iOS Mapview-缩放至图钉，然后激活标注

Question

I have a mapview in xcode, which is all working well.

What my page does just now is like this:

1. downloads a bunch of data and locations from a backend database
2. populates a mapview with locations and drops pins
3. populates a table underneath the mapview

That all works great, and I end up with a mapview with a load of pins, and a tableview that has the details of those pins.

What I want to do now, is allow the user to tap on a row from the tableview, and have the map zoom and centre to the corresponding map pin, and then automatically activate the annotation pin callout.

In my 'didselectrow' method, I have the following:

MKCoordinateSpan span = MKCoordinateSpanMake(0.1f, 0.1f);
CLLocationCoordinate2D coordinate = { [item.latitude floatValue], [item.longitude floatValue] };
MKCoordinateRegion region = { coordinate, span };
[self.mapView setRegion:region animated:YES];

This works great too. Tapping on the table row will zoom to and centre the map pin at this location.

I just can't get the last step of firing the annotation pin callout to work.

I have tried:

[mapview annotationsInMapRect:mapview.visibleMapRect];

But this isn't working, and it is possible that there still might be 2 or 3 map pins in the visible area.

What I need to do is to get the pin nearest to the centred location (see above - item.latitude / item.longitude) to automatically open it's callout.

Everything in the code is set up and working, and the map pins have callouts that fire when tapped on, I just need this last stage of having the pin nearest the centre location to open automatically.

Can anyone help with this?

I have tried various other suggestions on SO, but none seem to fit this requirement.

Answer 1

I think I have got solution for your problem you need to use this [_mapView setSelectedAnnotations:@[[[self.mapView annotations] lastObject]]];

For testing I have created an small project that have these 2 methods .

- (IBAction)buttonTouched:(id)sender {
    [_mapView showAnnotations:[self.mapView annotations] animated:YES];
    [self performSelector:@selector(showAnnotationCallOut) withObject:nil afterDelay:1.0f];
}

- (void) showAnnotationCallOut {
    [_mapView setSelectedAnnotations:@[[[self.mapView annotations] lastObject]]];
}

Note: I have called just one annotation for test that why I am calling last object. You'll need to call it for specific annotation of your annotation array.

Edit: According to Richerd's comment here is solution for problem of finding the annotion and showing the callout fro that.

    for (MapViewAnnotation *annotion in [self.mapView annotion]) {
        if ([annotion.identifire isEqualToString:annotationToCallCallOutIdentifier]) {
            //[_mapView setSelectedAnnotations:@[annotation]];
            [_mapView selectAnnotation:annotation animated:YES];
            break;//don't break if there are can be more than one callouts
        }
    }