ios - 如何确定我的 iOS 文档目录中是否存在某个名称的文件

Question

我正在尝试在 iPhone 文档目录中下载和缓存数据。我希望能够检查文件是否存在，如果存在，则用本地数据填充我的 UITableViewCell，如果不存在，则远程加载数据。

这是我用来下载数据的代码。

    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *path = [paths objectAtIndex:0];
    operation.outputStream = [NSOutputStream outputStreamToFileAtPath:path append:NO];

    [operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
        NSLog(@"Successfully downloaded file to %@", path);
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        NSLog(@"The Error Is: %@", error);
    }];

Answer 1

NSFileManager *fileManager = [NSFileManager defaultManager];
NSString *pathToMyFile = [path stringByAppendingPathComponent:@"myDataFile"];
if ([fileManager fileExistsAtPath:pathToMyFile]) {
    // file exists
}
else {
    // file doesn't exist
}