[camera] update for camera ^0.10.0+1 / flutter 3.3.0 release (#57)

* Update for camera ^0.10.0+1 / flutter 3.3.0 release Signed-off-by: Hidenori Matsubayashi <[email protected]>
2022-09-19 14:47:24 +09:00
parent 02260a1eab
commit 1dd2b8bbfa
9 changed files with 389 additions and 197 deletions
@@ -2,19 +2,22 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

-// ignore_for_file: public_member_api_docs
-
 import 'dart:async';
 import 'dart:io';

 import 'package:camera/camera.dart';
-import 'package:flutter/gestures.dart';
+import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
+import 'package:flutter/scheduler.dart';
 import 'package:video_player/video_player.dart';

+/// Camera example home widget.
 class CameraExampleHome extends StatefulWidget {
+  /// Default Constructor
+  const CameraExampleHome({Key? key}) : super(key: key);
+
  @override
-  _CameraExampleHomeState createState() {
+  State<CameraExampleHome> createState() {
    return _CameraExampleHomeState();
  }
 }
@@ -33,7 +36,7 @@ IconData getCameraLensIcon(CameraLensDirection direction) {
  }
 }

-void logError(String code, String? message) {
+void _logError(String code, String? message) {
  if (message != null) {
    print('Error: $code\nError Message: $message');
  } else {
@@ -105,6 +108,7 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
    super.dispose();
  }

+  // #docregion AppLifecycle
  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    final CameraController? cameraController = controller;
@@ -120,13 +124,11 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
      onNewCameraSelected(cameraController.description);
    }
  }
-
-  final GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();
+  // #enddocregion AppLifecycle

