我可以在适用于 iOS 的 GoogleMaps SDK 中为比例标记设置动画吗？

Question

参考Do marker animations exist on GoogleMaps SDK for iOS? 和Google Dev Guide 我知道我只能在标记出现时使用appearAnimation 设置动画，并通过GMSMarkerLayer 设置不透明度的动画

因为GMSMarkerLayer.icon 是UIImage。我可以像一个名为Find My Friends 的应用程序一样设置缩放GMSMarker 图标的动画吗？ （当点击标记时，它会动画缩放或放大标记图标）

谢谢。

Answer 1

您可以通过更改分配给它的 ui 图像来缩放 gmsMarker 图标。

理想情况下，您应该从 ui 线程（在 sn-p 中通过另一个线程完成）回调动画函数以防止闪烁。

这里有一个示例代码 sn-p 来测试这个概念：

BOOL runInflateAnimation=YES;
float curScaleFactor=1.0f;
float curScaleDirection=-1.0f;
float scaleStep=0.2f;
float scaleMin=0.5f;
float scaleMax=2.0f;

double lastTimeStamp;
-(void) startBouncyAnimation
{
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW,(unsigned   long)NULL), ^(void)
               {
                   while (runBouncyAnimation)
                   {

                       double curTimeStamp =[[NSDate date] timeIntervalSince1970];
                       double delta;
                       if (lastTimeStamp>0)
                       {
                           delta = curTimeStamp - lastTimeStamp;
                           curScaleFactor+=scaleStep*curScaleDirection * delta;
                           if (curScaleFactor<scaleMin)
                           {
                               curScaleFactor=scaleMin;
                               curScaleDirection*=-1.0f;
                           } else if (curScaleFactor>scaleMax)
                           {
                               curScaleFactor=scaleMax;
                               curScaleDirection*=-1.0f;
                           }
                           [self hackAnimation];

                       }
                       lastTimeStamp =curTimeStamp;
                       [NSThread sleepForTimeInterval:0.1f];
                   }

               }
               );
}


-(void) hackAnimation
{
    if (![NSThread isMainThread])
    {
        [self performSelectorOnMainThread:@selector(hackAnimation) withObject:nil waitUntilDone:NO];
    }
@synchronized(currentLocationMarker)
{
GMSMarker* theMarker = currentLocationMarker;
UIImage* curImage = [UIImage imageNamed:@"myMarker.png"];
UIImage* scaled = [UIImage imageWithData:UIImagePNGRepresentation(curImage) scale:curScaleFactor];
theMarker.icon=scaled;
}

}

Answer 2

如果您希望标记被点击后的增长动画而不是有弹性的动画，请像这样初始化您的标记图像：

kStartingImageScale = 3.0 // make it available in your class.

marker.icon = UIImage(data: UIImagePNGRepresentation(UIImage(named: "marker")!)!, scale: CGFloat(kStartingImageScale))!

然后使用@MichaelCMS稍微修改的方法

func startAnimation(shouldGrow:Bool) {

    let scaleMin:Double = 2.0;
    let scaleMax:Double = kStartingImageScale;
    var curScaleFactor:Double = shouldGrow ? scaleMax: scaleMin;
    var curScaleDirection:Double = 1.0;
    let scaleStep:Double = 4.0;

    let priority = DISPATCH_QUEUE_PRIORITY_DEFAULT
    dispatch_async(dispatch_get_global_queue(priority, 0)) {

        var runAnimation: Bool = true

        var lastTimeStamp:Double?

        while (runAnimation)
        {

            let curTimeStamp:Double = NSDate().timeIntervalSince1970
            var delta:Double;
            if (lastTimeStamp>0)
            {
                delta = curTimeStamp - lastTimeStamp!;
                curScaleFactor+=scaleStep*curScaleDirection*delta;
                if (curScaleFactor < scaleMin)
                {
                    curScaleFactor = scaleMin;
                    curScaleDirection = curScaleDirection*(-1.0);

                    runAnimation = !shouldGrow

                }
                else if (curScaleFactor>scaleMax)
                {
                    curScaleFactor = scaleMax;
                    curScaleDirection = curScaleDirection*(-1.0);

                    runAnimation = shouldGrow

                }
                self.hackAnimation(curScaleFactor)

            }

            lastTimeStamp = curTimeStamp;
            NSThread.sleepForTimeInterval(0.01)
        }
    }
}

func hackAnimation(curScaleFactor:Double)
{
    let theMarker:GMSMarker = self.marker!;
    let curImage:UIImage = UIImage(named: "marker")!
    let scaled:UIImage  = UIImage(data: UIImagePNGRepresentation(curImage)!, scale: CGFloat(curScaleFactor))!

    dispatch_async(dispatch_get_main_queue(), { () -> Void in
        theMarker.icon=scaled;
    })
}

// MARK: - GMSMapViewDelegate

var grooow:Bool = true;

func mapView(mapView: GMSMapView!, didTapMarker marker: GMSMarker!) -> Bool {

    DDLogDebug("Marker tapped \(marker)")
    startAnimation(grooow)
    grooow = !grooow

    return true
}