diff --git a/app/src/main/java/io/legado/app/api/ReaderProvider.kt b/app/src/main/java/io/legado/app/api/ReaderProvider.kt
index d7802f235..fcf50aa9c 100644
--- a/app/src/main/java/io/legado/app/api/ReaderProvider.kt
+++ b/app/src/main/java/io/legado/app/api/ReaderProvider.kt
@@ -24,28 +24,27 @@ import java.util.*
  */
 class ReaderProvider : ContentProvider() {
     private enum class RequestCode {
-        saveSource, saveSources, saveBook, deleteSources, getSource, getSources, getBookshelf, getChapterList, getBookContent
+        SaveSource, SaveSources, SaveBook, DeleteSources, GetSource, GetSources, GetBookshelf, GetChapterList, GetBookContent
     }
 
     private val postBodyKey = "json"
     private val sMatcher by lazy {
-        val uriMatcher = UriMatcher(UriMatcher.NO_MATCH)
-        val authority = "${context?.applicationInfo?.packageName}.readerProvider"
-        uriMatcher.addURI(authority, "source/insert", RequestCode.saveSource.ordinal)
-        uriMatcher.addURI(authority, "sources/insert", RequestCode.saveSources.ordinal)
-        uriMatcher.addURI(authority, "book/insert", RequestCode.saveBook.ordinal)
-        uriMatcher.addURI(authority, "sources/delete", RequestCode.deleteSources.ordinal)
-        uriMatcher.addURI(authority, "source/query", RequestCode.getSource.ordinal)
-        uriMatcher.addURI(authority, "sources/query", RequestCode.getSources.ordinal)
-        uriMatcher.addURI(authority, "books/query", RequestCode.getBookshelf.ordinal)
-        uriMatcher.addURI(authority, "book/chapter/query", RequestCode.getChapterList.ordinal)
-        uriMatcher.addURI(authority, "book/content/query", RequestCode.getBookContent.ordinal)
-        return@lazy uriMatcher
+        UriMatcher(UriMatcher.NO_MATCH).apply {
+            "${context?.applicationInfo?.packageName}.readerProvider".also { authority ->
+                addURI(authority, "source/insert", RequestCode.SaveSource.ordinal)
+                addURI(authority, "sources/insert", RequestCode.SaveSources.ordinal)
+                addURI(authority, "book/insert", RequestCode.SaveBook.ordinal)
+                addURI(authority, "sources/delete", RequestCode.DeleteSources.ordinal)
+                addURI(authority, "source/query", RequestCode.GetSource.ordinal)
+                addURI(authority, "sources/query", RequestCode.GetSources.ordinal)
+                addURI(authority, "books/query", RequestCode.GetBookshelf.ordinal)
+                addURI(authority, "book/chapter/query", RequestCode.GetChapterList.ordinal)
+                addURI(authority, "book/content/query", RequestCode.GetBookContent.ordinal)
+            }
+        }
     }
 
-    override fun onCreate(): Boolean {
-        return false
-    }
+    override fun onCreate() = false
 
     override fun delete(
         uri: Uri,
@@ -54,7 +53,7 @@ class ReaderProvider : ContentProvider() {
     ): Int {
         if (sMatcher.match(uri) < 0) return -1
         when (RequestCode.values()[sMatcher.match(uri)]) {
-            RequestCode.deleteSources -> SourceController.deleteSources(selection)
+            RequestCode.DeleteSources -> SourceController.deleteSources(selection)
             else -> throw IllegalStateException(
                 "Unexpected value: " + RequestCode.values()[sMatcher.match(uri)].name
             )
@@ -62,20 +61,18 @@ class ReaderProvider : ContentProvider() {
         return 0
     }
 
-    override fun getType(uri: Uri): String? {
-        throw UnsupportedOperationException("Not yet implemented")
-    }
+    override fun getType(uri: Uri) = throw UnsupportedOperationException("Not yet implemented")
 
     override fun insert(uri: Uri, values: ContentValues?): Uri? {
         if (sMatcher.match(uri) < 0) return null
         when (RequestCode.values()[sMatcher.match(uri)]) {
-            RequestCode.saveSource -> values?.let {
+            RequestCode.SaveSource -> values?.let {
                 SourceController.saveSource(values.getAsString(postBodyKey))
             }
-            RequestCode.saveBook -> values?.let {
+            RequestCode.SaveBook -> values?.let {
                 BookshelfController.saveBook(values.getAsString(postBodyKey))
             }
-            RequestCode.saveSources -> values?.let {
+            RequestCode.SaveSources -> values?.let {
                 SourceController.saveSources(values.getAsString(postBodyKey))
             }
             else -> throw IllegalStateException(
@@ -97,11 +94,11 @@ class ReaderProvider : ContentProvider() {
             map["index"] = arrayListOf(it)
         }
         return if (sMatcher.match(uri) < 0) null else when (RequestCode.values()[sMatcher.match(uri)]) {
-            RequestCode.getSource -> SimpleCursor(SourceController.getSource(map))
-            RequestCode.getSources -> SimpleCursor(SourceController.sources)
-            RequestCode.getBookshelf -> SimpleCursor(BookshelfController.bookshelf)
-            RequestCode.getBookContent -> SimpleCursor(BookshelfController.getBookContent(map))
-            RequestCode.getChapterList -> SimpleCursor(BookshelfController.getChapterList(map))
+            RequestCode.GetSource -> SimpleCursor(SourceController.getSource(map))
+            RequestCode.GetSources -> SimpleCursor(SourceController.sources)
+            RequestCode.GetBookshelf -> SimpleCursor(BookshelfController.bookshelf)
+            RequestCode.GetBookContent -> SimpleCursor(BookshelfController.getBookContent(map))
+            RequestCode.GetChapterList -> SimpleCursor(BookshelfController.getChapterList(map))
             else -> throw IllegalStateException(
                 "Unexpected value: " + RequestCode.values()[sMatcher.match(uri)].name
             )
@@ -111,9 +108,8 @@ class ReaderProvider : ContentProvider() {
     override fun update(
         uri: Uri, values: ContentValues?, selection: String?,
         selectionArgs: Array<String>?
-    ): Int {
-        throw UnsupportedOperationException("Not yet implemented")
-    }
+    ) = throw UnsupportedOperationException("Not yet implemented")
+    
 
