WKWebView 修改UA方案 兼容iOS8

我们有一个需求，需要在在原本UA的基础上添加一个值 XXX.app.ios_版本号

代码需要写在AppDelegate中

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions;

注意：否者,不能及时被更改!

1.导入头文件：

#import <WebKit/WebKit.h>

2.获取当前的版本号：

#define Version [[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleVersion"] //build 版本号

3.系统控制：

#define iOS9 ([[UIDevice currentDevice].systemVersion doubleValue] >= 9.0)

示例代码：

#pragma mark - 全局修改UA
-(void)modificationUA{
    WKWebView *wk = [[WKWebView alloc] init];
    
    NSString *currentUserAgent = [NSString stringWithFormat:@"XXX.app.ios_%@",Version];
    if (iOS9) {
        [wk evaluateJavaScript:@"navigator.userAgent" completionHandler:^(id result, NSError *error) {
            NSString *oldAgent = result;
            
            if (error) {
                oldAgent = [[[UIWebView alloc] init] stringByEvaluatingJavaScriptFromString:@"navigator.userAgent"];
            }
            
            if (![oldAgent hasPrefix:currentUserAgent]) {
                NSString *customUserAgent = [NSString stringWithFormat:@"%@ %@", currentUserAgent, oldAgent];
                [[NSUserDefaults standardUserDefaults] registerDefaults:@{@"UserAgent":customUserAgent, @"User-Agent":customUserAgent}];
            }
        }];
    }else{//适配iOS8，下面的方法不能少
        NSString *oldAgent = [[[UIWebView alloc] init] stringByEvaluatingJavaScriptFromString:@"navigator.userAgent"];
        
        if (![oldAgent hasPrefix:currentUserAgent]) {
            NSString *customUserAgent = [NSString stringWithFormat:@"%@ %@", currentUserAgent, oldAgent];
            
            NSDictionary *dictionnary = [[NSDictionary alloc] initWithObjectsAndKeys:customUserAgent, @"UserAgent", nil];
            [[NSUserDefaults standardUserDefaults] registerDefaults:dictionnary];
            
            [wk setValue:customUserAgent forKey:@"applicationNameForUserAgent"];
        }
    }
}