Chapter 58 — Task List

Level: intermediate Estimated time: 12 hours Prerequisites: PART 1A (chapters 01 to 18), PART 1B (chapters 43 to 54), and projects 55, 56, 57 What you will be able to do by the end: build a complete task management app from start to finish — a serializable data model, a swappable repository, a filterable, sortable, searchable list, a validated form, undoable deletion, centralized state with provider, on-disk persistence, and automated tests.

58.0 — Chapter Objectives

By the end of this chapter, you will be able to:

• model a task with a Dart class that has a priority enum, a DateTime due date, and tags;
• write fromJson and toJson on this model (a recap of chapter 17);
• write a correct copyWith method, including for a nullable field;
• define a repository interface (repository) and provide three implementations of it;
• display a collection with ListView.builder (a recap of chapter 48);
• handle a screen's empty state with care;
• check off a task and strike through its title with TextDecoration.lineThrough;
• add a task through a showDialog dialog (a recap of chapter 49);
• build a complete form with Form, TextFormField, and validator;
• reuse the same form for both creation and editing;
• delete by swiping with Dismissible and understand why the Key is mandatory;
• offer an undo for deletion with a SnackBar and its SnackBarAction;
• filter a list with where (a recap of chapter 14);
• sort by due date or by priority, handling null values cleanly;
• wire a search bar to the list;
• display counters and a progress LinearProgressIndicator;
• pick a date with showDatePicker;
• format a date in French with the intl package;
• highlight overdue tasks;
• extract all the state into a ChangeNotifier exposed by provider (a recap of chapter 52);
• persist tasks with shared_preferences (a recap of chapter 54);
• write the same persistence with sqflite and compare the two;
• add a switchable, persisted dark mode;
• write unit tests for the filtering and sorting logic.