Flutter手势密码的实现示例(附demo)

// point.dart
import 'package:flutter/material.dart';
import 'dart:math';

// 手势密码盘上的圆点
class GesturePoint {
  // 中心实心圆点的画笔
  static final pointPainter = Paint()
    ..style = PaintingStyle.fill
    ..color = Colors.blue;

  // 外层圆环的画笔
  static final linePainter = Paint()
    ..style = PaintingStyle.stroke
    ..strokeWidth = 1.2
    ..color = Colors.blue;

  // 圆点索引，0-9
  final int index;
  // 圆心坐标
  final double centerX;
  final double centerY;
  // 中心实心圆点的半径
  final double radius = 4;
  // 外层空心的圆环半径
  final double padding = 26;

  GesturePoint(this.index, this.centerX, this.centerY);

  // 绘制小圆点
  void drawCircle(canvas canvas) {
    // 绘制中心实心的圆点
    canvas.drawOval(
        Rect.fromCircle(center: Offset(centerX, centerY), radius: radius),
        pointPainter);

    // 绘制外层的圆环
    canvas.drawOval(
        Rect.fromCircle(center: Offset(centerX, centerY), radius: padding),
        linePainter);
  }

  // 判断坐标是否在小圆内（padding为半径）
  // 该方法用于在手指滑动时做判断，一旦坐标处于圆点内部，则认为选中该圆点
  bool checkInside(double x, double y) {
    var distance = sqrt(pow((x - centerX), 2) + pow((y - centerY), 2));
    return distance <= padding;
  }

  // 提供比较方法，用于判断List中是否存在某个点
  // 这个方法会在后面用到，当手势滑动到某个点时，如果之前滑动到过这个点，则这个点不能再被选中
  @override
  bool operator ==(Object other) {
    if (other is GesturePoint) {
      return this.index == other.index &&
          this.centerX == other.centerX &&
          this.centerY == other.centerY;
    }
    return false;
  }

  // 复写==方法时必须同时复写hashCode方法
  @override
  int get hashCode => super.hashCode;

}

// panel.dart
import 'package:flutter/material.dart';
import 'package:flutter_gesture_passWord/point.dart';

// 9个圆点视图
class GestureDotsPanel extends StatelessWidget {
  // 表示圆点盘的宽高
  final double width, height;
  // 装载9个圆点的集合，从外部传入
  final List<GesturePoint> points;
    
  // 构造方法
  GestureDotsPanel(this.width, this.height, this.points);

  @override
  Widget build(BuildContext context) {
    return Container(
      width: width,
      height: height,
      child: CustomPaint(
        painter: _PanelPainter(points),
      ),
    );
  }
}

// 自定义的Painter，用于从圆点集合中遍历所有圆点并依次画出
class _PanelPainter extends CustomPainter {
  final List<GesturePoint> points;

  _PanelPainter(this.points);

  @override
  void paint(Canvas canvas, Size size) {
    if (points.isNotEmpty) {
      for (var p in points) {
        // 画出所有的圆点
        p.drawCircle(canvas);
      }
    }
  }

  @override
  bool shouldRepaint(covariant CustomPainter oldDelegate) => false; // 不让更新

}

// path.dart
import 'package:flutter/material.dart';
import 'package:flutter_gesture_password/gesture_view.dart';
import 'package:flutter_gesture_password/point.dart';

// 手势密码路径视图
class GesturePathView extends StatefulWidget {
  // 手势密码路径视图的宽高，需要跟圆点视图保持一致，由构造方法传入
  final double width;
  final double height;
  // 手势密码中的9个点，由构造方法传入
  final List<GesturePoint> points;
  // 手势密码监听器，用于在手指抬起时触发，其定义为：typedef OnGestureCompleteListener = void Function(List<int>);
  final OnGestureCompleteListener listener;

  // 构造方法
  GesturePathView(this.width, this.height, this.points, this.listener);

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

class _GesturePathViewState extends State<GesturePathView> {
  // 记录手指按下或者滑动过程中，经过的最后一个点
  GesturePoint? lastPoint;
  // 记录手指滑动时的坐标
  Offset? movePos;
  // 记录手指滑动过程中所有经过的点
  List<GesturePoint> pathPoints = [];

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      child: CustomPaint(
        size: Size(widget.width, widget.height),    // 指定组件大小
        painter: _PathPainter(movePos, pathPoints), // 指定组件的绘制者，当movePos或者pathPoints更新时，整个组件也需要更新
      ),
      onPanDown: _onPanDown,     // 手指按下
      onPanUpdate: _onPanUpdate, // 手指滑动
      onPanEnd: _onPanEnd,       // 手指抬起
    );
  }

  // 手指按下
  _onPanDown(DragDownDetails e) {
    // 判断按下的坐标是否在某个点上
    // 注意：e.localPosition表示的坐标为相对整个组件的坐标
    // e.globalPosition表示的坐标为相对整个屏幕的坐标
    final x = e.localPosition.dx;
    final y = e.localPosition.dy;
    // 判断是否按在某个点上
    for (var p in widget.points) {
      if (p.checkInside(x, y)) {
        lastPoint = p;
      }
    }
    // 重置pathPoints
    pathPoints.clear();
  }

