apress / practical-flutter

Source Code for 'Practical Flutter' by Frank Zammetti

Apress Source Code

This repository accompanies Practical Flutter by Frank Zammetti (Apress, 2019).

Download the files as a zip using the green button, or clone the repository to your machine using Git.

Releases

Release v1.0 corresponds to the code in the published book, without corrections or updates.

Contributions

See the file Contributing.md for more information on how you can contribute to this repository.

practical-flutter's Issues

Workable Flutter_hero code

I add the following example from the book. This is a working flutter_hero code.

Flutter hero - https://github.com/DenisNaN/Flutterhero

Workable Flutter_book code

Just started my journey in mobile development. I really like the book, but the code in it does not work because of null safety. Therefore, I corrected the code due to my abilities. Don't scold too much. But for those who are starting to learn Flutter, it's better to face what works.

https://github.com/DenisNaN/Flutterbook

Flutter chat not working

I am using flutter v1.9.1+hotfix.5. Running the flutter chat application results in crashes on both iOS and Android. See the corresponding issues on the flutter_socket_io project:

WinkMeter/flutter_socket_io#17
WinkMeter/flutter_socket_io#18

flutter_book not working, missing stuff

Using Android Studio to build the flutter_book project. Getting
Resolving dependencies...
Running Gradle task 'assembleDebug'...
C:\Users\roger\AppData\Roaming\Pub\Cache\hosted\pub.dartlang.org\image_picker-0.4.12+1\android\src\main\java\io\flutter\plugins\imagepicker\ImagePickerDelegate.java:15: error: package android.support.annotation does not exist
import android.support.annotation.VisibleForTesting;
^
C:\Users\roger\AppData\Roaming\Pub\Cache\hosted\pub.dartlang.org\image_picker-0.4.12+1\android\src\main\java\io\flutter\plugins\imagepicker\ImagePickerDelegate.java:16: error: cannot find symbol
import android.support.v4.app.ActivityCompat;
^
symbol: class ActivityCompat
location: package android.support.v4.app
C:\Users\roger\AppData\Roaming\Pub\Cache\hosted\pub.dartlang.org\image_picker-0.4.12+1\android\src\main\java\io\flutter\plugins\imagepicker\ImagePickerDelegate.java:17: error: package android.support.v4.content does not exist
import android.support.v4.content.FileProvider;
^
C:\Users\roger\AppData\Roaming\Pub\Cache\hosted\pub.dartlang.org\image_picker-0.4.12+1\android\src\main\java\io\flutter\plugins\imagepicker\ImagePickerFileProvider.java:3: error: package android.support.v4.content does not exist
import android.support.v4.content.FileProvider;
^
C:\Users\roger\AppData\Roaming\Pub\Cache\hosted\pub.dartlang.org\image_picker-0.4.12+1\android\src\main\java\io\flutter\plugins\imagepicker\ImagePickerFileProvider.java:10: error: cannot find symbol
public class ImagePickerFileProvider extends FileProvider {}
^
symbol: class FileProvider
... and other errors. I suspect this has to do with an upgrade to flutter, dart, Android Studio or some such since the book version.
Any suggestions? Still rather new to flutter/dart.

Exception after Flutter Upgrade to 1.9

After the upgrade of Flutter to v1.9 I suddenly got this exception thrown that I didn't see before in your code that I didn't modify btw. Using Android Studio under Windows 10.

The following NoSuchMethodError was thrown building AppointmentsEntry(dirty):
The getter 'title' was called on null.
Receiver: null
Tried calling: title
User-created ancestor of the error-causing widget was:
IndexedStack file:///C:/Development/myFlutterProjects/flutter_book/lib/appointments/Appointments.dart:38:22

Stuck on white screen

I was constantly stuck on a white screen when trying to run the app, turns out the main method was missing the following line:
WidgetsFlutterBinding.ensureInitialized();

The error was due to mixing await and runApp() inside main().

Similar problem on Stackoverflow that fixed it for me:
(https://stackoverflow.com/questions/57689492/flutter-unhandled-exception-servicesbinding-defaultbinarymessenger-was-accesse

Ajuste no pubspec.yaml

Bom dia !!!

Tive que ajustar o arquivo pubspec.yaml nas dependências para :
flutter_slidable: 0.5.4

Está dando erro Appointments.dart nas linhas : 

                         return Slidable(
                              actionPane: SlidableDrawerActionPane(),

image_picker: 0.6.3+4

Neste caso estava dando erro na compilação.

Workable Flutter_chat code

I add the following example from the book. This is a working flutter_chat code.

Flutter chat - https://github.com/DenisNaN/Flutterchat
Flutter chat server node.js - https://github.com/DenisNaN/Flutterchat_server

AppointmentsEntry error during build

New to dart/flutter, so learning to debug with Android Studio. Interesting, but a bit confusing.
Using the git code, I have this error:
I/flutter (21442): ## AppointmentsEntry.build()
I/flutter (21442): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter (21442): The following NoSuchMethodError was thrown building AppointmentsEntry(dirty):
I/flutter (21442): The getter 'title' was called on null.
I/flutter (21442): Receiver: null
I/flutter (21442): Tried calling: title
I/flutter (21442):
I/flutter (21442): User-created ancestor of the error-causing widget was:
I/flutter (21442): IndexedStack file:///D:/FlutterProjects/flutter_book/lib/ap
pointments/Appointments.dart:38:18
I/flutter (21442):
I/flutter (21442): When the exception was thrown, this was the stack:
I/flutter (21442): #0 Object.noSuchMethod (dart:core-patch/object_patch.dart:51:5)
I/flutter (21442): #1 AppointmentsEntry.build (package:flutter_book/appointments/AppointmentsEntry.dart:49:72)
I/flutter (21442): #2 StatelessElement.build (package:flutter/src/widgets/framework.dart:4026:28)
... etc...

I tried just plugging a hard coded value to the text element, but to no avail.
This section of AppointmentsEntry...
print("## AppointmentsEntry.build()");

// Set value of controllers.
_titleEditingController.text = appointmentsModel.entityBeingEdited.title;
_descriptionEditingController.text = appointmentsModel.entityBeingEdited.description;

... seems to be where the title element of appointmentsModel.entityBeingEdited is assigned. According to the next "up" stack entry, Object.noSuchMethod implies this data element is a method, or the idea of an "=" assignment is in valid. Counterintuitive, at best.

What am I missing here? I keep looking at the class definitions, but nothing bad jumps out at me.

Does this code for for others?