Draw Text on Google Map no longer possible?

问题:

I'm upgrading an Android application from version 1 to version 2 of the android google maps API. In my version 1 code, I was able to draw text directly on the map in my subclass of ItemizedOverlay by overriding the draw() method, as follows. The text I want to draw is dynamic, an additional text item that I want to display next to each map marker, so the text will be added/removed frequently as different symbols are plotted / removed.

@Override
public boolean draw(Canvas canvas, MapView mapView, boolean shadow,
        long when) {
    if (!shadow) {              
            canvas.drawText("some text", (float) point.x + TextOffsetX , (float) point.y + TextOffsetY, m_paint);
     }


    return super.draw(canvas, mapView, shadow, when);
}

However, this doesn't seem possible in the version 2 of the API. THere's isn't really a concept of ItemizedOverlays and nothing can be subclassed. Is there some way I can draw text on the GoogleMap in the new API version?

回答1:

You can create a Marker from a View by using the following code:

public static Bitmap createDrawableFromView(Context context, View view) {
    DisplayMetrics displayMetrics = new DisplayMetrics();
    ((Activity) context).getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
    view.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
    view.measure(displayMetrics.widthPixels, displayMetrics.heightPixels);
    view.layout(0, 0, displayMetrics.widthPixels, displayMetrics.heightPixels);
    view.buildDrawingCache();
    Bitmap bitmap = Bitmap.createBitmap(view.getMeasuredWidth(), view.getMeasuredHeight(), Bitmap.Config.ARGB_8888);

    Canvas canvas = new Canvas(bitmap);
    view.draw(canvas);

    return bitmap;
}

Source: http://www.nasc.fr/android/android-using-layout-as-custom-marker-on-google-map-api/

edit: If you use more than a single marker, make sure you don't do the DisplayMetrics and view setup stuff (everything above Bitmap bitmap =.....) for every marker. That would slow down your app dramatically.

回答2:

I had the same problem, trying to upgrade from v1 to v2. Finally I used a marker, created a Bitmap with the text, and used it as icon of the marker.

First of all, you have to create de Bitmap with the text. Note: configure paintText with text properties (color, typeface, textalign,...)

Rect boundsText = new Rect();
paintText.getTextBounds(strText, 0, strText.length(), boundsText);
Bitmap.Config conf = Bitmap.Config.ARGB_8888;
Bitmap bmpText = Bitmap.createBitmap(boundsText.width(), boundsText.height(), conf);

Then, use Canvas for drawing the text. It is a little bit madness fix text with canvas dimenssion.

Canvas canvasText = new Canvas(bmpText);
canvasText.drawText(strText, canvasText.getWidth() / 2, canvasText.getHeight(), paintText);

Finally use Bitmap to create icon in MarkerOption

MarkerOptions markerOptions = new MarkerOptions()
    .position(latlngMarker)
    .icon(BitmapDescriptorFactory.fromBitmap(bmpText))
    .anchor(0.5f, 1);

Hope it could help you.