app-mirror-github/lib/pages/list/list.dart

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:vikunja_app/components/AddDialog.dart';
import 'package:vikunja_app/components/TaskTile.dart';
import 'package:vikunja_app/global.dart';
import 'package:vikunja_app/models/list.dart';
import 'package:vikunja_app/models/task.dart';
import 'package:vikunja_app/pages/list/list_edit.dart';
import 'package:vikunja_app/pages/list/task_edit.dart';
import 'package:vikunja_app/stores/list_store.dart';

class ListPage extends StatefulWidget {
  final TaskList taskList;

  ListPage({this.taskList}) : super(key: Key(taskList.id.toString()));

  @override
  _ListPageState createState() => _ListPageState();
}

class _ListPageState extends State<ListPage> {
  TaskList _list;
  List<Task> _loadingTasks = [];
  int _currentPage = 1;

  @override
  void initState() {
    _list = TaskList(
      id: widget.taskList.id,
      title: widget.taskList.title,
      tasks: [],
    );
    Future.microtask(() => _loadList());
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    final taskState = Provider.of<ListProvider>(context);
    return Scaffold(
      appBar: AppBar(
        title: Text(_list.title),
        actions: <Widget>[
          IconButton(
            icon: Icon(Icons.edit),
            onPressed: () => Navigator.push(
                context,
                MaterialPageRoute(
                  builder: (context) => ListEditPage(
                    list: _list,
                  ),
                )),
          ),
        ],
      ),
      // TODO: it brakes the flow with _loadingTasks and conflicts with the provider
      body: !taskState.isLoading
          ? RefreshIndicator(
              child: taskState.tasks.length > 0
                  ? ListenableProvider.value(
                      value: taskState,
                      child: ListView.builder(
                          padding: EdgeInsets.symmetric(vertical: 8.0),
                          itemBuilder: (context, i) {
                            if (i.isOdd) return Divider();

                            if (_loadingTasks.isNotEmpty) {
                              final loadingTask = _loadingTasks.removeLast();
                              return _buildLoadingTile(loadingTask);
                            }

                            final index = i ~/ 2;

                            // This handles the case if there are no more elements in the list left which can be provided by the api
                            if (taskState.maxPages == _currentPage &&
                                index == taskState.tasks.length - 1)
                              return null;

                            if (index >= taskState.tasks.length &&
                                _currentPage < taskState.maxPages) {
                              _currentPage++;
                              _loadTasksForPage(_currentPage);
                            }
                            return index < taskState.tasks.length
                                ? _buildTile(taskState.tasks[index])
                                : null;
                          }),
                    )
                  : Center(child: Text('This list is empty.')),
              onRefresh: _loadList,
            )
          : Center(child: CircularProgressIndicator()),
      floatingActionButton: Builder(
        builder: (context) => FloatingActionButton(
            onPressed: () => _addItemDialog(context), child: Icon(Icons.add)),
      ),
    );
  }

  TaskTile _buildTile(Task task) {
    return TaskTile(
      task: task,
      loading: false,
      onEdit: () => Navigator.push(
        context,
        MaterialPageRoute(
          builder: (context) => TaskEditPage(
            task: task,
          ),
        ),
      ),
      onMarkedAsDone: (done) {
        Provider.of<ListProvider>(context, listen: false).updateTask(
          context: context,
          id: task.id,
          done: done,
        );
      },
    );
  }

  TaskTile _buildLoadingTile(Task task) {
    return TaskTile(
      task: task,
      loading: true,
      onEdit: () => Navigator.push(
        context,
        MaterialPageRoute(
          builder: (context) => TaskEditPage(
            task: task,
          ),
        ),
      ),
    );
  }

  Future<void> _loadList() async {
    _loadTasksForPage(1);
  }

  void _loadTasksForPage(int page) {
    Provider.of<ListProvider>(context, listen: false).loadTasks(
      context: context,
      listId: _list.id,
      page: page,
    );
  }

  _addItemDialog(BuildContext context) {
    showDialog(
      context: context,
      builder: (_) => AddDialog(
        onAdd: (title) => _addItem(title, context),
        decoration: InputDecoration(
          labelText: 'Task Name',
          hintText: 'eg. Milk',
        ),
      ),
    );
  }

  _addItem(String title, BuildContext context) {
    var globalState = VikunjaGlobal.of(context);
    var newTask = Task(
      id: null,
      title: title,
      createdBy: globalState.currentUser,
      done: false,
    );
    setState(() => _loadingTasks.add(newTask));
    Provider.of<ListProvider>(context, listen: false)
        .addTask(
      context: context,
      newTask: newTask,
      listId: _list.id,
    )
        .then((_) {
      ScaffoldMessenger.of(context).showSnackBar(SnackBar(
        content: Text('The task was added successfully!'),
      ));
      setState(() {
        _loadingTasks.remove(newTask);
      });
    });
  }
}