  @override
  Widget build(BuildContext context) {
    return Scaffold(
-      key: _scaffoldKey,
      appBar: AppBar(
        title: const Text('Camera example'),
      ),
@@ -134,12 +136,6 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
        children: <Widget>[
          Expanded(
            child: Container(
-              child: Padding(
-                padding: const EdgeInsets.all(1.0),
-                child: Center(
-                  child: _cameraPreviewWidget(),
-                ),
-              ),
              decoration: BoxDecoration(
                color: Colors.black,
                border: Border.all(
@@ -150,6 +146,12 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
                  width: 3.0,
                ),
              ),
+              child: Padding(
+                padding: const EdgeInsets.all(1.0),
+                child: Center(
+                  child: _cameraPreviewWidget(),
+                ),
+              ),
            ),
          ),
          _captureControlRowWidget(),
@@ -157,7 +159,6 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
          Padding(
            padding: const EdgeInsets.all(5.0),
            child: Row(
-              mainAxisAlignment: MainAxisAlignment.start,
              children: <Widget>[
                _cameraTogglesRowWidget(),
                _thumbnailWidget(),
@@ -194,7 +195,8 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
              behavior: HitTestBehavior.opaque,
              onScaleStart: _handleScaleStart,
              onScaleUpdate: _handleScaleUpdate,
-              onTapDown: (details) => onViewFinderTap(details, constraints),
+              onTapDown: (TapDownDetails details) =>
+                  onViewFinderTap(details, constraints),
            );
          }),
        ),
@@ -228,27 +230,34 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
        child: Row(
          mainAxisSize: MainAxisSize.min,
          children: <Widget>[
-            localVideoController == null && imageFile == null
-                ? Container()
-                : SizedBox(
-                    child: (localVideoController == null)
-                        ? Image.file(File(imageFile!.path))
-                        : Container(
-                            child: Center(
-                              child: AspectRatio(
-                                  aspectRatio:
-                                      localVideoController.value.size != null
-                                          ? localVideoController
-                                              .value.aspectRatio
-                                          : 1.0,
-                                  child: VideoPlayer(localVideoController)),
-                            ),
-                            decoration: BoxDecoration(
-                                border: Border.all(color: Colors.pink)),
-                          ),
-                    width: 64.0,
-                    height: 64.0,
-                  ),
+            if (localVideoController == null && imageFile == null)
+              Container()
+            else
+              SizedBox(
+                width: 64.0,
+                height: 64.0,
+                child: (localVideoController == null)
+                    ? (
+                        // The captured image on the web contains a network-accessible URL
+                        // pointing to a location within the browser. It may be displayed
+                        // either with Image.network or Image.memory after loading the image
+                        // bytes to memory.
+                        kIsWeb
+                            ? Image.network(imageFile!.path)
+                            : Image.file(File(imageFile!.path)))
+                    : Container(
+                        decoration: BoxDecoration(
+                            border: Border.all(color: Colors.pink)),
+                        child: Center(
+                          child: AspectRatio(
+                              aspectRatio:
+                                  localVideoController.value.size != null
+                                      ? localVideoController.value.aspectRatio
+                                      : 1.0,
+                              child: VideoPlayer(localVideoController)),
+                        ),
+                      ),
+              ),
          ],
        ),
      ),
@@ -258,27 +267,33 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
  /// Display a bar with buttons to change the flash and exposure modes
  Widget _modeControlRowWidget() {
    return Column(
-      children: [
+      children: <Widget>[
        Row(
          mainAxisAlignment: MainAxisAlignment.spaceEvenly,
-          mainAxisSize: MainAxisSize.max,
          children: <Widget>[
            IconButton(
-              icon: Icon(Icons.flash_on),
+              icon: const Icon(Icons.flash_on),
              color: Colors.blue,
              onPressed: controller != null ? onFlashModeButtonPressed : null,
            ),
-            IconButton(
-              icon: Icon(Icons.exposure),
-              color: Colors.blue,
-              onPressed:
-                  controller != null ? onExposureModeButtonPressed : null,
-            ),
-            IconButton(
-              icon: Icon(Icons.filter_center_focus),
-              color: Colors.blue,
-              onPressed: controller != null ? onFocusModeButtonPressed : null,
-            ),
+            // The exposure and focus mode are currently not supported on the web.
+            ...!kIsWeb
+                ? <Widget>[
+                    IconButton(
+                      icon: const Icon(Icons.exposure),
+                      color: Colors.blue,
+                      onPressed: controller != null
+                          ? onExposureModeButtonPressed
+                          : null,
+                    ),
+                    IconButton(
+                      icon: const Icon(Icons.filter_center_focus),
+                      color: Colors.blue,
+                      onPressed:
+                          controller != null ? onFocusModeButtonPressed : null,
+                    )
+                  ]
+                : <Widget>[],
            IconButton(
              icon: Icon(enableAudio ? Icons.volume_up : Icons.volume_mute),
              color: Colors.blue,
@@ -308,10 +323,9 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
      child: ClipRect(
        child: Row(
          mainAxisAlignment: MainAxisAlignment.spaceEvenly,
-          mainAxisSize: MainAxisSize.max,
-          children: [
+          children: <Widget>[
            IconButton(
-              icon: Icon(Icons.flash_off),
+              icon: const Icon(Icons.flash_off),
              color: controller?.value.flashMode == FlashMode.off
                  ? Colors.orange
                  : Colors.blue,
@@ -320,7 +334,7 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
                  : null,
            ),
            IconButton(
-              icon: Icon(Icons.flash_auto),
+              icon: const Icon(Icons.flash_auto),
              color: controller?.value.flashMode == FlashMode.auto
                  ? Colors.orange
                  : Colors.blue,
@@ -329,7 +343,7 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
                  : null,
            ),
            IconButton(
-              icon: Icon(Icons.flash_on),
+              icon: const Icon(Icons.flash_on),
              color: controller?.value.flashMode == FlashMode.always
                  ? Colors.orange
                  : Colors.blue,
@@ -338,7 +352,7 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
                  : null,
            ),
            IconButton(
-              icon: Icon(Icons.highlight),
+              icon: const Icon(Icons.highlight),
              color: controller?.value.flashMode == FlashMode.torch
                  ? Colors.orange
                  : Colors.blue,
@@ -354,11 +368,15 @@ class _CameraExampleHomeState extends State<CameraExampleHome>

