Progress Bar With NSURLConnection - ios

Question

I want to show the progress bar while downloading a video from an url. I'm not able to figure out where I have gone wrong,and also expectedContentLength is always showing -1. Here is the code.
-(void)getResource{
bytesReceived = 0;
self.progressView.progress = 0.0;
NSString *string = #“MY_URL";
NSMutableURLRequest *request =[[NSMutableURLRequest alloc] initWithURL:
[NSURL URLWithString:string]];
[request setHTTPMethod:#"POST"];
[request setValue:#"application/json" forHTTPHeaderField:#"Content-length"];
[request setValue:#"application/json" forHTTPHeaderField:#"Content-Type"];
[request setValue:#"application/json" forHTTPHeaderField:#"Accept"];
self.feedConnection = [[NSURLConnection alloc]initWithRequest:request delegate:self]
}
-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{
self.responseData = [NSMutableData data];
[self.responseData setLength:0];
float length = [response expectedContentLength];
expectedBytes = [NSNumber numberWithUnsignedInteger:length];
NSLog(#"expected bytes %f %#",length,expectedBytes);
}
-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{
[self.responseData appendData:data];
float progress = (float)[self.responseData length]/[expectedBytes floatValue];
NSLog(#"%f / %f is %f", (float)[self.responseData length] ,[expectedBytes floatValue],progress);
self.progressView.progress = progress;
}
-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error{
self.feedConnection = nil;
}
-(void)connectionDidFinishLoading:(NSURLConnection *)connection{
self.feedConnection = nil;
[self.view setBackgroundColor:[UIColor blackColor]];
[self fetchedData:self.responseData];
self.responseData = nil;
}

Answer 1

I think,you Can use NSURLConnectionDownloadDelegate method in which will get the totalBytes and how much data has been downloaded.
- (void)connection:(NSURLConnection *)connection
didWriteData:(long long)bytesWritten
totalBytesWritten:(long long)totalBytesWritten
expectedTotalBytes:(long long) expectedTotalBytes;