gistfile1.txt

class FirstScreen extends StatefulWidget {
  @override
  _FirstScreenState createState() => _FirstScreenState();
}

class _FirstScreenState extends State<FirstScreen> with TickerProviderStateMixin {
  Animation _profSlideAnimation;
  Animation _profRotateAnimation;
  AnimationController _animationController;
  Animation<Offset> _firstOffset;
  Animation<Offset> _secondOffset;
  Animation<Offset> buttonOffset;
  Animation<double> _firstFadeAnimation;
  Animation<double> _secondFadeAnimation;
  Animation<double> _buttonAnimation;
  Animation<double> _tryDemoAnimation;
  AnimationController animateToNextPageController;
  Animation<Offset> animateToNextPageOffset;

  @override
  void initState() {
    super.initState();
    _animationController = AnimationController(duration: const Duration(seconds: 7), vsync: this);
    _profRotateAnimation = Tween<double>(begin: -math.pi / 4.0, end: 0).animate(
      CurvedAnimation(
        parent: _animationController,
        curve: Interval(0.0, 0.7, curve: Curves.ease),
      ),
    );
    _profSlideAnimation = Tween(
      begin: Offset(-1, 0.0),
      end: Offset(0.3, 0.0),
    ).animate(
      CurvedAnimation(
        parent: _animationController,
        curve: Interval(0.0, 0.4, curve: Curves.ease),
      ),
    );

    _firstOffset = Tween<Offset>(begin: Offset(0.3, 1.0), end: Offset(0.3, 0.0))
        .animate(CurvedAnimation(parent: _animationController, curve: Interval(0.4, 0.55)));
    _secondOffset = Tween<Offset>(begin: Offset(0.1, 1.0), end: Offset(0.1, 0.0))
        .animate(CurvedAnimation(parent: _animationController, curve: Interval(0.55, 0.7)));
    _firstFadeAnimation = Tween<double>(begin: 0.0, end: 1.0)
        .animate(CurvedAnimation(parent: _animationController, curve: Interval(0.4, 0.55)));
    _secondFadeAnimation = Tween<double>(begin: 0.0, end: 1.0)
        .animate(CurvedAnimation(parent: _animationController, curve: Interval(0.55, 0.7)));
    buttonOffset = Tween<Offset>(begin: Offset(0.1, 0.0), end: Offset(0.1, 0.0))
        .animate(CurvedAnimation(parent: _animationController, curve: Interval(0.7, 1.0)));
    _buttonAnimation = Tween<double>(begin: 0.0, end: 1.0).animate(CurvedAnimation(
        parent: _animationController, curve: Interval(0.7, 1.0, curve: Curves.elasticOut)));
    _tryDemoAnimation = Tween<double>(begin: 0.0, end: 1.0).animate(CurvedAnimation(
        parent: _animationController, curve: Interval(0.85, 1.0, curve: Curves.elasticOut)));
    _animationController.forward();
    animateToNextPageController =
        AnimationController(vsync: this, duration: Duration(milliseconds: 300));

    animateToNextPageOffset = Tween<Offset>(begin: Offset(0.0, 1.0), end: Offset(0.0, 0.0))
        .animate(CurvedAnimation(parent: animateToNextPageController, curve: Curves.easeIn));
  }

