diff --git a/app/src/main/java/io/legado/app/base/BaseFragment.kt b/app/src/main/java/io/legado/app/base/BaseFragment.kt
index 155bb6076..eb7805029 100644
--- a/app/src/main/java/io/legado/app/base/BaseFragment.kt
+++ b/app/src/main/java/io/legado/app/base/BaseFragment.kt
@@ -15,6 +15,7 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
 import kotlin.coroutines.CoroutineContext
 
+@Suppress("MemberVisibilityCanBePrivate")
 abstract class BaseFragment(layoutID: Int) : Fragment(layoutID),
     CoroutineScope {
     lateinit var job: Job
diff --git a/app/src/main/java/io/legado/app/base/BaseService.kt b/app/src/main/java/io/legado/app/base/BaseService.kt
index f00540526..192737447 100644
--- a/app/src/main/java/io/legado/app/base/BaseService.kt
+++ b/app/src/main/java/io/legado/app/base/BaseService.kt
@@ -18,7 +18,9 @@ abstract class BaseService : Service(), CoroutineScope by MainScope() {
         block: suspend CoroutineScope.() -> T
     ) = Coroutine.async(scope, context) { block() }
 
-    override fun onBind(intent: Intent?) = null
+    override fun onBind(intent: Intent?): IBinder? {
+        return null
+    }
 
     override fun onDestroy() {
         super.onDestroy()
diff --git a/app/src/main/java/io/legado/app/base/BaseViewModel.kt b/app/src/main/java/io/legado/app/base/BaseViewModel.kt
index c8332e0cc..e5432e204 100644
--- a/app/src/main/java/io/legado/app/base/BaseViewModel.kt
+++ b/app/src/main/java/io/legado/app/base/BaseViewModel.kt
@@ -11,6 +11,7 @@ import org.jetbrains.anko.AnkoLogger
 import org.jetbrains.anko.toast
 import kotlin.coroutines.CoroutineContext
 
+@Suppress("unused")
 open class BaseViewModel(application: Application) : AndroidViewModel(application),
     CoroutineScope by MainScope(),
     AnkoLogger {
diff --git a/app/src/main/java/io/legado/app/base/adapter/CommonRecyclerAdapter.kt b/app/src/main/java/io/legado/app/base/adapter/CommonRecyclerAdapter.kt
index 0ae540837..4fd0fd520 100644
--- a/app/src/main/java/io/legado/app/base/adapter/CommonRecyclerAdapter.kt
+++ b/app/src/main/java/io/legado/app/base/adapter/CommonRecyclerAdapter.kt
@@ -15,6 +15,7 @@ import java.util.*
  *
  * 通用的adapter 可添加header，footer，以及不同类型item
  */
+@Suppress("unused", "MemberVisibilityCanBePrivate")
 abstract class CommonRecyclerAdapter<ITEM>(protected val context: Context) :
     RecyclerView.Adapter<ItemViewHolder>() {
 
diff --git a/app/src/main/java/io/legado/app/base/adapter/InfiniteScrollListener.kt b/app/src/main/java/io/legado/app/base/adapter/InfiniteScrollListener.kt
index a679f3e08..08f9716f3 100644
--- a/app/src/main/java/io/legado/app/base/adapter/InfiniteScrollListener.kt
+++ b/app/src/main/java/io/legado/app/base/adapter/InfiniteScrollListener.kt
@@ -8,6 +8,7 @@ import androidx.recyclerview.widget.RecyclerView
  *
  * 上拉加载更多
  */
+@Suppress("unused")
 abstract class InfiniteScrollListener() : RecyclerView.OnScrollListener() {
     private val loadMoreRunnable = Runnable { onLoadMore() }
 
diff --git a/app/src/main/java/io/legado/app/base/adapter/ItemAnimation.kt b/app/src/main/java/io/legado/app/base/adapter/ItemAnimation.kt
index e2c37d708..3f70ca3ea 100644
--- a/app/src/main/java/io/legado/app/base/adapter/ItemAnimation.kt
+++ b/app/src/main/java/io/legado/app/base/adapter/ItemAnimation.kt
@@ -7,6 +7,7 @@ import io.legado.app.base.adapter.animations.*
 /**
  * Created by Invincible on 2017/12/15.
  */
+@Suppress("unused")
 class ItemAnimation private constructor() {
 
