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

1.  Bitmap 转化为 byte

 ByteArrayOutputStream out = newByteArrayOutputStream();

 bitmap.compress(Bitmap.CompressFormat.PNG,100, out);

 byte[] array= out.toByteArray();

 

2.byte转化为bitmap

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

 

3.bitmap转化为Drawable

 Drawable drawable = newFastBitmapDrawable(bitmap);

 

4.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 =activity.getResources().getDrawable(R.drawable.icon);

 

6.id转化成Bitmap

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