  @override
  Widget build(BuildContext context) {
    final _width = MediaQuery.of(context).size.width;
    final _height = MediaQuery.of(context).size.height;
    return Scaffold(
        backgroundColor: colors.BACKGROUND_COLOR,
        body: Stack(
          children: <Widget>[
            Column(
              children: <Widget>[
                SizedBox(
                  height: 90,
                ),
                AnimatedBuilder(
                  animation: _animationController,
                  builder: (_, child) {
                    return SlideTransition(
                      position: _profSlideAnimation,
                      child: Transform.rotate(
                        angle: _profRotateAnimation.value,
                        child: child,
                      ),
                    );
                  },
                  child: Image.asset(
                    'assets/images/prof_icon.png',
                    height: MediaQuery.of(context).size.width / 3,
                    width: MediaQuery.of(context).size.width / 3,
                  ),
                ),
                AnimatedBuilder(
                  animation: _animationController,
                  builder: (_, child) {
                    return SlideTransition(
                      position: _firstOffset,
                      child: FadeTransition(
                        opacity: _firstFadeAnimation,
                        child: child,
                      ),
                    );
                  },
                  child: Text(
                    strings.HI_IAM_FABI,
                    textAlign: TextAlign.center,
                    style: TextStyle(
                      color: Color(0xffffffff),
                      fontWeight: FontWeight.w900,
                      fontSize: 30,
                    ),
                  ),
                ),
                SizedBox(
                  height: _height / 30,
                ),
                AnimatedBuilder(
                  animation: _animationController,
                  builder: (_, child) {
                    return SlideTransition(
                      position: _secondOffset,
                      child: FadeTransition(
                        opacity: _secondFadeAnimation,
                        child: child,
                      ),
                    );
                  },
                  child: Text(
                    strings.FABI_GUIDE,
                    textAlign: TextAlign.center,
                    style: TextStyle(
                      color: Color(0xffffffff),
                      fontWeight: FontWeight.w500,
                      fontSize: 20,
                    ),
                  ),
                ),
                SizedBox(
                  height: _height / 30,
                ),
                Center(
                  child: AnimatedBuilder(
                    animation: _animationController,
                    builder: (_, child) {
                      return  Transform(
                          child: child,
                          alignment: Alignment.center,
                          transform: Matrix4.diagonal3Values(
                            _buttonAnimation.value,
                            _buttonAnimation.value,
                            1.0,
                          ),
                        );
                    },
                    child: MaterialButton(
                      onPressed: () => animateToNextPageController.forward(),
                      color: Color(0xffffffff),
                      padding:
                          EdgeInsets.fromLTRB(_width / 5, _height / 40, _width / 5, _height / 40),
                      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(35.0)),
                      child: Text(
                        strings.FABI_LETS_GO,
                        style: TextStyle(
                          color: Color(0xff6B94AD),
                          fontWeight: FontWeight.w700,
                          fontSize: 20,
                        ),
                      ),
                    ),
                  ),
                ),
                Center(
                  child: AnimatedBuilder(
                    animation: _animationController,
                    builder: (_, child) {
                      return  Transform(
                          child: child,
                          alignment: Alignment.center,
                          transform: Matrix4.diagonal3Values(
                            _buttonAnimation.value,
                            _buttonAnimation.value,
                            1.0,
                          ),
                        );
                    },
                    child: MaterialButton(
                      onPressed: () => Navigator.push(
                        context,
                        CupertinoPageRoute(
                          builder: (_) => LoginScreen(),
                        ),
                      ),
                      child: Text(
                        strings.ALREADY_HAVE_ACCOUNT,
                        style: TextStyle(
                          color: Color(0xffffffff),
                          fontWeight: FontWeight.w900,
                          fontSize: 20,
                        ),
                      ),
                    ),
                  ),
                ),
                Center(
                  child: AnimatedBuilder(
                    animation: _animationController,
                    builder: (_, child) {
                      return  Transform(
                          child: child,
                          alignment: Alignment.center,
                          transform: Matrix4.diagonal3Values(
                            _tryDemoAnimation.value,
                            _tryDemoAnimation.value,
                            1.0,
                          ),
                        );
                    },
                    child: MaterialButton(
                      onPressed: () {},
                      child: Text(
                        strings.TRY_DEMO,
                        style: TextStyle(
                          color: Color(0xffffffff),
                          fontWeight: FontWeight.w900,
                          fontSize: 20,
                        ),
                      ),
                    ),
                  ),
                )
              ],
            ),
            Align(
                alignment: Alignment.bottomCenter,
                child: SlideTransition(
                    position: animateToNextPageOffset,
                    child: EnterNameScreen(
                      controller: animateToNextPageController,
                    )))
          ],
        ));
  }
}