android在处理一写图片资源的时候，会进行一些类型的转换:
1 Drawable → Bitmap 的简单方法
((BitmapDrawable)res.getDrawable(R.drawable.youricon)).getBitmap();
2 Drawable → Bitmap
public static Bitmap drawableToBitmap(Drawable drawable) {
Bitmap bitmap = Bitmap.createBitmap(rawable.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;
}
3 Bitmap→Drawable的简单方法
BitmapDrawable bitmapDrawable = (BitmapDrawable)bitmap;
Drawable drawable = (Drawable)bitmapDrawable; Bitmap bitmap = new Bitmap (...);
Drawable drawable = new BitmapDrawable(bitmap);
4 从资源中获取Bitmap
Resources res = getResources();
Bitmap bmp = BitmapFactory.decodeResource(res, R.drawable.pic);
5 Bitmap → byte[]
private byte[] Bitmap2Bytes(Bitmap bm) {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bm.compress(Bitmap.CompressFormat.PNG, 100, baos);
return baos.toByteArray();
}
6 byte[] → Bitmap
private Bitmap Bytes2Bimap(byte[] b) {
if (b.length!=0) {
return BitmapFactory.decodeByteArray(b, 0, b.length);
} else {
return null;
}
}