iOS Google Map SDK Crash when adding GMSPolygon or GMSPolyline to Map

Question

Added everything according to the Getting Started guide. Map loads, and I can add GMSMarkers to the map without problem. I've got a method to draw a polygon, and the app crashes every time.

The method:

-(void)drawPolygon
{
    GMSMutablePath* path = [[GMSMutablePath alloc] init];
    [path addCoordinate:CLLocationCoordinate2DMake(-91.13343811039999, 42.6450805664)];
    [path addCoordinate:CLLocationCoordinate2DMake(-91.0180969238,42.6452140808)];
    [path addCoordinate:CLLocationCoordinate2DMake(-90.8977890015,42.6446838379)];
    [path addCoordinate:CLLocationCoordinate2DMake(-90.89622497560001,42.6696586609)];
    [path addCoordinate:CLLocationCoordinate2DMake(-90.8959732056,42.6752548218)];
    [path addCoordinate:CLLocationCoordinate2DMake(-90.88994598390001,42.6732940674)];

    GMSPolygon* poly = [GMSPolygon polygonWithPath:path];

    poly.strokeWidth = 2.0;
    poly.strokeColor = [UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:1.0];
    poly.fillColor = [UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:0.4];
    poly.map = _mapView;        //CRASH!!
}

Here's a backtrace:

thread #1: tid = 0x1c03, 0x0010ebde Maps`(anonymous namespace)::PolygonInstance::UpdateEntities(float, gmscore::base::reffed_ptr<gmscore::vector::Camera>, gmscore::renderer::EntityRenderer*, (anonymous namespace)::MarkupBehavior*) + 288, stop reason = EXC_BAD_ACCESS (code=2, address=0x4)
frame #0: 0x0010ebde Maps`(anonymous namespace)::PolygonInstance::UpdateEntities(float, gmscore::base::reffed_ptr<gmscore::vector::Camera>, gmscore::renderer::EntityRenderer*, (anonymous namespace)::MarkupBehavior*) + 288
frame #1: 0x00111f3c Maps`(anonymous namespace)::MarkupBehavior::Commit(gmscore::renderer::EntityRenderer*) + 978
frame #2: 0x0008aad2 Maps`gmscore::renderer::EntityRenderer::Draw(bool) + 634
frame #3: 0x000d6a46 Maps`-[GMSEntityRendererView draw] + 200
frame #4: 0x000d5a85 Maps`-[GMSEntityRendererView displayLinkFired:] + 33
frame #5: 0x00144399 Maps`-[GMSDisplayLink displayLinkFired:] + 351
frame #6: 0x00f9e2d2 QuartzCore`CA::Display::DisplayLink::dispatch(unsigned long long, unsigned long long) + 110
frame #7: 0x00f9e75f QuartzCore`CA::Display::TimerDisplayLink::callback(__CFRunLoopTimer*, void*) + 161
frame #8: 0x02519376 CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 22
frame #9: 0x02518e06 CoreFoundation`__CFRunLoopDoTimer + 534
frame #10: 0x02500a82 CoreFoundation`__CFRunLoopRun + 1810
frame #11: 0x024fff44 CoreFoundation`CFRunLoopRunSpecific + 276
frame #12: 0x024ffe1b CoreFoundation`CFRunLoopRunInMode + 123
frame #13: 0x038167e3 GraphicsServices`GSEventRunModal + 88
frame #14: 0x03816668 GraphicsServices`GSEventRun + 104
frame #15: 0x012bfffc UIKit`UIApplicationMain + 1211
frame #16: 0x0000298d Maps`main(argc=1, argv=0xbffff3e0) + 141 at main.m:16

I'm not trying to use MapKit at all. No other OpenGL contexts have been created. Can anyone provide me with a working example of GMSPolygon? I believe my example follows the official example.

Using SDK version 1.3.1. ARC is enabled. Single-View app using Storyboards. Pan/Zoom everything else works, just not shape drawing.

Answer 1

Have either of you found a solution to this issue? I am having the exact same problem, and even using the Google Maps SDK for iOS code verbatim it is still crashing. It crashes on the bolded item below:

GMSMutablePath *path = [GMSMutablePath path];
[path addCoordinate:CLLocationCoordinate2DMake(37.36, -122.0)];
[path addCoordinate:CLLocationCoordinate2DMake(37.45, -122.0)];
[path addCoordinate:CLLocationCoordinate2DMake(37.45, -122.2)];
[path addCoordinate:CLLocationCoordinate2DMake(37.36, -122.2)];
[path addCoordinate:CLLocationCoordinate2DMake(37.36, -122.0)];

**GMSPolyline *rectangle = [GMSPolyline polylineWithPath:path];**
rectangle.map = mapView_;

EDIT: I have found the solution for this behavior:

To correct the issue, simply wrap your current code in a dispatch block. Reason being, Google Maps SDK requires that all drawing events be done on the main thread. The below code works properly:

dispatch_async(dispatch_get_main_queue(), ^{
    GMSMutablePath *path = [GMSMutablePath path];
    [path addCoordinate:CLLocationCoordinate2DMake(37.36, -122.0)];
    [path addCoordinate:CLLocationCoordinate2DMake(37.45, -122.0)];
    [path addCoordinate:CLLocationCoordinate2DMake(37.45, -122.2)];
    [path addCoordinate:CLLocationCoordinate2DMake(37.36, -122.2)];
    [path addCoordinate:CLLocationCoordinate2DMake(37.36, -122.0)];

    **GMSPolyline *rectangle = [GMSPolyline polylineWithPath:path];**
    rectangle.map = mapView_;
});