Start trying to fix permission errors on Android

lib/pages/permsrequired.dart

@@ -0,0 +1,44 @@
+import 'package:flutter/material.dart';
+import 'package:nbteditor/Constants.dart';
+import 'package:permission_handler/permission_handler.dart';
+
+class PermissionsRequiredPage extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+        appBar: AppBar(
+          title: Text("NBT Editor - Permissions Denied"),
+          backgroundColor: Constants.TITLEBAR_COLOR,
+        ),
+        body: Padding(
+          padding: EdgeInsets.all(8),
+          child: SingleChildScrollView(
+            child: Column(
+              children: [
+                ListTile(
+                  title: Text(
+                      "We require only one permission, it is being denied by your device. Please grant file permissions to be able to open or save files."),
+                ),
+                ElevatedButton(
+                    onPressed: () async {
+                      if (await Permission.manageExternalStorage.isDenied) {
+                        var stat =
+                            await Permission.manageExternalStorage.request();
+                        if (stat.isPermanentlyDenied) {
+                          ScaffoldMessenger.of(context).showSnackBar(SnackBar(
+                              content: Text(
+                                  "The storage permission is reporting it is permanently denied. Please open settings and allow that permission.")));
+                        } else if (stat.isGranted) {
+                          Future.delayed(Duration(seconds: 5), () {
+                            Navigator.pushReplacementNamed(context, "/edit");
+                          });
+                        }
+                      }
+                    },
+                    child: Text("GRANT"))
+              ],
+            ),
+          ),
+        ));
+  }
+}