Question

我有多个地点，想要从百度地图中找到纬度和经度。有可能我可以在1个API调用中发送多个位置，它会返回多个位置的所有lat和long吗？或者我需要多次调用API？因为这不是一个好方法。请建议并给我解决方案。我从这里按照代码整合百度地图：https://github.com/SemperIdem/BaiduMapSDKDemo-Swift

Answer 1

我们无法放置地址数组，因为[geocoder geocodeAddressString: completionHandler:]使用字符串值。我们必须使用 异步地理编码请求以同步方式，然后您只需将请求添加到串行队列，请求将按顺序而不是并行执行。

CLGeocoder *geocoder = [[CLGeocoder alloc]init];
NSMutableArray *mapItems = [NSMutableArray array];

NSOperationQueue *queue = [[NSOperationQueue alloc] init];
queue.maxConcurrentOperationCount = 1;   // make it a serial queue

NSOperation *completionOperation = [NSBlockOperation blockOperationWithBlock:^{
    [MKMapItem openMapsWithItems:mapItems launchOptions:nil];
}];

NSArray *addresses = @[@"Mumbai, India", @"Delhi, India", @"Bangalore, India"];

for (NSString *address in addresses) {
    NSBlockOperation *operation = [NSBlockOperation blockOperationWithBlock:^{
        dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);

        [geocoder geocodeAddressString:address completionHandler:^(NSArray *placemarks, NSError *error) {
            if (error) {
                NSLog(@"%@", error);
            } else if ([placemarks count] > 0) {
                CLPlacemark *geocodedPlacemark = [placemarks objectAtIndex:0];
                MKPlacemark *placemark = [[MKPlacemark alloc] initWithCoordinate:geocodedPlacemark.location.coordinate
                                                               addressDictionary:geocodedPlacemark.addressDictionary];
                MKMapItem *mapItem = [[MKMapItem alloc] initWithPlacemark:placemark];
                [mapItem setName:geocodedPlacemark.name];

                [mapItems addObject:mapItem];
            }
            dispatch_semaphore_signal(semaphore);
        }];

        dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);
    }];

    [completionOperation addDependency:operation];
    [queue addOperation:operation];
}

[[NSOperationQueue mainQueue] addOperation:completionOperation];

如何从百度地图获取多个位置的lat和long？

1 个答案: