如何在Android谷歌地图中制作自定义瓷砖

Question

Android's Google Maps api v2 provides a TileOverlay to which TileProviders can be added. A TileProvider will generate a Tile object given the lat, long, and depth. In order to make a tile, one must give it width (easy), height (easy), and an image represented as a byte array (confusing me). If I wanted to 'draw' a simple object and then turn it into a byte array, how would I do this?

For instance I am looking for something that looks like

Canvas canvas = new canvas();
...
canvas.drawRect(); //Or something like this (just an example)
...
byte[] bytes = canvas.SomeConversionFunctionOrProcessThatIDontKnow();
return new Tile(1,1,bytes);

Answer 1

public byte[] getByteArray (String image) throws IOException {
 File yourImg = new File(image);
 BufferedImage bufferedImage = ImageIO.read(yourImg);
 WritableRaster wRaster = bufferedImage .getRaster();
 DataBufferByte data   = (DataBufferByte) wRaster.getDataBuffer();

 return data.getData();
}

This should do the trick ; )

Answer 2

Tile#data should be compressed image data in one of the supported image formats . In other words, the raw contents of an image file. If you already have a decoded Bitmap , use Bitmap#compress(...) to write it to a ByteArrayOutputStream , then get the byte[] from that.

Answer 3

Bitmap bitmap = Bitmap.createBitmap(TILE_DIMENSION, TILE_DIMENSION,Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
......
//draw something
......
Tile tile = convertBitmap(bitmap);
bitmap.recycle();
return tile;
}

private Tile convertBitmap(Bitmap bitmap){
    ByteArrayOutputStream stream = new ByteArrayOutputStream();
    bitmap.compress(Bitmap.CompressFormat.PNG, 100, stream);
    byte[] bitmapData = stream.toByteArray();

    return new Tile(TILE_DIMENSION, TILE_DIMENSION, bitmapData);
}