[super awakeFromNib];
}


First, setup your audio session to record audio:

NSURL *url = [NSURL fileURLWithPath:@"/dev/null"];
NSDictionary *settings = [NSDictionary dictionaryWithObjectsAndKeys:
   [NSNumber numberWithFloat: 44100.0],                 AVSampleRateKey,
   [NSNumber numberWithInt: kAudioFormatAppleLossless], AVFormatIDKey,
   [NSNumber numberWithInt: 1],                         AVNumberOfChannelsKey,
   [NSNumber numberWithInt: AVAudioQualityMax],         AVEncoderAudioQualityKey, nil];

recorder = [[AVAudioRecorder alloc] initWithURL:url settings:settings error:&error];
if (recorder) {
   [recorder prepareToRecord];
   recorder.meteringEnabled = YES;
   [recorder record];
} else {
   NSLog(@"Error: %@", error);
}

Then tell the device you want to record and play audio at the same time:

AVAudioSession *audioSession = [AVAudioSession sharedInstance];
NSError *err = nil;
[audioSession setCategory :AVAudioSessionCategoryPlayAndRecord error:&err];

Then, and this is the key, allow the volume from the speakers to also be loud when recording:

UInt32 audioRouteOverride = kAudioSessionOverrideAudioRoute_Speaker;
AudioSessionSetProperty (kAudioSessionProperty_OverrideAudioRoute,
sizeof(audioRouteOverride),&audioRouteOverride);

The end result? You can happily play audio at full volume while recording from the device’s microphone. Happy days.

-(UIImage *) convertToGreyscale:(UIImage *)i {

    int kRed = 1;
    int kGreen = 2;
    int kBlue = 4;

    int colors = kGreen;
    int m_width = i.size.width;
    int m_height = i.size.height;

    uint32_t *rgbImage = (uint32_t *) malloc(m_width * m_height * sizeof(uint32_t));
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    CGContextRef context = CGBitmapContextCreate(rgbImage, m_width, m_height, 8, m_width * 4, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipLast);
    CGContextSetInterpolationQuality(context, kCGInterpolationHigh);
    CGContextSetShouldAntialias(context, NO);
    CGContextDrawImage(context, CGRectMake(0, 0, m_width, m_height), [i CGImage]);
    CGContextRelease(context);
    CGColorSpaceRelease(colorSpace);

    // now convert to grayscale
    uint8_t *m_imageData = (uint8_t *) malloc(m_width * m_height);
    for(int y = 0; y < m_height; y++) {
        for(int x = 0; x < m_width; x++) {
			uint32_t rgbPixel=rgbImage[y*m_width+x];
			uint32_t sum=0,count=0;
			if (colors & kRed) {sum += (rgbPixel>>24)&255; count++;}
			if (colors & kGreen) {sum += (rgbPixel>>16)&255; count++;}
			if (colors & kBlue) {sum += (rgbPixel>>8)&255; count++;}
			m_imageData[y*m_width+x]=sum/count;
        }
    }
    free(rgbImage);

    // convert from a gray scale image back into a UIImage
    uint8_t *result = (uint8_t *) calloc(m_width * m_height *sizeof(uint32_t), 1);

    // process the image back to rgb
    for(int i = 0; i < m_height * m_width; i++) {
        result[i*4]=0;
        int val=m_imageData[i];
        result[i*4+1]=val;
        result[i*4+2]=val;
        result[i*4+3]=val;
    }

    // create a UIImage
    colorSpace = CGColorSpaceCreateDeviceRGB();
    context = CGBitmapContextCreate(result, m_width, m_height, 8, m_width * sizeof(uint32_t), colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipLast);
    CGImageRef image = CGBitmapContextCreateImage(context);
    CGContextRelease(context);
    CGColorSpaceRelease(colorSpace);
    UIImage *resultUIImage = [UIImage imageWithCGImage:image];
    CGImageRelease(image);

    // make sure the data will be released by giving it to an autoreleased NSData
    [NSData dataWithBytesNoCopy:result length:m_width * m_height];

    return resultUIImage;
}

Thanks to the friendly people at StackOverflow.com for this snipet.

You can hear more here:

What does iPhone OS 3.0 Mean for Your Apps (WSP Online)

NSString* theString = [[NSString alloc] initWithData:theData encoding:NSASCIIStringEncoding];

There is no delegate method or other built-in mechanism for detecting when your annotation is selected, however it does have a selected property.  So how to detect when the MKAnnotation is selected and then play my sounds?  The answer is key/value observing.

Setup an observer on our imageAnnontationView:

// At the top of the .m file put:
static NSString* const GMAP_ANNOTATION_SELECTED = @"gMapAnnontationSelected";

// Then later somewhere in your code, add the observer
[imageAnnotationView addObserver:self
		 forKeyPath:@"selected"
		options:NSKeyValueObservingOptionNew
		context:GMAP_ANNOTATION_SELECTED];

Then we get a callback whenever the selected property of our annotation changes:

- (void)observeValueForKeyPath:(NSString *)keyPath
                      ofObject:(id)object
                        change:(NSDictionary *)change
                       context:(void *)context{

    NSString *action = (NSString*)context;

    if([action isEqualToString:GMAP_ANNOTATION_SELECTED]){
      BOOL annotationAppeared = [[change valueForKey:@"new"] boolValue];
     // do something
   }
}

The value of annotationAppeared will change based on the state of the annontations selected property.  GMAP_ANOTATION_SELECTED is a constant string I set at the top of my file.

I’ve updated my post to make the GMAP_ANOTATION_SELECTED constant more obvious.  Hopefully this helps people use the snippet above.

So what to do?  Simple, implement the following CLLocationManager delegate method:

- (void)locationManager:(CLLocationManager *)manager
       didFailWithError:(NSError *)error

Inside this method, make sure you deal with not receiving any GPS locations in a sensible manner (show a popup, skip etc).

Then you get a message from the Application Loader:

Application failed codesign verification.

What the??  If you check the activity log you also see the following:

A sealed resource is missing or invalid

After countless hours trawling Google and finding nothing, I worked out that I needed to do two things:

1. Remove all files from the project that started with ._ (dot then underscore).  See my previous post for more, however you just open the terminal and run find . -name “._*” -print0 | xargs -0 rm -rf from the command line in the root of the project
2. Make sure that the Icon File setting in the info.plist file is empty

After making these two changes, and rebuilding my project (make sure you do a “clean all”) it submitted to Apple without problem.  I really hope that helps someone…

Sometimes you don’t want this ‘highlight’ to appear – or you want it to be another color.  Here is the code that will help you in this situation:

Remove the grey highlight completely:

-webkit-tap-highlight-color:rgba(0,0,0,0);

Change the color of the highlight:

-webkit-tap-highlight-color:your-color-here;

[self.popupPreviewView release];
self.popupPreviewView = nil;

The best way to solve this (that I’ve found – please post a comment if you can provide a better one) is to remove the view from it’s superview rather than release it:

[self.popupPreviewView removeFromSuperview];
self.popupPreviewView = nil;