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I am trying to call the server asynchronously (ARC -on):
NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:request delegate:self];
if (theConnection) {
content = [NSMutableData data];
NSLog(#"responseData from setup.php: %#", content);
} else {
// Inform the user that the connection failed.
NSLog(#"error from server response in set up");
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
NSLog(#"connection did receive response");
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
[content appendData:data];
NSLog(#"connection did receive data");
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSLog(#"connection did finish load");
NSLog(#"Succeeded! Received %# bytes of data",receivedData);
}
But i am having problem getting the content from the server:-
in didReceiveData function, following error is coming:-
No visible #interface for 'NSString' declares the selector 'appendData'
Can anybody suggest me where I could be wrong?
in your .h file in the interface section please declare the following
NSMutableData *content;
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MY Problem is that i connected connection with the delegate but it is not interrupting its delegate method. I want to fetch address for my annotation and display it in annotation view. i successfully fetched the address but the mapview loading takes time, that is why i used the NsConnection Method . Please help me if i have made any mistake.
CLLocationCoordinate2D coordinate;
coordinate.latitude = 28.6667;
coordinate.longitude = 77.2167;
clusterMap.region = MKCoordinateRegionMakeWithDistance(coordinate, 5000, 5000);
self.blocks = 4;
self.minimumClusterLevel = 100000;
// super.delegate = self;
zoomLevel = clusterMap.visibleMapRect.size.width * clusterMap.visibleMapRect.size.height;
NSMutableArray *pins = [[NSMutableArray alloc]init];
for(int i =0 ; i < 50; i++)
{
CGFloat latDelta = rand()*0.125/RAND_MAX - 0.02;
CGFloat lonDelta = rand()*0.130/RAND_MAX - 0.08;
newCoord.latitude = coordinate.latitude+latDelta;
newCoord.longitude = coordinate.longitude+lonDelta;
NSString *urlString = [NSString stringWithFormat:#"http://maps.googleapis.com/maps/api/geocode/json?latlng=%f,%f&sensor=false",newCoord.latitude, newCoord.longitude];
// NSLog(#"Is%# main thread", ([NSThread isMainThread] ? #"" : #" NOT"));
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:urlString]];
NSURLConnection *connection = [[NSURLConnection alloc]initWithRequest:request delegate:self];
[connection start];
customannView = [[AnnotationView alloc]initWithLatitude:newCoord.latitude andLongitude:newCoord.longitude];
// customannView.title = [NSString stringWithFormat:#"Pin %i",i];
customannView.title =locationString;
customannView.subtitle = [NSString stringWithFormat:#"Pin %i",i];
customannView.coordinate = newCoord;
customannView.imgName = #"bookmark1.png";
[pins addObject:customannView];
[connection cancel];
}
[self addAnnotations:pins];
UILongPressGestureRecognizer *dropPin = [[UILongPressGestureRecognizer alloc] init];
[dropPin addTarget:self action:#selector(handleLongPress:)];
dropPin.minimumPressDuration = 0.5;
[clusterMap addGestureRecognizer:dropPin];
}
// [self performSelector:#selector(mapViewWillStartLoadingMap:) withObject:nil afterDelay:0.01];
UILongPressGestureRecognizer *dropPin = [[UILongPressGestureRecognizer alloc] init];
[dropPin addTarget:self action:#selector(handleLongPress:)];
dropPin.minimumPressDuration = 0.5;
[clusterMap addGestureRecognizer:dropPin];
}
#pragma mark NSURLConnection Delegate Methods
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
// A response has been received, this is where we initialize the instance var you created
// so that we can append data to it in the didReceiveData method
// Furthermore, this method is called each time there is a redirect so reinitializing it
// also serves to clear it
[responseData setLength:0];
NSLog(#"Response :: %#",responseData);
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
// Append the new data to the instance variable you declared
[responseData appendData:data];
}
- (NSCachedURLResponse *)connection:(NSURLConnection *)connection
willCacheResponse:(NSCachedURLResponse*)cachedResponse {
// Return nil to indicate not necessary to store a cached response for this connection
return nil;
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
// The request is complete and data has been received
// You can parse the stuff in your instance variable now
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
// The request has failed for some reason!
// Check the error var
}
why are you doing
[connection cancel];
because it cancel the process before hitting the delegates.Remove that line and the code will work
The difficulty with your approach is that you are spawning a number of NSURLConnections and try then to handle with one delegate.
