how to display progressbar during downloading video file from the server in to the iphone?

I have implemented video play functionality in iphone.In which i am downloading video file from the server and then play. But I want to display progress bar during downloading video file.For progressbar 开发者_C百科i need to calculate timing i don't know how to calculate time how much will take time for downloading video.

So please help me for this query.

Thanks in advance.

You can get the expected total file size in the following callback method of NSURLConnection's NSURLConnectionDataDelegate:

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
   self.expectedTotalSize = response.expectedContentLength;
}

then in following callback method you can calculate how much data has been received:

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
   self.recievedData += data.length;
}

And you can use UIProgressView to show current downloading status on the screen.