Android如何在MapView中使用覆盖层自由绘制涂料？

Question

Android如何在MapView中使用覆盖层自由绘制涂料？

5

在我的应用中，我想在地图视图上自由绘制图画，但是在搜索了很多信息后，最终通过在地图视图上绘制矩形形状得到了帮助。但我想要绘制自由手绘的锯齿形状，要如何修改我的代码呢？如果有任何帮助，请告诉我。

MapOverlay.java

  public class MapOverlay extends Overlay {

private float x1,y1,x2,y2;
private GeoPoint p1=null,p2=null;
private MapExampleActivity mv = null;
private Paint paint = new Paint();
private Path path = new Path();
private boolean isUp = false;

//constructor receiving the initial point
  public MapOverlay(MapExampleActivity mapV,float x,float y){
    paint.setStrokeWidth(2.0f);
    x1 = x;
    y1 = y;
    mv = mapV;
    p1 = mapV.getMapView().getProjection().fromPixels((int)x1,(int)y1);
}
//override draw method to add our custom drawings
@Override
public boolean draw(Canvas canvas, MapView mapView, boolean shadow, long when) {

    if(p1 != null && p2 != null){
        //get the 2 geopoints defining the area and transform them to pixels
        //this way if we move or zoom the map rectangle will follow accordingly
        Point screenPts1 = new Point();
        mapView.getProjection().toPixels(p1, screenPts1);
        Point screenPts2 = new Point();
        mapView.getProjection().toPixels(p2, screenPts2);                

        //draw inner rectangle
        paint.setColor(Color.BLUE);
     //   paint.setStyle(Style.FILL);
        canvas.drawPath(path, paint);       
        canvas.drawRect(screenPts1.x, screenPts1.y, screenPts2.x, screenPts2.y, paint);
        //draw outline rectangle

    //  paint.setColor(Color.YELLOW);
        paint.setStyle(Style.STROKE);
    //  canvas.drawRect(screenPts1.x, screenPts1.y, screenPts2.x, screenPts2.y, paint);
        canvas.drawPath(path, paint); 
    }
    return true;
}    

@Override
public boolean onTouchEvent(MotionEvent e, MapView mapView) {
    if(mv.isEditMode() && !isUp){

        if(e.getAction() == MotionEvent.ACTION_DOWN){
            x1 = y1 = 0;
            x1 = e.getX();
            y1 = e.getY();
            p1 = mapView.getProjection().fromPixels((int)x1,(int)y1);               
        }

        //here we constantly change geopoint p2 as we move out finger
        if(e.getAction() == MotionEvent.ACTION_MOVE){
            x2 = e.getX();
            y2 = e.getY();
            p2 = mapView.getProjection().fromPixels((int)x2,(int)y2);               
        }

        //---when user lifts his finger---
        if (e.getAction() == MotionEvent.ACTION_UP) {                
            isUp = true;
        }    
        return true;
    }
    return false;
}

使用此方法，我能够绘制矩形形状并且可以在再次单击切换按钮后进行绘制（可以多次绘制）。

矩形形状

我想要像下面的图像一样绘制线条（可以多次绘制）。

输入图像描述

最后我找到了这个链接，它提供了绘制矩形形状的方法：http://n3vrax.wordpress.com/2011/08/13/drawing-overlays-on-android-map-view/

只需将矩形更改为任意绘制，有什么建议吗？

- NagarjunaReddy

1个回答

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- Luis · Accepted Answer

您可以使用下面的代码自由绘制一条线：

代码

public class HandDrawOverlay extends Overlay { 

private boolean editMode = false;
private boolean isTouched = false;
private Paint paint = new Paint(); 
private Point screenPt1 = new Point(); 
private Point screenPt2 = new Point(); 
private ArrayList<GeoPoint> points = null;

public HandDrawOverlay(){ 
    paint.setStrokeWidth(2.0f); 
    paint.setStyle(Style.STROKE); 
    paint.setColor(Color.BLUE); 
} 

@Override 
public void draw(Canvas canvas, MapView mapView, boolean shadow) {
    if(points != null && points.size() > 1){
        mapView.getProjection().toPixels(points.get(0), screenPt1); 
        for(int i=1; i<points.size();i++){
            mapView.getProjection().toPixels(points.get(i), screenPt2);
            canvas.drawLine(screenPt1.x, screenPt1.y, screenPt2.x, screenPt2.y, paint);
            screenPt1.set(screenPt2.x, screenPt2.y);
        }
    }
}     

@Override 
public boolean onTouchEvent(MotionEvent e, MapView mapView) { 
    if(editMode){ 
        int x = (int)e.getX();
        int y = (int)e.getY();
        GeoPoint geoP = mapView.getProjection().fromPixels(x,y);

        switch (e.getAction()) {
        case MotionEvent.ACTION_DOWN:
            isTouched = true;
            points = new ArrayList<GeoPoint>();
            points.add(geoP);
            break;
        case MotionEvent.ACTION_MOVE:
            if(isTouched)
                points.add(geoP);
            break;
        case MotionEvent.ACTION_UP:
            if(isTouched)
                points.add(geoP);
            isTouched = false;
            break;
        }
        mapView.invalidate();
        return true; 
    } 
    return false; 
}

/**
 * @return the editMode
 */
public boolean isEditMode() {
    return editMode;
}

/**
 * @param editMode the editMode to set
 */
public void setEditMode(boolean editMode) {
    this.editMode = editMode;
} 
}

使用

HandDrawOverlay handDrawOverlay;
handDrawOverlay = new HandDrawOverlay();
mapView.getOverlays().add(handDrawOverlay);

//Set edit mode to true to start drwaing
handDrawOverlay.setEditMode(true);

//Set edit mode to true to stop drwaing
handDrawOverlay.setEditMode(false);

注意

这是一个完整的示例，可以帮助您开始。但是，您应该优化代码使其更加高效（例如，在onDraw()中使用Path来存储绘图路径，在onTouch()中减少记录的点数等）。

享受吧。