2016-10-26o翻滾的牛寶寶oCocoaChina
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原文鏈接：http://www.lxweimin.com/p/4fa8c4eb1316
前言
Xcode8發(fā)布以后，編譯器開始不支持IOS7，所以很多應(yīng)用在適配IOS10之后都不在適配IOS7了，其中包括了很多大公司，網(wǎng)易新聞，滴滴出行等。因此，我們公司的應(yīng)用也打算淘汰IOS7。
支持到IOS8，第一個(gè)要改的自然是用WKWebView替換原來的UIWebView。WKWebView有很多明顯優(yōu)勢(shì):
更多的支持HTML5的特性
官方宣稱的高達(dá)60fps的滾動(dòng)刷新率以及內(nèi)置手勢(shì)
將UIWebViewDelegate與UIWebView拆分成了14類與3個(gè)協(xié)議,以前很多不方便實(shí)現(xiàn)的功能得以實(shí)現(xiàn)。文檔
Safari相同的JavaScript引擎
占用更少的內(nèi)存
UIWebView
WKWebView
因此，使用WkWebview替換UIWebView還是很有必要的。
基本使用方法
WKWebView有兩個(gè)delegate,WKUIDelegate和WKNavigationDelegate。
WKNavigationDelegate主要處理一些跳轉(zhuǎn)、加載處理操作，WKUIDelegate主要處理JS腳本，確認(rèn)框，警告框等。因此WKNavigationDelegate更加常用。
比較常用的方法：
#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
// 頁面開始加載時(shí)調(diào)用
- (void)webView:(WKWebView *)webView didStartProvisionalNavigation:(WKNavigation *)navigation{
}
// 當(dāng)內(nèi)容開始返回時(shí)調(diào)用
- (void)webView:(WKWebView *)webView didCommitNavigation:(WKNavigation *)navigation{
}
// 頁面加載完成之后調(diào)用
- (void)webView:(WKWebView *)webView didFinishNavigation:(WKNavigation *)navigation{
}
// 頁面加載失敗時(shí)調(diào)用
- (void)webView:(WKWebView *)webView didFailProvisionalNavigation:(WKNavigation *)navigation{
}
// 接收到服務(wù)器跳轉(zhuǎn)請(qǐng)求之后調(diào)用
- (void)webView:(WKWebView *)webView didReceiveServerRedirectForProvisionalNavigation:(WKNavigation *)navigation{
}
// 在收到響應(yīng)后，決定是否跳轉(zhuǎn)
- (void)webView:(WKWebView *)webView decidePolicyForNavigationResponse:(WKNavigationResponse *)navigationResponse decisionHandler:(void (^)(WKNavigationResponsePolicy))decisionHandler{
NSLog(@"%@",navigationResponse.response.URL.absoluteString);
//允許跳轉(zhuǎn)
decisionHandler(WKNavigationResponsePolicyAllow);
//不允許跳轉(zhuǎn)
//decisionHandler(WKNavigationResponsePolicyCancel);
}
// 在發(fā)送請(qǐng)求之前，決定是否跳轉(zhuǎn)
- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler{
NSLog(@"%@",navigationAction.request.URL.absoluteString);
//允許跳轉(zhuǎn)
decisionHandler(WKNavigationActionPolicyAllow);
//不允許跳轉(zhuǎn)
//decisionHandler(WKNavigationActionPolicyCancel);
}
#pragma mark - WKUIDelegate
// 創(chuàng)建一個(gè)新的WebView
- (WKWebView *)webView:(WKWebView *)webView createWebViewWithConfiguration:(WKWebViewConfiguration *)configuration forNavigationAction:(WKNavigationAction *)navigationAction windowFeatures:(WKWindowFeatures *)windowFeatures{
return [[WKWebView alloc]init];
}
// 輸入框
- (void)webView:(WKWebView *)webView runJavaScriptTextInputPanelWithPrompt:(NSString *)prompt defaultText:(nullable NSString *)defaultText initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(NSString * __nullable result))completionHandler{
completionHandler(@"http");
}
// 確認(rèn)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與JS交互
WKWebview提供了API實(shí)現(xiàn)js交互 不需要借助JavaScriptCore或者webJavaScriptBridge。使用WKUserContentController實(shí)現(xiàn)js native交互。簡單的說就是先注冊(cè)約定好的方法，然后再調(diào)用。
JS調(diào)用OC方法
oc代碼(有誤，內(nèi)存不釋放):
@interface ViewController (){
WKWebView * webView;
WKUserContentController* userContentController;
}
@end
@implementation ViewController
#pragma mark - lifeCircle
- (void)viewDidLoad {
[super viewDidLoad];
//配置環(huán)境
WKWebViewConfiguration * configuration = [[WKWebViewConfiguration alloc]init];
userContentController =[[WKUserContentController alloc]init];
