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我正在使用 Google Directions iOS API。我正在使用 JSON 而不是 XML 获取数据。但我AFNetworking习惯于为我简化这一点。AFNetworking可在 github 上找到。现在，我可以在MKMapView. 这是我的代码：

// AFNETWORKING ==========================================================

        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];

        } else {

        }

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

    [_httpClient enqueueHTTPRequestOperation:operation];

// ROUTE SETUP AND RESPONSE RECIEVED METHOD ==========================================================


- (void)parseResponse:(NSDictionary *)response {

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

NSDictionary *routePath = [routes lastObject];

if (routePath) {

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

    NSLog(@"Status: %@", [response objectForKey: @"status"]);

    NSLog(@"Legs: %@", [routePath objectForKey: @"legs[]"]);

    _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];
}

}

这是使路由正常运行的主要代码。而且效果很好！但现在我要做的是获取方向列表和完整的持续时间和摘要。因此，我深入研究了Google Directions API 文档，它告诉我使用其不同的字典、数组和对象。但我没有运气。我的状态为 OK。当我记录routes数组的计数时，它只有一个对象。然后最重要的是，legs[]数组是NULL.

    NSLog(@"Legs is: %@", [routePath objectForKey: @"legs[]"]);

输出：

腿是（空）

Legs[]包括所有重要的内容，例如方向列表和持续时间。Summary不是NULL，它给出了路线绕过的街道之一的名称。我不知道那是一个总结。可能是因为routes数组中只有一个对象。waypoint_order也是。warnings[]_ 当然是有效的，这就是我让路线工作的方式。NULLboundsoverview_polyline

那么这里有什么问题呢？NULL为什么 Google Directions API在我需要时会提供这么多对象？

谢谢！

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1 回答 1

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好的，问题是对指示的响应时间过长。我希望legs[]响应与overview_polyline. 所以我只需要等到响应进来，这让我有机会插入一个缓冲 UI。

于 2012-08-07T11:59:12.163 回答