优化代码

app/src/main/res/layout/fragment_book_source.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+<androidx.constraintlayout.widget.ConstraintLayout
+        xmlns:android="http://schemas.android.com/apk/res/android"
         xmlns:app="http://schemas.android.com/apk/res-auto"
         android:orientation="vertical"
         android:layout_width="match_parent"
@@ -13,4 +14,4 @@
             app:layout_constraintTop_toTopOf="parent"
             app:title="@string/book_source"/>
 
-</LinearLayout>
+</androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/layout/fragment_find_book.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+<androidx.constraintlayout.widget.ConstraintLayout
+        xmlns:android="http://schemas.android.com/apk/res/android"
         xmlns:app="http://schemas.android.com/apk/res-auto"
         android:orientation="vertical"
         android:layout_width="match_parent"
@@ -13,4 +14,5 @@
             app:layout_constraintTop_toTopOf="parent"
             app:title="@string/find"/>
 
-</LinearLayout>
+
+</androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/layout/fragment_my_config.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+<androidx.constraintlayout.widget.ConstraintLayout
+        xmlns:android="http://schemas.android.com/apk/res/android"
         xmlns:app="http://schemas.android.com/apk/res-auto"
         android:layout_width="match_parent"
         android:layout_height="match_parent">