IOS进阶之WKWebView

Cocoa开发者社区 · 公众号 · ios · 2016-10-26 08:02

正文

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原文链接：http://www.jianshu.com/p/4fa8c4eb1316

前言

Xcode8发布以后，编译器开始不支持IOS7，所以很多应用在适配IOS10之后都不在适配IOS7了，其中包括了很多大公司，网易新闻，滴滴出行等。因此，我们公司的应用也打算淘汰IOS7。

支持到IOS8，第一个要改的自然是用WKWebView替换原来的UIWebView。WKWebView有很多明显优势:

更多的支持HTML5的特性
官方宣称的高达60fps的滚动刷新率以及内置手势
将UIWebViewDelegate与UIWebView拆分成了14类与3个协议,以前很多不方便实现的功能得以实现。文档
Safari相同的JavaScript引擎
占用更少的内存

UIWebView

WKWebView

因此，使用WkWebview替换UIWebView还是很有必要的。

基本使用方法

WKWebView有两个delegate,WKUIDelegate 和 WKNavigationDelegate。

WKNavigationDelegate主要处理一些跳转、加载处理操作，WKUIDelegate主要处理JS脚本，确认框，警告框等。因此WKNavigationDelegate更加常用。

比较常用的方法：

#pragma mark - lifeCircle
- (void)viewDidLoad {
[super viewDidLoad];
webView = [[WKWebView alloc]init];
[self.view addSubview:webView];
[webView mas_makeConstraints:^(MASConstraintMaker *make) {
make.left.equalTo(self.view);
make.right.equalTo(self.view);
make.top.equalTo(self.view);
make.bottom.equalTo(self.view);
}];
webView.UIDelegate = self;
webView.navigationDelegate = self;
[webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.baidu.com"]]];
}
#pragma mark - WKNavigationDelegate
// 页面开始加载时调用
- (void)webView:(WKWebView *)webView didStartProvisionalNavigation:(WKNavigation *)navigation{
}
// 当内容开始返回时调用
- (void)webView:(WKWebView *)webView didCommitNavigation:(WKNavigation *)navigation{
}
// 页面加载完成之后调用
- (void)webView:(WKWebView *)webView didFinishNavigation:(WKNavigation *)navigation{
}
// 页面加载失败时调用
- (void)webView:(WKWebView *)webView didFailProvisionalNavigation:(WKNavigation *)navigation{
}
// 接收到服务器跳转请求之后调用
- (void)webView:(WKWebView *)webView didReceiveServerRedirectForProvisionalNavigation:(WKNavigation *)navigation{
}
// 在收到响应后，决定是否跳转
- (void)webView:(WKWebView *)webView decidePolicyForNavigationResponse:(WKNavigationResponse *)navigationResponse decisionHandler:(void (^)(WKNavigationResponsePolicy))decisionHandler{
NSLog(@"%@",navigationResponse.response.URL.absoluteString);
//允许跳转
decisionHandler(WKNavigationResponsePolicyAllow);
//不允许跳转
//decisionHandler(WKNavigationResponsePolicyCancel);
}
// 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(@"%@",navigationAction.request.URL.absoluteString);
//允许跳转
decisionHandler(WKNavigationActionPolicyAllow);
//不允许跳转
//decisionHandler(WKNavigationActionPolicyCancel);
}
#pragma mark - WKUIDelegate
// 创建一个新的WebView
- (WKWebView *)webView:(WKWebView *)webView createWebViewWithConfiguration:(WKWebViewConfiguration *)configuration forNavigationAction:(WKNavigationAction *)navigationAction windowFeatures:(WKWindowFeatures *)windowFeatures{
return [[WKWebView alloc]init];
}
// 输入框
- (void)webView:(WKWebView *)webView runJavaScriptTextInputPanelWithPrompt:(NSString *)prompt defaultText:(nullable NSString *)defaultText initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(NSString * __nullable result))completionHandler{
completionHandler(@"http");
}
// 确认框
- (void)webView:(WKWebView *)webView runJavaScriptConfirmPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(BOOL result))completionHandler{
completionHandler(YES);
}
// 警告框
- (void)webView:(WKWebView *)webView runJavaScriptAlertPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(void))completionHandler{
NSLog(@"%@",message);
completionHandler();
}

OC与JS交互

WKWebview提供了API实现js交互不需要借助JavaScriptCore或者webJavaScriptBridge。使用WKUserContentController实现js native交互。简单的说就是先注册约定好的方法，然后再调用。

