Resource，Drawable和Bitmap之间的转换

Drawable draw1 = this.getResources().getDrawable(R.drawable.icon);

static Bitmap drawableToBitmap(Drawable drawable) // drawable 转换成bitmap
{
int width = drawable.getIntrinsicWidth();// 取drawable的长宽
int height = drawable.getIntrinsicHeight();
Bitmap.Config config = drawable.getOpacity() != PixelFormat.OPAQUE ?Bitmap.Config.ARGB_8888:Bitmap.Config.RGB_565;// 取drawable的颜色格式
Bitmap bitmap = Bitmap.createBitmap(width, height, config);// 建立对应bitmap
Canvas canvas = new Canvas(bitmap);// 建立对应bitmap的画布
drawable.setBounds(0, 0, width, height);
drawable.draw(canvas);// 把drawable内容画到画布中
return bitmap;
}

Bitmap bitmap = ((android.graphics.drawable.BitmapDrawable) pm.getApplicationIcon(appInfo)).getBitmap();