diff --git a/app/src/main/java/com/kunfei/bookshelf/DbHelper.java b/app/src/main/java/com/kunfei/bookshelf/DbHelper.java
index 240be5a3db..9265cfcf1a 100644
--- a/app/src/main/java/com/kunfei/bookshelf/DbHelper.java
+++ b/app/src/main/java/com/kunfei/bookshelf/DbHelper.java
@@ -54,7 +54,7 @@ public static SQLiteDatabase getDb() {
         return getInstance().db;
     }
 
-    public class DaoOpenHelper extends DaoMaster.OpenHelper {
+    public static class DaoOpenHelper extends DaoMaster.OpenHelper {
         DaoOpenHelper(Context context, String name, SQLiteDatabase.CursorFactory factory) {
             super(context, name, factory);
         }
diff --git a/app/src/main/java/com/kunfei/bookshelf/base/BaseModelImpl.java b/app/src/main/java/com/kunfei/bookshelf/base/BaseModelImpl.java
index b7e0439ac2..6dcd201f22 100644
--- a/app/src/main/java/com/kunfei/bookshelf/base/BaseModelImpl.java
+++ b/app/src/main/java/com/kunfei/bookshelf/base/BaseModelImpl.java
@@ -191,7 +191,7 @@ public void onPageFinished(WebView view, String url) {
         });
     }
 
-    private class Web {
+    private static class Web {
         private String content;
         private String js = "document.documentElement.outerHTML";
 
diff --git a/app/src/main/java/com/kunfei/bookshelf/bean/BookKindBean.java b/app/src/main/java/com/kunfei/bookshelf/bean/BookKindBean.java
index eb4e5b2632..238e6de9bd 100644
--- a/app/src/main/java/com/kunfei/bookshelf/bean/BookKindBean.java
+++ b/app/src/main/java/com/kunfei/bookshelf/bean/BookKindBean.java
@@ -16,7 +16,7 @@ public BookKindBean(String kindS) {
         for (String kind : kindS.split("[,|\n]")) {
             if (StringUtils.isContainNumber(kind) && TextUtils.isEmpty(wordsS)) {
                 if (StringUtils.isNumeric(kind)) {
-                    int words = Integer.valueOf(kind);
+                    int words = Integer.parseInt(kind);
                     if (words > 0) {
                         wordsS = words + "字";
                         if (words > 10000) {
diff --git a/app/src/main/java/com/kunfei/bookshelf/bean/BookShelfBean.java b/app/src/main/java/com/kunfei/bookshelf/bean/BookShelfBean.java
index 2e916b9c81..11097659b4 100644
--- a/app/src/main/java/com/kunfei/bookshelf/bean/BookShelfBean.java
+++ b/app/src/main/java/com/kunfei/bookshelf/bean/BookShelfBean.java
@@ -263,7 +263,7 @@ public void setLastChapterName(String lastChapterName) {
 
     public int getUnreadChapterNum() {
         int num = getChapterListSize() - getDurChapter() - 1;
-        return num < 0 ? 0 : num;
+        return Math.max(num, 0);
     }
 
     public int getChapterListSize() {
diff --git a/app/src/main/java/com/kunfei/bookshelf/widget/HorizontalListView.java b/app/src/main/java/com/kunfei/bookshelf/widget/HorizontalListView.java
index 1a9e3dd5f4..9d01b7c83e 100644
--- a/app/src/main/java/com/kunfei/bookshelf/widget/HorizontalListView.java
+++ b/app/src/main/java/com/kunfei/bookshelf/widget/HorizontalListView.java
@@ -148,8 +148,7 @@ protected synchronized void onLayout(boolean changed, int left, int top, int rig
         }
 
         if(mScroller.computeScrollOffset()){
-            int scrollx = mScroller.getCurrX();
-            mNextX = scrollx;
+            mNextX = mScroller.getCurrX();
         }
 
         if(mNextX <= 0){
diff --git a/app/src/main/java/com/kunfei/bookshelf/widget/page/PageLoader.java b/app/src/main/java/com/kunfei/bookshelf/widget/page/PageLoader.java
index 3fc55ef660..3f8c59290e 100644
--- a/app/src/main/java/com/kunfei/bookshelf/widget/page/PageLoader.java
+++ b/app/src/main/java/com/kunfei/bookshelf/widget/page/PageLoader.java
@@ -1775,7 +1775,7 @@ private ChapterContainer nextChapter() {
 
     /*****************************************interface*****************************************/
 
-    class ChapterContainer {
+    static class ChapterContainer {
         TxtChapter txtChapter;
     }