How to show a UIProgressView for a download in my app?

I would like to show a progress bar indicating how much of a file has been downloaded in my iPhone app. I know how to set up the UIProgressView in IB and all that. But I need data such as file size in bytes to run it. How do I go about integrating such functionality with my byte download code (shown below)?

- (void)connection:(NSURLConnection *)theConnection didReceiveData:(NSData *)data
// A delegate method called by the NSURLConnection as data arrives.  We just 
// write the data to the file.
{
#pragma unused(theConnection)
    NSInteger       dataLength;
    const uint8_t * dataBytes;
    NSInteger       bytesWritten;
    NSInteger       bytesWrittenSoFar;

    assert(theConnection == self.connection);

    dataLength = [data length];
    dataBytes  = [data bytes];

    bytesWrittenSoFar = 0;
    do {
        bytesWritten = [self.fileStream writ开发者_开发问答e:&dataBytes[bytesWrittenSoFar] maxLength:dataLength - bytesWrittenSoFar];
        assert(bytesWritten != 0);
        if (bytesWritten == -1) {
            [self _stopReceiveWithStatus:@"File write error"];
            break;
        } else {
            bytesWrittenSoFar += bytesWritten;

        }
    } while (bytesWrittenSoFar != dataLength);
}

You can show show a byte-by-byte progress view if you switch to using the ASIHTTPRequest library.

I really recommend you at least check it out. It makes this stuff really simple on the iPhone and I use it for all my apps. It will do synchronous and asynchronous connections, deals with cookies and authentication, and makes composing POST requests really simple. It also has a built in network queue.

http://allseeing-i.com/ASIHTTPRequest/