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:
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
<!--index.wxml-->
<view class="container">
<canvas canvas-id="id-gesture-lock" class="gesture-lock" bindtouchstart="onTouchStart"
bindtouchmove="onTouchMove" bindtouchend="onTouchEnd"></canvas>
</view>
.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);
}
