error when PreferenceActivity
check this article:
https://blog.30sparks.com/preferenceactivity-under-appcompat/
不過要注意Setting layout .xml 內Toolbar要改:
xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical">
<androidx.appcompat.widget.Toolbar android:id="@+id/action_bar" android:layout_width="match_parent" android:layout_height="wrap_content" android:minHeight="?attr/actionBarSize" />
<FrameLayout android:id="@+id/content_wrapper" android:layout_width="match_parent" android:layout_height="0dp" android:layout_weight="1" />
</LinearLayout>