<shape android:shape="rectangle"
    xmlns:android="http://schemas.android.com/apk/res/android">
    <size android:width="2dp" />
    <solid android:color="@color/black"/>
</shape>

android:textCursorDrawable="@drawable/my_cursor"

<style name="MyAppTheme" parent="Theme.AppCompat.Light.NoActionBar">
        ...
        <item name="android:textCursorDrawable">@drawable/my_cursor</item>
        ...
</style>