NSFileHandle waitForDataInBackgroundAndNotify example ios

waitForDataInBackgroundAndNotify

Asynchronously checks to see if data is available.

- (void)waitForDataInBackgroundAndNotify

Discussion

When the data becomes available, this method posts a NSFileHandleDataAvailableNotification notification on the current thread.[NSFileHandle waitForDataInBackgroundAndNotify]

You must call this method from a thread that has an active run loop.

Example of [NSFileHandle waitForDataInBackgroundAndNotify]

/** * Fired whenever new data becomes available on STDERR * * @private */ -(void) errorData: (NSNotification *) notification { NSFileHandle *fileHandle = (NSFileHandle*) [notification object]; NSData *data = [fileHandle availableData]; if ([data length]) { // consume data // ... [fileHandle waitForDataInBackgroundAndNotify]; } else { // EOF was hit, remove observer [[NSNotificationCenter defaultCenter] removeObserver:self name:NSFileHandleDataAvailableNotification object:fileHandle]; } }

---------------------------------------------------------------------------

-(void) outData: (NSNotification *) notification
{
NSFileHandle *fileHandle = (NSFileHandle*) [notification object];
NSData *data = [fileHandle availableData];

if ([data length]) {

    NSString *currentString = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
    // do something 
}

[fileHandle waitForDataInBackgroundAndNotify]; //Checks to see if data is available in a background thread.
}

-(void) errData: (NSNotification *) notification
{
NSLog(@"errData");
NSFileHandle *fileHandle = (NSFileHandle*) [notification object];
[fileHandle waitForDataInBackgroundAndNotify];
}