前言
前一章我給大家介紹了iOS與HTML5的交互,用的是UIWebView,今天給大家介紹另外一種基於 iOS 8 新推出的 WKWebView 組件,構建出自己的混合開發框架。
WKWebView 簡介
WKWebView 是蘋果在 iOS 8 中引入的新組件,目的是給出一個新的高性能的 Web View 解決方案,擺脫過去 UIWebView 的老舊笨重特別是內存佔用量巨大的問題。
蘋果將 UIWebViewDelegate 與 UIWebView 重構成了 14 個類和 3 個協議,引入了不少新的功能和接口,這可以在一定程度上看做蘋果對其封鎖 Web View 內核的行爲作出的補償:既然你們都說 UIWebView 太渣,那我就造一個不渣的給你們用唄~~ 衆所周知,連 Chrome 的 iOS 版用的也是 UIWebView 的內核。
WKWebView 有哪些進步呢?
1.將瀏覽器內核渲染進程提取出 App,由系統進行統一管理,這減少了相當一部分的性能損失。
2.js 可以直接使用已經事先注入 js runtime 的 js 接口給 Native 層傳值,不必再通過苦逼的 iframe 製造頁面刷新再解析自定義協議的奇怪方式。
3.支持高達 60 fps 的滾動刷新率,內置了手勢探測。
WKWebView API介紹
WKWebView的頭文件聲明
@property (nonatomic, readonly, copy) WKWebViewConfiguration *configuration;
@property (nullable, nonatomic, weak) id <WKNavigationDelegate> navigationDelegate;
@property (nullable, nonatomic, weak) id <WKUIDelegate> UIDelegate;
@property (nonatomic, readonly, strong) WKBackForwardList *backForwardList;
- (instancetype)initWithFrame:(CGRect)frame configuration:(WKWebViewConfiguration *)configuration NS_DESIGNATED_INITIALIZER;
- (instancetype)initWithCoder:(NSCoder *)coder NS_UNAVAILABLE;
- (nullable WKNavigation *)loadRequest:(NSURLRequest *)request;
- (nullable WKNavigation *)loadFileURL:(NSURL *)URL allowingReadAccessToURL:(NSURL *)readAccessURL NS_AVAILABLE(10_11, 9_0);
- (nullable WKNavigation *)loadHTMLString:(NSString *)string baseURL:(nullable NSURL *)baseURL;
- (nullable WKNavigation *)loadData:(NSData *)data MIMEType:(NSString *)MIMEType characterEncodingName:(NSString *)characterEncodingName baseURL:(NSURL *)baseURL NS_AVAILABLE(10_11, 9_0);
- (nullable WKNavigation *)goToBackForwardListItem:(WKBackForwardListItem *)item;
@property (nullable, nonatomic, readonly, copy) NSString *title;
@property (nullable, nonatomic, readonly, copy) NSURL *URL;
@property (nonatomic, readonly, getter=isLoading) BOOL loading;
@property (nonatomic, readonly) double estimatedProgress;
@property (nonatomic, readonly) BOOL hasOnlySecureContent;
@property (nonatomic, readonly, copy) NSArray *certificateChain NS_AVAILABLE(10_11, 9_0);
@property (nonatomic, readonly) BOOL canGoBack;
@property (nonatomic, readonly) BOOL canGoForward;
- (nullable WKNavigation *)goBack;
- (nullable WKNavigation *)goForward;
- (nullable WKNavigation *)reload;
- (nullable WKNavigation *)reloadFromOrigin;
- (void)stopLoading;
- (void)evaluateJavaScript:(NSString *)javaScriptString completionHandler:(void (^ __nullable)(__nullable id, NSError * __nullable error))completionHandler;
@property (nonatomic) BOOL allowsBackForwardNavigationGestures;
@property (nullable, nonatomic, copy) NSString *customUserAgent NS_AVAILABLE(10_11, 9_0);
@property (nonatomic) BOOL allowsLinkPreview NS_AVAILABLE(10_11, 9_0);
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WKWebViewConfiguration配置
WKWebViewConfiguration *config = [[WKWebViewConfiguration alloc] init];
WKPreferences偏好設置
// 設置偏好設置
config.preferences = [[WKPreferences alloc] init]
