add structure

lib/pages/do/do_files.dart

@@ -0,0 +1,26 @@
+import 'dart:io';
+
+class DOFiles {
+  File doPaymentFile, storageChargeFile, licenseFile;
+  bool doFileChanged = false,
+      storageFileChanged = false,
+      licenseFileChanged = false;
+
+  set setDoPaymentFile(File file) {
+    doPaymentFile = file;
+    doFileChanged = true;
+  }
+
+  set setStorageChargeFile(File file) {
+    storageChargeFile = file;
+    storageFileChanged = true;
+  }
+
+  set setlicenseFile(File file) {
+    licenseFile = file;
+    licenseFileChanged = true;
+  }
+
+  bool get anyChanged =>
+      doFileChanged || storageFileChanged || licenseFileChanged;
+}