Question

我想根据iOS设备方向旋转我的地图视图，我实现如下

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

}

然后我遇到一个问题，当mapView的相机旋转时，mapView无法缩放。

我该如何解决这个问题？

Answer 1

我意识到MKMapCamera是iOS7中的一个新类，可能它不稳定。

最后，我以另一种方式实现了mapView旋转：

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 Delegate

中实现地图旋转

#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)];
}

完成！

Answer 2

初始化MKMapView时应尝试使用方法- (void)setUserTrackingMode:(MKUserTrackingMode)mode animated:(BOOL)animated，例如：

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

我的地图根据此代码的标题进行了旋转。

Answer 3

在MKMapView的委托中，只需设置一个标志来检查用户是否正在尝试缩放：

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

并在更改后将其关闭：

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

并仅在未触及的情况下更改标题：

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

顺便说一句，您可能还想减少从LocationManager开始的标题更新频率：

- (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];
  }
}

MKMapView在相机标题旋转时无法缩放

3 个答案: