diff --git a/app/build.gradle b/app/build.gradle
index 22574a10c..4891fcbfd 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -34,6 +34,12 @@ dependencies {
     implementation 'androidx.cardview:cardview:1.0.0'
     implementation 'com.google.android.material:material:1.0.0'
 
+    implementation 'androidx.lifecycle:lifecycle-extensions:2.0.0'
+    kapt 'androidx.lifecycle:lifecycle-compiler:2.0.0'
+
+    implementation 'androidx.room:room-runtime:2.0.0'
+    kapt 'androidx.room:room-compiler:2.0.0'
+
     implementation 'androidx.paging:paging-runtime:2.1.0'
 
     //anko
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
new file mode 100644
index 000000000..8082605ab
--- /dev/null
+++ b/app/src/main/java/io/legado/app/data/entities/Book.kt
@@ -0,0 +1,33 @@
+package io.legado.app.data.entities
+
+import android.os.Parcelable
+import androidx.room.*
+import kotlinx.android.parcel.Parcelize
+import java.util.*
+
+@Parcelize
+@Entity(tableName = "books",
+    indices = [(Index(value = ["url"]))])
+data class Book(@PrimaryKey
+                var url: String = "",
+                var name: String = "",
+                var tag: String = "",
+                var author: String? = null,
+                var coverUrl: String? = null,
+                var customCoverUrl: String? = null,
+                var introduction: String? = null,
+                var charset: String? = null,
+                var type: Int = 0,   // 0: text, 1: audio
+                var latestChapterName: String? = null,
+                var lastUpdateTime: Date? = null,
+                var latestChapterTime: Date? = null,
+                var durChapterIndex: Int = 0,
+                var durChapterPage: Int = 0,
+                var totalChapterNum: Int = 0,
+                var hasNewChapter: Boolean = false,
+                var allowUpdate: Boolean = true
+                ) : Parcelable {
+
+    fun getUnreadChapterNum() = Math.max(totalChapterNum - durChapterIndex - 1, 0)
+
+}
\ No newline at end of file
diff --git a/app/src/main/java/io/legado/app/ui/main/MainActivity.kt b/app/src/main/java/io/legado/app/ui/main/MainActivity.kt
index 5e1b735d6..18d6c561a 100644
--- a/app/src/main/java/io/legado/app/ui/main/MainActivity.kt
+++ b/app/src/main/java/io/legado/app/ui/main/MainActivity.kt
@@ -8,8 +8,8 @@ import androidx.appcompat.app.AppCompatActivity
 import androidx.core.view.GravityCompat
 import androidx.drawerlayout.widget.DrawerLayout
 import com.google.android.material.navigation.NavigationView
-import com.google.android.material.snackbar.Snackbar
 import io.legado.app.R
+import io.legado.app.utils.longSnackbar
 import kotlinx.android.synthetic.main.activity_main.*
 import kotlinx.android.synthetic.main.app_bar_main.*
 
@@ -22,10 +22,7 @@ class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelecte
 
         setSupportActionBar(toolbar)
 
-        fab.setOnClickListener { view ->
-            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
-                .setAction("Action", null).show()
-        }
+        fab.setOnClickListener { it.longSnackbar(R.string.action) }
 
         val toggle = ActionBarDrawerToggle(
             this, drawer_layout, toolbar,