     var itemAnimEnabled = false
diff --git a/app/src/main/java/io/legado/app/help/ActivityHelp.kt b/app/src/main/java/io/legado/app/help/ActivityHelp.kt
index 8d07a3500..9c9cb0175 100644
--- a/app/src/main/java/io/legado/app/help/ActivityHelp.kt
+++ b/app/src/main/java/io/legado/app/help/ActivityHelp.kt
@@ -10,6 +10,7 @@ import java.util.*
 /**
  * Activity管理器,管理项目中Activity的状态
  */
+@Suppress("unused")
 object ActivityHelp : Application.ActivityLifecycleCallbacks {
 
     private val activities: MutableList<WeakReference<Activity>> = arrayListOf()
diff --git a/app/src/main/java/io/legado/app/help/BlurTransformation.kt b/app/src/main/java/io/legado/app/help/BlurTransformation.kt
index 4493228c4..74de12038 100644
--- a/app/src/main/java/io/legado/app/help/BlurTransformation.kt
+++ b/app/src/main/java/io/legado/app/help/BlurTransformation.kt
@@ -28,7 +28,7 @@ class BlurTransformation(context: Context, private val radius: Int) : CenterCrop
         //图片缩小1/2
         val width = (min(outWidth, transform.width) / 2f).roundToInt()
         val height = (min(outHeight, transform.height) / 2f).roundToInt()
-        val blurredBitmap = Bitmap.createScaledBitmap(transform, width, height, false);
+        val blurredBitmap = Bitmap.createScaledBitmap(transform, width, height, false)
         // Allocate memory for Renderscript to work with
         //分配用于渲染脚本的内存
         val input = Allocation.createFromBitmap(
diff --git a/app/src/main/java/io/legado/app/help/BookHelp.kt b/app/src/main/java/io/legado/app/help/BookHelp.kt
index 32d5262ce..4f1a2ba9f 100644
--- a/app/src/main/java/io/legado/app/help/BookHelp.kt
+++ b/app/src/main/java/io/legado/app/help/BookHelp.kt
@@ -267,8 +267,9 @@ object BookHelp {
         }
     }
 
-    private val chapterNamePattern =
+    private val chapterNamePattern by lazy {
         Pattern.compile("^(.*?第([\\d零〇一二两三四五六七八九十百千万壹贰叁肆伍陆柒捌玖拾佰仟０-９\\s]+)[章节篇回集])[、，。　：:.\\s]*")
+    }
 
     private fun getChapterNum(chapterName: String?): Int {
         if (chapterName != null) {
@@ -280,15 +281,25 @@ object BookHelp {
         return -1
     }
 
-    private fun getPureChapterName(chapterName: String?): String {
+    @Suppress("SpellCheckingInspection")
+    private val regexOther by lazy {
         // 所有非字母数字中日韩文字 CJK区+扩展A-F区
+        return@lazy "[^\\w\\u4E00-\\u9FEF〇\\u3400-\\u4DBF\\u20000-\\u2A6DF\\u2A700-\\u2EBEF]".toRegex()
+    }
+
+    private val regexA by lazy {
+        return@lazy "\\s".toRegex()
+    }
+
+    private val regexB by lazy {
+        return@lazy "^第.*?章|[(\\[][^()\\[\\]]{2,}[)\\]]$".toRegex()
+    }
+
+    private fun getPureChapterName(chapterName: String?): String {
         return if (chapterName == null) "" else StringUtils.fullToHalf(chapterName)
-            .replace("\\s".toRegex(), "")
-            .replace("^第.*?章|[(\\[][^()\\[\\]]{2,}[)\\]]$".toRegex(), "")
-            .replace(
-                "[^\\w\\u4E00-\\u9FEF〇\\u3400-\\u4DBF\\u20000-\\u2A6DF\\u2A700-\\u2EBEF]".toRegex(),
-                ""
-            )
+            .replace(regexA, "")
+            .replace(regexB, "")
+            .replace(regexOther, "")
     }
 
     private var bookName: String? = null
diff --git a/app/src/main/java/io/legado/app/help/EventMessage.kt b/app/src/main/java/io/legado/app/help/EventMessage.kt
index fe9c80994..9e2606ea5 100644
--- a/app/src/main/java/io/legado/app/help/EventMessage.kt
+++ b/app/src/main/java/io/legado/app/help/EventMessage.kt
@@ -2,8 +2,7 @@ package io.legado.app.help
 
 import android.text.TextUtils
 
-import java.util.Arrays
-
+@Suppress("unused")
 class EventMessage {
 
     var what: Int?=null
diff --git a/app/src/main/java/io/legado/app/help/IntentHelp.kt b/app/src/main/java/io/legado/app/help/IntentHelp.kt
index d7ed03af1..05b580272 100644
--- a/app/src/main/java/io/legado/app/help/IntentHelp.kt
+++ b/app/src/main/java/io/legado/app/help/IntentHelp.kt
@@ -7,6 +7,7 @@ import android.os.Bundle
 import io.legado.app.R
 import org.jetbrains.anko.toast
 
