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，这样即使在图像被缩放或平移时，标记也会保持在指定的坐标处。我怎么能这样做？

Answer 1

扩展SubsamplingScaleImageView并覆盖其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;
        }



    }