Animating a sprite across a MKMapView - iphone

Question

Without getting into OpenGL (Quartz 2D is OK):
Let's say I have an image which I want to move across a map in some fluid way. For instance, an image of a plane "flying" across the map. I've been able to do this using an MKAnnotation, an NSTimer and fiddling with the rate of lat/lon change and timer rate. However, I assume this isn't ideal, although the results look pretty decent. Can you think of a better way?
Now let's say that I want this image to be animated (think: animated gif). I can't do the usual UIImageView with a series of animationFrames because all I have access to in MKAnnotationView is a UIImage. How would you guys tackle this?
I realize that #2 could be handled with a UIImageView on top of the map containing the animationImages. However, then I would have to manually handle translating the movement of the plane or rocket or whatever as the region of the mapview changed, depending on user movements in the real-world, or user zooming (scrolling is not allowed in my app).
What do you think?

Answer 1

I think I've figured out a solution to #2. I subclassed MKAnnotationView and wrote some code to add a UIImageView (with animation images) as a subview.
//AnimatedAnnotation.h
#import <Foundation/Foundation.h>
#import <MapKit/MapKit.h>
#interface AnimatedAnnotation : MKAnnotationView
{
UIImageView* _imageView;
NSString *imageName;
NSString *imageExtension;
int imageCount;
float animationDuration;
}
#property (nonatomic, retain) UIImageView* imageView;
#property (nonatomic, retain) NSString* imageName;
#property (nonatomic, retain) NSString* imageExtension;
#property (nonatomic) int imageCount;
#property (nonatomic) float animationDuration;
- (id)initWithAnnotation:(id <MKAnnotation>)annotation reuseIdentifier:(NSString *)reuseIdentifier imageName:(NSString *)name imageExtension:(NSString *)extension imageCount:(int)count animationDuration:(float)duration
;
#end
//AnimatedAnnotation.m
#import "AnimatedAnnotation.h"
#implementation AnimatedAnnotation
#synthesize imageView = _imageView;
#synthesize imageName, imageCount, imageExtension,animationDuration;
- (id)initWithAnnotation:(id <MKAnnotation>)annotation reuseIdentifier:(NSString *)reuseIdentifier imageName:(NSString *)name imageExtension:(NSString *)extension imageCount:(int)count animationDuration:(float)duration
{
self = [super initWithAnnotation:annotation reuseIdentifier:reuseIdentifier];
self.imageCount = count;
self.imageName = name;
self.imageExtension = extension;
self.animationDuration = duration;
UIImage *image = [UIImage imageNamed:[NSString stringWithFormat:#"%#0.%#",name,extension]];
self.frame = CGRectMake(0, 0, image.size.width, image.size.height);
self.backgroundColor = [UIColor clearColor];
_imageView = [[UIImageView alloc] initWithFrame:self.frame];
NSMutableArray *images = [[NSMutableArray alloc] init];
for(int i = 0; i < count; i++ ){
[images addObject:[UIImage imageNamed:[NSString stringWithFormat:#"%#%d.%#", name, i, extension]]];
}
_imageView.animationDuration = duration;
_imageView.animationImages = images;
_imageView.animationRepeatCount = 0;
[_imageView startAnimating];
[self addSubview:_imageView];
return self;
}
-(void) dealloc
{
[_imageView release];
[super dealloc];
}
#end