+@Suppress("unused")
 object IntentHelp {
 
 
diff --git a/app/src/main/java/io/legado/app/help/LayoutManager.kt b/app/src/main/java/io/legado/app/help/LayoutManager.kt
index e633993c7..79b54bb0c 100644
--- a/app/src/main/java/io/legado/app/help/LayoutManager.kt
+++ b/app/src/main/java/io/legado/app/help/LayoutManager.kt
@@ -6,6 +6,7 @@ import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import androidx.recyclerview.widget.StaggeredGridLayoutManager
 
+@Suppress("unused")
 object LayoutManager {
 
     interface LayoutManagerFactory {
diff --git a/app/src/main/java/io/legado/app/help/coroutine/CompositeCoroutine.kt b/app/src/main/java/io/legado/app/help/coroutine/CompositeCoroutine.kt
index 1eb1102ba..14c123378 100644
--- a/app/src/main/java/io/legado/app/help/coroutine/CompositeCoroutine.kt
+++ b/app/src/main/java/io/legado/app/help/coroutine/CompositeCoroutine.kt
@@ -1,5 +1,6 @@
 package io.legado.app.help.coroutine
 
+@Suppress("unused")
 class CompositeCoroutine : CoroutineContainer {
 
     private var resources: HashSet<Coroutine<*>>? = null
diff --git a/app/src/main/java/io/legado/app/help/coroutine/Coroutine.kt b/app/src/main/java/io/legado/app/help/coroutine/Coroutine.kt
index 0811eee10..a31c9d1e0 100644
--- a/app/src/main/java/io/legado/app/help/coroutine/Coroutine.kt
+++ b/app/src/main/java/io/legado/app/help/coroutine/Coroutine.kt
@@ -5,6 +5,7 @@ import kotlinx.coroutines.*
 import kotlin.coroutines.CoroutineContext
 
 
+@Suppress("unused")
 class Coroutine<T>(
     val scope: CoroutineScope,
     context: CoroutineContext = Dispatchers.IO,
diff --git a/app/src/main/java/io/legado/app/help/http/CookieStore.kt b/app/src/main/java/io/legado/app/help/http/CookieStore.kt
index 067435ddb..2f2bfaaec 100644
--- a/app/src/main/java/io/legado/app/help/http/CookieStore.kt
+++ b/app/src/main/java/io/legado/app/help/http/CookieStore.kt
@@ -1,3 +1,5 @@
+@file:Suppress("unused")
+
 package io.legado.app.help.http
 
 import android.text.TextUtils
diff --git a/app/src/main/java/io/legado/app/help/http/HttpHelper.kt b/app/src/main/java/io/legado/app/help/http/HttpHelper.kt
index 1d9252164..3728f4819 100644
--- a/app/src/main/java/io/legado/app/help/http/HttpHelper.kt
+++ b/app/src/main/java/io/legado/app/help/http/HttpHelper.kt
@@ -112,7 +112,7 @@ object HttpHelper {
         proxy: String? = null
     ): Retrofit {
         val r = Regex("(http|socks4|socks5)://(.*):(\\d{2,5})(@.*@.*)?")
-        val ms = proxy?.let { r.findAll(it) };
+        val ms = proxy?.let { r.findAll(it) }
         val group = ms?.first()
         var type = "direct"     //直接连接
         var host = "127.0.0.1"  //代理服务器hostname
@@ -135,9 +135,9 @@ object HttpHelper {
         val builder = client.newBuilder()
         if (type != "direct" && host != "") {
             if (type == "http") {
-                builder.proxy(Proxy(Proxy.Type.HTTP, InetSocketAddress(host, port)));
+                builder.proxy(Proxy(Proxy.Type.HTTP, InetSocketAddress(host, port)))
             } else {
-                builder.proxy(Proxy(Proxy.Type.SOCKS, InetSocketAddress(host, port)));
+                builder.proxy(Proxy(Proxy.Type.SOCKS, InetSocketAddress(host, port)))
             }
             if (username != "" && password != "") {
                 builder.proxyAuthenticator { _, response -> //设置代理服务器账号密码
diff --git a/app/src/main/java/io/legado/app/help/http/SSLHelper.kt b/app/src/main/java/io/legado/app/help/http/SSLHelper.kt
index 800304b62..52a131c71 100644
--- a/app/src/main/java/io/legado/app/help/http/SSLHelper.kt
+++ b/app/src/main/java/io/legado/app/help/http/SSLHelper.kt
@@ -12,6 +12,7 @@ import java.security.cert.CertificateFactory
 import java.security.cert.X509Certificate
 import javax.net.ssl.*
 