  // 手指滑动
  _onPanUpdate(DragUpdateDetails e) {
    // 如果手指按下时不在某个圆点上，则不处理滑动事件
    if (lastPoint == null) {
      return;
    }
    // 滑动时如果在某个圆点上，则将该圆点加入路径中
    final x = e.localPosition.dx;
    final y = e.localPosition.dy;
    // passPoint代表手指滑动时是否经过某个点，可为空
    GesturePoint? passPoint;
    for (var p in widget.points) {
      // 如果手指滑动经过某个点，且这个点之前没有经过，则记录下这个点
      if (p.checkInside(x, y) && !pathPoints.contains(p)) {
        passPoint = p;
        break;
      }
    }
    setState(() {
      // 如果经过点部为空，则需要刷新lastPoint和pathPoints，触发整个组件的更新
      if (passPoint != null) {
        lastPoint = passPoint;
        pathPoints.add(passPoint);
      }
      // 更新movePos的值
      movePos = Offset(x, y);
    });
  }

  // 手指抬起
  _onPanEnd(DragEndDetails e) {
    setState(() {
      // 将movePos设置为空，防止画出最后一个点到手指抬起时的坐标间的直线
      movePos = null;
    });
    // 调用Listener，返回手势经过的所有点
    List<int> arr = [];
    if (pathPoints.isNotEmpty) {
      for (var value in pathPoints) {
        arr.add(value.index);
      }
    }   
    widget.listener(arr);
  }
}

// 绘制手势路径
class _PathPainter extends CustomPainter {
  // 手指当前的坐标
  final Offset? movePos;
  // 手指经过点集合
  final List<GesturePoint> pathPoints;

  // 路径画笔
  final pathPainter = Paint()
    ..style = PaintingStyle.stroke
    ..strokeWidth = 6
    ..strokeCap = StrokeCap.round
    ..color = Colors.blue;

  _PathPainter(this.movePos, this.pathPoints);

  @override
  void paint(Canvas canvas, Size size) {
    _drawPassPath(canvas);
    _drawRTPath(canvas);
  }

  // 绘制手指一动过程中，经过的所有点之间的直线
  _drawPassPath(Canvas canvas) {
    if (pathPoints.length <= 1) {
      return;
    }
    for (int i = 0; i < pathPoints.length - 1; i++) {
      var start = pathPoints[i];
      var end = pathPoints[i + 1];
      canvas.drawLine(Offset(start.centerX, start.centerY),
          Offset(end.centerX, end.centerY), pathPainter);
    }
  }

  // 绘制实时的，最后一个经过点和当前手指坐标间的直线
  _drawRTPath(Canvas canvas) {
    if (pathPoints.isNotEmpty && movePos != null) {
      var lastPoint = pathPoints.last;
      canvas.drawLine(Offset(lastPoint.centerX, lastPoint.centerY), movePos!, pathPainter);
    }
  }

  @override
  bool shouldRepaint(covariant CustomPainter oldDelegate) => true;
}

import 'package:flutter/material.dart';
import 'package:flutter_gesture_password/path.dart';
import 'package:flutter_gesture_password/point.dart';
import 'package:flutter_gesture_password/panel.dart';

// 定义手势密码回调监听器
typedef OnGestureCompleteListener = void Function(List<int>);

class GestureView extends StatefulWidget {
  final double width, height;
  final OnGestureCompleteListener listener;

  GestureView({required this.width, required this.height, required this.listener});

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

class _GestureViewState extends State<GestureView> {
  List<GesturePoint> _points = [];

  @override
  void initState() {
    super.initState();
    // 计算9个圆点的位置坐标
    double deltaW = widget.width / 4;
    double deltaH = widget.height / 4;
    for (int row = 0; row < 3; row++) {
      for (int col = 0; col < 3; col++) {
        int index = row * 3 + col;
        var p = GesturePoint(index, (col + 1) * deltaW, (row + 1) * deltaH);
        _points.add(p);
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    return Stack(
      children: [
        GestureDotsPanel(widget.width, widget.height, _points),
        GesturePathView(widget.width, widget.height, _points, widget.listener)
      ],
    );
  }
}

import 'package:flutter/material.dart';
import 'package:flutter_gesture_password/gesture_view.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Gesture password',
      home: _Home(),
    );
  }
}

class _Home extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => _HomeState();
}

class _HomeState extends State<_Home> {
  List<int>? pathArr;

  @override
  Widget build(BuildContext context) {
    final screenWidth = MediaQuery.of(context).size.width;
    return Scaffold(
      appBar: AppBar(
        title: Text('Gesture password'),
      ),
      body: Column(
        children: [
          GestureView(
            width: screenWidth,
            height: screenWidth,
            listener: (arr) {
              setState(() {
                pathArr = arr;
              });
            },
          ),
          Text("${pathArr == null ? '' : pathArr}")
        ],
      ),
    );
  }
}

homepage: 「填写项目主页地址，这里可以直接用github仓库地址」
publish_to: 'Https://pub.dev' # 这个配置表示要把插件发布到哪里
version: 0.0.2 # 插件版本，每次更新记得修改这个version