手势解锁小程序

手势解锁是app上常见的解锁方式，相比输入密码方式操作起来要方便许多。下面展示如何基于微信小程序实现手机解锁。最终实现效果如下图:

微信小程序开发实例（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

XML/HTML代码

<!–index.wxml–>

1. <!–index.wxml–>
2. <view class=“container”>

1. <canvas canvas-id=“id-gesture-lock” class=“gesture-lock” bindtouchstart=“onTouchStart”
2. bindtouchmove=“onTouchMove” bindtouchend=“onTouchEnd”></canvas>

1. </view>

1. .gesture-lock {
2. margin: 100rpx auto;

1. width: 300px;
2. 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

JavaScript代码

1. constructor(canvasid, context, cb, opt){
2. this.touchPoints = [];

1. this.checkPoints = [];
2. this.canvasid = canvasid;

1. this.ctx = context;
2. this.width = opt && opt.width || 300; //画布长度

1. this.height = opt && opt.height || 300; //画布宽度
2. this.cycleNum = opt && opt.cycleNum || 3;

1. this.radius = 0; //触摸点半径
2. this.isParamOk = false;

1. this.marge = this.margeCircle = 25; //触摸点及触摸点和画布边界间隔
2. this.initColor = opt && opt.initColor || ‘#C5C5C3’;

1. this.checkColor = opt && opt.checkColor || ‘#5AA9EC’;
2. this.errorColor = opt && opt.errorColor || ‘#e19984’;

1. this.touchState = “unTouch”;
2. this.checkParam();

1. this.lastCheckPoint = null;
2. if (this.isParamOk) {

1. // 计算触摸点的半径长度
2. this.radius = (this.width – this.marge * 2 – (this.margeCircle * (this.cycleNum – 1))) / (this.cycleNum * 2)

1. this.radius = Math.floor(this.radius);
2. // 计算每个触摸点的圆心位置

1. this.calCircleParams();
2. }

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

JavaScript代码

1. calCircleParams() {
2. let n = this.cycleNum;

1. let count = 0;
2. for (let i = 0; i < n; i++) {

1. for (let j = 0; j < n; j++){
2. count++;

1. let touchPoint = {
2. x: this.marge + i * (this.radius * 2 + this.margeCircle) + this.radius,

1. y: this.marge + j * (this.radius * 2 + this.margeCircle) + this.radius,
2. index: count,

1. check: “uncheck”,
2. }

1. this.touchPoints.push(touchPoint)
2. }

}
}

绘制手势锁

JavaScript代码

1. for (let i = 0; i < this.touchPoints.length; i++){
2. 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

JavaScript代码

1. onTouchStart(e) {
2. // 不识别多点触控

1. if (e.touches.length > 1){
2. this.touchState = “unTouch”;

1. return;
2. }

1. this.touchState = “startTouch”;
2. this.checkTouch(e);

1. let point = {x:e.touches[0].x, y:e.touches[0].y};
2. this.drawCanvas(this.checkColor, point);

1. }

1. onTouchMove(e) {
2. if (e.touchState === “unTouch”) {

1. return;
2. }

1. if (e.touches.length > 1){
2. this.touchState = “unTouch”;

1. return;
2. }

1. this.checkTouch(e);
2. 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

JavaScript代码

1. checkTouch(e) {
2. for (let i = 0; i < this.touchPoints.length; i++){

1. let point = this.touchPoints[i];
2. if (isPointInCycle(e.touches[0].x, e.touches[0].y, point.x, point.y, this.radius)) {

1. if (point.check === ‘uncheck’) {
2. this.checkPoints.push(point);

1. this.lastCheckPoint = point;
2. }

1. point.check = “check”
2. return;

1. }
2. }

}

更新画布

JavaScript代码

1. drawCanvas(color, point) {
2. //每次更新之前先清空画布

1. this.ctx.clearRect(0, 0, this.width, this.height);
2. //使用不同颜色和形式绘制已触发和未触发的锁

1. for (let i = 0; i < this.touchPoints.length; i++){
2. let point = this.touchPoints[i];

1. if (point.check === “check”) {
2. this.drawCircle(point.x, point.y, this.radius, color);

1. this.drawCircleCentre(point.x, point.y, color);
2. }

1. else {
2. this.drawCircle(this.touchPoints[i].x, this.touchPoints[i].y, this.radius, this.initColor)

1. }
2. }

1. //绘制已识别锁之间的线段
2. if (this.checkPoints.length > 1) {

1. let lastPoint = this.checkPoints[0];
2. for (let i = 1; i < this.checkPoints.length; i++) {

1. this.drawLine(lastPoint, this.checkPoints[i], color);
2. lastPoint = this.checkPoints[i];

1. }
2. }

1. //绘制最后一个识别锁和当前触摸点之间的线段
2. if (this.lastCheckPoint && point) {

1. this.drawLine(this.lastCheckPoint, point, color);
2. }

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

JavaScript代码

1. onTouchEnd(e) {
2. typeof this.onEnd === ‘function’ && this.onEnd(this.checkPoints, false);

1. }

1. onTouchCancel(e) {
2. typeof this.onEnd === ‘function’ && this.onEnd(this.checkPoints, true);

}

重置和显示手势错误

JavaScript代码

1. gestureError() {
2. this.drawCanvas(this.errorColor)

1. }

1. reset() {
2. for (let i = 0; i < this.touchPoints.length; i++) {

1. this.touchPoints[i].check = ‘uncheck’;
2. }

1. this.checkPoints = [];
2. 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

JavaScript代码

1. onLoad: function () {
2. var s = this;

1. this.lock = new Lock(“id-gesture-lock”, wx.createCanvasContext(“id-gesture-lock”), function(checkPoints, isCancel) {
2. console.log(‘over’);

1. s.lock.gestureError();
2. setTimeout(function() {

1. s.lock.reset();
2. }, 1000);

1. }, {width:300, height:300})
2. this.lock.drawGestureLock();

1. console.log(‘onLoad’)
2. var that = this

1. //调用应用实例的方法获取全局数据
2. app.getUserInfo(function(userInfo){

1. //更新数据
2. that.setData({

1. userInfo:userInfo
2. })

1. that.update()
2. })

1. },
2. onTouchStart: function (e) {

1. this.lock.onTouchStart(e);
2. },

1. onTouchMove: function (e) {
2. this.lock.onTouchMove(e);

1. },
2. onTouchEnd: function (e) {

this.lock.onTouchEnd(e);
}

下载地址: 手势解锁