How can I pass a custom object when triggering a UIButton action? - ios

Question

I'm developing an iOS app with latest SDK.
I have a selector on the following method and I need to pass another argument:
- (MKAnnotationView *)mapView:(MKMapView *)theMapView viewForAnnotation:(id <MKAnnotation>)annotation
{
NSLog(#"viewForAnnotation");
MKAnnotationView *annotationView = nil;
// if it's the user location, just return nil.
if ([annotation isKindOfClass:[MKUserLocation class]])
return nil;
if ([annotation isKindOfClass:[ShopAnnotation class]])
{
// try to dequeue an existing pin view first
static NSString *ReusableAnnotationIdentifier = #"reusableShopAnnotationIdentifier";
MKPinAnnotationView *pinView = (MKPinAnnotationView *)[theMapView dequeueReusableAnnotationViewWithIdentifier:ReusableAnnotationIdentifier];
if (!pinView)
{
// if an existing pin view was not available, create one
MKPinAnnotationView *customPinView = [[MKPinAnnotationView alloc]
initWithAnnotation:annotation reuseIdentifier:ReusableAnnotationIdentifier];
customPinView.pinColor = MKPinAnnotationColorPurple;
customPinView.animatesDrop = YES;
customPinView.canShowCallout = YES;
// add a detail disclosure button to the callout which will open a new view controller page
UIButton* rightButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
[rightButton addTarget:self
action:#selector(showDetails:)
forControlEvents:UIControlEventTouchUpInside];
customPinView.rightCalloutAccessoryView = rightButton;
return customPinView;
}
else
{
pinView.annotation = annotation;
}
annotationView = pinView;
}
return annotationView;
}
I need to pass an object to showDetails::
// add a detail disclosure button to the callout which will open a new view controller page
UIButton* rightButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
[rightButton addTarget:self
action:#selector(showDetails:)
forControlEvents:UIControlEventTouchUpInside];
This is how showDetails is implemented:
- (void) showDetails:(id)sender
{
NSLog(#"Show Details");
DetailViewController* mvc = [[DetailViewController alloc] initWithNibName:#"DetailViewController_iPhone" bundle:nil];
mvc.delegate = self;
[self presentModalViewController:mvc animated:YES];
}
This is ShopAnnotation interface:
#import <Foundation/Foundation.h>
#import <MapKit/MapKit.h>
#import <CoreData/CoreData.h>
#interface ShopAnnotation : NSObject <MKAnnotation>
#property (nonatomic, readonly) CLLocationCoordinate2D coordinate;
#property (nonatomic, readonly, strong) NSString *title;
#property (nonatomic, readonly, strong) NSString *subtitle;
#property (nonatomic, readonly, strong) NSManagedObject* shop;
-(id)initWithCoordinate:(CLLocationCoordinate2D) c
title:(NSString *) t
subtitle:(NSString *) st
shop:(NSManagedObject*) shop;
#end
How can I add another argument to showDetails and how can I pass it?
showDetails will be:
- (void) showDetails:(id)sender shop:(NSManagedObject*)shop
And, what is this (id)sender? It is an annotation I could use to pass this NSManagedObject.

Answer 1

See how you're passing a "sender" parameter in your "showDetails:" method?
Why not subclass "UIButton" (e.g. name it "VansFannelButton") and give that new object's "#interface" a bonus ivar which can be your payload.
Then you can do:
- (void) showDetails: (VansFannelButton*) sender
{
if (sender)
{
// do something with the managed object payload
NSManagedObject * mObject = [sender payload];
}
}

Answer 2

Use Associated Objects for passing more argument to buttons's object
Refer associated-objects link.

Answer 3

You can try adding a property
int ID;
into your ShopAnnotation class, and when you are populating the ShopAnnotation class you can easily set your own unique ID. Then in
- (MKAnnotationView *)mapView:(MKMapView *)theMapView viewForAnnotation:(id <MKAnnotation>)annotation
{
if (!pinView)
{
// if an existing pin view was not available, create one
MKPinAnnotationView *customPinView = [[MKPinAnnotationView alloc]
initWithAnnotation:annotation reuseIdentifier:ReusableAnnotationIdentifier];
customPinView.pinColor = MKPinAnnotationColorPurple;
customPinView.animatesDrop = YES;
customPinView.canShowCallout = YES;
// add a detail disclosure button to the callout which will open a new view controller page
UIButton* rightButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
[rightButton addTarget:self
action:#selector(showDetails:)
forControlEvents:UIControlEventTouchUpInside];
//Set tag of the button same as ID
rightButton.tag=((ShopAnnotation*)annotation).ID;
customPinView.rightCalloutAccessoryView = rightButton;
return customPinView;
}
}
And in you showDetails action you can do the following
- (void) showDetails:(id)sender
{
UIButton *btn=(UIButton*)sender;
ShopAnnotation *selectedAnnotation=nil;
for(ShopAnnotation *a in arrAnnotations){
if(a.ID == btn.tag){
selectedAnnotation=a; break;
}
}
// Use your ShopAnnotation for you further processing.
}
I hope this helps..
Thanks.