  Widget _exposureModeControlRowWidget() {
    final ButtonStyle styleAuto = TextButton.styleFrom(
+      // TODO(darrenaustin): Migrate to new API once it lands in stable: https://github.com/flutter/flutter/issues/105724
+      // ignore: deprecated_member_use
      primary: controller?.value.exposureMode == ExposureMode.auto
          ? Colors.orange
          : Colors.blue,
    );
    final ButtonStyle styleLocked = TextButton.styleFrom(
+      // TODO(darrenaustin): Migrate to new API once it lands in stable: https://github.com/flutter/flutter/issues/105724
+      // ignore: deprecated_member_use
      primary: controller?.value.exposureMode == ExposureMode.locked
          ? Colors.orange
          : Colors.blue,
@@ -370,16 +388,14 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
        child: Container(
          color: Colors.grey.shade50,
          child: Column(
-            children: [
-              Center(
-                child: Text("Exposure Mode"),
+            children: <Widget>[
+              const Center(
+                child: Text('Exposure Mode'),
              ),
              Row(
                mainAxisAlignment: MainAxisAlignment.spaceEvenly,
-                mainAxisSize: MainAxisSize.max,
-                children: [
+                children: <Widget>[
                  TextButton(
-                    child: Text('AUTO'),
                    style: styleAuto,
                    onPressed: controller != null
                        ? () =>
@@ -391,24 +407,31 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
                        showInSnackBar('Resetting exposure point');
                      }
                    },
+                    child: const Text('AUTO'),
                  ),
                  TextButton(
-                    child: Text('LOCKED'),
                    style: styleLocked,
                    onPressed: controller != null
                        ? () =>
                            onSetExposureModeButtonPressed(ExposureMode.locked)
                        : null,
+                    child: const Text('LOCKED'),
+                  ),
+                  TextButton(
+                    style: styleLocked,
+                    onPressed: controller != null
+                        ? () => controller!.setExposureOffset(0.0)
+                        : null,
+                    child: const Text('RESET OFFSET'),
                  ),
                ],
              ),
-              Center(
-                child: Text("Exposure Offset"),
+              const Center(
+                child: Text('Exposure Offset'),
              ),
              Row(
                mainAxisAlignment: MainAxisAlignment.spaceEvenly,
-                mainAxisSize: MainAxisSize.max,
-                children: [
+                children: <Widget>[
                  Text(_minAvailableExposureOffset.toString()),
                  Slider(
                    value: _currentExposureOffset,
@@ -432,11 +455,15 @@ class _CameraExampleHomeState extends State<CameraExampleHome>

  Widget _focusModeControlRowWidget() {
    final ButtonStyle styleAuto = TextButton.styleFrom(
+      // TODO(darrenaustin): Migrate to new API once it lands in stable: https://github.com/flutter/flutter/issues/105724
+      // ignore: deprecated_member_use
      primary: controller?.value.focusMode == FocusMode.auto
          ? Colors.orange
          : Colors.blue,
    );
    final ButtonStyle styleLocked = TextButton.styleFrom(
+      // TODO(darrenaustin): Migrate to new API once it lands in stable: https://github.com/flutter/flutter/issues/105724
+      // ignore: deprecated_member_use
      primary: controller?.value.focusMode == FocusMode.locked
          ? Colors.orange
          : Colors.blue,
@@ -448,31 +475,32 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
        child: Container(
          color: Colors.grey.shade50,
          child: Column(
-            children: [
-              Center(
-                child: Text("Focus Mode"),
+            children: <Widget>[
+              const Center(
+                child: Text('Focus Mode'),
              ),
              Row(
                mainAxisAlignment: MainAxisAlignment.spaceEvenly,
-                mainAxisSize: MainAxisSize.max,
-                children: [
+                children: <Widget>[
                  TextButton(
-                    child: Text('AUTO'),
                    style: styleAuto,
                    onPressed: controller != null
                        ? () => onSetFocusModeButtonPressed(FocusMode.auto)
                        : null,
                    onLongPress: () {
-                      if (controller != null) controller!.setFocusPoint(null);
+                      if (controller != null) {
+                        controller!.setFocusPoint(null);
+                      }
                      showInSnackBar('Resetting focus point');
                    },
+                    child: const Text('AUTO'),
                  ),
                  TextButton(
-                    child: Text('LOCKED'),
                    style: styleLocked,
                    onPressed: controller != null
                        ? () => onSetFocusModeButtonPressed(FocusMode.locked)
                        : null,
+                    child: const Text('LOCKED'),
                  ),
                ],
              ),
@@ -489,7 +517,6 @@ class _CameraExampleHomeState extends State<CameraExampleHome>

