MKMapView的攝像頭旋轉時無法縮放

Question

我想根據iOS設備的方向旋轉地圖視圖，實現方式如下

- (void)locationManager:(CLLocationManager *)manager didUpdateHeading:(CLHeading *)newHeading
{
    self.userDirection = newHeading.trueHeading;
    self.mapView.camera.heading = newHeading.trueHeading;

}

然后我遇到一個問題，當mapView的攝像機旋轉時，mapView無法縮放。

我怎么解決這個問題？

Answer 1

我意識到MKMapCamera是MKMapCamera中的新類，也許是不穩定的。

最后，我以另一種方式實現mapView旋轉：

首先，我放大mapView

#pragma mark - Map View Setup
- (void)setupMapView
{
    // setup size
    double edgeLength = sqrt(pow(screenSize.size.width, 2) + pow(screenSize.size.height, 2));
    self.mapView = [[MKMapView alloc] initWithFrame:CGRectMake(0, 0, edgeLength, edgeLength)];
    self.mapView.center = screenCenter;
    self.mapView.delegate = self;
}

下一步，在CLLocationManager委托中實現地圖旋轉

#define DEGREES_TO_RADIANS(degrees) ((degrees / 180.0) * (M_PI))
...
...
- (void)locationManager:(CLLocationManager *)manager didUpdateHeading:(CLHeading *)newHeading
{
     double radians = DEGREES_TO_RADIANS(newHeading.trueHeading);
     [self.mapView setTransform:CGAffineTransformMakeRotation(-radians)];
}

做完了！

Answer 2

您應該嘗試使用方法- (void)setUserTrackingMode:(MKUserTrackingMode)mode animated:(BOOL)animated在初始化MKMapView時設置- (void)setUserTrackingMode:(MKUserTrackingMode)mode animated:(BOOL)animated例如：

self.mapView.delegate = self
self.mapView.setUserTrackingMode(MKUserTrackingModeFollowWithHeading, animated: true)

我的地圖確實按照此代碼的標題旋轉。

Answer 3

在MKMapView的委托中，只需設置一個標志來檢查用戶是否正在嘗試縮放：

- (void)mapView:(MKMapView *)mapView regionWillChangeAnimated:(BOOL)animated
{
  isTouching = YES;
}

並在更改后將其關閉：

- (void)mapView:(MKMapView *)mapView regionDidChangeAnimated:(BOOL)animated
{
  isTouching = NO;
}

並僅在不觸摸的情況下更改標題：

- (void)changeMapHeading:(CLLocationDirection)heading
{
  if (!isTouching)
  {
    targetMapView.camera.heading = heading;
  }
}

順便說一句，您可能還想減少LocationManager中標題的更新頻率：

- (void)locationManager:(CLLocationManager *)manager didUpdateHeading:(CLHeading *)newHeading
{
  NSDate *now = [NSDate date];
  NSTimeInterval diff = [now timeIntervalSinceDate:lastHeadingUpdateTime];
  if (diff > 0.1)
  {
    lastHeadingUpdateTime = now;
    [[NSNotificationCenter defaultCenter] postNotificationName:kNotificationTrackingHeadingUpdated object:newHeading];
  }
}