In order to figure out which connection and response data is associated to which latitude/longitude and response data object in your delegate method you would need to obtain the original request from the connection and then parse the URL which contains that info. This is cumbersome at least.
I would suggest to create a class (or use a third party library) that encapsulates one NSURLConnection request, the response data and possibly other state info. Purposefully, this class has a completion block where it becomes easy to associate the latitude/longitude and response data from the call site with each completion handler of a finished connection.
i m working on a project that connect to server and download data from it. i like to support resume download if connection gets interrupt. my approach is to save the downloaded portion of data to a destination file; and if connection gets interrupted, i want to mark the downloaded portion using connection:didWriteData:totalBytesWritten:expectedTotalBytes and later resume from the stopped portion with server.
my code:
- (IBAction)connectToServer:(UIButton *)sender
{
// setup url and send request to server
NSURL *url = [NSURL URLWithString:BASED_URL];
self.urlRequest = [[NSMutableURLRequest alloc] initWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60.0];
self.urlConnection = [[NSURLConnection alloc] initWithRequest:self.urlRequest delegate:self];
// start receive data if connection established
if (self.urlConnection){
self.receivedData = [NSMutableData data];
NSLog(#"starting to receive data");
} else {
// handle error
NSLog(#"failed to connect to server");
}
}
- (void)doSomethingWithData
{
// handle data here
}
#pragma NSURLConnectionDataDelegate
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
[self.receivedData setLength:0];
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
// received data
[self.receivedData appendData:data];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
// error connection
NSLog(#"connection failed");
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSLog(#"Data receiving succeed, received: %d bytes of data", [self.receivedData length]);
}
- (void)connection:(NSURLConnection *)connection didWriteData:(long long)bytesWritten totalBytesWritten:(long long)totalBytesWritten expectedTotalBytes:(long long)expectedTotalBytes
{
NSLog(#"not getting called");
}
my question is how come the "connection:didWriteData:totalBytesWritten:expectedTotalBytes" method never get called?
thanks so much!
chris
Have u added this in .h file:
#interface yourViewContoller : UIViewController <NSURLConnectionDataDelegate, NSURLConnectionDelegate>
According to Apple's documentation:
The NSURLConnectionDownloadDelegate protocol describes methods that should be implemented by the delegate of instances of NSURLConnection created using Newsstand Kit’s downloadWithDelegate: method.
Also, it says:
If you are using NSURLConnection directly, your delegate class should instead implement the methods defined in the NSURLConnectionDataDelegate protocol.
I've been reading several threads and questions about this issue but I didn't find the solution.
I have some asynchronous calls performed with
[NSURLConnection connectionWithRequest:anURLRequest delegate:self];
The problem is that I want the interface to be operative but it is blocked until the connection is finished.
Is this solved launching another thread? Where is exactly the problem?
EDIT
Ok, after retrieve data I parse it with NSXMLParser, that do it synchronously and blocks main thread. Is this correct? Then, maybe I need to parse in another thread. Anyone has a guide?
From the docs:
Messages to the delegate will be sent on the thread that calls this method. For the connection to work correctly the calling thread’s run loop must be operating in the default run loop mode.
Are you sure that this code is being called on a run loop in default mode and not from a thread created by yourself with a different type of run loop mode?
The UI should not be locking up when you use connectionWithRequest. Try creating a label in your UI and have your connection update it with the current amount of data, like so:
- (void)downloadContentFromUrl:(NSURL *)url {
NSURLRequest *request = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:10.0];
NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
if (connection) {
receivedData = [[NSMutableData data] retain];
self.downloadProgressLabel.text = #"Downloading...";
} else {
// oh noes!
}
}
- (void) connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
[receivedData setLength:0];
}
- (void) connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
[receivedData appendData:data];
int kb = [receivedData length] / 1024;
self.downloadProgressLabel.text = [NSString stringWithFormat:#"Downloaded\n%d kB", kb];
}
connectionWithRequest does indeed run in it's own thread - no need for you to worry about this. In fact it must be started from the main thread. Check out the NSUrlConnection doc for more info.
+ (id)connectionWithRequest:(NSURLRequest *)request delegate:(id)delegate];
This method should create an asynchronous-request (that means that it runs in the background and it doesn't block the UI). You should check if there's another class/method in your file that blocks the UI (for example NSData's '+ (NSData *)dataWithContentsOfURL:(NSURL *)URL').
