Question

我需要上传图片到网络服务。下面是我返回上传图片的代码段。图像尺寸非常大（约6Mb）。我正在使用GCD在后台线程中上传该图像。

       if([VSCore ConnectedToInternet ])
       {
         bgTask = [[UIApplication sharedApplication]beginBackgroundTaskWithExpirationHandler: ^{
                            dispatch_async(dispatch_get_main_queue(), ^{
                                //[application endBackgroundTask:self->bgTask];
                                //self->bgTask = UIBackgroundTaskInvalid;
                            });
                        }];

                        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

                            [vrs write:data toURI:URI];

                           [[UIApplication sharedApplication]endBackgroundTask:bgTask];
                             bgTask = UIBackgroundTaskInvalid;
                        });

//
}

-(BOOL)write:(NSData *)data toURI:(NSString *)URI
{
BOOL retVal = NO;
NSString* requestDataLengthString = [[NSString alloc] initWithFormat:@"%d", [data length]];

NSRange range = [URI rangeOfString:@"http"];//Is http?  
if(range.location != NSNotFound) 
{   
    //Yes, http
    NSMutableURLRequest *httpRequest = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:URI]];

    [httpRequest setHTTPMethod:@"POST"];
    [httpRequest setHTTPBody:data];
    [httpRequest setValue:@"application/xml" forHTTPHeaderField:@"Content-Type"];
    [httpRequest setValue:requestDataLengthString forHTTPHeaderField:@"Content-Length"];

    NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:httpRequest delegate:self];

    [theConnection release];
    [httpRequest release];

    if (theConnection) 
    {
        receivedData=[[NSMutableData data] retain];
        retVal = YES;
    } 
    else 
    {                                            
        NSError *error = [NSError alloc];
        NSLog(@"Connection failed! Error - %@ %@",
            [error localizedDescription],
            [[error userInfo] objectForKey:NSURLErrorFailingURLStringErrorKey]);
            [error release];

        retVal = NO;
    }

}                                            
return retVal;

}

现在我面临的问题是，如果我尝试在后台线程上传图像请求不会到服务器（我正在检查服务器上的日志文件）。但是如果我在主线程中上传图像请求将转到服务器（仅用于测试目的，我知道在主线程中上传大图像不是一个好主意）。那我在这里做错了什么？背景线程有什么问题吗？ Plz救救我。提前谢谢。

Answer 1

而不是在后台线程上执行此操作。你可以创建一个像你这样做网络连接的类。

您只需添加字段即可发布图片。

- (void)send: (NSString *)urlString {

self.receivedData = [[NSMutableData alloc] init];

NSURLRequest *request = [[NSURLRequest alloc]
                         initWithURL: [NSURL URLWithString:urlString]
                         cachePolicy: NSURLRequestReloadIgnoringLocalCacheData
                         timeoutInterval: 20
                         ];

NSURLConnection *connection = [[NSURLConnection alloc]
                               initWithRequest:request
                               delegate:self
                               startImmediately:YES];
if(!connection) {
    NSLog(@"connection failed :(");
} else {
    NSLog(@"connection succeeded  :)");

}

}


- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
//NSLog(@"Received response: %@", response);

[receivedData setLength:0];
}

-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
//NSLog(@"Received %d bytes of data", [data length]); 

[receivedData appendData:data];
//NSLog(@"Received data is now %d bytes", [receivedData length]); 

}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
NSLog(@"Error receiving response: %@", error);
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
// Once this method is invoked, "responseData" contains the complete result
//NSLog(@"Succeeded! Received %d bytes of data", [receivedData length]); 

NSString *dataStr=[[NSString alloc] initWithData:receivedData encoding:NSASCIIStringEncoding];

NSLog(@"%@",dataStr);

}

你在标题中需要这个：

@interface NetConnection : NSObject

{
NSMutableData *receivedData;

}

@property (nonatomic,retain) NSMutableData *receivedData;
@property (nonatomic,retain) NSString *callback;

在背景螺纹上载大图象。

1 个答案: