objective-c - 将 sendAsynchronously 与 RKRequest 一起使用时应用程序崩溃

Question

我想使用 Restkit 异步下载文件。但是，当使用 sendAsynchronously 方法时应用程序崩溃。如果我使用 sendSynchronously 而不是 sendAsynchronously，它不会崩溃。有没有人知道为什么？

这是我的代码

NSString *passURL = @"https://s3.amazonaws.com/mheydt-mhtnd/2012-03-13-1.png";
        RKRequest *request = [RKRequest requestWithURL:[NSURL URLWithString: passURL]];
        request.delegate = self;
        [request sendAsynchronously];


- (void)request:(RKRequest *)request didReceiveResponse:(RKResponse *)response {
    NSLog(@"didReceiveResponse");
}

- (void)request:(RKRequest *)request didLoadResponse:(RKResponse *)response {
   NSLog(@"didLoadResponse");   
}

非常感谢！

Answer 1

以这种方式使用sendAsynchronously时，请求不会被保留。您最好使用send在实例中添加请求的方法RKRequestQueue（这可以防止请求过早释放）：

[request send];

或者，您可以自己强烈引用请求。您的代码将变为：

@interface MyClass
{
    RKRequest *request;
}

我们假设这是一个强有力的参考。在实施中，您将拥有：

@implementation MyClass

- (void)sendTheRequest
{
    NSString *passURL = @"https://s3.amazonaws.com/mheydt-mhtnd/2012-03-13-1.png";
    request = [RKRequest requestWithURL:[NSURL URLWithString: passURL]];
    request.delegate = self;
    [request sendAsynchronously];
}

- (void)request:(RKRequest *)request didReceiveResponse:(RKResponse *)response {
    NSLog(@"didReceiveResponse");
    request = nil;
}

- (void)request:(RKRequest *)request didLoadResponse:(RKResponse *)response {
    NSLog(@"didLoadResponse");
    request = nil;
}

- (void)request:(RKRequest *)request didFailLoadWithError:(NSError *)error {
    NSLog(@"didFailLoadWithError");
    request = nil;
}

@end