下面是@Chris提供的答案的Kotlin版本。Jenkins在这里:https://stackoverflow.com/a/27543712/1016462

fun Drawable.toBitmap(): Bitmap {
  if (this is BitmapDrawable) {
    return bitmap
  }

  val width = if (bounds.isEmpty) intrinsicWidth else bounds.width()
  val height = if (bounds.isEmpty) intrinsicHeight else bounds.height()

  return Bitmap.createBitmap(width.nonZero(), height.nonZero(), Bitmap.Config.ARGB_8888).also {
    val canvas = Canvas(it)
    setBounds(0, 0, canvas.width, canvas.height)
    draw(canvas)
  }
}

private fun Int.nonZero() = if (this <= 0) 1 else this

BitmapFactory.decodeResource()自动缩放位图，因此您的位图可能会变得模糊。为了防止结垢，请这样做:

BitmapFactory.Options options = new BitmapFactory.Options();
options.inScaled = false;
Bitmap source = BitmapFactory.decodeResource(context.getResources(),
                                             R.drawable.resource_name, options);

or

InputStream is = context.getResources().openRawResource(R.drawable.resource_name)
bitmap = BitmapFactory.decodeStream(is);

这是更好的分辨率

public static Bitmap drawableToBitmap (Drawable drawable) {
    if (drawable instanceof BitmapDrawable) {
        return ((BitmapDrawable)drawable).getBitmap();
    }

    Bitmap bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(), Config.ARGB_8888);
    Canvas canvas = new Canvas(bitmap); 
    drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
    drawable.draw(canvas);

    return bitmap;
}

public static InputStream bitmapToInputStream(Bitmap bitmap) {
    int size = bitmap.getHeight() * bitmap.getRowBytes();
    ByteBuffer buffer = ByteBuffer.allocate(size);
    bitmap.copyPixelsToBuffer(buffer);
    return new ByteArrayInputStream(buffer.array());
}

如何将可绘制的位读取为输入流的代码

Bitmap Bitmap = BitmapFactory.decodeResource(context.getResources()， R.drawable.icon);

这将不会每次工作，例如，如果你的可绘制层列表可绘制，然后它给出一个空响应，所以作为一个替代方案，你需要绘制你的可绘制到画布，然后保存为位图，请参考下面的一杯代码。

public void drawableToBitMap(Context context, int drawable, int widthPixels, int heightPixels) {
    try {
        File file = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS) + "/", "drawable.png");
        FileOutputStream fOut = new FileOutputStream(file);
        Drawable drw = ResourcesCompat.getDrawable(context.getResources(), drawable, null);
        if (drw != null) {
            convertToBitmap(drw, widthPixels, heightPixels).compress(Bitmap.CompressFormat.PNG, 100, fOut);
        }
        fOut.flush();
        fOut.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

private Bitmap convertToBitmap(Drawable drawable, int widthPixels, int heightPixels) {
    Bitmap bitmap = Bitmap.createBitmap(widthPixels, heightPixels, Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(bitmap);
    drawable.setBounds(0, 0, widthPixels, heightPixels);
    drawable.draw(canvas);
    return bitmap;
}

以上代码保存为drawable.png在下载目录

这段代码有帮助。

Bitmap icon = BitmapFactory.decodeResource(context.getResources(),
                                           R.drawable.icon_resource);

这里是下载图像的版本。

String name = c.getString(str_url);
URL url_value = new URL(name);
ImageView profile = (ImageView)v.findViewById(R.id.vdo_icon);
if (profile != null) {
    Bitmap mIcon1 =
        BitmapFactory.decodeStream(url_value.openConnection().getInputStream());
    profile.setImageBitmap(mIcon1);
}

这将BitmapDrawable转换为Bitmap。

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