// 默認爲0
config.preferences.minimumFontSize = 10
// 默認認爲YES
config.preferences.javaScriptEnabled = YES
// 在iOS上默認爲NO,表示不能自動通過窗口打開
config.preferences.javaScriptCanOpenWindowsAutomatically = NO
WKProcessPool內容處理池
WKProcessPool並沒有公開任何的屬性或者方法,不需要配置:
config.processPool = [[WKProcessPool alloc] init];
WKUserContentController內容交互控制器
我們要通過JS與webview內容交互,就需要到這個類了,它的所有屬性及方法說明如下:
@property (nonatomic, readonly, copy) NSArray<WKUserScript *> *userScripts;
- (void)addUserScript:(WKUserScript *)userScript;
- (void)removeAllUserScripts;
- (void)addScriptMessageHandler:(id <WKScriptMessageHandler>)scriptMessageHandler name:(NSString *)name;
- (void)removeScriptMessageHandlerForName:(NSString *)name;
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WKUserScript
在WKUserContentController中,所有使用到WKUserScript。WKUserContentController是用於與JS交互的類,而所注入的JS是WKUserScript對象。它的所有屬性和方法如下:
@property (nonatomic, readonly, copy) NSString *source;
@property (nonatomic, readonly) WKUserScriptInjectionTime injectionTime;
@property (nonatomic, readonly, getter=isForMainFrameOnly) BOOL forMainFrameOnly;
- (instancetype)initWithSource:(NSString *)source injectionTime:(WKUserScriptInjectionTime)injectionTime forMainFrameOnly:(BOOL)forMainFrameOnly;
WKUserScriptInjectionTime
它是一個枚舉類型,只有在文檔開始加載時注入和加載結束時注入。
typedef NS_ENUM(NSInteger, WKUserScriptInjectionTime) {
WKUserScriptInjectionTimeAtDocumentStart,
WKUserScriptInjectionTimeAtDocumentEnd
} NS_ENUM_AVAILABLE(10_10, 8_0);
WKWebsiteDataStore存儲的Web內容
iOS9.0以後才能使用這個類。它是代表webview不同的數據類型,包括cookies、disk、memory caches、WebSQL、IndexedDB數據庫和本地存儲。
從這裏看,要優化Webview好像可以通過它來實現,不過要求iOS9.0以上才能使用。現在6.0都沒有拋棄的我,從來不能考慮這種最新的。
WKProcessPool並沒有公開任何的屬性或者方法,不需要配置:
+ (WKWebsiteDataStore *)defaultDataStore;
+ (WKWebsiteDataStore *)nonPersistentDataStore;
- (instancetype)init NS_UNAVAILABLE;
@property (nonatomic, readonly, getter=isPersistent) BOOL persistent;
+ (NSSet<NSString *> *)allWebsiteDataTypes;
- (void)fetchDataRecordsOfTypes:(NSSet<NSString *> *)dataTypes completionHandler:(void (^)(NSArray<WKWebsiteDataRecord *> *))completionHandler;
- (void)removeDataOfTypes:(NSSet<NSString *> *)dataTypes forDataRecords:(NSArray<WKWebsiteDataRecord *> *)dataRecords completionHandler:(void (^)(void))completionHandler;
- (void)removeDataOfTypes:(NSSet<NSString *> *)websiteDataTypes modifiedSince:(NSDate *)date completionHandler:(void (^)(void))completionHandler;
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所有的dataTypes是下面這些系統所定義的:
WK_EXTERN NSString * const WKWebsiteDataTypeDiskCache NS_AVAILABLE(10_11, 9_0);
WK_EXTERN NSString * const WKWebsiteDataTypeMemoryCache NS_AVAILABLE(10_11, 9_0);
WK_EXTERN NSString * const WKWebsiteDataTypeOfflineWebApplicationCache NS_AVAILABLE(10_11, 9_0);
WK_EXTERN NSString * const WKWebsiteDataTypeCookies NS_AVAILABLE(10_11, 9_0);
WK_EXTERN NSString * const WKWebsiteDataTypeSessionStorage NS_AVAILABLE(10_11, 9_0);
WK_EXTERN NSString * const WKWebsiteDataTypeLocalStorage NS_AVAILABLE(10_11, 9_0);
WK_EXTERN NSString * const WKWebsiteDataTypeWebSQLDatabases NS_AVAILABLE(10_11, 9_0);
WK_EXTERN NSString * const WKWebsiteDataTypeIndexedDBDatabases NS_AVAILABLE(10_11, 9_0);
WKWebsiteDataRecord
iOS9.0以後纔可用。
website的數據存儲記錄類型,它只有兩個屬性:
@property (nonatomic, readonly, copy) NSString *displayName;
@property (nonatomic, readonly, copy) NSSet<NSString *> *dataTypes;
WKSelectionGranularity選擇粒度
它表示在webview上選擇內容的粒度,只有下面這兩種類型:
typedef NS_ENUM(NSInteger, WKSelectionGranularity) {
WKSelectionGranularityDynamic,
WKSelectionGranularityCharacter,
} NS_ENUM_AVAILABLE_IOS(8_0);
它是用於webview內容交互時選擇內容的粒度類型設置。比如說,當使用WKSelectionGranularityDynamic時,而所選擇的內容是單個塊,這時候granularity可能會是單個字符;當所選擇的web內容不限制於某個塊時,granularity可能會是單個塊。
WKNavigationDelegate
@protocol WKNavigationDelegate <NSObject>
@optional
// 決定導航的動作,通常用於處理跨域的鏈接能否導航。WebKit對跨域進行了安全檢查限制,不允許跨域,因此我們要對不能跨域的鏈接
// 單獨處理。但是,對於Safari是允許跨域的,不用這麼處理。
// 這個是決定是否Request
- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler;
// 決定是否接收響應
// 這個是決定是否接收response
// 要獲取response,通過WKNavigationResponse對象獲取
- (void)webView:(WKWebView *)webView decidePolicyForNavigationResponse:(WKNavigationResponse *)navigationResponse decisionHandler:(void (^)(WKNavigationResponsePolicy))decisionHandler;
// 當main frame的導航開始請求時,會調用此方法
- (void)webView:(WKWebView *)webView didStartProvisionalNavigation:(null_unspecified WKNavigation *)navigation;
// 當main frame接收到服務重定向時,會回調此方法
- (void)webView:(WKWebView *)webView didReceiveServerRedirectForProvisionalNavigation:(null_unspecified WKNavigation *)navigation;
// 當main frame開始加載數據失敗時,會回調
- (void)webView:(WKWebView *)webView didFailProvisionalNavigation:(null_unspecified WKNavigation *)navigation withError:(NSError *)error;
// 當main frame的web內容開始到達時,會回調
- (void)webView:(WKWebView *)webView didCommitNavigation:(null_unspecified WKNavigation *)navigation;
// 當main frame導航完成時,會回調
- (void)webView:(WKWebView *)webView didFinishNavigation:(null_unspecified WKNavigation *)navigation;
// 當main frame最後下載數據失敗時,會回調
- (void)webView:(WKWebView *)webView didFailNavigation:(null_unspecified WKNavigation *)navigation withError:(NSError *)error;
// 這與用於授權驗證的API,與AFN、UIWebView的授權驗證API是一樣的
- (void)webView:(WKWebView *)webView didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disposition, NSURLCredential *__nullable credential))completionHandler;
// 當web content處理完成時,會回調
- (void)webViewWebContentProcessDidTerminate:(WKWebView *)webView NS_AVAILABLE(10_11, 9_0);
@end
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WKNavigationActionPolicy
導航動作決定策略:
typedef NS_ENUM(NSInteger, WKNavigationActionPolicy) {
WKNavigationActionPolicyCancel,
WKNavigationActionPolicyAllow,
} NS_ENUM_AVAILABLE(10_10, 8_0);
它是枚舉類型,只有Cancel和Allow這兩種。設置爲Cancel就是不允許導航,就不會跳轉鏈接。
WKNavigationResponse
WKNavigationResponse是導航響應類,通過它可以獲取相關響應的信息:
NS_CLASS_AVAILABLE(10_10, 8_0)