+@Suppress("unused")
 object SSLHelper {
 
     /**
diff --git a/app/src/main/java/io/legado/app/help/permission/Permissions.kt b/app/src/main/java/io/legado/app/help/permission/Permissions.kt
index 236691f7f..978541f69 100644
--- a/app/src/main/java/io/legado/app/help/permission/Permissions.kt
+++ b/app/src/main/java/io/legado/app/help/permission/Permissions.kt
@@ -1,5 +1,6 @@
 package io.legado.app.help.permission
 
+@Suppress("unused")
 object Permissions {
 
     const val READ_CALENDAR = "android.permission.READ_CALENDAR"
diff --git a/app/src/main/java/io/legado/app/help/permission/PermissionsCompat.kt b/app/src/main/java/io/legado/app/help/permission/PermissionsCompat.kt
index 17104108b..1d118fd0e 100644
--- a/app/src/main/java/io/legado/app/help/permission/PermissionsCompat.kt
+++ b/app/src/main/java/io/legado/app/help/permission/PermissionsCompat.kt
@@ -5,6 +5,7 @@ import androidx.appcompat.app.AppCompatActivity
 import androidx.fragment.app.Fragment
 import java.util.*
 
+@Suppress("unused")
 class PermissionsCompat private constructor() {
 
     private var request: Request? = null
@@ -16,11 +17,11 @@ class PermissionsCompat private constructor() {
     companion object {
         // 检查权限, 如果已经拥有返回 true
         fun check(activity: AppCompatActivity, vararg permissions: String): Boolean {
-            var request = Request(activity)
-            var pers = ArrayList<String>()
+            val request = Request(activity)
+            val pers = ArrayList<String>()
             pers.addAll(listOf(*permissions))
-            var data = request.getDeniedPermissions(pers.toTypedArray())
-            return data == null;
+            val data = request.getDeniedPermissions(pers.toTypedArray())
+            return data == null
         }
     }
 
diff --git a/app/src/main/java/io/legado/app/help/storage/ImportOldData.kt b/app/src/main/java/io/legado/app/help/storage/ImportOldData.kt
index a1741c845..6648363df 100644
--- a/app/src/main/java/io/legado/app/help/storage/ImportOldData.kt
+++ b/app/src/main/java/io/legado/app/help/storage/ImportOldData.kt
@@ -100,7 +100,7 @@ object ImportOldData {
         return bookSources.size
     }
 
-    fun importOldReplaceRule(json: String): Int {
+    private fun importOldReplaceRule(json: String): Int {
         val rules = OldReplace.jsonToReplaceRules(json)
         App.db.replaceRuleDao().insert(*rules.toTypedArray())
         return rules.size
diff --git a/app/src/main/java/io/legado/app/help/storage/OldRule.kt b/app/src/main/java/io/legado/app/help/storage/OldRule.kt
index 83084d5f3..616d0d359 100644
--- a/app/src/main/java/io/legado/app/help/storage/OldRule.kt
+++ b/app/src/main/java/io/legado/app/help/storage/OldRule.kt
@@ -9,6 +9,7 @@ import io.legado.app.help.storage.Restore.jsonPath
 import io.legado.app.utils.*
 import java.util.regex.Pattern
 
+@Suppress("RegExpRedundantEscape")
 object OldRule {
     private val headerPattern = Pattern.compile("@Header:\\{.+?\\}", Pattern.CASE_INSENSITIVE)
     private val jsPattern = Pattern.compile("\\{\\{.+?\\}\\}", Pattern.CASE_INSENSITIVE)
diff --git a/app/src/main/java/io/legado/app/lib/theme/ATH.kt b/app/src/main/java/io/legado/app/lib/theme/ATH.kt
index f69c5d40a..a7a3bd6d7 100644
--- a/app/src/main/java/io/legado/app/lib/theme/ATH.kt
+++ b/app/src/main/java/io/legado/app/lib/theme/ATH.kt
@@ -30,6 +30,7 @@ import org.jetbrains.anko.backgroundColor
 /**
  * @author Karim Abou Zeid (kabouzeid)
  */
+@Suppress("unused", "MemberVisibilityCanBePrivate")
 object ATH {
 
     @SuppressLint("CommitPrefEdits")
diff --git a/app/src/main/java/io/legado/app/lib/theme/DrawableUtils.kt b/app/src/main/java/io/legado/app/lib/theme/DrawableUtils.kt
index 660448088..d1bf3c499 100644
--- a/app/src/main/java/io/legado/app/lib/theme/DrawableUtils.kt
+++ b/app/src/main/java/io/legado/app/lib/theme/DrawableUtils.kt
@@ -11,6 +11,7 @@ import androidx.core.graphics.drawable.DrawableCompat
 /**
  * @author Karim Abou Zeid (kabouzeid)
  */
+@Suppress("unused")
 object DrawableUtils {
 
     fun createTransitionDrawable(@ColorInt startColor: Int, @ColorInt endColor: Int): TransitionDrawable {
diff --git a/app/src/main/java/io/legado/app/lib/theme/MaterialValueHelper.kt b/app/src/main/java/io/legado/app/lib/theme/MaterialValueHelper.kt
index 018e3dd60..5dadc5d85 100644
--- a/app/src/main/java/io/legado/app/lib/theme/MaterialValueHelper.kt
+++ b/app/src/main/java/io/legado/app/lib/theme/MaterialValueHelper.kt
@@ -1,3 +1,5 @@
+@file:Suppress("unused")
+
 package io.legado.app.lib.theme
 
 import android.annotation.SuppressLint
diff --git a/app/src/main/java/io/legado/app/lib/theme/NavigationViewUtils.kt b/app/src/main/java/io/legado/app/lib/theme/NavigationViewUtils.kt
index c199ba855..28def35f1 100644
--- a/app/src/main/java/io/legado/app/lib/theme/NavigationViewUtils.kt
+++ b/app/src/main/java/io/legado/app/lib/theme/NavigationViewUtils.kt
@@ -8,6 +8,7 @@ import com.google.android.material.navigation.NavigationView
 /**
  * @author Karim Abou Zeid (kabouzeid)
  */
+@Suppress("unused")
 object NavigationViewUtils {
 
     fun setItemIconColors(navigationView: NavigationView, @ColorInt normalColor: Int, @ColorInt selectedColor: Int) {
diff --git a/app/src/main/java/io/legado/app/lib/theme/Selector.kt b/app/src/main/java/io/legado/app/lib/theme/Selector.kt
index 89a71198b..f98508b62 100644
--- a/app/src/main/java/io/legado/app/lib/theme/Selector.kt
+++ b/app/src/main/java/io/legado/app/lib/theme/Selector.kt
@@ -13,6 +13,7 @@ import androidx.annotation.DrawableRes
 import androidx.annotation.IntDef
 import androidx.core.content.ContextCompat
 
+@Suppress("unused")
 object Selector {
     fun shapeBuild(): ShapeSelector {
         return ShapeSelector()
@@ -260,7 +261,8 @@ object Selector {
      * @author hjy
      * created at 2017/12/11 22:34
      */
-    class DrawableSelector constructor() {
+    @Suppress("MemberVisibilityCanBePrivate")
+    class DrawableSelector {
 
         private var mDefaultDrawable: Drawable? = null
         private var mDisabledDrawable: Drawable? = null
@@ -355,7 +357,7 @@ object Selector {
      * @author hjy
      * created at 2017/12/11 22:26
      */
-    class ColorSelector constructor() {
+    class ColorSelector {
 
         private var mDefaultColor: Int = 0
         private var mDisabledColor: Int = 0
diff --git a/app/src/main/java/io/legado/app/lib/theme/ThemeStore.kt b/app/src/main/java/io/legado/app/lib/theme/ThemeStore.kt
index 92ce315ed..182db2d40 100644
--- a/app/src/main/java/io/legado/app/lib/theme/ThemeStore.kt
+++ b/app/src/main/java/io/legado/app/lib/theme/ThemeStore.kt
@@ -16,6 +16,7 @@ import io.legado.app.utils.ColorUtils
 /**
  * @author Aidan Follestad (afollestad), Karim Abou Zeid (kabouzeid)
  */
+@Suppress("unused")
 class ThemeStore @SuppressLint("CommitPrefEdits")
 private constructor(private val mContext: Context) : ThemeStoreInterface {
     private val mEditor: SharedPreferences.Editor
diff --git a/app/src/main/java/io/legado/app/lib/theme/TintHelper.kt b/app/src/main/java/io/legado/app/lib/theme/TintHelper.kt
index 76313cd46..a719cc1b1 100644
--- a/app/src/main/java/io/legado/app/lib/theme/TintHelper.kt
+++ b/app/src/main/java/io/legado/app/lib/theme/TintHelper.kt
@@ -23,6 +23,7 @@ import io.legado.app.utils.ColorUtils
 /**
  * @author afollestad, plusCubed
  */
+@Suppress("MemberVisibilityCanBePrivate")
 object TintHelper {
 
     @SuppressLint("PrivateResource")
@@ -37,7 +38,10 @@ object TintHelper {
         )
     }
 
-    private fun getDisabledColorStateList(@ColorInt normal: Int, @ColorInt disabled: Int): ColorStateList {
+    private fun getDisabledColorStateList(
+        @ColorInt normal: Int,
+        @ColorInt disabled: Int
+    ): ColorStateList {
         return ColorStateList(
             arrayOf(
                 intArrayOf(-android.R.attr.state_enabled),
@@ -61,48 +65,52 @@ object TintHelper {
         )
 
         val sl: ColorStateList
-        if (view is Button) {
-            sl = getDisabledColorStateList(color, disabled)
-            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP && view.getBackground() is RippleDrawable) {
-                val rd = view.getBackground() as RippleDrawable
-                rd.setColor(ColorStateList.valueOf(rippleColor))
-            }
+        when (view) {
+            is Button -> {
+                sl = getDisabledColorStateList(color, disabled)
+                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP && view.getBackground() is RippleDrawable) {
+                    val rd = view.getBackground() as RippleDrawable
+                    rd.setColor(ColorStateList.valueOf(rippleColor))
+                }
 
-            // Disabled text color state for buttons, may get overridden later by ATE tags
-            view.setTextColor(
-                getDisabledColorStateList(
-                    textColor,
-                    ContextCompat.getColor(
-                        view.getContext(),
-                        if (useDarkTheme) R.color.ate_button_text_disabled_dark else R.color.ate_button_text_disabled_light
+                // Disabled text color state for buttons, may get overridden later by ATE tags
+                view.setTextColor(
+                    getDisabledColorStateList(
+                        textColor,
+                        ContextCompat.getColor(
+                            view.getContext(),
+                            if (useDarkTheme) R.color.ate_button_text_disabled_dark else R.color.ate_button_text_disabled_light
+                        )
                     )
                 )
-            )
-        } else if (view is FloatingActionButton) {
-            // FloatingActionButton doesn't support disabled state?
-            sl = ColorStateList(
-                arrayOf(
-                    intArrayOf(-android.R.attr.state_pressed),
-                    intArrayOf(android.R.attr.state_pressed)
-                ), intArrayOf(color, pressed)
-            )
+            }
+            is FloatingActionButton -> {
+                // FloatingActionButton doesn't support disabled state?
+                sl = ColorStateList(
+                    arrayOf(
+                        intArrayOf(-android.R.attr.state_pressed),
+                        intArrayOf(android.R.attr.state_pressed)
+                    ), intArrayOf(color, pressed)
+                )
 
-            view.rippleColor = rippleColor
-            view.backgroundTintList = sl
-            if (view.drawable != null)
-                view.setImageDrawable(createTintedDrawable(view.drawable, textColor))
-            return
-        } else {
-            sl = ColorStateList(
-                arrayOf(
-                    intArrayOf(-android.R.attr.state_enabled),
-                    intArrayOf(android.R.attr.state_enabled),
-                    intArrayOf(android.R.attr.state_enabled, android.R.attr.state_pressed),
-                    intArrayOf(android.R.attr.state_enabled, android.R.attr.state_activated),
-                    intArrayOf(android.R.attr.state_enabled, android.R.attr.state_checked)
-                ),
-                intArrayOf(disabled, color, pressed, activated, activated)
-            )
+                view.rippleColor = rippleColor
+                view.backgroundTintList = sl
+                if (view.drawable != null)
+                    view.setImageDrawable(createTintedDrawable(view.drawable, textColor))
+                return
+            }
+            else -> {
+                sl = ColorStateList(
+                    arrayOf(
+                        intArrayOf(-android.R.attr.state_enabled),
+                        intArrayOf(android.R.attr.state_enabled),
+                        intArrayOf(android.R.attr.state_enabled, android.R.attr.state_pressed),
+                        intArrayOf(android.R.attr.state_enabled, android.R.attr.state_activated),
+                        intArrayOf(android.R.attr.state_enabled, android.R.attr.state_checked)
+                    ),
+                    intArrayOf(disabled, color, pressed, activated, activated)
+                )
+            }
         }
 
         var drawable: Drawable? = view.background
@@ -386,7 +394,11 @@ object TintHelper {
         return createTintedDrawable(from, sl)
     }
 
-    fun setTint(switchView: Switch, @ColorInt color: Int, useDarker: Boolean) {
+    fun setTint(
+        @SuppressLint("UseSwitchCompatOrMaterialCode") switchView: Switch,
+        @ColorInt color: Int,
+        useDarker: Boolean
+    ) {
         if (switchView.trackDrawable != null) {
             switchView.trackDrawable = modifySwitchDrawable(
                 switchView.context,
diff --git a/app/src/main/java/io/legado/app/lib/theme/ViewUtils.kt b/app/src/main/java/io/legado/app/lib/theme/ViewUtils.kt
index f3afa243c..bcbb794a1 100644
--- a/app/src/main/java/io/legado/app/lib/theme/ViewUtils.kt
+++ b/app/src/main/java/io/legado/app/lib/theme/ViewUtils.kt
@@ -10,6 +10,7 @@ import androidx.annotation.ColorInt
 /**
  * @author Karim Abou Zeid (kabouzeid)
  */
+@Suppress("unused")
 object ViewUtils {
 
     fun removeOnGlobalLayoutListener(v: View, listener: ViewTreeObserver.OnGlobalLayoutListener) {
diff --git a/app/src/main/java/io/legado/app/lib/webdav/WebDav.kt b/app/src/main/java/io/legado/app/lib/webdav/WebDav.kt
index 03fc0d974..ab4f3303c 100644
--- a/app/src/main/java/io/legado/app/lib/webdav/WebDav.kt
+++ b/app/src/main/java/io/legado/app/lib/webdav/WebDav.kt
@@ -14,6 +14,7 @@ import java.net.URL
 import java.net.URLEncoder
 import java.util.*
 
+@Suppress("unused")
 class WebDav(urlStr: String) {
     companion object {
         // 指定返回哪些属性
@@ -60,9 +61,9 @@ class WebDav(urlStr: String) {
             return field
         }
 
-    fun getPath() = url.toString()
+    val path get() = url.toString()
 
-    fun getHost() = url.host
+    val host: String? get() = url.host
 
     /**
      * 填充文件信息。实例化WebDAVFile对象时，并没有将远程文件的信息填充到实例中。需要手动填充！
diff --git a/app/src/main/java/io/legado/app/model/analyzeRule/AnalyzeByJSonPath.kt b/app/src/main/java/io/legado/app/model/analyzeRule/AnalyzeByJSonPath.kt
index e4c2829e8..85b4e1649 100644
--- a/app/src/main/java/io/legado/app/model/analyzeRule/AnalyzeByJSonPath.kt
+++ b/app/src/main/java/io/legado/app/model/analyzeRule/AnalyzeByJSonPath.kt
@@ -8,6 +8,7 @@ import io.legado.app.utils.splitNotBlank
 import java.util.*
 import java.util.regex.Pattern
 
+@Suppress("RegExpRedundantEscape")
 @Keep
 class AnalyzeByJSonPath {
     private lateinit var ctx: ReadContext
diff --git a/app/src/main/java/io/legado/app/model/rss/RssParserDefault.kt b/app/src/main/java/io/legado/app/model/rss/RssParserDefault.kt
index 2a02c2bdc..2cb3d6c17 100644
--- a/app/src/main/java/io/legado/app/model/rss/RssParserDefault.kt
+++ b/app/src/main/java/io/legado/app/model/rss/RssParserDefault.kt
@@ -8,6 +8,7 @@ import org.xmlpull.v1.XmlPullParserFactory
 import java.io.IOException
 import java.io.StringReader
 
+@Suppress("unused")
 object RssParserDefault {
 
     @Throws(XmlPullParserException::class, IOException::class)
diff --git a/app/src/main/java/io/legado/app/ui/book/read/page/entities/TextLine.kt b/app/src/main/java/io/legado/app/ui/book/read/page/entities/TextLine.kt
index 9457bff37..7610ad9d3 100644
--- a/app/src/main/java/io/legado/app/ui/book/read/page/entities/TextLine.kt
+++ b/app/src/main/java/io/legado/app/ui/book/read/page/entities/TextLine.kt
@@ -4,6 +4,7 @@ import android.text.TextPaint
 import io.legado.app.ui.book.read.page.provider.ChapterProvider
 import io.legado.app.ui.book.read.page.provider.ChapterProvider.textHeight
 
+@Suppress("unused")
 data class TextLine(
     var text: String = "",
     val textChars: ArrayList<TextChar> = arrayListOf(),
diff --git a/app/src/main/java/io/legado/app/ui/filechooser/adapter/FileAdapter.kt b/app/src/main/java/io/legado/app/ui/filechooser/adapter/FileAdapter.kt
index 4458b692e..12c45477a 100644
--- a/app/src/main/java/io/legado/app/ui/filechooser/adapter/FileAdapter.kt
+++ b/app/src/main/java/io/legado/app/ui/filechooser/adapter/FileAdapter.kt
@@ -23,10 +23,10 @@ class FileAdapter(context: Context, val callBack: CallBack) :
     private var rootPath: String? = null
     var currentPath: String? = null
         private set
-    private val homeIcon = ConvertUtils.toDrawable(FilePickerIcon.getHOME())
-    private val upIcon = ConvertUtils.toDrawable(FilePickerIcon.getUPDIR())
-    private val folderIcon = ConvertUtils.toDrawable(FilePickerIcon.getFOLDER())
-    private val fileIcon = ConvertUtils.toDrawable(FilePickerIcon.getFILE())
+    private val homeIcon = ConvertUtils.toDrawable(FilePickerIcon.getHome())
+    private val upIcon = ConvertUtils.toDrawable(FilePickerIcon.getUpDir())
+    private val folderIcon = ConvertUtils.toDrawable(FilePickerIcon.getFolder())
+    private val fileIcon = ConvertUtils.toDrawable(FilePickerIcon.getFile())
     private val primaryTextColor = context.getPrimaryTextColor(!AppConfig.isNightTheme)
     private val disabledTextColor = context.getPrimaryDisabledTextColor(!AppConfig.isNightTheme)
 
diff --git a/app/src/main/java/io/legado/app/ui/filechooser/adapter/PathAdapter.kt b/app/src/main/java/io/legado/app/ui/filechooser/adapter/PathAdapter.kt
index 86ccf67c0..9d8cf6fab 100644
--- a/app/src/main/java/io/legado/app/ui/filechooser/adapter/PathAdapter.kt
+++ b/app/src/main/java/io/legado/app/ui/filechooser/adapter/PathAdapter.kt
@@ -17,7 +17,7 @@ class PathAdapter(context: Context, val callBack: CallBack) :
     private val paths = LinkedList<String>()
     @Suppress("DEPRECATION")
     private val sdCardDirectory = Environment.getExternalStorageDirectory().absolutePath
-    private val arrowIcon = ConvertUtils.toDrawable(FilePickerIcon.getARROW())
+    private val arrowIcon = ConvertUtils.toDrawable(FilePickerIcon.getArrow())
 
     fun getPath(position: Int): String {
         val tmp = StringBuilder("$sdCardDirectory/")
diff --git a/app/src/main/java/io/legado/app/ui/filechooser/utils/FilePickerIcon.java b/app/src/main/java/io/legado/app/ui/filechooser/utils/FilePickerIcon.java
index 6732626e4..c53ab6631 100644
--- a/app/src/main/java/io/legado/app/ui/filechooser/utils/FilePickerIcon.java
+++ b/app/src/main/java/io/legado/app/ui/filechooser/utils/FilePickerIcon.java
@@ -8,23 +8,23 @@ package io.legado.app.ui.filechooser.utils;
  */
 public class FilePickerIcon {
 
-    public static byte[] getFILE() {
+    public static byte[] getFile() {
         return FILE;
     }
 
-    public static byte[] getFOLDER() {
+    public static byte[] getFolder() {
         return FOLDER;
     }
 
-    public static byte[] getHOME() {
+    public static byte[] getHome() {
         return HOME;
     }
 
-    public static byte[] getUPDIR() {
+    public static byte[] getUpDir() {
         return UPDIR;
     }
 
-    public static byte[] getARROW() {
+    public static byte[] getArrow() {
         return ARROW;
     }