缩放以适合所有注释的区域 - 最终在注释之间放大

Question

我在将所有注释适合屏幕时遇到问题...有时它会显示所有注释，但有时应用程序会在两个注释之间放大，因此它们都不可见... 我希望应用程序始终使区域适合注释，而不是在它们之间放大...我做错了什么？

if ([mapView.annotations count] == 2) { 
 CLLocationCoordinate2D SouthWest = location;
 CLLocationCoordinate2D NorthEast = savedPosition;

 NorthEast.latitude = MAX(NorthEast.latitude, savedPosition.latitude);
 NorthEast.longitude = MAX(NorthEast.longitude, savedPosition.longitude); 

 SouthWest.latitude = MIN(SouthWest.latitude, location.latitude);
 SouthWest.longitude = MIN(SouthWest.longitude, location.longitude);

 CLLocation *locSouthWest = [[CLLocation alloc] initWithLatitude:SouthWest.latitude longitude:SouthWest.longitude];
 CLLocation *locNorthEast = [[CLLocation alloc] initWithLatitude:NorthEast.latitude longitude:NorthEast.longitude];

 CLLocationDistance meter = [locSouthWest distanceFromLocation:locNorthEast];

 MKCoordinateRegion region;
 region.span.latitudeDelta = meter / 111319.5;
 region.span.longitudeDelta = 0.0;
 region.center.latitude = (SouthWest.latitude + NorthEast.latitude) / 2.0;
 region.center.longitude = (SouthWest.longitude + NorthEast.longitude) / 2.0;

 region = [mapView regionThatFits:region];
 [mapView setRegion:region animated:YES];

 [locSouthWest release];
 [locNorthEast release]; 
}

有什么想法吗？

谢谢！！

Answer 1

使用以下代码

-(void)zoomToFitMapAnnotations:(MKMapView*)mapView{
    if([mapView.annotations count] == 0)
        return;

    CLLocationCoordinate2D topLeftCoord;
    topLeftCoord.latitude = -90;
    topLeftCoord.longitude = 180;

    CLLocationCoordinate2D bottomRightCoord;
    bottomRightCoord.latitude = 90;
    bottomRightCoord.longitude = -180;

    for(FSMapAnnotation* annotation in mapView.annotations)
    {
        topLeftCoord.longitude = fmin(topLeftCoord.longitude, annotation.coordinate.longitude);
        topLeftCoord.latitude = fmax(topLeftCoord.latitude, annotation.coordinate.latitude);

        bottomRightCoord.longitude = fmax(bottomRightCoord.longitude, annotation.coordinate.longitude);
        bottomRightCoord.latitude = fmin(bottomRightCoord.latitude, annotation.coordinate.latitude);
    }

    MKCoordinateRegion region;
    region.center.latitude = topLeftCoord.latitude - (topLeftCoord.latitude - bottomRightCoord.latitude) * 0.5;
    region.center.longitude = topLeftCoord.longitude + (bottomRightCoord.longitude - topLeftCoord.longitude) * 0.5;
    region.span.latitudeDelta = fabs(topLeftCoord.latitude - bottomRightCoord.latitude) * 1.1; // Add a little extra space on the sides
    region.span.longitudeDelta = fabs(bottomRightCoord.longitude - topLeftCoord.longitude) * 1.1; // Add a little extra space on the sides

    region = [mapView regionThatFits:region];
    [mapView setRegion:region animated:YES];
}

Answer 2

而不是：

region.span.latitudeDelta = meter / 111319.5;
 region.span.longitudeDelta = 0.0;
 region.center.latitude = (SouthWest.latitude + NorthEast.latitude) / 2.0;
 region.center.longitude = (SouthWest.longitude + NorthEast.longitude) / 2.0;

尝试添加：

region.span.latitudeDelta = fabs(NorthEast.latitude - SouthWest.latitude) * 1.2; 
region.span.longitudeDelta = fabs(SouthWest.longitude - NorthEast.longitude) * 1.2; 
region.center.latitude = NorthEast.latitude - (NorthEast.latitude - SouthWest.latitude) * 0.5;
region.center.longitude = NorthEast.longitude + (SouthWest.longitude - NorthEast.longitude) * 0.5;

并删除：

CLLocationDistance meter = [locSouthWest distanceFromLocation:locNorthEast];