@interface WKNavigationResponse : NSObject
@property (nonatomic, readonly, getter=isForMainFrame) BOOL forMainFrame;
@property (nonatomic, readonly, copy) NSURLResponse *response;
@property (nonatomic, readonly) BOOL canShowMIMEType;
@end
只有接收響應與不接收響應兩種。
WKNavigationAction
WKNavigationAction對象包含關於導航的action的信息,用於make policy decisions。它只有以下幾個屬性:
@property (nonatomic, readonly, copy) WKFrameInfo *sourceFrame;
@property (nullable, nonatomic, readonly, copy) WKFrameInfo *targetFrame;
@property (nonatomic, readonly) WKNavigationType navigationType;
@property (nonatomic, readonly, copy) NSURLRequest *request;
WKNavigationType
WKNavigationType類型是枚舉類型,它的可選值如下:
typedef NS_ENUM(NSInteger, WKNavigationType) {
WKNavigationTypeLinkActivated,
WKNavigationTypeFormSubmitted,
WKNavigationTypeBackForward,
WKNavigationTypeReload,
WKNavigationTypeFormResubmitted,
WKNavigationTypeOther = -1,
} NS_ENUM_AVAILABLE(10_10, 8_0);
WKUIDelegate
@protocol WKUIDelegate <NSObject>
@optional
// 創建新的webview
// 可以指定配置對象、導航動作對象、window特性
- (nullable WKWebView *)webView:(WKWebView *)webView createWebViewWithConfiguration:(WKWebViewConfiguration *)configuration forNavigationAction:(WKNavigationAction *)navigationAction windowFeatures:(WKWindowFeatures *)windowFeatures;
// webview關閉時回調
- (void)webViewDidClose:(WKWebView *)webView NS_AVAILABLE(10_11, 9_0);
// 調用JS的alert()方法
- (void)webView:(WKWebView *)webView runJavaScriptAlertPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(void))completionHandler;
// 調用JS的confirm()方法
- (void)webView:(WKWebView *)webView runJavaScriptConfirmPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(BOOL result))completionHandler;
// 調用JS的prompt()方法
- (void)webView:(WKWebView *)webView runJavaScriptTextInputPanelWithPrompt:(NSString *)prompt defaultText:(nullable NSString *)defaultText initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(NSString * __nullable result))completionHandler;
@end
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WKBackForwardList
WKBackForwardList表示webview中可以前進或者後退的頁面列表。其聲明如下:
NS_CLASS_AVAILABLE(10_10, 8_0)
@interface WKBackForwardList : NSObject
@property (nullable, nonatomic, readonly, strong) WKBackForwardListItem *currentItem;
@property (nullable, nonatomic, readonly, strong) WKBackForwardListItem *backItem;
@property (nullable, nonatomic, readonly, strong) WKBackForwardListItem *forwardItem;
- (nullable WKBackForwardListItem *)itemAtIndex:(NSInteger)index;
@property (nonatomic, readonly, copy) NSArray<WKBackForwardListItem *> *backList;
@property (nonatomic, readonly, copy) NSArray *forwardList;
@end
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WKBackForwardListItem
頁面導航前進、後退列表項:
@interface WKBackForwardListItem : NSObject
@property (readonly, copy) NSURL *URL;
@property (nullable, readonly, copy) NSString *title;
@property (readonly, copy) NSURL *initialURL;
@end
結束
這樣這個框架基本介紹完了,實戰下一篇會給大家着重介紹如何使用