I don't know if it could help anyone, but I've the same problem (asynchronous URL request blocking the UI) but it was due to:
NSLog(#"dataReceived: %#", data);
in the connectionDidReceiveData method.
In my case I was trying to update the UIProgressView.progress property. I calculated the new value like that
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{
[self.progress setProgress:self.downloadedData.length / self.fileSize ];
[self.downloadedData appendData:data];
}
Which doesn't work, I replaced this snippet of code with
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{
self.downloadedSize += data.length;
[self.progress setProgress:self.downloadedSize / self.fileSize ];
[self.downloadedData appendData:data];
}
And now the progress view updates with no problem.
I saw similar questions here, but I couldn't find solution to my problem.
I have a simple NSURLConnection in main thread (At least I didn't create any other threads), but my delegate methods aren't get called
[[[NSURLConnection alloc] initWithRequest:request delegate:self] autorelease];
and no methods called, e.g.
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
NSLog(#"didReceiveResponse");
}
self is also a delegate for NSXMLParser, but I think it should not be a problem, as I have this working in my other class in the same project. I checked everything 10 times already, but can't find any problem.
I've seen some hack to solve it here: http://www.depl0y.com/?p=345 but I don't like it, May be someone knows better solution? thanks
The only reason I know is a separate thread (that is already terminated when the delegate methods are called).
Try to NSLog(#"Is%# main thread", ([NSThread isMainThread] ? #"" : #" NOT"));right before the url connection creation
Try running your connection on main thread:
NSURLConnection * connection = [[NSURLConnection alloc] initWithRequest:request
delegate:self startImmediately:NO];
[connection scheduleInRunLoop:[NSRunLoop mainRunLoop]
forMode:NSDefaultRunLoopMode];
[connection start];
The autorelease is dangerous. The calls to the delegate are made after your function returns (asynchronously). Are you retaining it somewhere else?
You have to release the NSURLConnection object in the - (void)connectionDidFinishLoading:(NSURLConnection *)connection callback as pointed out in the Apple documentation, not elsewhere:
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
// Do whatever you want here
// Release the connection
[connection release];
}
Don't release it with autorelease, as Lou Franco suggested.
If it is not the problem, then maybe you have to implement all the required methods in the delegate class:
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
The delegate is retained by NSURLConnection so you don't have to worry about it.
I think you may have missed NSURLConnectionDelegate in your class header file.
For example:
#interface yourClass : NSObject <NSURLConnectionDelegate>
i'm a beginner to iphone.i want to create a login page for my application.i cant figure out how to connect to a php page and retrieve corresponding data from mysql database to the iphone.could any one guide me how to go about it.
what does the iphone have to do with a connection between php and mysql ?
PHP will run with on a web server probably apache installed on some computer and it will connect to a MySQL db .. and u will access that php page from your iphone with a browser. Not sure what part will the iphone have in all this other than providing the browser
You might want to have a look at NSURLRequest which you can use with a NSURLConnection to send e.g. GET-Parameters to a URL. You can then implment the NSURLConnectionDelegate to respond to incoming data:
1) setup connection
receivedData =[NSMutableData data];
NSURLRequest *theRequest=[NSURLRequest requestWithURL:[NSURL URLWithString:url]
cachePolicy:NSURLRequestUseProtocolCachePolicy
timeoutInterval:20.0];
NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
2) Setup delegate methods in self:
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse*)response {
NSHTTPURLResponse * httpResponse = (NSHTTPURLResponse *) response;
if([httpResponse statusCode]==200)
[receivedData setLength:0];
else
NSLog(#"Http-Reponse %u",[httpResponse statusCode]);
// HANDLE ERROR!
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
// append the new data to the receivedData
// receivedData is declared as a method instance elsewhere
[receivedData appendData:data];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
// HANDLE THE CONNECTION ERROR
// release the connection, and the data object
[connection release];
// receivedData is declared as a method instance elsewhere
[receivedData release];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
// receivedData contains the data
// convert to string:
NSLog(#"finished loading: %#",[[[NSString alloc] initWithData:receivedData encoding:NSUTF8StringEncoding] autorelease]);
[connection release];
[receivedData release];
}
You'll want to expose the authentication functionality as a web service, then use the URL Loading code posted by Felix L. to initiate an actual connection to the web service.
You'll probably want to send a response from the server as XML, if so, you'll parse that response with an NSXMLParser, otherwise you can just send the response in whatever format you'd like and parse it appropriately.