iphone - iPhone：MKMapView缩小和缩小导致地图region.center漂移

我有一个使用MKMapView的简单iphone应用程序。它有一个分段控件，可以调整区域进行缩放（街道，社区，城市，州，世界）。它工作正常，但如果我缩小到州级并回到街道，我注意到中心点已经移动。

以下是在区域更改之前和之后调用的两个委托方法以及由分段控件调用的changeZoom方法：

- (void)mapView:(MKMapView *)mView regionDidChangeAnimated:(BOOL)animated
{
 MKCoordinateRegion region = [mapView region];

 NSLog(@"Region DID change.   Center is now %f,%f,  Deltas=%f,%f", 
    region.center.latitude, region.center.longitude,
    region.span.latitudeDelta, region.span.longitudeDelta);
}

- (void)mapView:(MKMapView *)mView regionWillChangeAnimated:(BOOL)animated
{
 MKCoordinateRegion region = [mapView region];

 NSLog(@"Region WILL change.   Center is now %f,%f,  Deltas=%f,%f", 
    region.center.latitude, region.center.longitude,
    region.span.latitudeDelta, region.span.longitudeDelta);
}


- (IBAction)changeZoom:(id)sender
{
 UISegmentedControl *sc = (UISegmentedControl *)sender;

 float mile_range = 1;

 NSLog(@"changeZoom called.   MapView currently is Center=%f,%f  Deltas=%f,%f", 
    mapView.region.center.latitude, mapView.region.center.longitude,
    mapView.region.span.latitudeDelta, mapView.region.span.longitudeDelta );

 switch ( [sc selectedSegmentIndex] )
 {
  case 0: /* Street */
   mile_range=1;
   break;
  case 1: /* Hood */
   mile_range=2;
   break;
  case 2: /* City */
   mile_range=30;
   break;
  case 3: /* State */
   mile_range=500;
   break;
  case 4: /* World */
   mile_range=4000;
   break;
  default: /* Error */
   NSLog(@"Unknown segment selected from the UISegmentedControl!!!!!!!!!!!!!!");
   return;
   break;
 }

 originalZoomCenter = mapView.region.center;
 MKCoordinateRegion region;
    region = MKCoordinateRegionMakeWithDistance( originalZoomCenter, mile_range/MILES_PER_METER, mile_range/MILES_PER_METER );
    region = [mapView regionThatFits: region];

 NSLog(@"Calling setRegion Center=%f,%f  Deltas=%f,%f", 
    region.center.latitude, region.center.longitude,
    region.span.latitudeDelta, region.span.longitudeDelta );

    [mapView setRegion: region animated: YES];

 NSLog(@"After setRegion Center=%f,%f  Deltas=%f,%f", 
    mapView.region.center.latitude, mapView.region.center.longitude,
    mapView.region.span.latitudeDelta, mapView.region.span.longitudeDelta );
}

如果我运行应用程序并且它在我当前位置的街道缩放级别开始，然后我点击缩小到州级别并回到街道级别，我在控制台中得到以下输出：

Region WILL change.   Center is now 30.145127,-40.078125,  Deltas=151.851332,225.000000
Region DID change.   Center is now 37.331676,-122.030725,  Deltas=0.024842,0.027466
changeZoom called.   MapView currently is Center=37.331676,-122.030725  Deltas=0.024842,0.027466
Calling setRegion Center=37.331676,-122.030725  Deltas=12.708100,14.062500
Region WILL change.   Center is now 37.331676,-122.030725,  Deltas=0.024842,0.027466
After setRegion Center=37.331676,-122.030725  Deltas=0.024842,0.027466
Region DID change.   Center is now 37.335224,-122.036133,  Deltas=12.707505,14.062500 
changeZoom called.   MapView currently is Center=37.335224,-122.036133  Deltas=12.707505,14.062500
Calling setRegion Center=37.335224,-122.036133  Deltas=0.024841,0.027466
Region WILL change.   Center is now 37.335224,-122.036133,  Deltas=12.707505,14.062500
After setRegion Center=37.335224,-122.036133  Deltas=12.707505,14.062500
Region DID change.   Center is now 37.335224,-122.036133,  Deltas=0.024841,0.027466

因此，我在代码中进行的所有调用都按预期进行，并且中心没有变化，但是当我监视MKMapViewDelegate方法regionDidChangeAnimated时，我看到中心被移动了。如果我在那里设置断点，我会看到一个如下所示的堆栈：

#0 0x00034c4c in -[MapViewController mapView:regionDidChangeAnimated:] at MapViewController.m:209
#1 0x01fbf7bf in -[MKMapView _didChangeRegionMidstream:]
#2 0x003e11f5 in -[UIView(Gestures) animator:stopAnimation:]
#3 0x003743be in -[UIAnimator stopAnimation:]
#4 0x00374154 in -[UIAnimator(Static) _advance:]
#5 0x0264d719 in HeartbeatTimerCallback
#6 0x01d28ac0 in CFRunLoopRunSpecific
#7 0x01d27c48 in CFRunLoopRunInMode
#8 0x0264a78d in GSEventRunModal
#9 0x0264a852 in GSEventRun
#10 0x00307003 in UIApplicationMain
#11 0x00002194 in main at main.m:14

这并没有真正帮助我理解为什么中心会移动。我已经在模拟器和设备上运行了它，这让我有点疯狂。

如果有人对导致中心转移的原因有任何了解，我将不胜感激。

iPhone：MKMapView缩小和缩小导致地图region.center漂移

1 个答案: