如何缓存html5文件（UIWebView）

Question

我使用 UIWebView 加载作为 HTML5 应用程序的 URL。
我要做的是缓存 HTML 文件，当没有网络连接时，它会加载缓存。
当连接可以使用时，它会再次加载 URL 以查看是否有新数据

Answer 1

你可以试试这样的：

#define APP_PATH_HTML_PAGES_CACHE [[NSHomeDirectory() stringByAppendingPathComponent:@"Library/Caches"] stringByAppendingPathComponent:@"html_pages_cache"]

- (void)setUrlString:(NSString *)urlString{
    if (![_urlString isEqualToString:urlString]) {
        NSURL *url = nil;
        _urlString = urlString;
        NSString *fileName = [self fileNameFromUrl:_urlString];
        if(isInternetConnected){//load page and store on file system
            url = [NSURL URLWithString:_urlString];
            [self downloadPageWithName:fileName andUrl:url];//download to cache
        }else{
            //network is not available, check for cached file
            if ([self isFileExistInCacheDirectory:fileName]) {
                url = [NSURL fileURLWithPath:[APP_PATH_HTML_PAGES_CACHE stringByAppendingPathComponent:fileName]];
            }
        else {
            //TODO: show offline/error alert
        }
    }
    //load local or remote page
    // here url can point to local file or web page
    NSURLRequest* request = [[NSURLRequest alloc]initWithURL:url];
    //to be sure that view components did initialized.
    if ([self view]) {
        [self.webView loadRequest:request];
    }
}


- (void)downloadPageWithName:(NSString*)fileName andUrl:(NSURL*)url
{
  `dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    [self checkIsCacheDirectoryExistOrCreate];`

    NSString *filePath = [APP_PATH_HTML_PAGES_CACHE stringByAppendingPathComponent:fileName];
    NSData *data = [NSData dataWithContentsOfURL:url];
    [data writeToFile:filePath atomically:YES];
    NSLog(@"Download: %@ -> %@", url.absoluteString, filePath);
});

}