iOS GoogleMaps SDK - animateToCameraPosition anima

问题:

Currently I am using the GoogleMaps SDK for iOS for various operations. When calling

[self.googleMapsView animateToCameraPosition:[GMSCameraPosition 
                            cameraWithLatitude:LATITUDE
                                     longitude:LONGITUDE
                                          zoom:ZOOM]];

is there a completion handler to determine wether the animation finished or not?

Of course I get with the GMSMapViewDelegate updates about the cameraPosition but how should I check if the animation finished?

- (void)mapView:(GMSMapView *)mapView 
didChangeCameraPosition:(GMSCameraPosition *)position;

回答1:

For the reference of future readers of this post, Google Maps SDK for iOS Version 1.4.0 released in July 2013 has added a new delegate method mapView:idleAtCameraPosition: which will be fired at the end of any camera movement - be it programatic animation like in this question or user triggered movements.

回答2:

This might work (I haven't tried it):

[CATransaction begin];
[CATransaction setValue:[NSNumber numberWithFloat: 1.0f] forKey:kCATransactionAnimationDuration];
[self.googleMapsView animateToCameraPosition:[GMSCameraPosition 
                        cameraWithLatitude:LATITUDE
                                 longitude:LONGITUDE
                                      zoom:ZOOM]];
[CATransaction setCompletionBlock:^{
    // ... whatever you want to do when the animation is complete
}];
[CATransaction commit];

Basically, this creates an animation transaction that animates your camera movement (change the value for numberWithFloat: to change the speed) and you set your own completion block stating what you want to do when the animation is over. [CATransaction commit] is what fires the animation off.

Note: this answer partially based off this answer.

回答3:

I don't believe there is, however...

A method that has worked well for me so far is to set a timer to fire (very) shortly after the location stops updating:

- (void)mapView:(GMSMapView*)mapView didChangeCameraPosition:(GMSCameraPosition*)position {
  // _panTimer is an instance variable of the delegate.
  [_panTimer invalidate];
  _panTimer = [NSTimer timerWithTimeInterval:0.2
                                      target:self
                                    selector:@selector(_mapHasStoppedMoving)
                                    userInfo:nil
                                     repeats:NO];
  [[NSRunLoop currentRunLoop] addTimer:_panTimer forMode:NSDefaultRunLoopMode];
}

回答4:

I came across the issue of google's animation methods lacking completion handlers recently.
The best solution I've found so far is to attach my own completion handler via CATransation API.

private func attachCompletionHandlerToGoogleAnimations(@noescape animations: () -> Void, #completion: (() -> Void)!) {
    CATransaction.begin()
    CATransaction.setCompletionBlock(completion)
    animations()
    CATransaction.commit()
}

Example usage:

attachCompletionHandlerToGoogleAnimations({
    googleMapView.animateToLocation(coordinate)
}) {
    println("camera moved to location \(coordinate)")
}

回答5:

SWIFT version example:

let vancouver = CLLocationCoordinate2D(latitude: 49.26, longitude: -123.11)
let calgary = CLLocationCoordinate2D(latitude: 51.05,longitude: -114.05)
let bounds = GMSCoordinateBounds(coordinate: vancouver, coordinate: calgary)
let cameraPosition = GMSCameraUpdate.fit(bounds)

CATransaction.begin()
CATransaction.setValue(1.0/*duration in seconds*/, forKey: kCATransactionAnimationDuration)
CATransaction.setCompletionBlock({
    print("animation complete, do whatever you want here")
})
mMapView.animate(with: cameraPosition)
CATransaction.commit()