Question

在下面的代码中运行，所以我从url获得响应，但是当我尝试获取encodedPoints时，它会给我一个空值。我也更新了RegexKitLite但问题。没解决。欢迎任何建议谢谢你提前。

 NSString* saddr = [NSString stringWithFormat:@"%f,%f", f.latitude, f.longitude];
            NSString* daddr = [NSString stringWithFormat:@"%f,%f", t.latitude, t.longitude];
            NSString* apiUrlStr = [NSString stringWithFormat:@"http://maps.googleapis.com/maps/api/directions/json?origin=%@&destination=%@&sensor=false", saddr, daddr];
    //      http://maps.googleapis.com/maps/api/directions/json?origin=41.029598,28.972985&destination=41.033586,28.984546&sensor=false%EF%BB%BF%EF%BB%BF
            NSURL *apiUrl = [NSURL URLWithString:[apiUrlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
            NSLog(@"api url: %@", apiUrl);
           NSString *apiResponse = [NSString stringWithContentsOfURL:apiUrl encoding:nil error:nil];
            NSString* encodedPoints = [apiResponse stringByMatching:@"points:\\\"([^\\\"]*)\\\"" capture:1L];
            NSLog(@"encodedPoints: %@", encodedPoints);
            if (encodedPoints) {
                return [self decodePolyLine:[encodedPoints mutableCopy]];
            }
            else {
                return NO;
            }

Answer 1

我认为这不是同步执行API请求的好方法，尤其是当用户＆＃39;手机连接不良，会降低应用程序的响应速度。因此，您应该使用NSURLSession执行异步API请求。

此外，Directions API可能会为您的请求返回多个路由。因此，最好使用NSArray来存储折线点。

示例代码：

- (void)getPolyline {
    NSURL *url = [[NSURL alloc] initWithString:@"https://maps.googleapis.com/maps/api/directions/json?origin=Chicago,IL&destination=Los+Angeles,CA&key=YOUR_API_KEY"];
    NSURLRequest *request = [[NSURLRequest alloc] initWithURL: url];
    NSURLSession *session = [NSURLSession sharedSession];

    [[session dataTaskWithRequest:request completionHandler:
      ^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
          if (!error) {
              NSError *jsonError;
              NSDictionary *dict = (NSDictionary*)[NSJSONSerialization JSONObjectWithData:data options:nil error:&jsonError];
              if (!jsonError) {

                  NSArray *routesArray = (NSArray*)dict[@"routes"];

                  NSMutableArray *points = [NSMutableArray array];

                  for (NSDictionary *route in routesArray) {
                      NSDictionary *overviewPolyline = route[@"overview_polyline"];
                      [points addObject:overviewPolyline[@"points"]];
                  }

                  NSLog(@"%@", points);

              }
          } else {
              //print error message
              NSLog(@"%@", [error localizedDescription]);
          }
      }] resume];
}

在ios中使用google api显示方向

1 个答案: