diff --git a/app/src/main/java/io/legado/app/ui/widget/DetailSeekBar.kt b/app/src/main/java/io/legado/app/ui/widget/DetailSeekBar.kt
index 5198599e4..010ebba78 100644
--- a/app/src/main/java/io/legado/app/ui/widget/DetailSeekBar.kt
+++ b/app/src/main/java/io/legado/app/ui/widget/DetailSeekBar.kt
@@ -13,7 +13,10 @@ import io.legado.app.utils.progressAdd
 import kotlinx.android.synthetic.main.view_detail_seek_bar.view.*
 import org.jetbrains.anko.sdk27.listeners.onClick
 
-class DetailSeekBar(context: Context, attrs: AttributeSet?) : FrameLayout(context, attrs),
+class DetailSeekBar @JvmOverloads constructor(
+    context: Context,
+    attrs: AttributeSet? = null
+) : FrameLayout(context, attrs),
     SeekBar.OnSeekBarChangeListener {
     private val isBottomBackground: Boolean
     var valueFormat: ((progress: Int) -> String)? = null
diff --git a/app/src/main/java/io/legado/app/ui/widget/LabelsBar.kt b/app/src/main/java/io/legado/app/ui/widget/LabelsBar.kt
index 4d51c5b80..01c4957db 100644
--- a/app/src/main/java/io/legado/app/ui/widget/LabelsBar.kt
+++ b/app/src/main/java/io/legado/app/ui/widget/LabelsBar.kt
@@ -8,7 +8,10 @@ import io.legado.app.ui.widget.text.AccentBgTextView
 import io.legado.app.utils.dp
 
 @Suppress("unused", "MemberVisibilityCanBePrivate")
-class LabelsBar(context: Context, attrs: AttributeSet?) : LinearLayout(context, attrs) {
+class LabelsBar @JvmOverloads constructor(
+    context: Context,
+    attrs: AttributeSet? = null
+) : LinearLayout(context, attrs) {
 
     private val unUsedViews = arrayListOf<TextView>()
     private val usedViews = arrayListOf<TextView>()
diff --git a/app/src/main/java/io/legado/app/ui/widget/SelectActionBar.kt b/app/src/main/java/io/legado/app/ui/widget/SelectActionBar.kt
index fd478ae42..3fc481e8b 100644
--- a/app/src/main/java/io/legado/app/ui/widget/SelectActionBar.kt
+++ b/app/src/main/java/io/legado/app/ui/widget/SelectActionBar.kt
@@ -17,7 +17,10 @@ import kotlinx.android.synthetic.main.view_select_action_bar.view.*
 import org.jetbrains.anko.sdk27.listeners.onClick
 
 @Suppress("unused")
-class SelectActionBar(context: Context, attrs: AttributeSet?) : FrameLayout(context, attrs) {
+class SelectActionBar @JvmOverloads constructor(
+    context: Context,
+    attrs: AttributeSet? = null
+) : FrameLayout(context, attrs) {
     private var callBack: CallBack? = null
     private var selMenu: PopupMenu? = null
 
diff --git a/app/src/main/java/io/legado/app/ui/widget/ShadowLayout.kt b/app/src/main/java/io/legado/app/ui/widget/ShadowLayout.kt
index 76668e772..95e54ac63 100644
--- a/app/src/main/java/io/legado/app/ui/widget/ShadowLayout.kt
+++ b/app/src/main/java/io/legado/app/ui/widget/ShadowLayout.kt
@@ -14,11 +14,10 @@ import io.legado.app.utils.getCompatColor
 /**
  * ShadowLayout.java
  *
- *
  * Created by lijiankun on 17/8/11.
  */
 @Suppress("unused")
-class ShadowLayout(
+class ShadowLayout @JvmOverloads constructor(
     context: Context,
     attrs: AttributeSet? = null
 ) : RelativeLayout(context, attrs) {
diff --git a/app/src/main/java/io/legado/app/ui/widget/TitleBar.kt b/app/src/main/java/io/legado/app/ui/widget/TitleBar.kt
index a30873671..51a04f97d 100644
--- a/app/src/main/java/io/legado/app/ui/widget/TitleBar.kt
+++ b/app/src/main/java/io/legado/app/ui/widget/TitleBar.kt
@@ -22,7 +22,10 @@ import org.jetbrains.anko.bottomPadding
 import org.jetbrains.anko.topPadding
 
 @Suppress("unused")
-class TitleBar(context: Context, attrs: AttributeSet?) : AppBarLayout(context, attrs) {
+class TitleBar @JvmOverloads constructor(
+    context: Context,
+    attrs: AttributeSet? = null
+) : AppBarLayout(context, attrs) {
 
     val toolbar: Toolbar
     val menu: Menu