Theme.kt: Modify functions into assigning style

Signed-off-by: 1552980358 <1552980358@qq.com>

app/src/main/java/io/legado/app/constant/Theme.kt

@@ -7,18 +7,13 @@ enum class Theme {
     Dark, Light, Auto, Transparent;
 
     companion object {
-        fun getTheme(): Theme {
+        fun getTheme() =
-            return if (AppConfig.isNightTheme) {
+            if (AppConfig.isNightTheme) Dark
-                Dark
+            else Light
-            } else Light
+
-        }
+        fun getTheme(backgroundColor: Int) =
+            if (ColorUtils.isColorLight(backgroundColor)) Light
+            else Dark
         
-        fun getTheme(backgroundColor: Int): Theme {
-            return if (ColorUtils.isColorLight(backgroundColor)) {
-                Light
-            } else {
-                Dark
-            }
-        }
     }
 }