iPhone Dev = maps and deselecting annotations

Question

I am successfully drawing annotations on a map using an array of annotations. I can even click on the annotation and change it’s colour or image. My problem arises when the use selects the second annotation and I want to dynamically change the colour or image of the first one back to a non-selected colour/image. I can get the array of all the annotations and work through the array but once I try to set the colour or image ot the array I get a similar error.

for (MKAnnotationView *ann in map.selectedAnnotations){ if ([ann isMemberOfClass:[Place class]]) { place = (Place *)ann; if (currentPlaceID != place.placeID) { UIImage *i = [UIImage imageNamed:@"pin.png"];

ann.image = i; }

}

the above code works ok until I get to ann.image = i; then it errors. The errors I get are:-

• -[Place setImage:]: unrecognized selector sent to instance 0x4514370 Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '** -[Place setImage:]: unrecognized selector sent to instance 0x4514370'

Please advise as I have been going around in circles on this one for 2 days now!!!!

Any ideas on how best to do this?

thanks in advance Cheryl

Answer 1

Do you have a property on the class Place called image?

Something like... @property (nonatomic, retain) UIImage* image; and is it properly synthesized? @synthesize image;?

The error is pretty straight forward, some object is receiving a message that it doesn't respond to, namely 'setImage' which is invoked by the .image.

Here is your code:

1. for (MKAnnotationView *ann in map.selectedAnnotations) {
2.    if ([ann isMemberOfClass:[Place class]]) {
3.        place = (Place *)ann;
4.        if (currentPlaceID != place.placeID) {
5.           UIImage *i = [UIImage imageNamed:@"pin.png"];
6.           ann.image = i;
7.        }
8.    }
9. }

What I can see:

• ann is an MKAnnotationView (from map.selectedAnnotations)
• you are typecasting your annotation to a place on line 3 (is this right? Does Place subclass MKAnnotationView?)
• you are properly setting the image to the annotation

What this means:

• If Place is indeed a subclass of MKAnnotationView, you hid the setImage (somehow) method
• If Place is NOT a subclass of MKAnnotationView, you've added an invalid annotation to the annotations (sure) that you're trying to treat as an annotation.

Answer 2

I finally figured out how to do this. As usual it's not that hard once you know how. Just thought I would pass this on.

`- (void)setSelected:(BOOL)selected animated:(BOOL)animated{ [super setSelected:selected animated:animated];

NSLog(@"here I am in set selected");

if (YES == selected){
 NSLog(@"I am selected");
}else {
 self.backgroundColor = [UIColor clearColor];
 NSLog(@"not selected");
}

}`