Android計算Android中的網格角位置Google地圖

Question

我想要Googmap上的4行和3列的網格。我想在由網格製成的每個Rectangle的topLeft和右下角顯示標記。

這裏是我使用

public void getVisibleRegionGrids(final VisibleRegion region) 
{ 
    int columns = 3; 
    int rows = 4; 

    double mainTopLat = region.latLngBounds.southwest.latitude; // (c, d) 
    double mainTopLng = region.latLngBounds.northeast.longitude; 

    double mainBottomLat = region.latLngBounds.northeast.latitude; 
    double mainBottomLng = region.latLngBounds.southwest.longitude; 

    double horizontalDiff = Math.abs ((mainBottomLat - mainTopLat)/columns); // 1 
    double verticalDiff = Math.abs ((mainBottomLng - mainTopLng)/rows); // 1 

    double topLat = mainTopLat; // (c, d) 
    double topLng = mainTopLng; 

    //double bottomLat = mainTopLat + horizontalDiff; 
    //double bottomLng = mainTopLng + verticalDiff; 

    for (int i = 0; i < rows; i++) 
    { 
     for (int x = 0; x < columns ; x++) 
     { 
      double currentTopLat = (topLat + (i * verticalDiff)) + (x * horizontalDiff); 
      double currentTopLng = (topLng + (i * verticalDiff)) + (x * horizontalDiff); 

      double currentBottomLat = currentTopLat + horizontalDiff; 
      double currentBottomLng = currentTopLng + verticalDiff; 
      try 
      { 
       MarkerOptions markerOptions = new MarkerOptions() 
         .draggable(false) 
         .position(new LatLng(Double.valueOf(currentTopLat), Double.valueOf(currentTopLng)) 
         ); 
       mMap.addMarker(markerOptions); 

       markerOptions = new MarkerOptions() 
         .draggable(false) 
         .position(new LatLng(Double.valueOf(currentBottomLat), Double.valueOf(currentBottomLng)) 
       ); 
       mMap.addMarker(markerOptions); 

      }catch (Exception e) 
      {} 
     } 
    } 
} 

我無法得到它的邏輯工作的代碼。我計算了topLeft和右下角的分數。從topLeft開始，我想繼續。我能做些什麼

更新

感謝的幫助下，我設法使它工作

public void getVisibleRegionGrids(final VisibleRegion region) 
{ 
    int columns = 3; 
    int rows = 4; 

    double mainTopLat = region.latLngBounds.northeast.latitude; // (c, d) 
    double mainMaxLng = region.latLngBounds.northeast.longitude; 

    double mainBottomLat = region.latLngBounds.southwest.latitude; 
    double mainMinLng = region.latLngBounds.southwest.longitude; 

    double horizontalDiff = Math.abs ((mainMaxLng - mainMinLng)/columns); // 1 
    double verticalDiff = Math.abs ((mainTopLat - mainBottomLat)/rows); // 1 

    double topLat = mainTopLat; // (c, d) 
    double topLng = mainMinLng; 
    int position = 0; 

    for (int i = 0; i < rows; i++) 
    { 
     for (int x = 0; x < columns ; x++) 
     { 
      double currentTopLat = (topLat - (i * verticalDiff)); 
      double currentLeftLng = (topLng + (x * horizontalDiff)); 

      if(position == i) 
      { 
       currentTopLat = (topLat - (i * verticalDiff)); 
       currentLeftLng = (topLng + (x * horizontalDiff)); 
      } 

      position = -1; 

      if(x == columns) 
       position = i + 1; 

      try 
      { 
       MarkerOptions markerOptions = new MarkerOptions() 
         .draggable(false) 
         .position(new LatLng(Double.valueOf(currentTopLat), Double.valueOf(currentLeftLng))); 
       mMap.addMarker(markerOptions); 

       double currentBottomLat = currentTopLat - verticalDiff; 
       double currentRightLng = currentLeftLng + horizontalDiff; 
       markerOptions = new MarkerOptions() 
         .draggable(false) 
         .position(new LatLng(Double.valueOf(currentBottomLat), Double.valueOf(currentRightLng))); 
       mMap.addMarker(markerOptions); 

      }catch (Exception e) 
      {} 
     } 
    } 
} 

Answer 1

你的代碼似乎有關於座標的幾個誤區。 西南是左下角，東北是右上角。 所以

• mainTopLat是northeast.latitude
• mainTopLng是northeast.longitude - >應該叫mainMaxLng
• mainBottomLat是southwest.latitude
• mainBottomLng是southwest.longitude - >應該被稱爲mainMinLng

我正在修改內聯代碼，以便它可能包含錯誤，但它應該適用於您的情況。除了最後一行和最後一列以外，不要繪製右下角的標記，因爲它會畫出重複的標記！

public void getVisibleRegionGrids(final VisibleRegion region) 
{ 
    int columns = 3; 
    int rows = 4; 

    double mainTopLat = region.latLngBounds.northeast.latitude; // (c, d) 
    double mainMaxLng = region.latLngBounds.northeast.longitude; 

    double mainBottomLat = region.latLngBounds.southwest.latitude; 
    double mainMinLng = region.latLngBounds.southwest.longitude; 

    double horizontalDiff = Math.abs ((mainMaxLng - mainMinLng)/columns); // 1 
    double verticalDiff = Math.abs ((mainTopLat - mainBottomLat)/rows); // 1 

    double topLat = mainTopLat; // (c, d) 
    double rightLng = mainMaxLng; 

    for (int i = 0; i < rows; i++) 
    { 
     for (int x = 0; x < columns ; x++) 
     { 
      double currentTopLat = (topLat - (i * verticalDiff)); 
      double currentLeftLng = (topLng + (x * horizontalDiff)); 

      try 
      { 
       MarkerOptions markerOptions = new MarkerOptions() 
         .draggable(false) 
         .position(new LatLng(Double.valueOf(currentTopLat), Double.valueOf(currentLeftLng))); 
       mMap.addMarker(markerOptions); 

       if ((i==(rows-1))|| (x==columns-1){//add the lowerright marker only on the last line or column, avoid duplicated markers 
       double currentBottomLat = currentTopLat - verticalDiff; 
       double currentRightLng = currentLeftLng + horizontalDiff; 
       markerOptions = new MarkerOptions() 
           .draggable(false) 
           .position(new LatLng(Double.valueOf(currentBottomLat), Double.valueOf(currentBottomLng))); 
        mMap.addMarker(markerOptions); 
    } 
      }catch (Exception e) 
      {} 
     } 
    } 
}