子采样比例图像视图中的位置标记

Question

我正在使用Dave Morrissey的子采样比例图像视图来显示高分辨率的地图图像。我想在地图上的预定义坐标处添加位置标记，以便即使图像放大或平移时，标记仍保持放置在指定坐标处。我怎样才能做到这一点？

Answer 1

延长SubsamplingScaleImageView并覆盖其的onDraw（）方法

public class MapView extends SubsamplingScaleImageView { 

    private PointF sPin; 

    ArrayList<MapPin> mapPins; 
    ArrayList<DrawnPin> drawnPins; 
    Context context; 
    String tag = getClass().getSimpleName(); 

    public MapView(Context context) { 
     this(context, null); 
     this.context = context; 
    } 

    public MapView(Context context, AttributeSet attr) { 
     super(context, attr); 
     this.context = context; 
     initialise(); 
    } 

    public void setPins(ArrayList<MapPin> mapPins) 
    { 
     this.mapPins = mapPins; 
     initialise(); 
     invalidate(); 
    } 


    public PointF getPin() { 
     return sPin; 
    } 

    private void initialise() { 

    } 

    @Override 
    protected void onDraw(Canvas canvas) { 
     super.onDraw(canvas); 

     // Don't draw pin before image is ready so it doesn't move around during setup. 
     if (!isReady()) { 
      return; 
     } 

     drawnPins = new ArrayList<>(); 

     Paint paint = new Paint(); 
     paint.setAntiAlias(true); 
     float density = getResources().getDisplayMetrics().densityDpi; 


     for(int i=0;i<mapPins.size();i++) 
     { 
      MapPin mPin = mapPins.get(i); 
      Bitmap bmpPin = Utils.getBitmapFromAsset(context, mPin.getPinImgSrc()); 

      float w = (density/420f) * bmpPin.getWidth(); 
      float h = (density/420f) * bmpPin.getHeight(); 
      bmpPin = Bitmap.createScaledBitmap(bmpPin, (int)w, (int)h, true); 

      PointF vPin = sourceToViewCoord(mPin.getPoint()); 
      //in my case value of point are at center point of pin image, so we need to adjust it here 

      float vX = vPin.x - (bmpPin.getWidth()/2); 
      float vY = vPin.y - (bmpPin.getHeight()/2); 

      canvas.drawBitmap(bmpPin, vX, vY, paint); 
     //add added pin to an Array list to get touched pin 
      DrawnPin dPin = new DrawnPin(); 
      dPin.setStartX(mPin.getX()-w/2); 
      dPin.setEndX(mPin.getX()+w/2); 
      dPin.setStartY(mPin.getY()-h/2); 
      dPin.setEndY(mPin.getY()+h/2); 
      dPin.setId(mPin.getId()); 
      drawnPins.add(dPin); 
     } 

    } 

    public int getPinIdByPoint(PointF point) 
    { 

     for(int i=drawnPins.size()-1;i>=0;i--) 
     { 
      DrawnPin dPin = drawnPins.get(i); 
      if(point.x >= dPin.getStartX() && point.x<=dPin.getEndX()) 
      { 
       if(point.y >= dPin.getStartY() && point.y<=dPin.getEndY()) 
       { 
        return dPin.getId(); 
       } 
      } 
     } 
     return -1; //negative no means no pin selected 
    } 

    class DrawnPin 
    { 
     float startX,startY,endX,endY; 
     int id; 

     public DrawnPin(float startX, float startY, float endX, float endY, int id) 
     { 
      this.startX = startX; 
      this.startY = startY; 
      this.endX = endX; 
      this.endY = endY; 
      this.id = id; 
     } 
    public DrawnPin() 
    { 
     //empty 
    } 
     public float getStartX() 
     { 
      return startX; 
     } 

     public void setStartX(float startX) 
     { 
      this.startX = startX; 
     } 

     public float getStartY() 
     { 
      return startY; 
     } 

     public void setStartY(float startY) 
     { 
      this.startY = startY; 
     } 

     public float getEndX() 
     { 
      return endX; 
     } 

     public void setEndX(float endX) 
     { 
      this.endX = endX; 
     } 

     public float getEndY() 
     { 
      return endY; 
     } 

     public void setEndY(float endY) 
     { 
      this.endY = endY; 
     } 

     public int getId() 
     { 
      return id; 
     } 

     public void setId(int id) 
     { 
      this.id = id; 
     } 



    }