ios - 如何在 mapKit 中获取路线长度

Question

我正在使用 mapKit 绘制点到点的路线。我做到了。但我想获得路线长度而不是直线距离。

nextView.startPoint = [NSString stringWithFormat:@"%f,%f", userLatitude , userLongitude];
nextView.endPoint = [NSString stringWithFormat:@"%f,%f", 30.793636, 31.009641];
[diretions loadWithStartPoint:startPoint endPoint:endPoint options:options];

此外，我想给它一个中间点。

Answer 1

要做到这一点，您将不得不使用方向 API，最好是 Google Directions API .您应该查看该链接并通读它，Apple 没有内置的方向 API。您可以向它发送请求并要求 JSON 响应，我会使用 AFNetworking to make like easier (on Github)和 JSONKit also on Github为了那个原因。然后发送请求并解析 JSON 响应。在响应中，您需要编码点，这是一组基本上追踪路线的坐标。然后，您需要将其显示在叠加层上。以下是一些示例代码，但在复制并粘贴之前，请确保阅读 GDirections API 站点，您将更容易理解所有内容，并可以学习如何做更多事情:

// DRAG IN AFNETWORKING FILES AND JSON KIT FILES TO YOUR PROJECT AND ALSO IMPORT THE MAP KIT AND CORE LOCATION FRAMEWORKS

// IMPORT FILES

#import "StringHelper.h"
#import "JSONKit.h"
#import "AFJSONRequestOperation.h"
#import "AFHTTPClient.h"
#import <MapKit/MapKit.h>
#import <CoreLocation/CoreLocation.h>

// DECLARE MUTABLE ARRAY IN .H:

NSMutableArray *_path;

// ADD THIS CODE TO WHEN YOU WANT TO REQUEST FOR DIRECTIONS

    AFHTTPClient *_httpClient = [AFHTTPClient clientWithBaseURL:[NSURL URLWithString:@"http://maps.googleapis.com/"]];

    [_httpClient registerHTTPOperationClass: [AFJSONRequestOperation class]];

    [_httpClient setDefaultHeader:@"Accept" value:@"application/json"];

    NSMutableDictionary *parameters = [[NSMutableDictionary alloc] init];

    [parameters setObject:[NSString stringWithFormat:@"%f,%f", location.coordinate.latitude, location.coordinate.longitude] forKey:@"origin"];

    [parameters setObject:[NSString stringWithFormat:@"%f,%f", location2.coordinate.latitude, location2.coordinate.longitude] forKey:@"destination"];

    [parameters setObject:@"false" forKey:@"sensor"];

    [parameters setObject:@"driving" forKey:@"mode"];

    [parameters setObject:@"metric" forKey: @"units"];

    NSMutableURLRequest *request = [_httpClient requestWithMethod:@"GET" path: @"maps/api/directions/json" parameters:parameters];

    request.cachePolicy = NSURLRequestReloadIgnoringLocalCacheData;

    AFHTTPRequestOperation *operation = [_httpClient HTTPRequestOperationWithRequest:request success:^(AFHTTPRequestOperation *operation, id responseObject) {

        NSInteger statusCode = operation.response.statusCode;

        if (statusCode == 200) {

            [self parseResponse:responseObject];

        }

    } failure:^(AFHTTPRequestOperation *operation, NSError *error) { }];

    [_httpClient enqueueHTTPRequestOperation:operation];

    // NOW ADD THE PARSERESPONSE METHOD
- (void)parseResponse:(NSDictionary *)response {

NSString *status = [response objectForKey: @"status"];

NSArray *routes = [response objectForKey:@"routes"];

NSDictionary *routePath = [routes lastObject];

if (routePath) {

    NSString *overviewPolyline = [[routePath objectForKey: @"overview_polyline"] objectForKey:@"points"];

    _path = [self decodePolyLine:overviewPolyline];

    NSInteger numberOfSteps = _path.count;

    CLLocationCoordinate2D coordinates[numberOfSteps];
    for (NSInteger index = 0; index < numberOfSteps; index++) {
        CLLocation *location = [_path objectAtIndex:index];
        CLLocationCoordinate2D coordinate = location.coordinate;

        coordinates[index] = coordinate;
    }

    polyLine = [MKPolyline polylineWithCoordinates:coordinates count:numberOfSteps];
    [self.mapView addOverlay:polyLine];
}

}

// IMPLEMENTING THE DECODEPOLYLINE METHOD:

-(NSMutableArray *)decodePolyLine:(NSString *)encodedStr {

NSMutableString *encoded = [[NSMutableString alloc] initWithCapacity:[encodedStr length]];
[encoded appendString:encodedStr];
[encoded replaceOccurrencesOfString:@"\\\\" withString:@"\\"
                            options:NSLiteralSearch
                              range:NSMakeRange(0, [encoded length])];
NSInteger len = [encoded length];
NSInteger index = 0;
NSMutableArray *array = [[NSMutableArray alloc] init];
NSInteger lat=0;
NSInteger lng=0;
while (index < len) {
    NSInteger b;
    NSInteger shift = 0;
    NSInteger result = 0;
    do {
        b = [encoded characterAtIndex:index++] - 63;
        result |= (b & 0x1f) << shift;
        shift += 5;
    } while (b >= 0x20);
    NSInteger dlat = ((result & 1) ? ~(result >> 1) : (result >> 1));
    lat += dlat;
    shift = 0;
    result = 0;
    do {
        b = [encoded characterAtIndex:index++] - 63;
        result |= (b & 0x1f) << shift;
        shift += 5;
    } while (b >= 0x20);
    NSInteger dlng = ((result & 1) ? ~(result >> 1) : (result >> 1));
    lng += dlng;
    NSNumber *latitude = [[NSNumber alloc] initWithFloat:lat * 1e-5];
    NSNumber *longitude = [[NSNumber alloc] initWithFloat:lng * 1e-5];

    CLLocation *location = [[CLLocation alloc] initWithLatitude:[latitude floatValue] longitude:[longitude floatValue]];
    [array addObject:location];
}

return array;

}


// IMPLEMENTING THE VIEWFOROVERLAY DELEGATE METHOD (MAKE SURE TO SET YOUR MAP VIEW'S DELEGATE TO SELF OR THIS WONT GET CALLED) 

- (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id <MKOverlay>)overlay {

MKPolylineView *polylineView = [[MKPolylineView alloc] initWithPolyline:overlay];

polylineView.strokeColor = [UIColor blueColor];
polylineView.lineWidth = 5.0;
polylineView.alpha = 0.7;

return polylineView;

}

这应该会让您的定向路线启动并运行!