Ios 使用Google Maps SDK在地图上绘制错误的多段线

我正在尝试使用谷歌地图SDK在地图上绘制路线。 是我正在调用的URL，我将JSON响应解析为坐标数组：

    id jsonResponse = [NSJSONSerialization JSONObjectWithData:responseObject options:NSJSONReadingMutableContainers error:nil];

    int points_count = 0;
    points_count = [[[[[[jsonResponse objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"steps"] count];

    NSArray *steps = nil;
    if (points_count && [[[[jsonResponse objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] count])
    {
        steps = [[[[[jsonResponse objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"steps"];
    }

    NSMutableArray *coordinates = [[NSMutableArray alloc] initWithCapacity:points_count];
    for (int i = 0; i < points_count; i++)
    {
        NSDictionary *start;
        NSDictionary *finish;

        double st_lat = [[[[steps objectAtIndex:i] objectForKey:@"start_location"] valueForKey:@"lat"] doubleValue];
        double st_lon = [[[[steps objectAtIndex:i] objectForKey:@"start_location"] valueForKey:@"lng"] doubleValue];

        if (st_lat > 0.0f && st_lon > 0.0f)
        {
            start = @{ @"latitude" : [NSNumber numberWithDouble:st_lat], @"longitude" : [NSNumber numberWithDouble:st_lon] };
        }

        double end_lat = [[[[steps objectAtIndex:i] objectForKey:@"end_location"] valueForKey:@"lat"] doubleValue];
        double end_lon = [[[[steps objectAtIndex:i] objectForKey:@"end_location"] valueForKey:@"lng"] doubleValue];

        if (end_lat > 0.0f && end_lon > 0.0f)
        {
            finish = @{ @"latitude" : [NSNumber numberWithDouble:end_lat], @"longitude" : [NSNumber numberWithDouble:end_lon] };
        }

        [coordinates addObject:@{ @"start" : start, @"finish" : finish }];
    }

为什么画成这样，而不是自己上街

---

我在这里做错了什么？

所以问题是我使用了

开始位置

和

结束位置

，而不是

多段线

->

点

。将我的代码修复为：

请求URL例如：

https://maps.googleapis.com/maps/api/directions/json?origin=40.716072，-74.008836&目的地=40.697545，-73.983892&传感器=假&航路点=优化：真&模式=驾驶

id jsonResponse = [NSJSONSerialization JSONObjectWithData:responseObject options:NSJSONReadingMutableContainers error:nil];

int points_count = 0;
points_count = [[[[[[jsonResponse objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"steps"] count];

NSArray *steps = nil;
if (points_count && [[[[jsonResponse objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] count])
{
    steps = [[[[[jsonResponse objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"steps"];
}

NSMutableArray *coordinates = [[NSMutableArray alloc] initWithCapacity:points_count];
for (int i = 0; i < points_count; i++)
{
    NSString *toDecode = [[[steps objectAtIndex:i] objectForKey:@"polyline"] valueForKey:@"points"];
    NSArray *locations = [AppUtils decodePolylineWithString:toDecode];

    for (int i = 0 ; i < locations.count ; i++)
    {
        if (i != locations.count - 1) {
            CLLocation *start = [locations objectAtIndex:i];
            CLLocation *finish = [locations objectAtIndex:i + 1];
            [coordinates addObject:@{ @"start" : start, @"finish" : finish }];
        }
    }
}

GMSMutablePath *path = [GMSMutablePath path];
for (NSDictionary *d in directions)
{
    CLLocation *start = d[@"start"];
    CLLocation *finish = d[@"finish"];

    [path addCoordinate:start.coordinate];
    [path addCoordinate:finish.coordinate];
}

GMSPolyline *line = [GMSPolyline polylineWithPath:path];
line.strokeColor = [UIColor redColor];
line.strokeWidth = 2.0f;
line.map = self.mapView;


+ (NSArray*)decodePolylineWithString:(NSString *)encodedString
{
    NSMutableArray *coordinates = [NSMutableArray array];
    const char *bytes = [encodedString UTF8String];
    NSUInteger length = [encodedString lengthOfBytesUsingEncoding:NSUTF8StringEncoding];
    NSUInteger idx = 0;

    NSUInteger count = length / 4;
    CLLocationCoordinate2D *coords = calloc(count, sizeof(CLLocationCoordinate2D));
    NSUInteger coordIdx = 0;

    float latitude = 0;
    float longitude = 0;
    while (idx < length) {
       char byte = 0;
        int res = 0;
        char shift = 0;

        do {
            byte = bytes[idx++] - 63;
            res |= (byte & 0x1F) << shift;
            shift += 5;
        } while (byte >= 0x20);

        float deltaLat = ((res & 1) ? ~(res >> 1) : (res >> 1));
        latitude += deltaLat;

        shift = 0;
        res = 0;

        do {
            byte = bytes[idx++] - 0x3F;
            res |= (byte & 0x1F) << shift;
            shift += 5;
        } while (byte >= 0x20);

        float deltaLon = ((res & 1) ? ~(res >> 1) : (res >> 1));
        longitude += deltaLon;

        float finalLat = latitude * 1E-5;
        float finalLon = longitude * 1E-5;

        CLLocationCoordinate2D coord = CLLocationCoordinate2DMake(finalLat, finalLon);
        coords[coordIdx++] = coord;
        CLLocation *location = [[CLLocation alloc] initWithLatitude:finalLat longitude:finalLon];
        [coordinates addObject:location];

        if (coordIdx == count) {
            NSUInteger newCount = count + 10;
            coords = realloc(coords, newCount * sizeof(CLLocationCoordinate2D));
            count = newCount;
        }
    }

    free(coords);
    return coordinates;
}

id jsonResponse=[NSJSONSerialization JSONObjectWithData:responseobjectoptions:NSJSONReadingMutableContainers错误：nil]；
int points_count=0；
points_count=[jsonResponse objectForKey:@“routes”]objectAtIndex:0]objectForKey:@“legs”]objectAtIndex:0]objectForKey:@“steps”]count]；
NSArray*步数=零；
如果（点数和[[[jsonResponse objectForKey:@“routes”]objectAtIndex:0]objectForKey:@“legs”]count]）
{
步骤=[jsonResponse objectForKey:@“路由”]objectAtIndex:0]objectForKey:@“腿”]objectAtIndex:0]objectForKey:@“步骤”]；
}
NSMUTABLEARRY*坐标=[[NSMUTABLEARRY alloc]initWithCapacity:点计数]；
对于（int i=0；i>1）：（res>>1））；
纬度+=三角洲；
移位=0；
res=0；
做{
字节=字节[idx++]-0x3F；
res |=（字节&0x1F）=0x20）；
浮点数=（（res&1）～（res>>1）：（res>>1））；
经度+=三角洲；
浮点数=纬度*1E-5；
浮动最终=经度*1E-5；
CLLocationCoordinate2D coord=CLLocationCoordinate2DMake（最终，最终）；
coords[coordIdx++]=coord；
CLLocation*location=[[CLLocation alloc]initWithLatitude:finalLat经度：finalLon]；
[坐标添加对象：位置]；
如果（坐标dx==计数）{
NSU整数newCount=计数+10；
coords=realloc（coords，newCount*sizeof（CLLocationCoordinate2D））；
计数=新计数；
}
}
免费（coords）；
返回坐标；
}

我知道这有点脏，但这是工作，而且效果很好

---

享受。

试试这个，它画出了精确的路径，就像在驾驶模式-街道模式中一样，以下是我的代码：

---

@adijazz91如果我保持在同一位置，我会崩溃，你有样品发送吗

id jsonResponse = [NSJSONSerialization JSONObjectWithData:responseObject options:NSJSONReadingMutableContainers error:nil];

int points_count = 0;
points_count = [[[[[[jsonResponse objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"steps"] count];

NSArray *steps = nil;
if (points_count && [[[[jsonResponse objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] count])
{
    steps = [[[[[jsonResponse objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"steps"];
}

NSMutableArray *coordinates = [[NSMutableArray alloc] initWithCapacity:points_count];
for (int i = 0; i < points_count; i++)
{
    NSString *toDecode = [[[steps objectAtIndex:i] objectForKey:@"polyline"] valueForKey:@"points"];
    NSArray *locations = [AppUtils decodePolylineWithString:toDecode];

    for (int i = 0 ; i < locations.count ; i++)
    {
        if (i != locations.count - 1) {
            CLLocation *start = [locations objectAtIndex:i];
            CLLocation *finish = [locations objectAtIndex:i + 1];
            [coordinates addObject:@{ @"start" : start, @"finish" : finish }];
        }
    }
}

GMSMutablePath *path = [GMSMutablePath path];
for (NSDictionary *d in directions)
{
    CLLocation *start = d[@"start"];
    CLLocation *finish = d[@"finish"];

    [path addCoordinate:start.coordinate];
    [path addCoordinate:finish.coordinate];
}

GMSPolyline *line = [GMSPolyline polylineWithPath:path];
line.strokeColor = [UIColor redColor];
line.strokeWidth = 2.0f;
line.map = self.mapView;


+ (NSArray*)decodePolylineWithString:(NSString *)encodedString
{
    NSMutableArray *coordinates = [NSMutableArray array];
    const char *bytes = [encodedString UTF8String];
    NSUInteger length = [encodedString lengthOfBytesUsingEncoding:NSUTF8StringEncoding];
    NSUInteger idx = 0;

    NSUInteger count = length / 4;
    CLLocationCoordinate2D *coords = calloc(count, sizeof(CLLocationCoordinate2D));
    NSUInteger coordIdx = 0;

    float latitude = 0;
    float longitude = 0;
    while (idx < length) {
       char byte = 0;
        int res = 0;
        char shift = 0;

        do {
            byte = bytes[idx++] - 63;
            res |= (byte & 0x1F) << shift;
            shift += 5;
        } while (byte >= 0x20);

        float deltaLat = ((res & 1) ? ~(res >> 1) : (res >> 1));
        latitude += deltaLat;

        shift = 0;
        res = 0;

        do {
            byte = bytes[idx++] - 0x3F;
            res |= (byte & 0x1F) << shift;
            shift += 5;
        } while (byte >= 0x20);

        float deltaLon = ((res & 1) ? ~(res >> 1) : (res >> 1));
        longitude += deltaLon;

        float finalLat = latitude * 1E-5;
        float finalLon = longitude * 1E-5;

        CLLocationCoordinate2D coord = CLLocationCoordinate2DMake(finalLat, finalLon);
        coords[coordIdx++] = coord;
        CLLocation *location = [[CLLocation alloc] initWithLatitude:finalLat longitude:finalLon];
        [coordinates addObject:location];

        if (coordIdx == count) {
            NSUInteger newCount = count + 10;
            coords = realloc(coords, newCount * sizeof(CLLocationCoordinate2D));
            count = newCount;
        }
    }

    free(coords);
    return coordinates;
}