Android中Bitmap, Drawable, Byte,ID之间的转化

1. Bitmap 转化为 byte

ByteArrayOutputStream out = new ByteArrayOutputStream();bitmap.compress(Bitmap.CompressFormat.PNG, 100, out);byte[] array= out.toByteArray();

1. byte转化为bitmap

Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);

1. bitmap转化为Drawable

Drawable drawable = new FastBitmapDrawable(bitmap);

1. Drawable转化为bitmap
   a. BitmapDrawable, FastBitmapDrawable直接用getBitmap
   b. 其他类型的Drawable用Canvas画到一个bitmap上

    Canvas canvas = new Canvas(bitmap)      drawable.draw(canvas)

5.id转化graphic.drawable

   Drawable drawable = getResources().getDrawable(R.drawable.icon);

6.id转化成Bitmap

 Bitmap bitmap = BitmapFactory. decodeResource (Resources   res, int id)