Fix issue java.lang.IllegalStateException: Fragment already added: LoadingDialog

Author: Pisey-Nguon

material_dialog/src/main/java/com/example/material_dialog/MaterialLoadingDialog.kt

@@ -44,7 +44,8 @@ class MaterialLoadingDialog(private val context: Context): MaterialLoadingInterf
     }
 
     override fun dismiss() {
-        loadingDialog.dismissAllowingStateLoss()
+        if (loadingDialog.isAdded)
+            loadingDialog.dismissAllowingStateLoss()
     }
 
 }