task_page_2.dart

import 'package:flutter/material.dart';

class TaskPage extends StatefulWidget {
  @override
  _TaskPageState createState() => _TaskPageState();
}

class Task {
  final String task;
  final bool isFinish;
  const Task(this.task, this.isFinish);
}

final List<Task> _taskList = [
  new Task("Call Tom about appointment", false),
  new Task("Fix onboarding experience", false),
  new Task("Edit API documentation", false),
  new Task("Setup user focus group", false),
  new Task("Have coffe with Sam", true),
  new Task("Meet with sales", true),
];

class _TaskPageState extends State<TaskPage> {
  @override
  Widget build(BuildContext context) {
    return ListView.builder(
      padding: const EdgeInsets.all(0),
      itemCount: _taskList.length,
      itemBuilder: (context, index) {
        return _taskList[index].isFinish
            ? _taskComplete(_taskList[index].task)
            : _taskUncomplete(_taskList[index].task);
      },
    );
  }

  Widget _taskUncomplete(String task) {
    return Padding(
      padding: const EdgeInsets.only(left: 20.0, bottom: 24.0),
      child: Row(
        children: <Widget>[
          Icon(
            Icons.radio_button_unchecked,
            color: Theme.of(context).accentColor,
            size: 20,
          ),
          SizedBox(
            width: 28,
          ),
          Text(task)
        ],
      ),
    );
  }

  Widget _taskComplete(String task) {
    return Container(
      foregroundDecoration: BoxDecoration(color: Color(0x60FDFDFD)),
      child: Padding(
        padding: const EdgeInsets.only(left: 20.0, top: 24.0),
        child: Row(
          children: <Widget>[
            Icon(
              Icons.radio_button_checked,
              color: Theme.of(context).accentColor,
              size: 20,
            ),
            SizedBox(
              width: 28,
            ),
            Text(task)
          ],
        ),
      ),
    );
  }
}