1、增加showLongToast

lib/utils/toast_util.dart

@@ -19,6 +19,10 @@ class ToastUtil {
         textColor: Colors.white,
         fontSize: 16.0);
   }
+
+  static void showLongToast(String? txt) {
+    showToast(txt, toastDuration: ToastDuration.long);
+  }
 }
 
 enum ToastDuration {