Sound null safety is available in Dart 2.12 and Flutter 2.

This issue could be a big problem for a beginner using the latest version of Dart.

I want to accomplish chapter 4, but the assets folder is empty. Where is the images?

I had to look up answer myself. Added these lines to android/app/src/debug/AndroidManifest.xml:

    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

Hi!

I am trying to get the device camera example from the cookbook running but get the following compile error. I used the main.dart, camera.dart, picture.dart and pubspec.yaml file provided here without changing anything.

This is the error stack I am getting:

Running "flutter pub get" in camera_app...
The plugin firebase_mlkit_language uses a deprecated version of the Android embedding.
To avoid unexpected runtime failures, or future build failures, try to see if this plugin supports the Android V2 embedding. Otherwise, consider removing it since a future release of Flutter will remove these deprecated APIs.
If you are plugin author, take a look at the docs for migrating the plugin to the V2 embedding: https://flutter.dev/go/android-plugin-migration.
Launching lib/main.dart on HUAWEI TAG L21 in debug mode...
Running Gradle task 'assembleDebug'...
Warning: Mapping new ns http://schemas.android.com/repository/android/common/02 to old ns http://schemas.android.com/repository/android/common/01
Warning: Mapping new ns http://schemas.android.com/repository/android/generic/02 to old ns http://schemas.android.com/repository/android/generic/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/addon2/02 to old ns http://schemas.android.com/sdk/android/repo/addon2/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/repository2/02 to old ns http://schemas.android.com/sdk/android/repo/repository2/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/sys-img2/02 to old ns http://schemas.android.com/sdk/android/repo/sys-img2/01
/Users/stefvenmans/Development/flutter/.pub-cache/hosted/pub.dartlang.org/camera-0.7.0+4/android/src/main/java/io/flutter/plugins/camera/CameraUtils.java:138: warning: [deprecation] get(int,int) in CamcorderProfile has been deprecated
return CamcorderProfile.get(cameraId, CamcorderProfile.QUALITY_HIGH);
^
/Users/stefvenmans/Development/flutter/.pub-cache/hosted/pub.dartlang.org/camera-0.7.0+4/android/src/main/java/io/flutter/plugins/camera/CameraUtils.java:142: warning: [deprecation] get(int,int) in CamcorderProfile has been deprecated
return CamcorderProfile.get(cameraId, CamcorderProfile.QUALITY_2160P);
^
/Users/stefvenmans/Development/flutter/.pub-cache/hosted/pub.dartlang.org/camera-0.7.0+4/android/src/main/java/io/flutter/plugins/camera/CameraUtils.java:146: warning: [deprecation] get(int,int) in CamcorderProfile has been deprecated
return CamcorderProfile.get(cameraId, CamcorderProfile.QUALITY_1080P);
^
/Users/stefvenmans/Development/flutter/.pub-cache/hosted/pub.dartlang.org/camera-0.7.0+4/android/src/main/java/io/flutter/plugins/camera/CameraUtils.java:150: warning: [deprecation] get(int,int) in CamcorderProfile has been deprecated
return CamcorderProfile.get(cameraId, CamcorderProfile.QUALITY_720P);
^
/Users/stefvenmans/Development/flutter/.pub-cache/hosted/pub.dartlang.org/camera-0.7.0+4/android/src/main/java/io/flutter/plugins/camera/CameraUtils.java:154: warning: [deprecation] get(int,int) in CamcorderProfile has been deprecated
return CamcorderProfile.get(cameraId, CamcorderProfile.QUALITY_480P);
^
/Users/stefvenmans/Development/flutter/.pub-cache/hosted/pub.dartlang.org/camera-0.7.0+4/android/src/main/java/io/flutter/plugins/camera/CameraUtils.java:158: warning: [deprecation] get(int,int) in CamcorderProfile has been deprecated
return CamcorderProfile.get(cameraId, CamcorderProfile.QUALITY_QVGA);
^
/Users/stefvenmans/Development/flutter/.pub-cache/hosted/pub.dartlang.org/camera-0.7.0+4/android/src/main/java/io/flutter/plugins/camera/CameraUtils.java:162: warning: [deprecation] get(int,int) in CamcorderProfile has been deprecated
return CamcorderProfile.get(cameraId, CamcorderProfile.QUALITY_LOW);
^
error: warnings found and -Werror specified
/Users/stefvenmans/Development/flutter/.pub-cache/hosted/pub.dartlang.org/camera-0.7.0+4/android/src/main/java/io/flutter/plugins/camera/media/MediaRecorderBuilder.java:15: warning: [deprecation] MediaRecorder() in MediaRecorder has been deprecated
return new MediaRecorder();
^
1 error
8 warnings

