use androidx.preference.ListPreference instead of android.support.v7.preference.ListPreference

Author: debugly

android/ijkplayer/ijkplayer-example/src/main/java/tv/danmaku/ijk/media/example/widget/preference/IjkListPreference.java

@@ -19,7 +19,7 @@
 
 import android.content.Context;
 import android.content.res.TypedArray;
-import android.support.v7.preference.ListPreference;
+import androidx.preference.ListPreference;
 import android.text.TextUtils;
 import android.util.AttributeSet;