     /**
      * Simple inner class to deliver json callback data.
@@ -124,82 +120,46 @@ class ReaderProvider : ContentProvider() {
 
         private val mData: String = Gson().toJson(data)
 
-        override fun getCount(): Int {
-            return 1
-        }
+        override fun getCount() = 1
 
-        override fun getPosition(): Int {
-            return 0
-        }
+        override fun getPosition() = 0
 
-        override fun move(i: Int): Boolean {
-            return true
-        }
+        override fun move(i: Int) = true
 
-        override fun moveToPosition(i: Int): Boolean {
-            return true
-        }
+        override fun moveToPosition(i: Int) = true
 
-        override fun moveToFirst(): Boolean {
-            return true
-        }
+        override fun moveToFirst() = true
 
-        override fun moveToLast(): Boolean {
-            return true
-        }
+        override fun moveToLast() = true
 
-        override fun moveToNext(): Boolean {
-            return true
-        }
+        override fun moveToNext() = true
 
-        override fun moveToPrevious(): Boolean {
-            return true
-        }
+        override fun moveToPrevious() = true
 
-        override fun isFirst(): Boolean {
-            return true
-        }
+        override fun isFirst() = true
 
-        override fun isLast(): Boolean {
-            return true
-        }
+        override fun isLast() = true
 
-        override fun isBeforeFirst(): Boolean {
-            return false
-        }
+        override fun isBeforeFirst() = true
 
-        override fun isAfterLast(): Boolean {
-            return false
-        }
+        override fun isAfterLast() = true
 
-        override fun getColumnIndex(s: String): Int {
-            return 0
-        }
+        override fun getColumnIndex(s: String) = 0
 
         @Throws(IllegalArgumentException::class)
         override fun getColumnIndexOrThrow(s: String): Int {
             throw UnsupportedOperationException("Not yet implemented")
         }
 
-        override fun getColumnName(i: Int): String? {
-            return null
-        }
+        override fun getColumnName(i: Int) = null as String?
 
-        override fun getColumnNames(): Array<String> {
-            return arrayOf()
-        }
+        override fun getColumnNames() = arrayOf<String>()
 
-        override fun getColumnCount(): Int {
-            return 0
-        }
+        override fun getColumnCount() = 0
 
-        override fun getBlob(i: Int): ByteArray {
-            return ByteArray(0)
-        }
+        override fun getBlob(i: Int) = ByteArray(0)
 
-        override fun getString(i: Int): String {
-            return mData
-        }
+        override fun getString(i: Int) = mData
 
         override fun copyStringToBuffer(
             i: Int,
@@ -207,43 +167,26 @@ class ReaderProvider : ContentProvider() {
         ) {
         }
 
-        override fun getShort(i: Int): Short {
-            return 0
-        }
+        override fun getShort(i: Int) = 0.toShort()
+        
 
-        override fun getInt(i: Int): Int {
-            return 0
-        }
+        override fun getInt(i: Int) = 0
 
-        override fun getLong(i: Int): Long {
-            return 0
-        }
+        override fun getLong(i: Int) = 0L
 
-        override fun getFloat(i: Int): Float {
-            return 0f
-        }
+        override fun getFloat(i: Int) = 0F
 
-        override fun getDouble(i: Int): Double {
-            return 0.0
-        }
+        override fun getDouble(i: Int) = 0.toDouble()
 
-        override fun getType(i: Int): Int {
-            return 0
-        }
+        override fun getType(i: Int) = 0
 
-        override fun isNull(i: Int): Boolean {
-            return false
-        }
+        override fun isNull(i: Int) = false
 
         override fun deactivate() {}
-        override fun requery(): Boolean {
-            return false
-        }
+        override fun requery() = false
 
         override fun close() {}
-        override fun isClosed(): Boolean {
-            return false
-        }
+        override fun isClosed() = false
 
         override fun registerContentObserver(contentObserver: ContentObserver) {}
         override fun unregisterContentObserver(contentObserver: ContentObserver) {}
@@ -251,22 +194,14 @@ class ReaderProvider : ContentProvider() {
         override fun unregisterDataSetObserver(dataSetObserver: DataSetObserver) {}
         override fun setNotificationUri(contentResolver: ContentResolver, uri: Uri) {}
 
-        override fun getNotificationUri(): Uri? {
-            return null
-        }
+        override fun getNotificationUri() = null as Uri?
 
-        override fun getWantsAllOnMoveCalls(): Boolean {
-            return false
-        }
+        override fun getWantsAllOnMoveCalls() = false
 
         override fun setExtras(bundle: Bundle) {}
-        override fun getExtras(): Bundle? {
-            return null
-        }
-
-        override fun respond(bundle: Bundle): Bundle? {
-            return null
-        }
+        override fun getExtras() = null as Bundle?
+        
+        override fun respond(bundle: Bundle) = null as Bundle?
 
     }
 }
\ No newline at end of file
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 372426236..c1e56316f 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.1.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.3-all.zip