iOS 百度地图当前位置方向问题解决方案

大家都知道，如果需要百度地图当前位置能跟随手机方向而改变方向的话，使用百度地图自身的跟随模式BMKUserTrackingModeFollow就可以做到，但是有个问题，当点击当前滑动地图后，方向就不会改变了；那有没有其他方法能解决这个问题了？

我的做法是：不是用百度地图自身的跟随模式，也不是用百度地图自身的当前位置，而是自己添加一个annotation：

定义三个变量：

MyLocationAnnotation *myLocationAnnotation;

BMKAnnotationView *myLocationAnnotationView;

UIImage *myLocationImage;

一：在百度地图位置更新方法didUpdateBMKUserLocation里面调用下面的方法：
-(void) addMyLocationView {
bmkmapView.showsUserLocation = NO;
if(nil == myLocationAnnotation) {
myLocationAnnotation = [[MyLocationAnnotation alloc] init];
myLocationAnnotation.coordinate = myOutdoorLocation.location.coordinate;
[bmkmapView addAnnotation:myLocationAnnotation];
} else {
myLocationAnnotation.coordinate = myOutdoorLocation.location.coordinate;
}
}

二：在回调方法里面

-(BMKAnnotationView *)mapView:(BMKMapView *)mapView viewForAnnotation:(id<BMKAnnotation>)annotation{if ([annotation isKindOfClass:[MyLocationAnnotationclass]])
{

NSString *AnnotationViewID = @"locationMark";

BMKPinAnnotationView *animationView = (BMKPinAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:AnnotationViewID];

if(animationView ==nil){

animationView = [[BMKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:AnnotationViewID];

}

animationView.annotation = annotation;

myLocationAnnotationView = animationView;

myLocationImage = animationView.image = [UIImage imageNamed:@"my_loc"];//带箭头方向的图片

animationView.centerOffset = CGPointMake(0, animationView.frame.size.height/2);

return animationView;

}

}

三：在百度地图回调方法didUpdateUserHeading里，根据百度地图放回的方向设置当前位置的方向：

-(void) setUserHeading:(BMKUserLocation*)userHeading {

if(nil == userHeading ||
nil == userHeading.heading

|| userHeading.heading.headingAccuracy <
0) {

return;

}

CLLocationDirection theHeading = userHeading.heading.magneticHeading;

double d = 360 - theHeading;

float direction = theHeading;

if(nil !=
myLocationAnnotationView) {

if (direction >
180)

{

direction = 360 - direction;

}

else

{

direction = 0 - direction;

}

myLocationAnnotationView.image = [myLocationImage
imageRotatedByDegrees:-direction];

}

}

- (UIImage*) imageRotatedByDegrees:(CGFloat)degrees

{

CGFloat width =
CGImageGetWidth(self.CGImage);

CGFloat height =
CGImageGetHeight(self.CGImage);

CGSize rotatedSize;

rotatedSize.width = width;

rotatedSize.height = height;

UIGraphicsBeginImageContext(rotatedSize);

CGContextRef bitmap =
UIGraphicsGetCurrentContext();

CGContextTranslateCTM(bitmap, rotatedSize.width/2, rotatedSize.height/2);

CGContextRotateCTM(bitmap, degrees *
M_PI / 180);

CGContextRotateCTM(bitmap,
M_PI);

CGContextScaleCTM(bitmap, -1.0,
1.0);

CGContextDrawImage(bitmap,
CGRectMake(-rotatedSize.width/2, -rotatedSize.height/2, rotatedSize.width,
rotatedSize.height),
self.CGImage);

UIImage* newImage =
UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return newImage;

}