微信小程序开发之手势解锁代码实例

手势解锁

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 || &＃39;#C5C5C3&＃39;;   
        this.checkColor = opt && opt.checkColor || &＃39;#5AA9EC&＃39;;
        this.errorColor = opt && opt.errorColor || &＃39;#e19984&＃39;;
        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 
绘制手势锁
     for (let i = 0; i 
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 
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  1) {
             let lastPoint = this.checkPoints[0];
             for (let i = 1; i 
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=== &＃39;function&＃39; && this.onEnd(this.checkPoints, false);
    }

    onTouchCancel(e) {
        typeof this.OnEnd=== &＃39;function&＃39; && 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 
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(&＃39;over&＃39;);
      s.lock.gestureError();
      setTimeout(function() {
        s.lock.reset();
      }, 1000);
    }, {width:300, height:300})
    this.lock.drawGestureLock();
    console.log(&＃39;onLoad&＃39;)
    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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