如何在MKMapView上绘制UIBezierPath覆盖

Question

我尝试从MKOverlayPathRenderer派生并实现-createPath

- (void)createPath
{
    MKPolyline *line = (id)self.overlay;
    MKMapPoint *points = line.points;
    NSUInteger pointCount = line.pointCount;
    CGMutablePathRef path = CGPathCreateMutable();
    CGPathMoveToPoint(path, NULL, points[0].x, points[0].y);
    for (int i = 1; i < pointCount; i++) {
        CGPathAddLineToPoint(path, NULL, points[i].x, points[i].y);
    }
    [self setPath:path];
}

我在这里创建覆盖：

CLLocationCoordinate2D coordinates[events.count];
for (int i; i < events.count; i++) {
    coordinates[i] = [events[i] coordinate];
}
MKPolyline *line = [MKPolyline polylineWithCoordinates:coordinates count:events.count];
[mapView addOverlay:line];

然后在这里创建渲染器：

- (MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay:(MKPolyline *)overlay
{
    MKBezierPathRenderer *r = [[MKBezierPathRenderer alloc] initWithOverlay:overlay];
    r.lineWidth = 8.f;
    r.strokeColor = [UIColor redColor];
    r.fillColor = [UIColor redColor];
    return r;
}

但我在地图上看不到任何线条。我该怎么办？Thanx。

p.S.CGPathAddLineToPoint现在用于测试，在生产中我需要曲线。

Answer 1

根据Anna的回答，您应该使用[self pointForMapPoint:points[i]]而不是points[i]

- (void)createPath
{
    MKPolyline *line = (id)self.overlay;
    MKMapPoint *points = line.points;
    NSUInteger pointCount = line.pointCount;
    CGMutablePathRef path = CGPathCreateMutable();
    CGPoint point = [self pointForMapPoint:points[0]];
    CGPathMoveToPoint(path, NULL, point.x, point.y);
    for (int i = 1; i < pointCount; i++) {
        point = [self pointForMapPoint:points[i]];
        CGPathAddLineToPoint(path, NULL, point.x, point.y);
    }
    [self setPath:path];
}