workouttest_app/lib/widgets/app_bar.dart

import 'dart:async';

import 'package:aitrainer_app/bloc/menu/menu_bloc.dart';
import 'package:aitrainer_app/localization/app_localization.dart';
import 'package:aitrainer_app/model/cache.dart';
import 'package:aitrainer_app/repository/exercise_repository.dart';
import 'package:aitrainer_app/util/common.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:percent_indicator/linear_percent_indicator.dart';
import 'package:rainbow_color/rainbow_color.dart';


class AppBarNav extends StatefulWidget implements PreferredSizeWidget  {
  final MenuBloc menuBloc;
  final bool isMenu;
  final int depth;
  const AppBarNav({this.menuBloc, this.isMenu, this.depth});

  @override
  _AppBarNav createState() => _AppBarNav();

  @override
  Size get preferredSize => const Size.fromHeight(50);
}

class _AppBarNav extends State<AppBarNav>  with SingleTickerProviderStateMixin, Common {
  Animation<Color> colorAnim;
  AnimationController colorController;
  MenuBloc menuBloc;

  @override
  void initState() {

    colorController =
      AnimationController(duration: Duration(seconds: 4), vsync:this);

    colorAnim = RainbowColorTween([Colors.white70,
      Colors.blueGrey,
      Colors.blueAccent,
      Colors.lightBlue,
      Colors.lightBlueAccent,
      Colors.yellowAccent,
      Colors.orange,
      Colors.orangeAccent,
      Colors.yellowAccent,
      Color(0xffcce6ff)])
      .animate(colorController)
      ..addListener(() { setState(() {}); })
      ..addStatusListener((status) {
        if (status == AnimationStatus.completed) {
          Timer(Duration(seconds: 10), () {
            if ( mounted ) {
              colorController.forward();
            }
          });
        } else if (status == AnimationStatus.dismissed) {
            colorController.forward();
        }
      });
    colorController.forward();
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    menuBloc = BlocProvider.of<MenuBloc>(context);

    return AppBar(
        backgroundColor: Colors.black,
        title: Row(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: <Widget>[

            getAnimatedWidget(),
            Image.asset(
              'asset/image/WT_long_logo.png',
              //fit: BoxFit.cover,
              height: 45.0,
            ),
          ],
        ),
        leading: IconButton(
          icon: Icon(Icons.arrow_back, color: Colors.white),
          onPressed: () =>
          {
            if ( widget.isMenu != null ) {
              if ( menuBloc.workoutItem != null ) {
                menuBloc.add(MenuTreeUp(parent: menuBloc.workoutItem.parent)),
              }
            } else if ( widget.depth != null ) {
              if ( widget.depth == 0 ) {
                Navigator.of(context).pushNamed('home')
              } else {
                Navigator.of(context).pop()
              }
            }
          },
        )
    );
  }

  @override
  void dispose() {
    colorController.dispose();
    super.dispose();
  }

  Widget getAnimatedWidget() {
    double cWidth = mediaSizeWidth(context);
    double percent = Cache().getPercentExercises();
    if ( percent == -1) {
      menuBloc.menuTreeRepository.createTree();
      ExerciseRepository exerciseRepository = ExerciseRepository();
      exerciseRepository.getBaseExerciseFinishedPercent();
      percent = Cache().getPercentExercises();
    }
    int sizeExerciseList = Cache().getExercises() == null? 0 : Cache().getExercises().length;
    if ( sizeExerciseList == 0  ) {
      String text = AppLocalizations.of(context).translate("Make your first test");
      double fontSize = text.length > 24 ? 10 : 16;
      return Stack(
        alignment: Alignment.topLeft,
        overflow: Overflow.clip,
        children: [
          Text(text,
            style: TextStyle(fontSize: fontSize, color: colorAnim.value, shadows: [Shadow(color: Colors.purple , blurRadius: 15)]),

          ),
          //TestProgress(animation: sizeAnim),
        ]
      );
    } else {

      return Stack(
        alignment: Alignment.topLeft,
        children: [
           LinearPercentIndicator(
              width: cWidth / 4,
              lineHeight: 14.0,
              percent: percent,
              center: Text(
                (percent * 100).toStringAsFixed(0) + "% " + AppLocalizations.of(context).translate("finished"),
                style: new TextStyle(fontSize: 10.0),
              ),
              trailing: Icon(percent > 0.6 ? Icons.mood : Icons.mood_bad, color: colorAnim.value,),
              linearStrokeCap: LinearStrokeCap.roundAll,
              backgroundColor: colorAnim.value,
              progressColor: Color(0xff73e600),
              animation: true,
          ),
        ],
      );
    }
  }
}