NSURLConnection,NSMutableURLRequest的设置范围错误

Question

我试图通过使用setValue:forHTTPHeaderField来实现下载恢复功能.但每当我使用这种方法时,我都会得到一个

[NSURLRequest setValue:forHTTPHeaderField:]:无法识别的选择器发送到实例0x4e0b710 2011-08-08 22:44:36.469补丁[9140:207] * 由于未捕获的异常'NSInvalidArgumentException'终止应用程序,原因:' - [NSURLRequest setValue:forHTTPHeaderField :]:无法识别的选择器发送到实例0x4e0b710'

错误.

没有那种方法我的代码工作正常但是当我包含这段代码时,我得到上面的错误

NSMutableURLRequest* request = [NSURLRequest requestWithURL:[NSURL URLWithString:URL]
                                         cachePolicy:NSURLRequestUseProtocolCachePolicy
                                     timeoutInterval:60.0];

//---------------- setting range for download resume -----------------------
NSString* range = @"bytes=";
range = [range stringByAppendingString:[[NSNumber numberWithInt:offset] stringValue]];
range = [range stringByAppendingString:@"-"];
NSLog(@"range: %@", range);

[request setValue:range forHTTPHeaderField:@"Range"];

请帮帮我...非常感谢你

Answer 1

你需要创建NSMutableURLRequest一个NSMutableURLRequest.

NSMutableURLRequest* request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:URL]
                                         cachePolicy:NSURLRequestUseProtocolCachePolicy
                                     timeoutInterval:60.0];