Android的谷歌地图groundoverlay [英] Android google maps groundoverlay

问题描述

在谷歌地图的JavaScript API，你可以添加一个groundoverlay，只是传递两个点，该点lefttoplat和放大器; lefttoplong和点rightbottomlat和放大器; rightbottomlong ......（正常覆盖不这两个点之间留下，但留下来的当你放大或缩小尺寸相同。）

In the google maps javascript api you can add a groundoverlay and just pass two points, the point lefttoplat&lefttoplong and the point rightbottomlat&rightbottomlong... (The normal overlays don't stay between these two points, but stay the same size when you zoom in or out.)

我一直在寻找类似的东西在Android谷歌地图的API，但我找不到它的任何地方。有没有在Android地图API这样的事情，如果有没有，什么是模拟这种功能的最佳方法是什么？

I have been searching for something like that in the Android google maps api, but I can't find it anywhere. Is there such a thing in the android maps api and if there's not, what's the best way to simulate this function?

推荐答案

这是更好的。使用拉伸方法可以确保只绘制位图，实际上是在屏幕上的一部分。我仍然获得了超过VM-预算错误的时候。我仍然在寻找到这一点。

This is better. Using the draw-method makes sure you only draw the part of the bitmap that is actually on the screen. I still get the exceeded VM-budget error sometimes. I'm still looking into that.

public class GroundOverlay extends Overlay {

Bitmap original;
Bitmap resized;
int lastZoomlevel;
SnowmapsOverlayObject snowmapsObject;
public static Boolean DRAW = false;
GeoPoint topGeoPoint;
GeoPoint bottomGeoPoint;

OnReady _onReady = null;

Boolean ready = false;

public GroundOverlay(Bitmap original, SnowmapsOverlayObject snowmapsObject) {
    this.original = Bitmap.createScaledBitmap(original, original.getWidth(), original.getHeight(), true);
    this.snowmapsObject = snowmapsObject;

    topGeoPoint = new GeoPoint((int) ((snowmapsObject.topLat).doubleValue() * 1E6), (int) ((snowmapsObject.topLng).doubleValue() * 1E6));
    bottomGeoPoint = new GeoPoint((int) ((snowmapsObject.bottomLat).doubleValue() * 1E6), (int) ((snowmapsObject.bottomLng).doubleValue() * 1E6));
}

@Override
public void draw(Canvas canvas, MapView mapView, boolean shadow) {
        super.draw(canvas, mapView, false);

        Projection projection = mapView.getProjection();

        Point leftTop = new Point();
        Point rightTop = new Point();
        Point rightBottom = new Point();
        Point leftBottom = new Point();

        projection.toPixels(topGeoPoint, leftTop);
        projection.toPixels(new GeoPoint(topGeoPoint.getLatitudeE6(), bottomGeoPoint.getLongitudeE6()), rightTop);
        projection.toPixels(bottomGeoPoint, rightBottom);
        projection.toPixels(new GeoPoint(bottomGeoPoint.getLatitudeE6(), topGeoPoint.getLongitudeE6()), leftBottom);

        if (
                (leftTop.x < 0 || leftTop.y < 0) && 
                (rightTop.x < 0 || rightTop.y < 0) && 
                (rightBottom.x < 0 || rightBottom.y < 0) && 
                (leftBottom.x < 0 || leftBottom.y < 0)) {
            // Not on screen? Don't draw the overlay
            return;
        }

        //      GeoPoint mapCenter = mapView.getMapCenter();
        Paint paint = new Paint();
        paint.setFilterBitmap(true);
        paint.setAntiAlias(true);

        canvas.drawBitmap(original, null, new Rect(leftTop.x, leftTop.y, rightBottom.x, rightBottom.y), paint);

        if (!ready && _onReady != null) {
            ready = true;
            _onReady.done();
        }
}


@Override
public boolean onTouchEvent(MotionEvent e, MapView mapView) {
    super.onTouchEvent(e, mapView);

    if (e.getAction() == MotionEvent.ACTION_UP) {
        setDrawTrue();
    }

    return false;
}

private void setDrawTrue() {
    DRAW = true;
    new Handler().postDelayed(new Runnable() {

        @Override
        public void run() {
            DRAW = false;
        }
    }, 100);
}

public void setOnReady(OnReady onReady) {
    this._onReady = onReady;
}

public interface OnReady {
    public void done();
}

}

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