最后尝试我[self.mapView removeOverlays：self.mapView.overlays];它仍然不起作用.任何想法如何删除这些叠加？

谢谢.

更新1

我有错误：malloc：***错误的对象0x5adc0c0：指针被释放没有分配
***在malloc_error_break中设置一个断点来进行调试

我想我知道为什么,但不知道如何解决它？
以下是我需要在mapView上绘制另一行的代码：

// Create a c array of points. 
MKMapPoint *pointsArray = malloc(sizeof(CLLocationCoordinate2D) * 2);

// Create 2 points.
MKMapPoint startPoint = MKMapPointForCoordinate(CLLocationCoordinate2DMake(oldLatitude,oldLongitude));
MKMapPoint endPoint = MKMapPointForCoordinate(CLLocationCoordinate2DMake(newLatitude,newLongitude));

// Fill the array.
pointsArray[0] = startPoint;
pointsArray[1] = endPoint;

// Erase polyline and polyline view if not nil.
if (self.routeLine != nil) {
    [_routeLine release];
    self.routeLine = nil;
}

if (self.routeLineView != nil) {
    [_routeLineView release];
    self.routeLineView = nil;
}

// Create the polyline based on the array of points.
self.routeLine = [MKPolyline polylineWithPoints:pointsArray count:2];

// Add overlay to map.
[self.mapView addOverlay:self.routeLine];

// clear the memory allocated earlier for the points.
free(pointsArray);

// Save old coordinates.
oldLatitude = newLatitude;
oldLongitude = newLongitude;

所以我释放了以前的叠加层的routeLine对象.所以当我试图删除它,它崩溃,因为它已被释放.

以下是用于添加重叠式视图的mapView代理的代码：

- (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id <MKOverlay>)overlay
{
    MKOverlayView* overlayView = nil;

    if(overlay == _routeLine) {
        // If we have not yet created an overlay view for this overlay,create it now. 
        if(self.routeLineView == nil) {
            self.routeLineView = [[[MKPolylineView alloc] initWithPolyline:_routeLine] autorelease];

            self.routeLineView.fillColor = [UIColor blueColor];
            self.routeLineView.strokeColor = [UIColor blueColor];

            // Size of the trace.
            self.routeLineView.lineWidth = routeLineWidth;
        }

        overlayView = self.routeLineView;
    }

    return overlayView;
}

如果你们知道如何解决这个问题,从MKMapView中删除所有的叠加层就会很棒！

更新2

我试图没有释放我的routeLine和routeLineView对象,它现在工作.似乎也没有泄漏.所以现在我这样做：

// Erase polyline and polyline view if not nil.
if (self.routeLine != nil) {
    //[_routeLine release];
    self.routeLine = nil;
}

if (self.routeLineView != nil) {
    //[_routeLineView release];
    self.routeLineView = nil;
}