Though usually not visible to the application, Drawables may take a variety of forms: 盡管通常情況下對于應用是不可見的,Drawables 可以采取很多形式:Bitmap: the simplest Drawable, a PNG or JPEG image. Bitmap: 簡單化的Drawable, PNG 或JPEG圖像. Nine Patch: an extension to the PNG format allows it to specify information about how to stretch it and place things inside of it.Shape: contains simple drawing commands instead of a raw bitmap, allowing it to resize better in some cases.Layers: a compound drawable, which draws multiple underlying drawables on top of each other.States: a compound drawable that selects one of a set of drawables based on its state.Levels: a compound drawable that selects one of a set of drawables based on its level.Scale: a compound drawable with a single child drawable, whose overall size is modified based on the current level.

//setImageResource()public void setImageResource (int resId)//占用UI thread;// setImageBitmap()ImageView iv;String fileName = "/data/data/com.test/aa.png";Bitmap bm = BitmapFactory.decodeFile(fileName); iv.setImageBitmap(bm); //占用內存// setImageBitmap()Bitmap image = BitmapFactory.decodeFile(imgFile.getAbsolutePath());imageView.setImageBitmap(image);// Bitmap轉換成DrawableBitmap image = BitmapFactory.decodeFile(imgFile.getAbsolutePath());BitmapDrawable bitmapDrawable = new BitmapDrawable(image);imageView.setImageDrawable(bitmapDrawable);// 結論：Bitmap是Drawable . Drawable不一定是Bitmap