iphone - Mapkit 绘制路线问题

Question

我正在开发一个应用程序，我需要在其中使用 lat/long 在两点之间绘制一条路线。

我已经使用谷歌 API 来获取折线并在解码后绘制它。

问题：

1. 路线不在路中间（附图_1）

2. 放大/缩小路线未完全绘制（附图片_2）

下面是代码：

    if(!routeView)
        routeView = [[UIImageView alloc] initWithFrame:CGRectMake(0, self.mapView.frame.origin.y, mapView.frame.size.width, self.mapView.frame.size.height)];
    routeView.userInteractionEnabled = NO;
    [mapView addSubview:routeView];

    [self.lat1 resignFirstResponder];
    [self.long1 resignFirstResponder];
    [self.lat2 resignFirstResponder];
    [self.long2 resignFirstResponder];

    NSString* saddr = [NSString stringWithFormat:@"%@,%@",self.lat1.text,self.long1.text];

    NSString* daddr = [NSString stringWithFormat:@"%@,%@",self.lat2.text,self.long2.text];

    NSString* apiUrlStr = [NSString stringWithFormat:@"http://maps.apple.com/maps/api/directions/json?origin=%@&destination=%@&sensor=false", saddr, daddr];

    NSURL* apiUrl = [NSURL URLWithString:apiUrlStr];

    NSError *error;
    NSString *apiResponse = [NSString stringWithContentsOfURL:apiUrl encoding:NSUTF8StringEncoding error:&error];


    NSData *responseData = [apiResponse dataUsingEncoding:NSUTF8StringEncoding];


    NSError* error1;
    NSDictionary* json = [NSJSONSerialization JSONObjectWithData:responseData
                                                         options:NSJSONReadingMutableLeaves
                                                           error:&error1];
    NSLog(@"Error: %@\n%@",[error1 localizedDescription],[error1 localizedFailureReason]);


   if([[json objectForKey:@"status"] isEqualToString:@"OK"])
    {
        NSArray *routes1 = [json objectForKey:@"routes"];
        NSDictionary *route = [routes1 lastObject];

        if (route)
        {
            NSString *overviewPolyline = [[route objectForKey: @"overview_polyline"] objectForKey:@"points"];

            routes = [self decodePolyLine:overviewPolyline];

            //NSLog(@"%@",[routes objectAtIndex:0]);

            [self updateRouteView];
            [self centerMap];
        }
    }


-(void) updateRouteView
{
 CGContextRef context =     CGBitmapContextCreate(nil,
                                                 routeView.frame.size.width,
                                              routeView.frame.size.height,
                                              8,
                                              4 * routeView.frame.size.width,
                                              CGColorSpaceCreateDeviceRGB(),
                                              kCGImageAlphaPremultipliedLast);

CGContextSetStrokeColorWithColor(context, [UIColor redColor].CGColor);
CGContextSetRGBFillColor(context, 0.0, 0.0, 1.0, 1.0);
CGContextSetLineWidth(context, 3.0);

for(int i = 0; i < routes.count; i++) {
    CLLocation* location = [routes objectAtIndex:i];
    CGPoint point = [mapView convertCoordinate:location.coordinate toPointToView:routeView];

    if(i == 0) {
        CGContextMoveToPoint(context, point.x, routeView.frame.size.height - point.y);
    } else {
        CGContextAddLineToPoint(context, point.x, routeView.frame.size.height - point.y);
    }
}

CGContextStrokePath(context);

CGImageRef image = CGBitmapContextCreateImage(context);
UIImage* img = [UIImage imageWithCGImage:image];

routeView.image = img;
CGContextRelease(context);

}

Answer 1

您的路线未对齐的一个可能原因是您的路线来自 Google（http://maps.apple.com/maps重定向到http://maps.google.com/maps）并且您在 Apple 的地图上绘制它. 他们的数据略有不同。

我无法解决部分绘制的路线，但我建议您添加 MKPolyline 而不是静态图像叠加。他们发明了那个画线工具是有充分理由的。