A Flutter hobby project using redux for state management. The UI has been inspired from a dribbble by DhipuMathew.

I have been playing with flutter for about 3 weeks(sep 2018). This is my very first flutter app I built to check out the framework. The codebase is not well structured and also can be coded better. It is me just playing with the framework and quickly prototyping a working app.

The App's state consists of:

1. list of todos
2. current tab the user is on i.e ''today'' or ''week'' or ''month''
3. boolean editing
4. list of categories

The app consists of two pages:

1. home page: it displays the user info, the tab view showing the upcoming todos and the todo categoris grid view.
2. todos list page: displays all the todos belonging to a particular category.

The home page is essentially a Stack widget consisting of two layers:

1. Main Layer: This layer displays the appbar, user info, the upcoming todos(in a tabbed view) and all the todo categories.
2. AddTodo Layer: This consists of the 'ADD TODO' button and the form that appears when the button is clicked.

Explanation of the add todo animation:

The AddTodo layer is a Stack itself. This stack consist of two children:

1. AddTodoForm
2. AddTodoButton

These both are PositionedTransition widgets which is the animated version of Positioned widgets.

The initial position of the form is completely pushed of the screen downwards which is derived from the RelativeRectTween as below:

    _rectAnimation = RelativeRectTween(
      begin: RelativeRect.fromLTRB(0.0, size.height, 0.0, -size.height),
      end: RelativeRect.fromLTRB(0.0, 0.0, 0.0, 0.0),
    ).animate(_animCntroller);

	...
    ...
    ...

  @override
  Widget build(BuildContext context) {
    return PositionedTransition(
      rect: _rectAnimation,
      child: Column(
        ...
      ),
    );
  }

Similarly the button also has its own animations which control its position and the button text. These animations are deferred using an Interval. The button moves down and expands for the 70% of the animation and the the text animates for the remaining 30%

//animation that animates the position: 0.0 -> 0.7
_buttonAnimation = RelativeRectTween(
    begin: RelativeRect.fromLTRB(
        initialLeftRight, top - 25.0, initialLeftRight, 25.0),
    end: RelativeRect.fromLTRB(0.0, top, 0.0, 0.0),
  ).animate(CurvedAnimation(curve: Interval(0.0, 0.7), parent: _controller));


//animation that animates the text: 0.7 -> 1.0
_buttonTextAnimation = Tween<double>(begin: 0.0, end: 1.0).animate(
    CurvedAnimation(curve: Interval(0.7, 1.0), parent: _controller));

When the button is pressed initially it triggers a redux action mutating the editing state of the store to true. This causes the re-render of the widgets. Both these widgets has a didUpdateWidget lifecycle hook. This lifecycle hook gets called when the widget's parent rebuilds and passes new properties to the widgets. In this lifecycle hook we perform the animation depending on the editing property.