需求：hybrid混合開發(fā)，大概就是把.html和.css等資源文件存在本地，通過jsBridge.js來進行交互，提高在app中加載h5頁面的加載速度和用戶體驗等問題，減少app端需要發(fā)包才能解決的一些業(yè)務(wù)問題。

最近將hybrid框架中的UIWebView換成WKWebView遇到的問題，主要是加載jsBridge.js文件遇到的問題。

1. UIWebView中的加載jsBridge.js，代碼如下：

- (void)webViewDidStartLoad:(UIWebView *)webView
{
    if (webView != self) { return; }
    
    [webView stringByEvaluatingJavaScriptFromString:[self jsString]];
    
    if ([self.webViewDelegate respondsToSelector:@selector(webViewDidStartLoad:)]) {
        [self.webViewDelegate webViewDidStartLoad:webView];
    }
}

- (NSString *)jsString {
    NSString *result = [NSString stringWithContentsOfFile:JSBridgePath encoding:NSUTF8StringEncoding error:nil];
    if (result == nil) {
        result = [NSString stringWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"jsBridge" ofType:@"js"] encoding:NSUTF8StringEncoding error:nil];
    }
    return result;
}

像正常加載url的方法一樣就可以了

- (void)reloadWebViewRequest
{
    [self.webView loadRequest:[NSURLRequest requestWithURL:self.url]];
}

2.WKWebView中的加載jsBridge.js，一開始也是直接像UIWebView一樣在代理方法執(zhí)行jsBridge.js，雖然js代碼執(zhí)行成功了，但是加載不了存在本地的.html和.css等文件，頁面就加載不出來，代碼如下：

- (void)webView:(WKWebView *)webView didFinishNavigation:(WKNavigation *)navigation
{
    if (webView != self) { return; }
    
    [webView evaluateJavaScript:[self jsString] completionHandler:^(id _Nullable, NSError * _Nullable error) {
        
    }];
    
    if ([self.webViewDelegate respondsToSelector:@selector(webView:didFinishNavigation:)]) {
        [self.webViewDelegate webView:webView didFinishNavigation:navigation];
    }
}

后來在網(wǎng)上找了好多資料，具體實現(xiàn)如下：

// 初始化webview
- (void)viewDidLoad {
    [super viewDidLoad];
    [self installStartTime];
    
    WKWebViewConfiguration *config = [[WKWebViewConfiguration alloc] init];
    self.webview = [[JSBWebView alloc] initWithFrame:self.view.bounds configuration:config];
    self.webview.navigationDelegate = self;
    self.webview.UIDelegate = self;
}

- (instancetype)initWithFrame:(CGRect)frame configuration:(WKWebViewConfiguration *)configuration
{
    WKUserScript *script = [[WKUserScript alloc] initWithSource:[self jsString] injectionTime:WKUserScriptInjectionTimeAtDocumentStart forMainFrameOnly:YES];
    [configuration.userContentController addUserScript:script];
    [configuration.preferences setValue:@YES forKey:@"allowFileAccessFromFileURLs"];

    self = [super initWithFrame:frame configuration:configuration];
    if (self) {
        [self setup];
    }
    return self;
}

說明，一定要設(shè)置[configuration.preferences setValue:@YES forKey:@"allowFileAccessFromFileURLs"];

參考資料：
https://stackoverflow.com/questions/36013645/setting-disable-web-security-and-allow-file-access-from-files-in-ios-wkwebvi

加載文件一定要用loadFileURL:allowingReadAccessToURL:這個才會生效

- (void)reloadWebViewRequest
{
    NSURL *accessURL = [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] objectAtIndex:0];
    [self.webview loadFileURL:self.url allowingReadAccessToURL:accessURL];
}

參考資料：
https://stackoverflow.com/questions/40472796/wkwebview-loadfileurl-works-only-once