    return Row(
      mainAxisAlignment: MainAxisAlignment.spaceEvenly,
-      mainAxisSize: MainAxisSize.max,
      children: <Widget>[
        IconButton(
          icon: const Icon(Icons.camera_alt),
@@ -512,8 +539,8 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
        IconButton(
          icon: cameraController != null &&
                  cameraController.value.isRecordingPaused
-              ? Icon(Icons.play_arrow)
-              : Icon(Icons.pause),
+              ? const Icon(Icons.play_arrow)
+              : const Icon(Icons.pause),
          color: Colors.blue,
          onPressed: cameraController != null &&
                  cameraController.value.isInitialized &&
@@ -531,7 +558,16 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
                  cameraController.value.isRecordingVideo
              ? onStopButtonPressed
              : null,
-        )
+        ),
+        IconButton(
+          icon: const Icon(Icons.pause_presentation),
+          color:
+              cameraController != null && cameraController.value.isPreviewPaused
+                  ? Colors.red
+                  : Colors.blue,
+          onPressed:
+              cameraController == null ? null : onPausePreviewButtonPressed,
+        ),
      ],
    );
  }
@@ -540,18 +576,21 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
  Widget _cameraTogglesRowWidget() {
    final List<Widget> toggles = <Widget>[];

-    final onChanged = (CameraDescription? description) {
+    void onChanged(CameraDescription? description) {
      if (description == null) {
        return;
      }

      onNewCameraSelected(description);
-    };
+    }

-    if (cameras.isEmpty) {
-      return const Text('No camera found');
+    if (_cameras.isEmpty) {
+      _ambiguate(SchedulerBinding.instance)?.addPostFrameCallback((_) async {
+        showInSnackBar('No camera found.');
+      });
+      return const Text('None');
    } else {
-      for (CameraDescription cameraDescription in cameras) {
+      for (final CameraDescription cameraDescription in _cameras) {
        toggles.add(
          SizedBox(
            width: 90.0,
@@ -575,8 +614,8 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
  String timestamp() => DateTime.now().millisecondsSinceEpoch.toString();

  void showInSnackBar(String message) {
-    // ignore: deprecated_member_use
-    _scaffoldKey.currentState?.showSnackBar(SnackBar(content: Text(message)));
+    ScaffoldMessenger.of(context)
+        .showSnackBar(SnackBar(content: Text(message)));
  }

  void onViewFinderTap(TapDownDetails details, BoxConstraints constraints) {
@@ -586,7 +625,7 @@ class _CameraExampleHomeState extends State<CameraExampleHome>

    final CameraController cameraController = controller!;

-    final offset = Offset(
+    final Offset offset = Offset(
      details.localPosition.dx / constraints.maxWidth,
      details.localPosition.dy / constraints.maxHeight,
    );
@@ -594,21 +633,32 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
    cameraController.setFocusPoint(offset);
  }

-  void onNewCameraSelected(CameraDescription cameraDescription) async {
-    if (controller != null) {
-      await controller!.dispose();
+  Future<void> onNewCameraSelected(CameraDescription cameraDescription) async {
+    final CameraController? oldController = controller;
+    if (oldController != null) {
+      // `controller` needs to be set to null before getting disposed,
+      // to avoid a race condition when we use the controller that is being
+      // disposed. This happens when camera permission dialog shows up,
+      // which triggers `didChangeAppLifecycleState`, which disposes and
+      // re-creates the controller.
+      controller = null;
+      await oldController.dispose();
    }
+
    final CameraController cameraController = CameraController(
      cameraDescription,
-      ResolutionPreset.medium,
+      kIsWeb ? ResolutionPreset.max : ResolutionPreset.medium,
      enableAudio: enableAudio,
      imageFormatGroup: ImageFormatGroup.jpeg,
    );
+
    controller = cameraController;

