Conditional Custom Annotation View in iphone MapView - iphone

Question

In my MapView, i read data from SQLite and display pins on it (up to 5000 record).
the database has the structure of ID| Longitude| Latitude | Title | subtitle
i used this code to make the pin clickable:
pin.rightCalloutAccessoryView = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
i need to add a new column (Clickable) in the database, and make the pin clickable just if the "Clickable" value is ON.
any detailed suggestion about the best idea to do that?

Answer 1

From my experience if you don't set any property of the annotation (title,subTitle,image,accessory-button) and tap on the pin, the callout is not displayed.
Instead, if you want show the callout but not call an action when the accessory button is tapped, you could use a thing like this:
(After downloading the data from the db, you could store each item as a NSDictionary and then all items in a NSArray)
- (void)mapView:(MKMapView *)mapView annotationView:(MKAnnotationView *)view calloutAccessoryControlTapped:(UIControl *)control{
NSString *clickable=[[yourArray objectAtIndex:yourIndex] objectForKey:#"clickable"];
if(![clickable isEqualToString:#"YES"]){
return;
}
}
Of course I used a string as example, you may also use NSNumbers or BOOLs.
Hope i understood your question.

Answer 2

To control whether the callout has the accessory button based on the "clickable" flag in the table, I suggest you add a clickable property to your annotation class and set it when adding the annotation. Then you can check this property when creating the annotation view in the viewForAnnotation method.
To add the annotations to the map view (ie. when you call addAnnotation), if you are currently using a pre-defined class like MKPointAnnotation, you'll need to instead define your own custom class that implements the MKAnnotation protocol. If you already have a custom class, add a clickable property to it.
Here's an example of a custom annotation class:
//CustomAnnotation.h...
#interface CustomAnnotation : NSObject<MKAnnotation>
#property (nonatomic, assign) CLLocationCoordinate2D coordinate;
#property (nonatomic, copy) NSString *title;
#property (nonatomic, copy) NSString *subtitle;
#property (nonatomic, assign) int annotationId;
#property (nonatomic, assign) BOOL clickable;
#end
//CustomAnnotation.m...
#implementation CustomAnnotation
#synthesize coordinate;
#synthesize title;
#synthesize subtitle;
#synthesize annotationId;
#synthesize clickable;
- (void)dealloc {
[title release];
[subtitle release];
[super dealloc];
}
#end
Here's an example of how you would create and add the annotations (the actual values for the annotation properties will come from your sql rows):
CustomAnnotation *ca1 = [[CustomAnnotation alloc] init];
ca1.annotationId = 1;
ca1.coordinate = CLLocationCoordinate2DMake(lat1,long1);
ca1.title = #"clickable";
ca1.subtitle = #"clickable subtitle";
ca1.clickable = YES;
[myMapView addAnnotation:ca1];
[ca1 release];
CustomAnnotation *ca2 = [[CustomAnnotation alloc] init];
ca2.annotationId = 2;
ca2.coordinate = CLLocationCoordinate2DMake(lat2,long2);
ca2.title = #"not clickable";
ca2.subtitle = #"not clickable subtitle";
ca2.clickable = NO;
[myMapView addAnnotation:ca2];
[ca2 release];
Then the viewForAnnotation will look like this:
-(MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id<MKAnnotation>)annotation
{
static NSString *reuseId = #"CustomAnnotation";
MKPinAnnotationView* customPinView = (MKPinAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:reuseId];
if (customPinView == nil) {
customPinView = [[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:reuseId] autorelease];
customPinView.pinColor = MKPinAnnotationColorPurple;
customPinView.animatesDrop = YES;
customPinView.canShowCallout = YES;
}
else {
customPinView.annotation = annotation;
}
CustomAnnotation *ca = (CustomAnnotation *)annotation;
if (ca.clickable)
customPinView.rightCalloutAccessoryView = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
else
customPinView.rightCalloutAccessoryView = nil;
return customPinView;
}
Finally, you can handle the button press in the calloutAccessoryControlTapped delegate method and access your custom annotation's properties:
-(void)mapView:(MKMapView *)mapView annotationView:(MKAnnotationView *)view calloutAccessoryControlTapped:(UIControl *)control
{
CustomAnnotation *ca = (CustomAnnotation *)view.annotation;
NSLog(#"annotation tapped, id=%d, title=%#", ca.annotationId, ca.title);
}