我使用Daniel在这里提供的自定义MKAnnotationView动画:子类化MKAnnotationView并重写setDragState，但我遇到了一个问题。
在大头针掉落动画之后，当我去移动地图时，mkannotationview跳回到最后一个大头针掉落动画块被调用之前的位置。
在我看来，dragState=MKAnnotationViewDragStateEnding在动画运行之前被调用?我怎样才能解决这个问题，并将mkannotationview的最后一个点设置为动画结束时它所在的点?
#import "MapPin.h"
NSString *const DPAnnotationViewDidFinishDrag = @"DPAnnotationViewDidFinishDrag";
NSString *const DPAnnotationViewKey = @"DPAnnotationView";
// Estimate a finger size
// This is the amount of pixels I consider
// that the finger will block when the user
// is dragging the pin.
// We will use this to lift the pin even higher during dragging
#define kFingerSize 20.0
@interface MapPin()
@property (nonatomic) CGPoint fingerPoint;
@end
@implementation MapPin
@synthesize dragState, fingerPoint, mapView;
- (void)setDragState:(MKAnnotationViewDragState)newDragState animated:(BOOL)animated
{
if(mapView){
id<MKMapViewDelegate> mapDelegate = (id<MKMapViewDelegate>)mapView.delegate;
[mapDelegate mapView:mapView annotationView:self didChangeDragState:newDragState fromOldState:dragState];
}
// Calculate how much to life the pin, so that it's over the finger, no under.
CGFloat liftValue = -(fingerPoint.y - self.frame.size.height - kFingerSize);
if (newDragState == MKAnnotationViewDragStateStarting)
{
CGPoint endPoint = CGPointMake(self.center.x,self.center.y-liftValue);
[MapPin animateWithDuration:0.2
animations:^{
self.center = endPoint;
}
completion:^(BOOL finished){
dragState = MKAnnotationViewDragStateDragging;
}];
}
else if (newDragState == MKAnnotationViewDragStateEnding)
{
// lift the pin again, and drop it to current placement with faster animation.
__block CGPoint endPoint = CGPointMake(self.center.x,self.center.y-liftValue);
[MapPin animateWithDuration:0.2
animations:^{
self.center = endPoint;
}
completion:^(BOOL finished){
endPoint = CGPointMake(self.center.x,self.center.y+liftValue);
[MapPin animateWithDuration:0.1
animations:^{
self.center = endPoint;
}
completion:^(BOOL finished){
dragState = MKAnnotationViewDragStateNone;
if(!mapView)
[[NSNotificationCenter defaultCenter] postNotificationName:DPAnnotationViewDidFinishDrag object:nil userInfo:[NSDictionary dictionaryWithObject:self.annotation forKey:DPAnnotationViewKey]];
}];
}];
}
else if (newDragState == MKAnnotationViewDragStateCanceling)
{
// drop the pin and set the state to none
CGPoint endPoint = CGPointMake(self.center.x,self.center.y+liftValue);
[UIView animateWithDuration:0.2
animations:^{
self.center = endPoint;
}
completion:^(BOOL finished){
dragState = MKAnnotationViewDragStateNone;
}];
}
}
- (UIView*)hitTest:(CGPoint)point withEvent:(UIEvent*)event
{
// When the user touches the view, we need his point so we can calculate by how
// much we should life the annotation, this is so that we don't hide any part of
// the pin when the finger is down.
fingerPoint = point;
return [super hitTest:point withEvent:event];
}
@end
我也遇到了同样的问题，特别是在iOS 8下。经过几个小时的测试，我相信iOS会在状态为MKAnnotationViewDragStateDragging时跟踪它认为注释的self.center所在的位置。当处理MKAnnotationViewDragStateEnding时，如果你动画self.center，你需要非常小心。你可以把这句话理解为"我永远无法做到这一点。"
MKAnnotationViewDragStateStarting和MKAnnotationViewDragStateCanceling时，我保留了Daniel的原始代码，我动画了self.center。当处理MKAnnotationViewDragStateEnding时，我动画self.transform而不是self.center。这将维护注释的实际位置，并更改其呈现方式。
这对我运行iOS 7.1和iOS 8.0都很有效。还修复了hitTest中的一个bug，并添加了一些代码来在拖动或取消注释后重新选择注释。我想这是MKPinAnnotationView的默认行为。
- (void)setDragState:(MKAnnotationViewDragState)newDragState animated:(BOOL)animated
{
if(mapView){
id<MKMapViewDelegate> mapDelegate = (id<MKMapViewDelegate>)mapView.delegate;
[mapDelegate mapView:mapView annotationView:self didChangeDragState:newDragState fromOldState:dragState];
}
// Calculate how much to lift the pin, so that it's over the finger, not under.
CGFloat liftValue = -(fingerPoint.y - self.frame.size.height - kFingerSize);
if (newDragState == MKAnnotationViewDragStateStarting)
{
CGPoint endPoint = CGPointMake(self.center.x,self.center.y-liftValue);
[UIView animateWithDuration:0.2
animations:^{
self.center = endPoint;
}
completion:^(BOOL finished){
dragState = MKAnnotationViewDragStateDragging;
}];
}
else if (newDragState == MKAnnotationViewDragStateEnding)
{
CGAffineTransform theTransform = CGAffineTransformMakeTranslation(0, -liftValue);
[UIView animateWithDuration:0.2
animations:^{
self.transform = theTransform;
}
completion:^(BOOL finished){
CGAffineTransform theTransform2 = CGAffineTransformMakeTranslation(0, 0);
[UIView animateWithDuration:0.2
animations:^{
self.transform = theTransform2;
}
completion:^(BOOL finished){
dragState = MKAnnotationViewDragStateNone;
if(!mapView)
[[NSNotificationCenter defaultCenter] postNotificationName:DPAnnotationViewDidFinishDrag object:nil userInfo:[NSDictionary dictionaryWithObject:self.annotation forKey:DPAnnotationViewKey]];
// Added this to select the annotation after dragging.
// This is the behavior for MKPinAnnotationView
if (mapView)
[mapView selectAnnotation:self.annotation animated:YES];
}];
}];
}
else if (newDragState == MKAnnotationViewDragStateCanceling)
{
// drop the pin and set the state to none
CGPoint endPoint = CGPointMake(self.center.x,self.center.y+liftValue);
[UIView animateWithDuration:0.2
animations:^{
self.center = endPoint;
}
completion:^(BOOL finished){
dragState = MKAnnotationViewDragStateNone;
// Added this to select the annotation after canceling.
// This is the behavior for MKPinAnnotationView
if (mapView)
[mapView selectAnnotation:self.annotation animated:YES];
}];
}
}
- (UIView*)hitTest:(CGPoint)point withEvent:(UIEvent*)event
{
// When the user touches the view, we need his point so we can calculate by how
// much we should life the annotation, this is so that we don't hide any part of
// the pin when the finger is down.
// Fixed a bug here. If a touch happened while the annotation view was being dragged
// then it screwed up the animation when the annotation was dropped.
if (dragState == MKAnnotationViewDragStateNone)
{
fingerPoint = point;
}
return [super hitTest:point withEvent:event];
}