    // If the controller is updated then update the UI.
    cameraController.addListener(() {
-      if (mounted) setState(() {});
+      if (mounted) {
+        setState(() {});
+      }
      if (cameraController.value.hasError) {
        showInSnackBar(
            'Camera error ${cameraController.value.errorDescription}');
@@ -617,22 +667,52 @@ class _CameraExampleHomeState extends State<CameraExampleHome>

    try {
      await cameraController.initialize();
-      await Future.wait([
-        cameraController
-            .getMinExposureOffset()
-            .then((value) => _minAvailableExposureOffset = value),
-        cameraController
-            .getMaxExposureOffset()
-            .then((value) => _maxAvailableExposureOffset = value),
+      await Future.wait(<Future<Object?>>[
+        // The exposure mode is currently not supported on the web.
+        ...!kIsWeb
+            ? <Future<Object?>>[
+                cameraController.getMinExposureOffset().then(
+                    (double value) => _minAvailableExposureOffset = value),
+                cameraController
+                    .getMaxExposureOffset()
+                    .then((double value) => _maxAvailableExposureOffset = value)
+              ]
+            : <Future<Object?>>[],
        cameraController
            .getMaxZoomLevel()
-            .then((value) => _maxAvailableZoom = value),
+            .then((double value) => _maxAvailableZoom = value),
        cameraController
            .getMinZoomLevel()
-            .then((value) => _minAvailableZoom = value),
+            .then((double value) => _minAvailableZoom = value),
      ]);
    } on CameraException catch (e) {
-      _showCameraException(e);
+      switch (e.code) {
+        case 'CameraAccessDenied':
+          showInSnackBar('You have denied camera access.');
+          break;
+        case 'CameraAccessDeniedWithoutPrompt':
+          // iOS only
+          showInSnackBar('Please go to Settings app to enable camera access.');
+          break;
+        case 'CameraAccessRestricted':
+          // iOS only
+          showInSnackBar('Camera access is restricted.');
+          break;
+        case 'AudioAccessDenied':
+          showInSnackBar('You have denied audio access.');
+          break;
+        case 'AudioAccessDeniedWithoutPrompt':
+          // iOS only
+          showInSnackBar('Please go to Settings app to enable audio access.');
+          break;
+        case 'AudioAccessRestricted':
+          // iOS only
+          showInSnackBar('Audio access is restricted.');
+          break;
+        default:
+          _showCameraException(e);
+          break;
+      }
    }

    if (mounted) {
@@ -648,7 +728,9 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
          videoController?.dispose();
          videoController = null;
        });
-        if (file != null) showInSnackBar('Picture saved to ${file.path}');
+        if (file != null) {
+          showInSnackBar('Picture saved to ${file.path}');
+        }
      }
    });
  }
@@ -690,50 +772,64 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
    }
  }

-  void onCaptureOrientationLockButtonPressed() async {
-    if (controller != null) {
-      final CameraController cameraController = controller!;
-      if (cameraController.value.isCaptureOrientationLocked) {
-        await cameraController.unlockCaptureOrientation();
-        showInSnackBar('Capture orientation unlocked');
-      } else {
-        await cameraController.lockCaptureOrientation();
-        showInSnackBar(
-            'Capture orientation locked to ${cameraController.value.lockedCaptureOrientation.toString().split('.').last}');
+  Future<void> onCaptureOrientationLockButtonPressed() async {
+    try {
+      if (controller != null) {
+        final CameraController cameraController = controller!;
+        if (cameraController.value.isCaptureOrientationLocked) {
+          await cameraController.unlockCaptureOrientation();
+          showInSnackBar('Capture orientation unlocked');
+        } else {
+          await cameraController.lockCaptureOrientation();
+          showInSnackBar(
+              'Capture orientation locked to ${cameraController.value.lockedCaptureOrientation.toString().split('.').last}');
+        }
      }
+    } on CameraException catch (e) {
+      _showCameraException(e);
    }
  }

  void onSetFlashModeButtonPressed(FlashMode mode) {
    setFlashMode(mode).then((_) {
-      if (mounted) setState(() {});
+      if (mounted) {
+        setState(() {});
+      }
      showInSnackBar('Flash mode set to ${mode.toString().split('.').last}');
    });
  }

  void onSetExposureModeButtonPressed(ExposureMode mode) {
    setExposureMode(mode).then((_) {
-      if (mounted) setState(() {});
+      if (mounted) {
+        setState(() {});
+      }
      showInSnackBar('Exposure mode set to ${mode.toString().split('.').last}');
    });
  }

  void onSetFocusModeButtonPressed(FocusMode mode) {
    setFocusMode(mode).then((_) {
-      if (mounted) setState(() {});
+      if (mounted) {
+        setState(() {});
+      }
      showInSnackBar('Focus mode set to ${mode.toString().split('.').last}');
    });
  }

  void onVideoRecordButtonPressed() {
    startVideoRecording().then((_) {
-      if (mounted) setState(() {});
+      if (mounted) {
+        setState(() {});
+      }
    });
  }

  void onStopButtonPressed() {
-    stopVideoRecording().then((file) {
-      if (mounted) setState(() {});
+    stopVideoRecording().then((XFile? file) {
+      if (mounted) {
+        setState(() {});
+      }
      if (file != null) {
        showInSnackBar('Video recorded to ${file.path}');
        videoFile = file;
@@ -742,16 +838,39 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
    });
  }

