在 Android 上的 Google 地图视图上绘制多边形的问题

Question

所以我正在为安卓制作游戏，我需要在谷歌地图窗口上覆盖区域或多边形。

到目前为止，我做了以下工作：

    class polygonOverlay extends Overlay {
    //this is the array of vertices we need to draw
    GeoPoint[] vet;
    Point[] points;
    private float[] fVet;
    //get the vertices

    public polygonOverlay(GeoPoint[] v) {
        vet = v;
        points = new Point[v.length];
        fVet = new float[(v.length)*2];

    }

    //this is how we draw it.
    @Override
    public void draw(Canvas canvas, MapView mapv, boolean shadow) {

        super.draw(canvas,mapv, shadow);

        //do some things
        //set all the points to a point.
        for(int i = 0; i < points.length; i++) {
            points[i] = new Point();
        }

        //convert from the array of geoPoints to the array of points using the projection.
        for(int i = 0; i < vet.length; i++){
        projection.toPixels(vet[i], points[i]);

        }

        //convert the point to the float array
        for(int i = 0; i < points.length; i++) {
        fVet[2*i] = points[i].x;
        fVet[(2*i)+1]  = points[i].y;
        }
        //things be done...

        //create a array of int colors.
        int[] colorArray = new int[points.length];

        for(int i = 0; i < points.length; i++) {
            colorArray[i] = Color.RED;
        }

        //if we are drawing a shadow, then dont draw anything
        Paint mPaint = new Paint();
        mPaint.setDither(true);
        mPaint.setColor(Color.RED);
        mPaint.setStyle(Paint.Style.FILL_AND_STROKE);
        mPaint.setStrokeJoin(Paint.Join.ROUND);
        mPaint.setStrokeCap(Paint.Cap.ROUND);
        mPaint.setStrokeWidth(4);
        //lets draw some things.
        canvas.drawLine(points[1].x, points[1].y, 200, 200, mPaint);
        canvas.drawVertices(
                Canvas.VertexMode.TRIANGLES,
                fVet.length,
                fVet,
                0,
                null,
                0,
                colorArray,
                0,
                null,
                0,
                0,
                mPaint
                ); 


    }

}

但问题是它不会显示多边形。我已经尝试了所有方法，昨晚一直到凌晨 2 点才这样做，但它就是行不通。

我开始认为这是我的手机而不是我的密码...

谁能看到我做错了什么？

Answer 1

多边形创建很简单：

首先定义一个Paint对象：

Paint mPaint = new Paint();
mPaint.setStrokeWidth(2);  //2 pixel line width
mPaint.setColor(0xFF097286); //tealish with no transparency
mPaint.setStyle(Paint.Style.STROKE); //stroked, aka a line with no fill
mPaint.setAntiAlias(true);  // no jagged edges, etc

然后绘制路径：

yourCanvas.drawPath(path,mPaint);

这里是地图叠加的链接：android maps circle overlay, dynamically change radius?

Answer 2

bug in the drawVertices method 要求 colorArray 与代码中的 fVet 数组大小相同。
注意：只有第一个fVet/2颜色实际用于绘制，其他被忽略。