JS调用OC方法

oc代码(有误，内存不释放):

@interface ViewController (){
WKWebView * webView;
WKUserContentController* userContentController;
}
@end
@implementation ViewController
#pragma mark - lifeCircle
- (void)viewDidLoad {
[super viewDidLoad];
//配置环境
WKWebViewConfiguration * configuration = [[WKWebViewConfiguration alloc]init];
userContentController =[[WKUserContentController alloc]init];
configuration.userContentController = userContentController;
webView = [[WKWebView alloc]initWithFrame:CGRectMake(0, 0, 100, 100) configuration:configuration];
//注册方法
[userContentController addScriptMessageHandler:self name:@"sayhello"];//注册一个name为sayhello的js方法
[self.view addSubview:webView];
[webView mas_makeConstraints:^(MASConstraintMaker *make) {
make.left.equalTo(self.view);
make.right.equalTo(self.view);
make.top.equalTo(self.view);
make.bottom.equalTo(self.view);
}];
webView.UIDelegate = self;
webView.navigationDelegate = self;
[webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.test.com"]]];
}
- (void)dealloc{
//这里需要注意，前面增加过的方法一定要remove掉。
[userContentController removeScriptMessageHandlerForName:@"sayhello"];
}
#pragma mark - WKScriptMessageHandler
- (void)userContentController:(WKUserContentController *)userContentController didReceiveScriptMessage:(WKScriptMessage *)message{
NSLog(@"name:%@\\\\n body:%@\\\\n frameInfo:%@\\\\n",message.name,message.body,message.frameInfo);
}
@end

上面的OC代码如果认证测试一下就会发现dealloc并不会执行，这样肯定是不行的，会造成内存泄漏。原因是[userContentController addScriptMessageHandler:self name:@"sayhello"];这句代码造成无法释放内存。（ps:试了下用weak指针还是不能释放，不知道是什么原因。）因此还需要进一步改进，正确的写法是用一个新的controller来处理,新的controller再绕用delegate绕回来。

oc代码(正确写法):

@interface ViewController (){
WKWebView * webView;
WKUserContentController* userContentController;
}
@end
@implementation ViewController
#pragma mark - lifeCircle
- (void)viewDidLoad {
[super viewDidLoad];
//配置环境
WKWebViewConfiguration * configuration = [[WKWebViewConfiguration alloc]init];
userContentController =[[WKUserContentController alloc]init];
configuration.userContentController = userContentController;
webView = [[WKWebView alloc]initWithFrame:CGRectMake(0, 0, 100, 100) configuration:configuration];
//注册方法
WKDelegateController * delegateController = [[WKDelegateController alloc]init];
delegateController.delegate = self;
[userContentController addScriptMessageHandler:delegateController name:@"sayhello"];
[self.view addSubview:webView];
[webView mas_makeConstraints:^(MASConstraintMaker *make) {
make.left.equalTo(self.view);
make.right.equalTo(self.view);
make.top.equalTo(self.view);
make.bottom.equalTo(self.view);
}];
webView.UIDelegate = self;
webView.navigationDelegate = self;
[webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.test.com"]]];
}
- (void)dealloc{
//这里需要注意，前面增加过的方法一定要remove掉。
[userContentController removeScriptMessageHandlerForName:@"sayhello"];
}
#pragma mark - WKScriptMessageHandler
- (void)userContentController:(WKUserContentController *)userContentController didReceiveScriptMessage:(WKScriptMessage *)message{
NSLog(@"name:%@\\\\n body:%@\\\\n frameInfo:%@\\\\n",message.name,message.body,message.frameInfo);
}
@end

WKDelegateController代码：

#import
#import
@protocol WKDelegate
- (void)userContentController:(WKUserContentController *)userContentController didReceiveScriptMessage:(WKScriptMessage *)message;
@end
@interface WKDelegateController : UIViewController
@property (weak , nonatomic) id delegate;
@end

.m代码：

#import "WKDelegateController.h"
@interface WKDelegateController ()
@end
@implementation WKDelegateController
- (void)viewDidLoad {
[super viewDidLoad];
}
- (void)userContentController:(WKUserContentController *)userContentController didReceiveScriptMessage:(WKScriptMessage *)message{
if ([self.delegate respondsToSelector:@selector(userContentController:didReceiveScriptMessage:)]) {
[self.delegate userContentController:userContentController didReceiveScriptMessage:message];
}
}
@end

h5代码: