MKUserTrackingModeFollowWithHeading，zoom

Question

我使用MKUserTrackingModeFollowWithHeading，以便地圖跟隨用戶位置並旋轉。問題是縮放級別不堅持。這裏是我的代碼

-(void) viewWillAppear:(BOOL)animated { 
[super viewWillAppear:animated]; 
self.locMapView.delegate = self; 
[self.locMapView setUserTrackingMode:MKUserTrackingModeFollowWithHeading animated:YES]; 

}

-(void) viewDidAppear:(BOOL)animated{ 
[super viewDidAppear:animated]; 

MKMapPoint pt = MKMapPointForCoordinate(_locMapView.userLocation.coordinate); 
double w = MKMapPointsPerMeterAtLatitude(_locMapView.userLocation.coordinate.latitude) * 500; 
MKMapRect zoomRect = MKMapRectMake(pt.x - w/2.0, pt.y - w/2.0, w, w); 

[_locMapView setVisibleMapRect:zoomRect animated:YES]; 

}

我試圖設置縮放級別viewDidLoad中也沒有多少運氣。

當UserTrackingMode設置爲MKUserTrackingModeFollowWithHeading時，如何使地圖粘到縮放級別？

Answer 1

下面是我解決這個問題的技巧：在放大/縮小之前設置mapView.userTrackingMode = MKUserTrackingModeNone，然後設置= MKUserTrackingModeFollowWithHeading。

@property (assign, nonatomic) MKUserTrackingMode lastTrackingMode; 

- (IBAction)zoomInButtonPressed:(id)sender { 
    self.mapView.userTrackingMode = MKUserTrackingModeNone; 

    MKCoordinateRegion newRegion = MKCoordinateRegionMake(self.mapView.region.center,MKCoordinateSpanMake(self.mapView.region.span.latitudeDelta*0.5, self.mapView.region.span.longitudeDelta*0.5)); 
    [self.mapView setRegion:newRegion]; 

    self.mapView.userTrackingMode = self.lastTrackingMode; 
} 

- (IBAction)zoomOutButtonPressed:(id)sender { 
    self.mapView.userTrackingMode = MKUserTrackingModeNone; 

    // Zoom-out code goes here 

    self.mapView.userTrackingMode = self.lastTrackingMode; 
}