+  Future<void> onPausePreviewButtonPressed() async {
+    final CameraController? cameraController = controller;
+
+    if (cameraController == null || !cameraController.value.isInitialized) {
+      showInSnackBar('Error: select a camera first.');
+      return;
+    }
+
+    if (cameraController.value.isPreviewPaused) {
+      await cameraController.resumePreview();
+    } else {
+      await cameraController.pausePreview();
+    }
+
+    if (mounted) {
+      setState(() {});
+    }
+  }
+
  void onPauseButtonPressed() {
    pauseVideoRecording().then((_) {
-      if (mounted) setState(() {});
+      if (mounted) {
+        setState(() {});
+      }
      showInSnackBar('Video recording paused');
    });
  }

  void onResumeButtonPressed() {
    resumeVideoRecording().then((_) {
-      if (mounted) setState(() {});
+      if (mounted) {
+        setState(() {});
+      }
      showInSnackBar('Video recording resumed');
    });
  }
@@ -796,7 +915,7 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
    final CameraController? cameraController = controller;

    if (cameraController == null || !cameraController.value.isRecordingVideo) {
-      return null;
+      return;
    }

    try {
@@ -811,7 +930,7 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
    final CameraController? cameraController = controller;

    if (cameraController == null || !cameraController.value.isRecordingVideo) {
-      return null;
+      return;
    }

    try {
@@ -882,12 +1001,16 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
      return;
    }

-    final VideoPlayerController vController =
-        VideoPlayerController.file(File(videoFile!.path));
+    final VideoPlayerController vController = kIsWeb
+        ? VideoPlayerController.network(videoFile!.path)
+        : VideoPlayerController.file(File(videoFile!.path));
+
    videoPlayerListener = () {
      if (videoController != null && videoController!.value.size != null) {
        // Refreshing the state to update video player with the correct ratio.
-        if (mounted) setState(() {});
+        if (mounted) {
+          setState(() {});
+        }
        videoController!.removeListener(videoPlayerListener!);
      }
    };
@@ -917,7 +1040,7 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
    }

    try {
-      XFile file = await cameraController.takePicture();
+      final XFile file = await cameraController.takePicture();
      return file;
    } on CameraException catch (e) {
      _showCameraException(e);
@@ -926,41 +1049,35 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
  }

  void _showCameraException(CameraException e) {
-    logError(e.code, e.description);
+    _logError(e.code, e.description);
    showInSnackBar('Error: ${e.code}\n${e.description}');
  }
 }

+/// CameraApp is the Main Application.
 class CameraApp extends StatelessWidget {
+  /// Default Constructor
+  const CameraApp({Key? key}) : super(key: key);
+
  @override
  Widget build(BuildContext context) {
-    return MaterialApp(
-      scrollBehavior: MyCustomScrollBehavior(),
+    return const MaterialApp(
      home: CameraExampleHome(),
    );
  }
 }

-class MyCustomScrollBehavior extends MaterialScrollBehavior {
-  // Override behavior methods and getters like dragDevices
-  @override
-  Set<PointerDeviceKind> get dragDevices => {
-        PointerDeviceKind.touch,
-        PointerDeviceKind.mouse,
-      };
-}
-
-List<CameraDescription> cameras = [];
+List<CameraDescription> _cameras = <CameraDescription>[];

 Future<void> main() async {
  // Fetch the available cameras before initializing the app.
  try {
    WidgetsFlutterBinding.ensureInitialized();
-    cameras = await availableCameras();
+    _cameras = await availableCameras();
  } on CameraException catch (e) {
-    logError(e.code, e.description);
+    _logError(e.code, e.description);
  }
-  runApp(CameraApp());
+  runApp(const CameraApp());
 }

 /// This allows a value of type T or T? to be treated as a value of type T?.