Completing tasks
- Dart course
- Beginner
- Lesson 86/116
- 6 min
Learn to update task status with completeTask.
The completeTask method
The last method is completeTask: it marks a task as done. It is declared as void completeTask(int i); the i parameter is the task index.
The body is one line: tasks[i].done = true;. This sets the done field of the i-th task to true. When the user finishes a task, its status updates.
Call: list.completeTask(0) — marks the first task as done. This is the project's last core operation. After this we will wire all pieces together.
Checking task status
To read a task's status use tasks[i].done. It returns true or false. You can extend listTasks to show the status too.
Example: print('${tasks[i].title} - ${tasks[i].done}') prints both the name and the status. This makes the CLI more informative.
Later the menu loop will call completeTask; the user enters a number and that task is finished. This comes together in the project's final lesson.
Practice Add the completeTask method
Add a void completeTask(int i) method to the TodoList class; its body should do tasks[i].done = true. Inside main add list.addTask('Kitap oku') and list.completeTask(0) calls, and print the status with print(list.tasks[0].done).
Starter code
class Task {
String title;
bool done = false;
Task(this.title);
}
class TodoList {
List<Task> tasks = [];
void addTask(String title) {
tasks.add(Task(title));
}
void listTasks() {
for (var i = 0; i < tasks.length; i++) {
print('${i + 1}. ${tasks[i].title}');
}
}
// add the completeTask method
}
void main() {
var list = TodoList();
list.addTask('Kitap oku');
// completeTask and status print
}Sample solution
class Task {
String title;
bool done = false;
Task(this.title);
}
class TodoList {
List<Task> tasks = [];
void addTask(String title) {
tasks.add(Task(title));
}
void listTasks() {
for (var i = 0; i < tasks.length; i++) {
print('${i + 1}. ${tasks[i].title}');
}
}
void completeTask(int i) {
tasks[i].done = true;
}
}
void main() {
var list = TodoList();
list.addTask('Kitap oku');
list.completeTask(0);
print(list.tasks[0].done);
}Expected output
true
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Match the completeTask parts
| Term | Meaning |
|---|---|
void |
No return |
completeTask |
Method name |
int i |
Index parameter |
tasks[i].done = true |
Assignment |
2 What does completeTask(0) do?
- Deletes the first task
- Clears the list
- Marks the first task done Correct answer
- Throws
Explanation: completeTask(0) sets the first task's done to true.
3 The done assignment
void completeTask(int i) {
tasks[i].____ = true;
}void completeTask(int i) {
tasks[i].done = true;
}Explanation: the done field is set to true.