在和前端交互過程中育勺，為了區(qū)分是我們APP內(nèi)加載網(wǎng)頁還是其他應(yīng)用或瀏覽器加載的網(wǎng)頁姐呐，我們需要使用在UserAgent后追加字符串來區(qū)分聚至。下面介紹全局和局部修改UserAgent化戳。

設(shè)置全局UserAgent

下面兩種方法都可以修改全局UserAgent宜雀，因為修改的是系統(tǒng)配置切平，等于全局公用屬性，所以不論使用UIWebView還是WKWebview州袒，修改都是同一個屬性揭绑。

方法一：WKWebView配置UserAgent

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    
    self.webView = [[WKWebView alloc] init];
    [self.webView evaluateJavaScript:@"navigator.userAgent" completionHandler:^(id result, NSError *error) {
        NSString *userAgent = result;
        NSString *newUserAgent = [userAgent stringByAppendingString:@" Appended Custom User Agent"];
        NSDictionary *dictionary = [NSDictionary dictionaryWithObjectsAndKeys:newUserAgent, @"UserAgent", nil];
        [[NSUserDefaults standardUserDefaults] registerDefaults:dictionary];
    }];
    
    return YES;
}

注意：WKWebView不能使用局部聲明，需要放在類擴展中郎哭，否則無效

方法二：UIWebView配置UserAgent

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    
    UIWebView *webView = [[UIWebView alloc] init];
    NSString *userAgent = [webView stringByEvaluatingJavaScriptFromString:@"navigator.userAgent"];
    NSString *newUserAgent = [userAgent stringByAppendingString:@" Appended Custom User Agent"];
    NSDictionary *dictionary = [NSDictionary dictionaryWithObjectsAndKeys:newUserAgent, @"UserAgent", nil];
    [[NSUserDefaults standardUserDefaults] registerDefaults:dictionary];
    
    return YES;
}

• 方法二放在其他ViewController也是可以使用他匪，webView初始化要放在設(shè)置UserAgent后才會生效。
• 需要注意的是在當(dāng)前頁面銷毀后夸研，設(shè)置的UserAgen就會失效邦蜜，如果push或者present后面的頁面，UserAgen依然有效亥至。
• AppDelegate不會銷毀以一直有效

設(shè)置局部UserAgent

UIWebView *tempWebView = [[UIWebView alloc] init];
NSString *userAgent = [tempWebView stringByEvaluatingJavaScriptFromString:@"navigator.userAgent"];
NSString *newUserAgent = [userAgent stringByAppendingString:@" Appended Custom User Agent"];
self.webView.customUserAgent = newUserAgent;
// 下面這句了打印userAgent悼沈，可以不要
[self.webView evaluateJavaScript:@"navigator.userAgent" completionHandler:^(id result, NSError *error) {
    NSLog(@"%@", result);
}];

總結(jié)：

• WKWebView需要等待回調(diào)才能設(shè)置UserAgent贱迟；
• UIWebView可以直接返回UserAgent效率更高；