在 iPhone 中下载最大 50 MB 的大型 zip 文件

Question

我想在我的 iPhone 中从服务器下载一个最大 50 MB 的大型 zip 文件。所以请任何人建议我如何下载大的 zip 文件。

我有下载普通 zip 文件的实现代码，但我想下载大文件。

Answer 1

下载任何大小的文件应该没有问题。查看NSURLConnection：

http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/URLLoadingSystem/Tasks/UsingNSURLConnection.html

Answer 2

直接取自项目：

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {

    bytesCount = bytesCount + [data length];
    [receivedData appendData:data]; 

    //If the size is over 10MB, then write the current data object to a file and clear the data
    if(receivedData.length > MAX_DATA_LENGHT){
        [fileHandle truncateFileAtOffset:[fileHandle seekToEndOfFile]]; //setting aFileHandle to write at the end of the file

        [fileHandle writeData:receivedData]; //actually write the data

        [receivedData release];
        receivedData = nil;
        receivedData = [[NSMutableData data] retain];
    }

    [progressView setProgress:(float)bytesCount/sizeOfDownload];
}


- (void)connectionDidFinishLoading:(NSURLConnection*)connection {

    DEBUG(@"Succeeded! Received %d bytes of data",[receivedData length]);

    //  Release and clean some ivars
    //
    [currentConnection release];
    currentConnection = nil;

    [fileHandle writeData:receivedData];
    [receivedData release];
    [fileHandle release];
..

这是开始下载例程的一部分：

...
//  create a path in doc's folder and initialize the file handler
        NSString *temporaryZipPath = [self temporaryZipPathForResource];
        NSMutableData *fake = [[NSMutableData alloc] initWithLength:0];
        BOOL result = [[NSFileManager defaultManager] createFileAtPath:temporaryZipPath
                                                              contents:fake 
                                                            attributes:nil];
        [fake release];

        if (!result) {
            [super showAlertWithErrorDescription:@"Error creating file"];
            return;
        }

        //
        fileHandle = [[NSFileHandle fileHandleForWritingAtPath:temporaryZipPath] retain];

        //
        NSURLRequest *request = [NSURLRequest requestWithURL:[self audioPackageURL]
                                                 cachePolicy:NSURLRequestReloadIgnoringCacheData 
                                             timeoutInterval:60.0f];

        currentConnection = [[NSURLConnection alloc] initWithRequest:request delegate:self];

        receivedData = [[NSMutableData data] retain];   
...

希望有帮助。