颤动自定义动画对话框

Question

我正在尝试在dart中设置自定义对话框的动画，这样当它弹出时会创建一些动画。在Android有一个带有动画对话框的库，在Flutter Sweet Alert Dialog有没有类似的库

我们怎样才能在颤动中实现相同的功能？

Answer 1

要创建对话框，您可以使用Overlay或Dialog类。如果要在给定框架中添加动画，可以使用以下示例中的AnimationController。 CurvedAnimation类用于创建动画的弹跳效果。

更新：通常最好使用showDialog函数显示对话框，因为关闭和手势由Flutter处理。我已经更新了示例，它现在与showDialog一起运行，您可以通过点击背景来关闭对话框。

您可以将以下代码复制并粘贴到新项目中并进行调整。它可以自己运行。

import 'package:flutter/material.dart';

void main() => runApp(new MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(title: 'Flutter Demo', theme: ThemeData(), home: Page());
  }
}

class Page extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: RaisedButton.icon(
            onPressed: () {
              showDialog(
                context: context,
                builder: (_) => FunkyOverlay(),
              );
            },
            icon: Icon(Icons.message),
            label: Text("PopUp!")),
      ),
    );
  }
}

class FunkyOverlay extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => FunkyOverlayState();
}

class FunkyOverlayState extends State<FunkyOverlay>
    with SingleTickerProviderStateMixin {
  AnimationController controller;
  Animation<double> scaleAnimation;

  @override
  void initState() {
    super.initState();

    controller =
        AnimationController(vsync: this, duration: Duration(milliseconds: 450));
    scaleAnimation =
        CurvedAnimation(parent: controller, curve: Curves.elasticInOut);

    controller.addListener(() {
      setState(() {});
    });

    controller.forward();
  }

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Material(
        color: Colors.transparent,
        child: ScaleTransition(
          scale: scaleAnimation,
          child: Container(
            decoration: ShapeDecoration(
                color: Colors.white,
                shape: RoundedRectangleBorder(
                    borderRadius: BorderRadius.circular(15.0))),
            child: Padding(
              padding: const EdgeInsets.all(50.0),
              child: Text("Well hello there!"),
            ),
          ),
        ),
      ),
    );
  }
}

Answer 2

每当你想用一些动画展示Dialog时，最好的方法是使用showGeneralDialog()

注意：必须提供所有参数，否则会发生一些错误。

showGeneralDialog(
                barrierColor: Colors.black.withOpacity(0.5), //SHADOW EFFECT
                transitionBuilder: (context, a1, a2, widget) {
                  return Center(
                    child: Container(
                      height: 100.0 * a1.value,  // USE PROVIDED ANIMATION
                      width: 100.0 * a1.value,
                      color: Colors.blue,
                    ),
                  );
                },
                transitionDuration: Duration(milliseconds: 200), // DURATION FOR ANIMATION
                barrierDismissible: true,
                barrierLabel: 'LABEL',
                context: context,
                pageBuilder: (context, animation1, animation2) {
                  return Text('PAGE BUILDER');
                });
          }, child: Text('Show Dialog'),),

如果你需要更多的自定义，那么扩展PopupRoute并创建你自己的_DialogRoute<T>和showGeneralDialog()

编辑

编辑回答尼克拉斯功能关闭Overlay :)

void main() => runApp(new MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(title: 'Flutter Demo', theme: ThemeData(), home: Page());
  }
}

class Page extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: RaisedButton.icon(
            onPressed: () {
              OverlayEntry overlayEntry;
              overlayEntry = OverlayEntry(builder: (c) {
                return FunkyOverlay(onClose: () => overlayEntry.remove());
              });
              Overlay.of(context).insert(overlayEntry);
            },
            icon: Icon(Icons.message),
            label: Text("PopUp!")),
      ),
    );
  }
}

class FunkyOverlay extends StatefulWidget {
  final VoidCallback onClose;

  const FunkyOverlay({Key key, this.onClose}) : super(key: key);

  @override
  State<StatefulWidget> createState() => FunkyOverlayState();
}

class FunkyOverlayState extends State<FunkyOverlay>
    with SingleTickerProviderStateMixin {
  AnimationController controller;
  Animation<double> opacityAnimation;
  Animation<double> scaleAnimatoin;

  @override
  void initState() {
    super.initState();

    controller =
        AnimationController(vsync: this, duration: Duration(milliseconds: 450));
    opacityAnimation = Tween<double>(begin: 0.0, end: 0.4).animate(
        CurvedAnimation(parent: controller, curve: Curves.fastOutSlowIn));
    scaleAnimatoin =
        CurvedAnimation(parent: controller, curve: Curves.elasticInOut);

    controller.addListener(() {
      setState(() {});
    });

    controller.forward();
  }

  @override
  Widget build(BuildContext context) {
    return Material(
      color: Colors.black.withOpacity(opacityAnimation.value),
      child: Center(
        child: ScaleTransition(
          scale: scaleAnimatoin,
          child: Container(
            decoration: ShapeDecoration(
                color: Colors.white,
                shape: RoundedRectangleBorder(
                    borderRadius: BorderRadius.circular(15.0))),
            child: Padding(
              padding: const EdgeInsets.all(50.0),
              child: OutlineButton(onPressed: widget.onClose, child: Text('Close!'),),
            ),
          ),
        ),
      ),
    );
  }
}

Answer 3

我试着做你的gif中显示的动画。要发布代码来帮助那些想要它的人，它并不完美，所以如果有人想帮助改进它就行了。

看起来如何：

码：

import 'package:flutter/material.dart';
import 'package:angles/angles.dart';
import 'dart:math';
import 'dart:core';

class CheckAnimation extends StatefulWidget {
  final double size;
  final VoidCallback onComplete;

  CheckAnimation({this.size, this.onComplete});

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

class _CheckAnimationState extends State<CheckAnimation>
    with SingleTickerProviderStateMixin {
  AnimationController _controller;
  Animation<double> curve;

  @override
  void initState() {
    // TODO: implement initState
    super.initState();
    _controller =
        AnimationController(duration: Duration(seconds: 2), vsync: this);
    curve = CurvedAnimation(parent: _controller, curve: Curves.bounceInOut);

    _controller.addListener(() {
      setState(() {});
      if(_controller.status == AnimationStatus.completed && widget.onComplete != null){
        widget.onComplete();
      }
    });
    _controller.forward();
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      height: widget.size ?? 100,
      width: widget.size ?? 100,
      color: Colors.transparent,
      child: CustomPaint(
        painter: CheckPainter(value: curve.value),
      ),
    );
  }

  @override
  void dispose() {
    // TODO: implement dispose
    _controller.dispose();
    super.dispose();
  }
}

class CheckPainter extends CustomPainter {
  Paint _paint;
  double value;

  double _length;
  double _offset;
  double _secondOffset;
  double _startingAngle;

  CheckPainter({this.value}) {
    _paint = Paint()
      ..color = Colors.greenAccent
      ..strokeWidth = 5.0
      ..strokeCap = StrokeCap.round
      ..style = PaintingStyle.stroke;
    assert(value != null);

    _length = 60;
    _offset = 0;
    _startingAngle = 205;
  }

  @override
  void paint(Canvas canvas, Size size) {
    // Background canvas
    var rect = Offset(0, 0) & size;
    _paint.color = Colors.greenAccent.withOpacity(.05);

    double line1x1 = size.width / 2 +
        size.width * cos(Angle.fromDegrees(_startingAngle).radians) * .5;
    double line1y1 = size.height / 2 +
        size.height * sin(Angle.fromDegrees(_startingAngle).radians) * .5;
    double line1x2 = size.width * .45;
    double line1y2 = size.height * .65;

    double line2x1 =
        size.width / 2 + size.width * cos(Angle.fromDegrees(320).radians) * .35;
    double line2y1 = size.height / 2 +
        size.height * sin(Angle.fromDegrees(320).radians) * .35;

    canvas.drawArc(rect, Angle.fromDegrees(_startingAngle).radians,
        Angle.fromDegrees(360).radians, false, _paint);
    canvas.drawLine(Offset(line1x1, line1y1), Offset(line1x2, line1y2), _paint);
    canvas.drawLine(Offset(line2x1, line2y1), Offset(line1x2, line1y2), _paint);

    // animation painter

    double circleValue, checkValue;
    if (value < .5) {
      checkValue = 0;
      circleValue = value / .5;
    } else {
      checkValue = (value - .5) / .5;
      circleValue = 1;
    }

    _paint.color = const Color(0xff72d0c3);
    double firstAngle = _startingAngle + 360 * circleValue;

    canvas.drawArc(
        rect,
        Angle.fromDegrees(firstAngle).radians,
        Angle.fromDegrees(
                getSecondAngle(firstAngle, _length, _startingAngle + 360))
            .radians,
        false,
        _paint);

    double line1Value = 0, line2Value = 0;
    if (circleValue >= 1) {
      if (checkValue < .5) {
        line2Value = 0;
        line1Value = checkValue / .5;
      } else {
        line2Value = (checkValue - .5) / .5;
        line1Value = 1;
      }
    }

    double auxLine1x1 = (line1x2 - line1x1) * getMin(line1Value, .8);
    double auxLine1y1 =
        (((auxLine1x1) - line1x1) / (line1x2 - line1x1)) * (line1y2 - line1y1) +
            line1y1;

    if (_offset < 60) {
      auxLine1x1 = line1x1;
      auxLine1y1 = line1y1;
    }

    double auxLine1x2 = auxLine1x1 + _offset / 2;
    double auxLine1y2 =
        (((auxLine1x1 + _offset / 2) - line1x1) / (line1x2 - line1x1)) *
                (line1y2 - line1y1) +
            line1y1;

    if (checkIfPointHasCrossedLine(Offset(line1x2, line1y2),
        Offset(line2x1, line2y1), Offset(auxLine1x2, auxLine1y2))) {
      auxLine1x2 = line1x2;
      auxLine1y2 = line1y2;
    }

    if (_offset > 0) {
      canvas.drawLine(Offset(auxLine1x1, auxLine1y1),
          Offset(auxLine1x2, auxLine1y2), _paint);
    }

    // SECOND LINE

    double auxLine2x1 = (line2x1 - line1x2) * line2Value;
    double auxLine2y1 =
        ((((line2x1 - line1x2) * line2Value) - line1x2) / (line2x1 - line1x2)) *
                (line2y1 - line1y2) +
            line1y2;

    if (checkIfPointHasCrossedLine(Offset(line1x1, line1y1),
        Offset(line1x2, line1y2), Offset(auxLine2x1, auxLine2y1))) {
      auxLine2x1 = line1x2;
      auxLine2y1 = line1y2;
    }
    if (line2Value > 0) {
      canvas.drawLine(
          Offset(auxLine2x1, auxLine2y1),
          Offset(
              (line2x1 - line1x2) * line2Value + _offset * .75,
              ((((line2x1 - line1x2) * line2Value + _offset * .75) - line1x2) /
                          (line2x1 - line1x2)) *
                      (line2y1 - line1y2) +
                  line1y2),
          _paint);
    }
  }

  double getMax(double x, double y) {
    return (x > y) ? x : y;
  }

  double getMin(double x, double y) {
    return (x > y) ? y : x;
  }

  bool checkIfPointHasCrossedLine(Offset a, Offset b, Offset point) {
    return ((b.dx - a.dx) * (point.dy - a.dy) -
            (b.dy - a.dy) * (point.dx - a.dx)) >
        0;
  }

  double getSecondAngle(double angle, double plus, double max) {
    if (angle + plus > max) {
      _offset = angle + plus - max;
      return max - angle;
    } else {
      _offset = 0;
      return plus;
    }
  }

  @override
  bool shouldRepaint(CheckPainter old) {
    return old.value != value;
  }
}

我用过angles package