ios - 如何取消 [NSURLConnection sendAsynchronousRequest :. ] 发送的请求。]

Question

我用这段代码发出请求:

- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText{
    // Here I want to cancel Request , Request Url contains searchBar Texts
    [NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
         NSXMLParser *p = [[NSXMLParser alloc] initWithData:reqData];
        [p setDelegate:self];
        [p parse];
    }];
}

Answer 1

你可以声明

@property (nonatomic, strong) NSOperationQueue *downloadQ;

然后，

    self.downloadQ = [NSOperationQueue new];
    self.downloadQ.name = @"download";

    [NSURLConnection sendAsynchronousRequest:request queue:self.downloadQ completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
        NSXMLParser *p = [[NSXMLParser alloc] initWithData:reqData];
        [p setDelegate:self];
        [p parse];
    }];

如果你需要停止

NSOperation *lastOp = [self.downloadQ.operations lastObject];
    [lastOp cancel];

更新:

现在，最好使用 NSURLSession，它有合适的方法:

- (void)getTasksWithCompletionHandler:(void (^)(NSArray *dataTasks, NSArray *uploadTasks, NSArray *downloadTasks))completionHandler;

然后检查返回任务的 task.originalRequest.URL 以找到您要取消的任务。