Drawable、Bitmap、byte[]之间的转换

1、Drawable → Bitmap

public static Bitmap drawableToBitmap(Drawable drawable) {

Bitmap bitmap = Bitmap .createBitmap(
drawable.getIntrinsicWidth(),                                          drawable.getIntrinsicHeight(),
drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888  : Bitmap.Config.RGB_565);
Canvas canvas = new Canvas(bitmap);
//canvas.setBitmap(bitmap);
drawable.setBounds(0, 0, drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight());
drawable.draw(canvas);
return bitmap;
}

2、Bitmap → byte[]

private byte[] Bitmap2Bytes(Bitmap bm){       ByteArrayOutputStream baos = new ByteArrayOutputStream();
bm.compress(Bitmap.CompressFormat.PNG, 100, baos);
return baos.toByteArray();
}

3、byte[] → Bitmap

private Bitmap Bytes2Bimap(byte[] b){
if(b.length!=0){
return BitmapFactory.decodeByteArray(b, 0, b.length);
}
else {
return null;
}
}

另外还有更简单的方法：

1、Bitmap to Drawable

BitmapDrawable bitmapDrawable = (BitmapDrawable)bitmap;
Drawable drawable = (Drawable)bitmapDrawable;
Bitmap bitmap = new Bitmap (...);
Drawable drawable = new BitmapDrawable(bitmap);

2、Drawable to Bitmap

Drawable d = ImagesList.get(0);
Bitmap bitmap = ((BitmapDrawable)d).getBitmap();