scriptWithDelegate:self] name:@"takePicturesByNative"];
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2.不在初始化时添加ScriptMessageHandler， 而是和Notificenter/KVC一个思路
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- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
[_webView.configuration.userContentController addScriptMessageHandler:self name:@"takePicturesByNative"];
}
- (void)viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
[_webView.configuration.userContentController removeScriptMessageHandlerForName:@"takePicturesByNative"];
}
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六、OC调用JS方法
七、给webview添加请求头
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NSString *urlString = @"https://www.baidu.com/";
NSURL *url = [NSURL URLWithString:urlString];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
[request addValue:@"123" forHTTPHeaderField:@"token"];
[self.webView loadRequest:request];
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注：在UIWeb里边是直接用的request 但是在这里需要写上navigationAction.出来的request
八、WKWebView加载不受信任的https
解决方法：在plist文件中设置Allow Arbitrary Loads in Web Content 置为 YES,并实现wkwebView下面的代理方法,就可解决
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- (void)webView:(WKWebView *)webView didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disposition, NSURLCredential * _Nullable credential))completionHandler{
if ([challenge.protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust]) {
NSURLCredential *card = [[NSURLCredential alloc]initWithTrust:challenge.protectionSpace.serverTrust];
completionHandler(NSURLSessionAuthChallengeUseCredential,card);
}
}
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九、监听WKWebView的进度条和标题
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[self.webView addObserver:self forKeyPath:@"estimatedProgress" options:NSKeyValueObservingOptionNew context:nil];
[self.webView addObserver:self forKeyPath:@"title" options:NSKeyValueObservingOptionNew context:NULL];
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@property (nonatomic, weak) CALayer *progressLayer;
UIView *progress = [[UIView alloc]init];
progress.frame = CGRectMake(0, 0, KScreenWidth, 3);
progress.backgroundColor = [UIColor clearColor];
[self.view addSubview:progress];
CALayer *layer = [CALayer layer];
layer.frame = CGRectMake(0, 0, 0, 3);
layer.backgroundColor = [UIColor greenColor].CGColor;
[progress.layer addSublayer:layer];
self.progressLayer = layer;
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#pragma mark - KVO回馈
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSKeyValueChangeKey,id> *)change context:(void *)context{
if ([keyPath isEqualToString:@"estimatedProgress"]) {
self.progressLayer.opacity = 1;
if ([change[@"new"] floatValue] <[change[@"old"] floatValue]) {
return;
}
self.progressLayer.frame = CGRectMake(0, 0, KScreenWidth*[change[@"new"] floatValue], 3);
if ([change[@"new"]floatValue] == 1.0) {
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(.5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
self.progressLayer.opacity = 0;
self.progressLayer.frame = CGRectMake(0, 0, 0, 3);
});
}
}else if ([keyPath isEqualToString:@"title"]){
self.title = change[@"new"];
}
}
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十、解决cookie问题
以前UIWebView会自动去NSHTTPCookieStorage中读取cookie，但是WKWebView并不会去读取,因此导致cookie丢失以及一系列问题，解决方式就是在request中手动帮其添加上。
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self.webView.UIDelegate = self;
self.webView.navigationDelegate = self;
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://www.test.com"]];
[request addValue:[self readCurrentCookieWithDomain:@"http://www.test.com/"] forHTTPHeaderField:@"Cookie"];
[self.webView loadRequest:request];
- (NSString *)readCurrentCookieWithDomain:(NSString *)domainStr{
NSHTTPCookieStorage*cookieJar = [NSHTTPCookieStorage sharedHTTPCookieStorage];
NSMutableString * cookieString = [[NSMutableString alloc]init];
for (NSHTTPCookie*cookie in [cookieJar cookies]) {
[cookieString appendFormat:@"%@=%@;",cookie.name,cookie.value];
}
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但是这只能解决第一次进入的cookie问题，如果页面内跳转（a标签等）还是取不到cookie，因此还要再加代码。
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- (void)webView:(WKWebView *)webView didFinishNavigation:(WKNavigation *)navigation {
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十一、加载页面后自动关闭的问题
问题描述，我加载一web页面后，进行各种操作，比说我充值，什么的，然后想要在充值提出成功后自顶关闭这个web页面回到上一层或者返回到某一个界面，就用下面的方法，一般判断URL 包含的字符串都是后台给定的，在这里只需要判断就好了！
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十二、清除缓存
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- (void)cleanCacheAndCookie {
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- (void)dealloc {
[_webView stopLoading];
[_webView setNavigationDelegate:nil];
[self clearCache];
[self cleanCacheAndCookie];
}
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附：demo中使用的返回上一页和关闭浏览器的方法
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#pragma mark - Actions
- (void)backNative {
//判断是否有上一层H5页面
if ([self.webView canGoBack]) {
//如果有则返回
[self.webView goBack];
//同时设置返回按钮和关闭按钮为导航栏左边的按钮
// self.navigationItem.leftBarButtonItems = @[self.backBtn, self.closeBtn];
}else {
[self closeNative];
}
}
- (void)closeNative {
if (self.webView.backForwardList.backList.count>0) { //得到栈里面的list
NSLog(@"backList==%@",self.webView.backForwardList.backList);
NSLog(@"currentItem==%@",self.webView.backForwardList.currentItem);
[self.webView goToBackForwardListItem:[self.webView.backForwardList.backList firstObject]];
// WKBackForwardListItem * item = self.webView.backForwardList.currentItem; //得到现在加载的list
// for (WKBackForwardListItem * backItem in self.webView.backForwardList.backList) { //循环遍历，得到你想退出到
// //添加判断条件
// [self.webView goToBackForwardListItem:[self.webView.backForwardList.backList firstObject]];
// }
}
[self.navigationController popViewControllerAnimated:YES];
}
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