FAILURE: Build failed with an exception.

• What went wrong:
  Execution failed for task ':camera:compileDebugJavaWithJavac'.

Compilation failed; see the compiler error output for details.

• Try:
  Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

• Get more help at https://help.gradle.org

BUILD FAILED in 1m 31s
*********************************************************
WARNING: This version of firebase_mlkit_language will break your Android build if it or its dependencies aren't compatible with AndroidX.
See https://goo.gl/CP92wY for more information on the problem and how to fix it.
This warning prints for all Android build failures. The real root cause of the error may be unrelated.
*********************************************************
Exception: Gradle task assembleDebug failed with exit code 1

Hi I'm doing the excercise on chapter 7 (Unfortunately my ebook doesn't show the page no) and I get the following error in main.dart file on line 41: return completer.future (underlined red):

A value of type 'Future<dynamic>' can't be returned from the method 'getNumber' because it has a return type of 'Future<int>'.

How to turn the completer into type future?

i'm using a new version of flutter
i get this error: type 'Null' is not a subtype of type 'String'

at the 3rd this line of the code (plan_services.dart):

  Plan createPlan(String name) {
    final model = _repository.create();
    print('my name $name');                                           //the name in not null here
    final plan = Plan.fromModel(model)..name = name;            //error here
    savePlan(plan);
    return plan;
  }

after debugging, i got name=null here (plan.dart)

  Plan.fromModel(Model model)
      : id = model.id,
        name = model.data['name'],             //the name is null here
        tasks = model.data['task']
                ?.map<Task>((task) => Task.fromModel(task))
                ?.toList() ??
            <Task>[];

can you explain why? thank you

For the pizza json chapter 8 I believe with a factory constructor, null cannot be returned. Please update the code. I have no idea what purpose the factory serves now except if there is a cache of instantiated pizzas in the pizza class which then could be used to optimize a bit by not having to instantiate every instance. But I am unclear on the "how" this works under the hood.

If you debug in Chrome and stretch the window's width, the heading: value text is left at the left edge while everything else centers. The stack should only include the background and photo and then be encapsulated by a Column so you can put the other text under the Stack in the column, all as children of the Column. Thus if you probably rotate screen to Landscape on a device the same thing happens. It's a shame because it's a good book but you did not test out your code a bit more to make it robust for various use cases. As of now it only looks nice when you have a device in Portrait mode or Chrome window at its narrowest width possible.

I like the book so far but I am a bit lost now: Where do I find the images used f.e. textiles.jpg and women_shopping.jpg in chapter 4?
Do I have to download some random images and name them as such on my own?

line 31
old： final id = plan.tasks.last?.id ?? 0 + 1;
new： final id = plan.tasks.length + 1;

Those chapters do not work due to null safety in Flutter 2.5 - it would be great if those could be updated

The recipe that shows how to upload the local file to the Cloud Storage clearly misses the step in which the Cloud Storage has to be "configured first", otherwise the Firebase will report the 404 error and a cryptic message ("File Not Found").
As someone who didn't work with the Firebase cloud storage before, it took me several attempts to figure out what needs to be done and for a beginner this may end up in a complete confusion.

This is disappointing that the authors seemed to have abandoned this project.