Android Studio Resource Manager vector drawable preview

Question

I have a lot of vector drawables in my project. All of them are being used a fillColor as a theme attribute. In this case, the Resource Manager preview is not being shown until set some color by tools to a drawable.

As you can see in the picture, ic_drag is red because of tools:fillColor="#ff0000". But the ic_arrow_back_on_primary preview is empty.

ic_drag:

 <vector xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:width="24dp"
    android:height="24dp"
    android:tint="?attr/colorControlNormal"
    android:viewportWidth="24"
    android:viewportHeight="24">
    <path
        android:fillColor="?banan"
        tools:fillColor="#ff0000"
        android:pathData="M20,9H4v2h16V9zM4,15h16v-2H4V15z" />
</vector>

ic_arrow_back_on_primary:

<vector xmlns:android="http://schemas.android.com/apk/res/android"
    android:width="24dp"
    android:height="24dp"
    android:tint="?attr/colorControlNormal"
    android:viewportWidth="24"
    android:viewportHeight="24">
    <path
        android:fillColor="?colorOnPrimary"
        android:pathData="M20,11H7.83l5.59,-5.59L12,4l-8,8 8,8 1.41,-1.41L7.83,13H20v-2z" />
</vector>

If open the drawable's editor, a preview is being shown for this drawable. Doesn't matter which way to use: attribute or direct color.

Is there any way to force the Resource Manager to show preview without adding "tools" attr?

Answer 1

For Android Studio to render that preview, it needs to know what color(s) to use.

In the case of ic_arrow_back_on_primary , both the android:tint attr and the android:fillColor attr are using theme attributes (anything that starts with a ? ). Theme attributes are, of course, dependent on the theme currently in use, and the resource manager doesn't (seem to) have a way to specify the theme to use for the previews.

So, no, there's no way to get the previews to display without adding a tools attribute, unless you are willing to use colors that aren't dependent on the current theme (which may not be viable for your use cases).