Question

我想将标记固定在地图的中心，而不管位置坐标如何。如果用户在地图上移动相机，我希望它继续显示在中心而没有任何闪烁的标记和该标记上的新位置显示，我该怎么做？请帮忙。

Answer 1

尝试以下目标C代码

不要忘记设置代表

  mapView.delegate=self;

创建ImageView并将其添加到地图中心

UIImageView *pin =[[UIImageView alloc]init];
pin.frame=CGRectMake(0, 0, 20, 20  );  
pin.center = mapView.center;
pin.image = [UIImage imageNamed:@"location.png"];
[self.view addSubview:pin];
[self.view bringSubviewToFront:pin];

然后使用谷歌地图的委托方法

//When You Will Scroll Map Then This Method Will Be Called
     - (void)mapView:(GMSMapView *)MapView didChangeCameraPosition:(GMSCameraPosition *)position {

            // Get Latitude And Longitude Of Your Pin(ImageView)
              CLLocationCoordinate2D newCoords = CLLocationCoordinate2DMake( position.target.latitude , position.target.longitude);

              NSLog(@"Latitude-%f\Longitude-%f\n",newCoords.latitude, newCoords.longitude);


     [[GMSGeocoder geocoder] reverseGeocodeCoordinate:CLLocationCoordinate2DMake(newCoords.latitude, newCoords.longitude) completionHandler:^(GMSReverseGeocodeResponse* response, NSError* error) {

             //Get Place Details
             NSLog(@"%@",[[response results]objectAtIndex:0].lines);

    }];           
              return;
     }

Answer 2

不移动标记

根据GMSMapView的框架在GMSMapView的中心创建一个Imageview或Button（如果可单击）。

如果您想获得坐标，可以使用mapView.projection.coordinateForPoint

这将移动标记

按照以下代码

查找谷歌地图的中心点

let centerCord = yourMapView.camera.target 

let marker = GMSMarker(position: centerCord)
marker.title = "Hello World"
marker.map = mapView

实现mapView：didChangeCameraPosition：

 func mapView(mapView: GMSMapView, didChangeCameraPosition position: GMSCameraPosition) {
     // to remove all markers       
     mapView.clear()

    //create new marker with new center
    let centerCord = [yourMapView.camera target] 

    let marker = GMSMarker(position: centerCord)
    marker.title = "Hello World"
    marker.map = mapView


    }

Answer 3

请尝试以下代码

--use 120s, 18 million data
    explain SELECT DISTINCT d.taid
    FROM tvassist_recommend_list_everyday_diverse d, tvassist_taid_all t
    WHERE d.taid = t.taid
      AND t.client_version >= '21004007'
      AND t.utdid IS NOT NULL
      AND d.recommend_day = '20170403'
    LIMIT 0, 10000

--use 3.6s repalce by straight join
 explain SELECT DISTINCT d.taid
    FROM tvassist_recommend_list_everyday_diverse d
    STRAIGHT_JOIN 
      tvassist_taid_all t on d.taid = t.taid 
    WHERE 
     t.client_version >= '21004007'
       AND d.recommend_day = '20170403'

      AND t.utdid IS NOT NULL  
    LIMIT 0, 10000

Objectivec固定标记在谷歌地图ios的中心

3 个答案: