參考文件

方式1: 判斷drawable 是否為BitmapDrawable

• 直接強(qiáng)轉(zhuǎn) Drawable 為 BitmapDrawable, 然后調(diào)用getBitmap() 函數(shù)返回Bitmap

方式2: 使用Canvas 繪制Bitmap

1. 創(chuàng)建Bitmap畫(huà)布對(duì)象
2. 判斷是否為ColorDrawable , 是的話, width = height =2 ?
3. 不是直接按照 drawable 的寬高, 和 ARGB_8888 創(chuàng)建一個(gè) Bitmap
4. 調(diào)用 drawable.draw(canvas) 函數(shù)繪制圖像, 并將drawable 保存在 Bitmap 上

private Bitmap getBitmapFromDrawable(Drawable drawable) {
  if (drawable == null) {
    return null;
  }

  if (drawable instanceof BitmapDrawable) {
    return ((BitmapDrawable) drawable).getBitmap();
  }

  try {
    Bitmap bitmap;

    //顏色Drawable
    if (drawable instanceof ColorDrawable) {
      //寬為2, 高為2 ??
      bitmap = Bitmap.createBitmap(COLORDRAWABLE_DIMENSION, COLORDRAWABLE_DIMENSION, BITMAP_CONFIG);
    } else {
      bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(), BITMAP_CONFIG);
    }

    Canvas canvas = new Canvas(bitmap);
    drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
    //將 drawable 的內(nèi)容繪制到 bitmap的canvas 上面去.
    drawable.draw(canvas);
    return bitmap;
  } catch (Exception e) {
    e.printStackTrace();
    return null;
  }
}