Merge branch 'add-open-file-hook'

src/main/java/com/kdanmobile/reader/ReaderActivity.kt

@@ -75,6 +75,7 @@ abstract class ReaderActivity : AppCompatActivity(), ReaderSettingListener, PdfT
     open fun insertToRecentDocumentList(filename: String) {}
     open fun saveCurrentPageIndex(filename: String, currentPage: Int) {}
     open fun loadCurrentPageIndex(filename: String, defaultValue: Int): Int = 0
+    open fun onOpenedFile() { /* do nothing */ }
 
     companion object {
         const val KEY_FILE_ABSOLUTE = "file_absolutepath"
@@ -475,6 +476,7 @@ abstract class ReaderActivity : AppCompatActivity(), ReaderSettingListener, PdfT
                 onCropModeEnableChanged(true)
             }
         }
+        onOpenedFile()
     }
 
     private fun initTextBoxContextMenuActions() {