SDK 与 Android Studio 绑定，无需单独下载.

The SDK is bundled with Android Studio, you don't have to download it separately.

我在安装了 Android Studio 的两台机器上都看到了这个问题 - 安装时没有创建附加组件"目录.

I've seen this issue on both machines I've installed Android Studio on - the "add-ons" directory doesn't get created at install.

假设您使用的是 64 位 Windows 并安装到默认位置，请看这里:

Assuming you're on 64 bit Windows and installed to default location, look here:

*C:Program Files (x86)Androidandroid-studiosdk*

如果您没有Program Files (x86)"文件夹，请查看Program Files"

If you don't have a "Program Files (x86)" folder, look in "Program Files"

我敢打赌那里没有附加组件"文件夹.如果没有，请创建一个然后启动 Android Studio.您应该没有发现任何问题.

I'd bet there's no "add-ons" folder in there. If not, create one and than start Android Studio. You should see no problems.