diff --git a/app/src/main/java/io/legado/app/constant/PageAnim.kt b/app/src/main/java/io/legado/app/constant/PageAnim.kt
new file mode 100644
index 000000000..ac98ef023
--- /dev/null
+++ b/app/src/main/java/io/legado/app/constant/PageAnim.kt
@@ -0,0 +1,22 @@
+package io.legado.app.constant
+
+import androidx.annotation.IntDef
+
+object PageAnim {
+
+    const val coverPageAnim = 0
+
+    const val slidePageAnim = 1
+
+    const val simulationPageAnim = 2
+
+    const val scrollPageAnim = 3
+
+    const val noAnim = 4
+
+    @Target(AnnotationTarget.VALUE_PARAMETER)
+    @Retention(AnnotationRetention.SOURCE)
+    @IntDef(coverPageAnim, slidePageAnim, simulationPageAnim, scrollPageAnim, noAnim)
+    annotation class Anim
+
+}
\ No newline at end of file
diff --git a/app/src/main/java/io/legado/app/data/entities/Book.kt b/app/src/main/java/io/legado/app/data/entities/Book.kt
index 02afb4f1a..4446d36eb 100644
--- a/app/src/main/java/io/legado/app/data/entities/Book.kt
+++ b/app/src/main/java/io/legado/app/data/entities/Book.kt
@@ -4,6 +4,7 @@ import android.os.Parcelable
 import androidx.room.*
 import io.legado.app.constant.AppPattern
 import io.legado.app.constant.BookType
+import io.legado.app.constant.PageAnim
 import io.legado.app.data.appDb
 import io.legado.app.help.config.AppConfig
 import io.legado.app.help.config.ReadBookConfig
@@ -207,7 +208,7 @@ data class Book(
 
     fun getPageAnim(): Int {
         var pageAnim = config.pageAnim
-            ?: if (type == BookType.image) 3 else ReadBookConfig.pageAnim
+            ?: if (type == BookType.image) PageAnim.scrollPageAnim else ReadBookConfig.pageAnim
         if (pageAnim < 0) {
             pageAnim = ReadBookConfig.pageAnim
         }
diff --git a/app/src/main/java/io/legado/app/help/config/ReadBookConfig.kt b/app/src/main/java/io/legado/app/help/config/ReadBookConfig.kt
index b2e166bb7..796a6866b 100644
--- a/app/src/main/java/io/legado/app/help/config/ReadBookConfig.kt
+++ b/app/src/main/java/io/legado/app/help/config/ReadBookConfig.kt
@@ -7,6 +7,7 @@ import android.graphics.drawable.Drawable
 import androidx.annotation.Keep
 import io.legado.app.R
 import io.legado.app.constant.AppLog
+import io.legado.app.constant.PageAnim
 import io.legado.app.constant.PreferKey
 import io.legado.app.help.DefaultData
 import io.legado.app.help.coroutine.Coroutine
@@ -173,7 +174,7 @@ object ReadBookConfig {
 
     var pageAnim: Int
         get() = config.curPageAnim()
-        set(value) {
+        set(@PageAnim.Anim value) {
             config.setCurPageAnim(value)
         }
 
@@ -515,7 +516,7 @@ object ReadBookConfig {
             }
         }
 
-        fun setCurPageAnim(anim: Int) {
+        fun setCurPageAnim(@PageAnim.Anim anim: Int) {
             when {
                 AppConfig.isEInkMode -> pageAnimEInk = anim
                 else -> pageAnim = anim
diff --git a/app/src/main/java/io/legado/app/ui/book/read/page/ReadView.kt b/app/src/main/java/io/legado/app/ui/book/read/page/ReadView.kt
index 7d29bbfdc..7610d17ca 100644
--- a/app/src/main/java/io/legado/app/ui/book/read/page/ReadView.kt
+++ b/app/src/main/java/io/legado/app/ui/book/read/page/ReadView.kt
@@ -12,6 +12,7 @@ import android.view.MotionEvent
 import android.view.ViewConfiguration
 import android.view.WindowInsets
 import android.widget.FrameLayout
+import io.legado.app.constant.PageAnim
 import io.legado.app.help.config.AppConfig
 import io.legado.app.help.config.ReadBookConfig
 import io.legado.app.lib.theme.accentColor
@@ -127,7 +128,7 @@ class ReadView(context: Context, attrs: AttributeSet) :
         super.dispatchDraw(canvas)
         pageDelegate?.onDraw(canvas)
         if (!isInEditMode && callBack.isAutoPage && !isScroll) {
-            // TODO 自动翻页
+            // 自动翻页
             nextPage.screenshot()?.let {
                 val bottom = callBack.autoPageProgress
                 autoPageRect.set(0, 0, width, bottom)
@@ -481,16 +482,16 @@ class ReadView(context: Context, attrs: AttributeSet) :
         isScroll = ReadBook.pageAnim() == 3
         ChapterProvider.upLayout()
         when (ReadBook.pageAnim()) {
-            0 -> if (pageDelegate !is CoverPageDelegate) {
+            PageAnim.coverPageAnim -> if (pageDelegate !is CoverPageDelegate) {
                 pageDelegate = CoverPageDelegate(this)
             }
-            1 -> if (pageDelegate !is SlidePageDelegate) {
+            PageAnim.slidePageAnim -> if (pageDelegate !is SlidePageDelegate) {
                 pageDelegate = SlidePageDelegate(this)
             }
-            2 -> if (pageDelegate !is SimulationPageDelegate) {
+            PageAnim.simulationPageAnim -> if (pageDelegate !is SimulationPageDelegate) {
                 pageDelegate = SimulationPageDelegate(this)
             }
-            3 -> if (pageDelegate !is ScrollPageDelegate) {
+            PageAnim.scrollPageAnim -> if (pageDelegate !is ScrollPageDelegate) {
                 pageDelegate = ScrollPageDelegate(this)
             }
             else -> if (pageDelegate !is NoAnimPageDelegate) {