configuration.userContentController = userContentController;
webView = [[WKWebView alloc]initWithFrame:CGRectMake(0, 0, 100, 100) configuration:configuration];
//注冊(cè)方法
[userContentController addScriptMessageHandler:self ?name:@"sayhello"];//注冊(cè)一個(gè)name為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{
//這里需要注意，前面增加過的方法一定要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代碼如果認(rèn)證測(cè)試一下就會(huì)發(fā)現(xiàn)dealloc并不會(huì)執(zhí)行，這樣肯定是不行的，會(huì)造成內(nèi)存泄漏。原因是[userContentController addScriptMessageHandler:self ?name:@"sayhello"];這句代碼造成無法釋放內(nèi)存。（ps:試了下用weak指針還是不能釋放，不知道是什么原因。）因此還需要進(jìn)一步改進(jìn)，正確的寫法是用一個(gè)新的controller來處理,新的controller再繞用delegate繞回來。
oc代碼(正確寫法):
@interface ViewController (){
WKWebView * webView;
WKUserContentController* userContentController;
}
@end
@implementation ViewController
#pragma mark - lifeCircle
- (void)viewDidLoad {
[super viewDidLoad];
//配置環(huán)境
WKWebViewConfiguration * configuration = [[WKWebViewConfiguration alloc]init];
userContentController =[[WKUserContentController alloc]init];
configuration.userContentController = userContentController;
webView = [[WKWebView alloc]initWithFrame:CGRectMake(0, 0, 100, 100) configuration:configuration];
//注冊(cè)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{
//這里需要注意，前面增加過的方法一定要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代碼：
#import
#import
@protocol WKDelegate
- (void)userContentController:(WKUserContentController *)userContentController didReceiveScriptMessage:(WKScriptMessage *)message;
@end
@interface WKDelegateController : UIViewController
@property (weak , nonatomic) id delegate;
@end
.m代碼：
#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代碼:
function say()
{
//前端需要用 window.webkit.messageHandlers.注冊(cè)的方法名.postMessage({body:傳輸?shù)臄?shù)據(jù)} 來給native發(fā)送消息
window.webkit.messageHandlers.sayhello.postMessage({body: 'hello world!'});
}
hello world
say hello
打印出的log：
name:sayhello
body:{
body = "hello world!";
}
frameInfo: { URL: http://www.test.com/ }>
注意點(diǎn)
addScriptMessageHandler要和removeScriptMessageHandlerForName配套出現(xiàn)，否則會(huì)造成內(nèi)存泄漏。
h5只能傳一個(gè)參數(shù)，如果需要多個(gè)參數(shù)就需要用字典或者json組裝。
oc調(diào)用JS方法
代碼如下：
- (void)webView:(WKWebView *)tmpWebView didFinishNavigation:(WKNavigation *)navigation{
//say()是JS方法名，completionHandler是異步回調(diào)block
[webView evaluateJavaScript:@"say()" completionHandler:^(id _Nullable result, NSError * _Nullable error) {
NSLog(@"%@",result);
}];
}
h5代碼同上。
WebViewJavascriptBridge
一般來說，一個(gè)好的UI總有一個(gè)大神會(huì)開發(fā)出一個(gè)好的第三方封裝框架。WebViewJavascriptBridge的作者也做了一套支持WKWebView與JS交互的第三方框架:WKWebViewJavascriptBridge。
cocoaPods: pod 'WebViewJavascriptBridge', '~> 5.0.5'
github地址：https://github.com/marcuswestin/WebViewJavascriptBridge
主要方法如下：
//初始化方法
+ (instancetype)bridgeForWebView:(WKWebView*)webView;
+ (void)enableLogging;
//注冊(cè)函數(shù)名
- (void)registerHandler:(NSString*)handlerName handler:(WVJBHandler)handler;
//調(diào)用函數(shù)名
- (void)callHandler:(NSString*)handlerName;
- (void)callHandler:(NSString*)handlerName data:(id)data;
- (void)callHandler:(NSString*)handlerName data:(id)data responseCallback:(WVJBResponseCallback)responseCallback;
//重置
- (void)reset;
//設(shè)置WKNavigationDelegate
- (void)setWebViewDelegate:(id)webViewDelegate;
基本的實(shí)現(xiàn)方法和上面寫的差不多，就是封裝了一下，有興趣的童鞋可以自己pod下來使用。
