Fix some linting issues

@@ -127,9 +127,6 @@ class MyAppState extends State<MyApp> with SingleTickerProviderStateMixin {
     final bytes = await build(pageFormat);
 
     final appDocDir = await getApplicationDocumentsDirectory();
-    if (appDocDir == null) {
-      return;
-    }
     final appDocPath = appDocDir.path;
     final file = File(appDocPath + '/' + 'document.pdf');
     print('Save as file ${file.path} ...');

 # Changelog
 
+## 3.0.2
+
+- Fix some linting issues
+
 ## 3.0.1
 
 - Improve internal null-safety

@@ -19,4 +19,4 @@ import 'package:archive/archive.dart';
 import 'package:pdf/pdf.dart';
 
 /// Zip compression function
-DeflateCallback defaultDeflate = ZLibEncoder().encode;
+DeflateCallback defaultDeflate = const ZLibEncoder().encode;

@@ -4,7 +4,7 @@ description: A pdf producer for Dart. It can create pdf files for both web or fl
 homepage: https://github.com/DavBfr/dart_pdf/tree/master/pdf
 repository: https://github.com/DavBfr/dart_pdf
 issue_tracker: https://github.com/DavBfr/dart_pdf/issues
-version: 3.0.1
+version: 3.0.2
 
 environment:
   sdk: ">=2.12.0-0 <3.0.0"

@@ -3,6 +3,7 @@
 ## 5.0.2
 
 - Fix iOS/macOS release build not working
+- Fix some linting issues
 
 ## 5.0.1
 

@@ -390,9 +390,9 @@ class _PdfPreviewState extends State<PdfPreview> {
               final key = keys[index];
               final val = _pageFormats[key];
               return DropdownMenuItem<PdfPageFormat>(
+                value: val,
                 child: Text(key,
                     style: TextStyle(color: theme.accentIconTheme.color)),
-                value: val,
               );
             },
           ),
@@ -418,11 +418,6 @@ class _PdfPreviewState extends State<PdfPreview> {
             color: disabledColor,
             selectedBorderColor: color,
             selectedColor: color,
-            children: <Widget>[
-              Transform.rotate(
-                  angle: -pi / 2, child: const Icon(Icons.note_outlined)),
-              const Icon(Icons.note_outlined),
-            ],
             onPressed: (int index) {
               setState(() {
                 horizontal = index == 1;
@@ -430,6 +425,11 @@ class _PdfPreviewState extends State<PdfPreview> {
               });
             },
             isSelected: <bool>[horizontal == false, horizontal == true],
+            children: <Widget>[
+              Transform.rotate(
+                  angle: -pi / 2, child: const Icon(Icons.note_outlined)),
+              const Icon(Icons.note_outlined),
+            ],
           ),
         );
       }

@@ -84,6 +84,7 @@ mixin Printing {
             for (final printer in printers)
               if (printer.isAvailable)
                 SimpleDialogOption(
+                  onPressed: () => Navigator.of(context).pop(printer),
                   child: Text(
                     printer.name,
                     style: TextStyle(
@@ -92,7 +93,6 @@ mixin Printing {
                           : FontStyle.normal,
                     ),
                   ),
-                  onPressed: () => Navigator.of(context).pop(printer),
                 ),
           ],
         ),