How can I access and modify the alpha property of an MKOverlayRenderer after it has already been passed to the Map?
Indeed I can modify the alpha attribute in the rendererForOverlay method :
- (MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay:(id <MKOverlay>)overlay
{
if ([overlay isKindOfClass:[MKTileOverlay class]]) {
MKTileOverlayRenderer *renderer = [[MKTileOverlayRenderer alloc] initWithTileOverlay:overlay];
renderer.alpha = 0.6;
return renderer;
}
return nil;
}
But this method is only called when I add an Overlay to the mapView right?
So my question is : Is there a way to have the possibility to change and set the value of this alpha attribute even after my Overlay is already rendered on the map ?
I tried to add the renderer to a NSMutableArray with :
- (MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay:(id <MKOverlay>)overlay
{
if ([overlay isKindOfClass:[MKTileOverlay class]]) {
_allRenderer = [[NSMutableArray alloc] init];
MKTileOverlayRenderer *renderer = [[MKTileOverlayRenderer alloc] initWithTileOverlay:overlay];
renderer.alpha = 0.0;
[_allRenderer addObject:renderer];
return renderer;
}
return nil;
}
And then I can change the transparency by calling this method I made :
-(void)changeAlpha:(NSUInteger)index : (BOOL)isOpaque {
if (isOpaque)
[[_allRenderer objectAtIndex:index] setAlpha:0.0];
else
[[_allRenderer objectAtIndex:index] setAlpha:1.0];
}
Are there any better ways to do this ? It's seems kind of a slow process just to set the alpha value.
Actually I would like to switch from 0 to 1 the alpha value of my OverlayRenderer dynamically, so that I can display 1 Overlay, hide it, display an other one, hide it etc...
So basically what you can do is: rather than trying to set different alpha.
You can toggle between having an overlay and removing it and having an initial value for alpha.
For reference, please try this link: https://github.com/mapbox/mbxmapkit/issues/7