微信小程序开发手势解锁实例代码

整个功能基于canvas实现，首先添加画布组件，并设定样式

.gesture-lock {  margin: 100rpx auto;  width: 300px;  height: 300px;  background-color: #ffffff;}

手势解锁实现代码在gesture_lock.js中(完整源码地址见末尾)。

初始化

  constructor(canvasid, context, cb, opt){    this.touchPoints = [];    this.checkPoints = [];    this.canvasid = canvasid;    this.ctx = context;    this.width = opt && opt.width || 300; //画布长度    this.height = opt && opt.height || 300; //画布宽度    this.cycleNum = opt && opt.cycleNum || 3;    this.radius = 0; //触摸点半径    this.isParamOk = false;    this.marge = this.margeCircle = 25; //触摸点及触摸点和画布边界间隔    this.initColor = opt && opt.initColor || '#C5C5C3';      this.checkColor = opt && opt.checkColor || '#5AA9EC';    this.errorColor = opt && opt.errorColor || '#e19984';    this.touchState = "unTouch";    this.checkParam();    this.lastCheckPoint = null;    if (this.isParamOk) {      // 计算触摸点的半径长度      this.radius = (this.width - this.marge * 2 - (this.margeCircle * (this.cycleNum - 1))) / (this.cycleNum * 2)      this.radius = Math.floor(this.radius);      // 计算每个触摸点的圆心位置      this.calCircleParams();    }    this.onEnd = cb; //滑动手势结束时的回调函数  }

主要设置一些参数，如canvas的长宽，canvas的context，手势锁的个数(3乘3, 4乘4)，手势锁的颜色，手势滑动结束时的回调函数等。并计算出手势锁的半径。

计算每个手势锁的圆心位置

  calCircleParams() {    let n = this.cycleNum;    let count = 0;    for (let i = 0; i < n; i++) {      for (let j = 0; j < n; j++){        count++;        let touchPoint = {          x: this.marge + i * (this.radius * 2 + this.margeCircle) + this.radius,          y: this.marge + j * (this.radius * 2 + this.margeCircle) + this.radius,          index: count,          check: "uncheck",        }        this.touchPoints.push(touchPoint)      }    }  }

绘制手势锁

   for (let i = 0; i < this.touchPoints.length; i++){      this.drawCircle(this.touchPoints[i].x, this.touchPoints[i].y, this.radius, this.initColor)   }   this.ctx.draw(true);

接下来就是识别用户的滑动行为，判断用户划过了哪些圆圈，进而识别出用户的手势。

在touchstart和touchmove事件中检测触发并更新画布

  onTouchStart(e) {    // 不识别多点触控    if (e.touches.length > 1){      this.touchState = "unTouch";      return;    }    this.touchState = "startTouch";    this.checkTouch(e);    let point = {x:e.touches[0].x, y:e.touches[0].y};    this.drawCanvas(this.checkColor, point);  }  onTouchMove(e) {    if (e.touchState === "unTouch") {      return;    }    if (e.touches.length > 1){      this.touchState = "unTouch";      return;    }    this.checkTouch(e);    let point = {x:e.touches[0].x, y:e.touches[0].y};    this.drawCanvas(this.checkColor, point);  }

检测用户是否划过某个圆圈

  checkTouch(e) {    for (let i = 0; i < this.touchPoints.length; i++){      let point = this.touchPoints[i];      if (isPointInCycle(e.touches[0].x, e.touches[0].y, point.x, point.y, this.radius)) {        if (point.check === 'uncheck') {          this.checkPoints.push(point);          this.lastCheckPoint = point;        }        point.check = "check"        return;      }    }  }

更新画布

   drawCanvas(color, point) {    //每次更新之前先清空画布    this.ctx.clearRect(0, 0, this.width, this.height);    //使用不同颜色和形式绘制已触发和未触发的锁    for (let i = 0; i < this.touchPoints.length; i++){      let point = this.touchPoints[i];      if (point.check === "check") {        this.drawCircle(point.x, point.y, this.radius, color);        this.drawCircleCentre(point.x, point.y, color);      }      else {        this.drawCircle(this.touchPoints[i].x, this.touchPoints[i].y, this.radius, this.initColor)      }    }    //绘制已识别锁之间的线段    if (this.checkPoints.length > 1) {       let lastPoint = this.checkPoints[0];       for (let i = 1; i < this.checkPoints.length; i++) {         this.drawLine(lastPoint, this.checkPoints[i], color);         lastPoint = this.checkPoints[i];       }    }    //绘制最后一个识别锁和当前触摸点之间的线段    if (this.lastCheckPoint && point) {      this.drawLine(this.lastCheckPoint, point, color);    }    this.ctx.draw(true);  }

当用户滑动结束时调用回调函数并传递识别出的手势

  onTouchEnd(e) {    typeof this.onEnd === 'function' && this.onEnd(this.checkPoints, false);  }  onTouchCancel(e) {    typeof this.onEnd === 'function' && this.onEnd(this.checkPoints, true);  }

重置和显示手势错误

  gestureError() {    this.drawCanvas(this.errorColor)  }  reset() {    for (let i = 0; i < this.touchPoints.length; i++) {      this.touchPoints[i].check = 'uncheck';    }    this.checkPoints = [];    this.lastCheckPoint = null;    this.drawCanvas(this.initColor);  }

如何调用

在onload方法中创建lock对象并在用户触摸事件中调用相应方法

 onLoad: function () {  var s = this;  this.lock = new Lock("id-gesture-lock", wx.createCanvasContext("id-gesture-lock"), function(checkPoints, isCancel) {   console.log('over');   s.lock.gestureError();   setTimeout(function() {    s.lock.reset();   }, 1000);  }, {width:300, height:300})  this.lock.drawGestureLock();  console.log('onLoad')  var that = this  //调用应用实例的方法获取全局数据  app.getUserInfo(function(userInfo){   //更新数据   that.setData({    userInfo:userInfo   })   that.update()  }) }, onTouchStart: function (e) {  this.lock.onTouchStart(e); }, onTouchMove: function (e) {  this.lock.onTouchMove(e); }, onTouchEnd: function (e) {  this.lock.onTouchEnd(e); }

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