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

一个可绘制对象可以被绘制到画布上，一个画布可以被位图支持:

(更新到处理BitmapDrawables的快速转换，并确保创建的位图具有有效的大小)

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

    int width = drawable.getIntrinsicWidth();
    width = width > 0 ? width : 1;
    int height = drawable.getIntrinsicHeight();
    height = height > 0 ? height : 1;

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

    return bitmap;
}

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

最新的androidx核心库(androidx.core:core-ktx:1.2.0)现在有一个扩展函数:Drawable. tobitmap(…)来将Drawable转换为Bitmap。

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);
}

我在这个帖子上使用了一些答案，但其中一些并没有像预期的那样工作(也许他们在旧版本中工作)，但我想在尝试了几次和错误后分享我的答案，使用扩展函数:

val markerOption = MarkerOptions().apply {
    position(LatLng(driver.lat, driver.lng))
    icon(R.drawabel.your_drawable.toBitmapDescriptor(context))
    snippet(driver.driverId.toString())
}
mMap.addMarker(markerOption)

这是扩展函数:

fun Int.toBitmapDescriptor(context: Context): BitmapDescriptor {
    val vectorDrawable = ResourcesCompat.getDrawable(context.resources, this, context.theme)
    val bitmap = vectorDrawable?.toBitmap(
        vectorDrawable.intrinsicWidth,
        vectorDrawable.intrinsicHeight,
        Bitmap.Config.ARGB_8888
    )
    return BitmapDescriptorFactory.fromBitmap(bitmap!!)
}